Merge lp:~sajoupa/ubuntu-repository-cache/layer-black-reformatting into lp:ubuntu-repository-cache

[Laurent Sesquès]

auto reformatting by make lint (black)

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This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

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Change successfully merged at revision 286

=== modified file 'hooks/hooks.py'
--- hooks/hooks.py	2020-05-14 02:15:28 +0000
+++ hooks/hooks.py	2020-10-06 10:05:01 +0000
@@ -29,10 +29,8 @@
 
 def parse_config(conf=service.CONFIG_PATH):
     keys = {}
-    cmd = ['bash', '-c', "trap 'env -0' exit; source {} > /dev/null 2>&1"
-           .format(conf)]
-    output = subprocess.Popen(cmd, shell=False,
-                              stdout=subprocess.PIPE).communicate()[0]
+    cmd = ['bash', '-c', "trap 'env -0' exit; source {} > /dev/null 2>&1".format(conf)]
+    output = subprocess.Popen(cmd, shell=False, stdout=subprocess.PIPE).communicate()[0]
     for ll in output.decode('utf-8').split('\x00'):
         if not ll:
             continue
@@ -45,11 +43,11 @@
 @HOOKS.hook('ubuntu_repository_cache_sync')
 @util.run_as_user('www-sync')
 def ubuntu_repository_cache_sync():
-    '''Notify clustered peers that metadata is available.
+    """Notify clustered peers that metadata is available.
 
     An external system (a cron job) will trigger this hook after it has
     finished syncing metadata from upstream. This will notify the peers that
-    metadata is ready.'''
+    metadata is ready."""
 
     LOG('Notifying peers of metadata update')
     # We can't use hookenv.config() here because the persistent config
@@ -72,8 +70,7 @@
         link_dir = '/'.join((apache_data, 'ubuntu_active'))
         LOG('Pushing updates to peers', hookenv.DEBUG)
         source = meta_dir + '/'
-        successful_peers = mirror.rsync_to_peers(
-            source, dest, link_dir=link_dir)
+        successful_peers = mirror.rsync_to_peers(source, dest, link_dir=link_dir)
 
         # Push metaversion_good canary to indicate a complete sync
         canary = '_'.join((meta_dir, 'good'))

=== modified file 'lib/ubuntu_repository_cache/apache.py'
--- lib/ubuntu_repository_cache/apache.py	2020-05-13 03:19:35 +0000
+++ lib/ubuntu_repository_cache/apache.py	2020-10-06 10:05:01 +0000
@@ -86,9 +86,7 @@
         'maxconnectionsperchild': config['apache2_mpm_maxconnectionsperchild'],
     }
     conf_mpm_worker = '/etc/apache2/conf-available/000mpm-worker.conf'
-    templating.render('apache2/mpm_worker.template',
-                      conf_mpm_worker,
-                      mpm_context)
+    templating.render('apache2/mpm_worker.template', conf_mpm_worker, mpm_context)
     subprocess.check_call(['a2enconf', '000mpm-worker'])
     mods_mpm_worker = '/etc/apache2/mods-available/mpm_worker.conf'
     if not os.path.exists(mods_mpm_worker):
@@ -107,9 +105,7 @@
         'server_signature': config['apache2_server_signature'],
         'trace_enabled': config['apache2_trace_enabled'],
     }
-    templating.render('apache2/security.template',
-                      '/etc/apache2/conf-available/security.conf',
-                      security_context)
+    templating.render('apache2/security.template', '/etc/apache2/conf-available/security.conf', security_context)
     subprocess.check_call(['a2enconf', 'security'])
 
 
@@ -126,15 +122,16 @@
     failover_host = util.get_failover_host()
     if util.in_failover() and failover_host:
         uri = 'http://%s:80' % failover_host
-        metaproxy_conf = ('ProxyRemote      http://{disp}/ {uri}\n'
-                          '\tProxyPass        / http://{disp}/\n'
-                          '\tProxyPassReverse / http://{disp}/').format(
-                              uri=uri, disp=config['display-host'])
+        metaproxy_conf = (
+            'ProxyRemote      http://{disp}/ {uri}\n'
+            '\tProxyPass        / http://{disp}/\n'
+            '\tProxyPassReverse / http://{disp}/'
+        ).format(uri=uri, disp=config['display-host'])
     apache_context['MetadataProxy'] = metaproxy_conf
 
-    templating.render('apache2/archive_ubuntu_com.conf',
-                      '/etc/apache2/sites-available/archive_ubuntu_com.conf',
-                      apache_context)
+    templating.render(
+        'apache2/archive_ubuntu_com.conf', '/etc/apache2/sites-available/archive_ubuntu_com.conf', apache_context
+    )
     subprocess.call(['a2ensite', 'archive_ubuntu_com'])
     start()
 
@@ -146,8 +143,7 @@
         LOG('Apache remoteip_logging changed')
         if config['remoteip_logging'] is True:
             subprocess.check_call(['a2enmod', 'remoteip'])
-            templating.render('apache2/remoteip.conf',
-                              '/etc/apache2/conf-available/remoteip.conf', {})
+            templating.render('apache2/remoteip.conf', '/etc/apache2/conf-available/remoteip.conf', {})
             subprocess.check_call(['a2enconf', 'remoteip'])
             LOG('Enabled remoteip logging')
         else:
@@ -196,22 +192,24 @@
     else:
         # try to find proof we're in Azure
         # in any version of the status json
-        if any('DataSourceAzure' in x.get('datasource', '')
-                for x in status_json.values()):
+        if any('DataSourceAzure' in x.get('datasource', '') for x in status_json.values()):
             # In azure, we rely on cloud services
             # instead of doing our own haproxy work
             nrpe_config.add_check(
                 shortname='load-balancer',
                 description='e2e check that regional load balancer is functioning',
-                check_cmd=('check_http '
-                           '--hostname ubuntu-archive-asm.trafficmanager.net '
-                           '--url "/{}/" --string "dists/" '
-                           '--expect \"200\\ OK\"').format(path_base),
+                check_cmd=(
+                    'check_http '
+                    '--hostname ubuntu-archive-asm.trafficmanager.net '
+                    '--url "/{}/" --string "dists/" '
+                    '--expect \"200\\ OK\"'
+                ).format(path_base),
             )
 
     nrpe_config.add_check(
         shortname='apache',
         description='Apache2 serving archive metadata',
-        check_cmd=('check_http --hostname localhost --url "/{}/" '
-                   '--string "dists/" --expect \"200\\ OK\"').format(path_base),
-        )
+        check_cmd=('check_http --hostname localhost --url "/{}/" ' '--string "dists/" --expect \"200\\ OK\"').format(
+            path_base
+        ),
+    )

=== modified file 'lib/ubuntu_repository_cache/metadata_sync.py'
--- lib/ubuntu_repository_cache/metadata_sync.py	2020-10-05 14:35:30 +0000
+++ lib/ubuntu_repository_cache/metadata_sync.py	2020-10-06 10:05:01 +0000
@@ -14,12 +14,7 @@
 from datetime import datetime
 from itertools import cycle
 
-from subprocess import (
-    CalledProcessError,
-    check_call,
-    check_output,
-    STDOUT
-)
+from subprocess import CalledProcessError, check_call, check_output, STDOUT
 
 from .util import (
     FileSemaphore,
@@ -55,14 +50,15 @@
 
 class ContentBad(Exception):
     '''Mirror content is inconsistent'''
+
     pass
 
 
 class UpstreamMirrorSyncError(Exception):
-    '''The upstream mirror is currently syncing.
+    """The upstream mirror is currently syncing.
 
     We shouldn't sync with it right now since we will certainly get an invalid
-    snapshot of its state.'''
+    snapshot of its state."""
 
 
 # VENDORING OF CHARMHELPERS FUNCTIONS.
@@ -70,8 +66,8 @@
 # hook environment. There are lifted and adapted: they are mostly thin wrappers
 # around subprocess - ~tribaal
 
-def rsync(from_path, to_path, options, log, flags="-r",
-          check_output=check_output, user=None, timeout=None):
+
+def rsync(from_path, to_path, options, log, flags="-r", check_output=check_output, user=None, timeout=None):
     """
     A wrapper around subprocess to execute an rsync between a source and a
     destination.
@@ -119,8 +115,7 @@
     This function has side-effects through os, pwd and grp
     """
     if log:
-        log("Making dir {} {}:{} {:o}".format(path, owner, group,
-                                              perms))
+        log("Making dir {} {}:{} {:o}".format(path, owner, group, perms))
     uid = pwd.getpwnam(owner).pw_uid
     gid = grp.getgrnam(group).gr_gid
     realpath = os.path.abspath(path)
@@ -139,26 +134,25 @@
     """
     log("WARNING: {}".format(message))
 
+
 # END OF VENDORING OF CHARMHELPERS FUNCTIONS.
 
 
 def mirror_archive(hostname, apache_root, local_unit, log, mirror_series, rsync_module='ubuntu'):  # NOQA: C901
-    '''Sync Ubuntu repository metadata to the mirror.
+    """Sync Ubuntu repository metadata to the mirror.
 
     Metadata synchronization is performed and then the metadata is
     verified.
 
     Returns metadata version (destination file name)
-    '''
+    """
 
     now = datetime.utcnow().replace(microsecond=0)
 
     apache_data = '/'.join((apache_root, 'data'))
     link_active = '/'.join((apache_data, 'ubuntu_active'))
     link_next = '/'.join((apache_data, 'ubuntu_next'))
-    dest = '/'.join((apache_data, 'ubuntu_{}_u{}'.format(
-        now.isoformat(sep='_'),
-        local_unit.split('/')[-1])))
+    dest = '/'.join((apache_data, 'ubuntu_{}_u{}'.format(now.isoformat(sep='_'), local_unit.split('/')[-1])))
     log('Performing sync to %s' % dest)
 
     # The archive may have multiple IP addresses, try each several times.
@@ -243,16 +237,16 @@
     # Delete all unused archive metadata mirror directories
     log('Removing old, unused repository mirrors.')
     clean_metadata_dir(
-        apache_root, log, keep=set((os.path.realpath(dest),
-                                    os.path.realpath('_'.join((dest, 'good'))),
-                                    os.path.realpath(link_active))))
+        apache_root,
+        log,
+        keep=set((os.path.realpath(dest), os.path.realpath('_'.join((dest, 'good'))), os.path.realpath(link_active))),
+    )
     log('Unused repository mirrors removed.')
 
     return os.path.basename(dest)
 
 
-def main(environment, log, mirror_archive=mirror_archive,
-         check_call=check_call):
+def main(environment, log, mirror_archive=mirror_archive, check_call=check_call):
     """The main function for this script.
 
     This is called at the very bottom of this file should the file be executed
@@ -269,8 +263,7 @@
     unit_path = environment["UNIT_PATH"]
     mirror_series = environment["MIRROR_SERIES"]
 
-    meta_ver = mirror_archive(sync_host, apache_root, local_unit, log,
-                              mirror_series, rsync_module=rsync_module)
+    meta_ver = mirror_archive(sync_host, apache_root, local_unit, log, mirror_series, rsync_module=rsync_module)
     if meta_ver is None:
         # If we failed to download and/or validate a new version of the
         # archives, don't propagate the information to other units.
@@ -281,7 +274,7 @@
 
     # Call the sync hook inside the juju environment to propagate changes to
     # other units
-    path = ('/usr/local/sbin/charm-env /var/lib/juju/agents/{}/charm/hooks/ubuntu-repository-cache-sync {}')
+    path = '/usr/local/sbin/charm-env /var/lib/juju/agents/{}/charm/hooks/ubuntu-repository-cache-sync {}'
     path = path.format(unit_path, meta_ver)
     cmd = ['juju-run', local_unit, path]
 
@@ -293,30 +286,32 @@
 
 
 def rsync_should_giveup(exception):
-    '''Based on the provided returncode, should rsync be retried or aborted.
+    """Based on the provided returncode, should rsync be retried or aborted.
 
     This function has no side-effects.
-    '''
+    """
 
     returncode = exception.returncode
     # Exit values for rsync that will trigger a retry of the operation
-    exitval_retry = frozenset((
-        5,      # Error starting client-server protocol
-        6,      # Daemon unable to append to log-file
-        10,     # Error in socket I/O
-        11,     # Error in file I/O
-        12,     # Error in rsync protocol data stream
-        13,     # Errors with program diagnostics
-        14,     # Error in IPC code
-        20,     # Received SIGUSR1 or SIGINT
-        21,     # Some error returned by waitpid()
-        22,     # Error allocating core memory buffers
-        23,     # Partial transfer due to error
-        24,     # Partial transfer due to vanished source files
-        25,     # The --max-delete limit stopped deletions
-        30,     # Timeout in data send/receive
-        35,     # Timeout waiting for daemon connection
-    ))
+    exitval_retry = frozenset(
+        (
+            5,  # Error starting client-server protocol
+            6,  # Daemon unable to append to log-file
+            10,  # Error in socket I/O
+            11,  # Error in file I/O
+            12,  # Error in rsync protocol data stream
+            13,  # Errors with program diagnostics
+            14,  # Error in IPC code
+            20,  # Received SIGUSR1 or SIGINT
+            21,  # Some error returned by waitpid()
+            22,  # Error allocating core memory buffers
+            23,  # Partial transfer due to error
+            24,  # Partial transfer due to vanished source files
+            25,  # The --max-delete limit stopped deletions
+            30,  # Timeout in data send/receive
+            35,  # Timeout waiting for daemon connection
+        )
+    )
 
     if returncode in exitval_retry:
         return False  # Don't give up
@@ -340,8 +335,7 @@
     # lots of time when we need to revert, instead of 15-20 mins to wait for a
     # complete sync.
     count = 0
-    entries = sorted(
-        [os.path.realpath(p) for p in glob.glob(glob_path)], reverse=True)
+    entries = sorted([os.path.realpath(p) for p in glob.glob(glob_path)], reverse=True)
     for entry in entries:
         if count < NUMBER_OF_REPOS_TO_KEEP and entry.endswith('_good'):
             keep.add(entry[:-5])
@@ -362,31 +356,32 @@
             log("Keeping {}".format(entry))
 
 
[e-mail]_exception(backoff.expo, CalledProcessError,
-                      max_tries=RSYNC_MAX_RETRIES, giveup=rsync_should_giveup)
[e-mail]_exception(backoff.expo, CalledProcessError, max_tries=RSYNC_MAX_RETRIES, giveup=rsync_should_giveup)
 def _mirror_metadata(archive_ip, dest, link_dest, log, mirror_series, rsync_module='ubuntu'):
     '''Mirror metadata from the archive.'''
 
     # Perform an rsync of the metadata, excluding some contents
     rsync_source = '{}::{}/'.format(archive_ip, rsync_module)
-    rsync_options = ('--quiet',
-                     '--recursive',
-                     '--links',
-                     '--perms',
-                     '--chmod=g+w',
-                     '--times',
-                     '--compress',
-                     '--delete',
-                     '--delete-during',
-                     '--link-dest=%s/' % link_dest,
-                     '--exclude=.trace',
-                     '--exclude=indices',
-                     '--exclude=project/trace',
-                     '--exclude=pool',
-                     '--exclude=dists/*/*/debian-installer',
-                     '--exclude=dists/*/*/dist-upgrader-all',
-                     '--exclude=dists/*/*/installer*',
-                     '--exclude=dists/*/*/uefi',)
+    rsync_options = (
+        '--quiet',
+        '--recursive',
+        '--links',
+        '--perms',
+        '--chmod=g+w',
+        '--times',
+        '--compress',
+        '--delete',
+        '--delete-during',
+        '--link-dest=%s/' % link_dest,
+        '--exclude=.trace',
+        '--exclude=indices',
+        '--exclude=project/trace',
+        '--exclude=pool',
+        '--exclude=dists/*/*/debian-installer',
+        '--exclude=dists/*/*/dist-upgrader-all',
+        '--exclude=dists/*/*/installer*',
+        '--exclude=dists/*/*/uefi',
+    )
     # Ordering of the include/exclude rules is important, rsync will
     # follow the first matching rule. So place the common rules above
     # the rules to limit by series.
@@ -400,18 +395,16 @@
     rsync(rsync_source, dest, rsync_options, log, user='www-sync', timeout=3600)
 
 
[e-mail]_exception(backoff.expo, CalledProcessError,
-                      max_tries=RSYNC_MAX_RETRIES, giveup=rsync_should_giveup)
[e-mail]_exception(backoff.expo, UpstreamMirrorSyncError,
-                      max_tries=UPSTREAM_SYNC_MAX_RETRIES, factor=60)
[e-mail]_exception(backoff.expo, CalledProcessError, max_tries=RSYNC_MAX_RETRIES, giveup=rsync_should_giveup)
[e-mail]_exception(backoff.expo, UpstreamMirrorSyncError, max_tries=UPSTREAM_SYNC_MAX_RETRIES, factor=60)
 def _mirror_base(apache_root, archive_ip, dest, log=None, rsync_module='ubuntu'):
-    '''Mirror just the root of the archive.
+    """Mirror just the root of the archive.
 
     This checks for the file 'Archive-Update-in-Progress-*' and
     throws ContentBad if the archive source isn't ready.
     Use this as a quick test prior to attempting a full mirror
     operation.
-    '''
+    """
 
     source = '{}::{}/'.format(archive_ip, rsync_module)
     mkdir(dest, owner='www-sync', group='www-data', perms=0o775, log=log)
@@ -419,8 +412,16 @@
     link_dest = '/'.join((apache_data, 'ubuntu_active'))
 
     # Sync just the root directory
-    rsync_options = ('--links', '--perms', '--times', '--dirs', '--chmod=g+w',
-                     '--delete', '--compress', '--link-dest=%s/' % link_dest)
+    rsync_options = (
+        '--links',
+        '--perms',
+        '--times',
+        '--dirs',
+        '--chmod=g+w',
+        '--delete',
+        '--compress',
+        '--link-dest=%s/' % link_dest,
+    )
     rsync(source, dest, rsync_options, log, flags='--quiet', user='www-sync', timeout=3600)
 
     # Check for file 'Archive-Update-in-Progress*' which signals
@@ -437,10 +438,14 @@
     # Traverse distributions and fail early by starting with the newest.
     # The newest (development branch) will have the highest rate of churn,
     # therefore the greatest chance of being invalid.
-    dists = sorted([ent for ent in os.listdir(dists_root) if
-                    os.path.isdir('/'.join((dists_root, ent))) and not
-                    os.path.islink('/'.join((dists_root, ent)))],
-                   reverse=True)
+    dists = sorted(
+        [
+            ent
+            for ent in os.listdir(dists_root)
+            if os.path.isdir('/'.join((dists_root, ent))) and not os.path.islink('/'.join((dists_root, ent)))
+        ],
+        reverse=True,
+    )
 
     for dist in dists:
         log('Verifying distribution %s' % dist)
@@ -448,18 +453,17 @@
         release = _parse_release_file(dist_dir)
         _verify_distribution(dist_dir, release)
 
-    for uip in glob.glob('/'.join((archive_root,
-                                   'Archive-Update-in-Progress-*'))):
+    for uip in glob.glob('/'.join((archive_root, 'Archive-Update-in-Progress-*'))):
         # XXX: Should be debug-only
         log('Removing {} from clean repository'.format(uip))
         os.remove(uip)
 
 
 def _parse_release_file(path):
-    '''Read a distribution Release file located at 'path'
+    """Read a distribution Release file located at 'path'
 
     Returns a dictionary describing Release file contents.
-    '''
+    """
 
     release = {}
     release['name'] = os.path.basename(path.strip('/'))
@@ -503,22 +507,20 @@
 
         size = int(files[filename]['size'])
         if disk_size != size:
-            msg = 'Sizes do not match for {} in {}'.format(filename,
-                                                           release['name'])
+            msg = 'Sizes do not match for {} in {}'.format(filename, release['name'])
             raise ContentBad(msg)
 
         with open(filepath, 'rb') as infile:
             sha256 = hashlib.sha256()
             while True:
-                buf = infile.read(1024*1024*100)
+                buf = infile.read(1024 * 1024 * 100)
                 if not buf:
                     break
                 sha256.update(buf)
         digest = sha256.hexdigest()
         if digest != files[filename]['SHA256']:
             file_mtime = os.stat(filepath).st_mtime
-            msg = 'SHA256 mismatch for {} in {}.'.format(filename,
-                                                         release['name'])
+            msg = 'SHA256 mismatch for {} in {}.'.format(filename, release['name'])
             if release['mtime'] < file_mtime:
                 ' '.join((msg, 'Stale Release file.'))
             raise ContentBad(msg)
@@ -549,11 +551,8 @@
 
     try:
         with FileSemaphore(SEMAPHORE_FILE):
-            cache_logger.info(
-                "Metadata sync started from metadata_sync.py:__main__")
+            cache_logger.info("Metadata sync started from metadata_sync.py:__main__")
             main(environment, cache_logger.info)
             cache_logger.info("Metadata sync from __main__ ended.")
     except SemaphoreExistsError:
-        cache_logger.info(
-            "Can't acquire semaphore: {} already exists.".format(
-                SEMAPHORE_FILE))
+        cache_logger.info("Can't acquire semaphore: {} already exists.".format(SEMAPHORE_FILE))

=== modified file 'lib/ubuntu_repository_cache/mirror.py'
--- lib/ubuntu_repository_cache/mirror.py	2020-10-06 10:05:01 +0000
+++ lib/ubuntu_repository_cache/mirror.py	2020-10-06 10:05:01 +0000
@@ -27,22 +27,23 @@
 SERVICE = 'ubuntu-repository-cache'
 
 
-def _rsync(source, dest, link_dest=None, optlist=None, user='www-sync',
-           retries=1):
+def _rsync(source, dest, link_dest=None, optlist=None, user='www-sync', retries=1):
     '''Perform an rsync as a specified user'''
 
-    options = ['--quiet',
-               '--recursive',
-               '--links',
-               '--perms',
-               '--chmod=g+w',
-               '--times',
-               '--compress',
-               '--delete',
-               '--delete-before',
-               '--timeout=120',
-               '-e', 'sudo -u {} ssh -l {}'.format(user, user),
-               ]
+    options = [
+        '--quiet',
+        '--recursive',
+        '--links',
+        '--perms',
+        '--chmod=g+w',
+        '--times',
+        '--compress',
+        '--delete',
+        '--delete-before',
+        '--timeout=120',
+        '-e',
+        'sudo -u {} ssh -l {}'.format(user, user),
+    ]
     if optlist:
         options.extend(optlist)
     if link_dest:
@@ -52,9 +53,7 @@
         try:
             host.rsync(source, dest, options=options, timeout=3600)
         except CalledProcessError as excp:
-            LOG('rsync failed({}): {}'.format(excp.returncode,
-                                              excp.output),
-                hookenv.WARNING)
+            LOG('rsync failed({}): {}'.format(excp.returncode, excp.output), hookenv.WARNING)
             if not metadata_sync.rsync_should_giveup(excp):
                 attempt += 1
                 if attempt < retries:
@@ -65,16 +64,13 @@
                     LOG('No retries left.')
                     raise
             else:
-                LOG('rsync failed({}): {}'.format(excp.returncode,
-                                                  excp.output),
-                    hookenv.WARNING)
+                LOG('rsync failed({}): {}'.format(excp.returncode, excp.output), hookenv.WARNING)
                 raise
         return
 
 
 @util.run_as_user('www-sync')
-def rsync_to_peers(source_dir, dest_dir, link_dir=None, user='www-sync',
-                   peers=None):
+def rsync_to_peers(source_dir, dest_dir, link_dir=None, user='www-sync', peers=None):
     """
     Use rsync to push a directory to all configured peers.
 
@@ -94,8 +90,7 @@
         rsync_dest = '{}@{}:{}'.format(user, peer, dest_dir)
         LOG('Syncing {} to {}.'.format(source_dir, rsync_dest))
         try:
-            _rsync(source_dir, rsync_dest, link_dest=link_dir,
-                   user=user, retries=10)
+            _rsync(source_dir, rsync_dest, link_dest=link_dir, user=user, retries=10)
         except Exception:
             LOG('Sync to {} failed'.format(peer))
             traceback.print_exc(file=sys.stdout)
@@ -106,25 +101,23 @@
 
 
 @util.run_as_user('www-sync')
-def rsync_from_peer(source_dir, dest_dir, peer_ip, link_dir=None,
-                    user='www-sync'):
+def rsync_from_peer(source_dir, dest_dir, peer_ip, link_dir=None, user='www-sync'):
     '''Use rsync to pull a directory from a configured peer.  '''
 
     rsync_source = '{}@{}:{}'.format(user, peer_ip, source_dir)
     LOG('Syncing {} to {}.'.format(rsync_source, dest_dir))
-    _rsync(rsync_source, dest_dir, link_dest=link_dir,
-           user=user, retries=10)
+    _rsync(rsync_source, dest_dir, link_dest=link_dir, user=user, retries=10)
     LOG('Sync to {} complete.'.format(peer_ip))
 
 
 def _leader_update_metadata():
-    '''Update the metadata on a leader in the cluster.
+    """Update the metadata on a leader in the cluster.
 
     If the leader is newly elected, it will pull down the latest
     metadata.  The metadata is not pushed to peers.  The peers will
     pull the metadata once on the next relation-changed hook triggered
     by setting the meta_version relation data.
-    '''
+    """
 
     LOG('Updating metadata on the leader')
     # Relation data
@@ -136,8 +129,7 @@
     leader_id = hookenv.leader_get(attribute="leader_id")
     # Log the race if it happened:
     if leader_id != hookenv.local_unit():
-        LOG('Leader changed between peer_update_metadata and '
-            '_leader_update_metadata', hookenv.WARNING)
+        LOG('Leader changed between peer_update_metadata and ' '_leader_update_metadata', hookenv.WARNING)
 
     leader_rel = rel[leader_id]
 
@@ -158,8 +150,7 @@
             LOG('Nothing to update')
     else:
         LOG('Leader missing expected metadata. Recovering.')
-        LOG('meta_ver:{} active_ver:{}'.format(meta_ver, active_ver),
-            hookenv.DEBUG)
+        LOG('meta_ver:{} active_ver:{}'.format(meta_ver, active_ver), hookenv.DEBUG)
         metadata_sync.clean_metadata_dir(apache_root, LOG)
 
         # Don't use the existing metadata.  If this is a current unit
@@ -175,16 +166,15 @@
         # reasonable to panic and just explode (hence the absence of try block)
         with util.FileSemaphore(util.SEMAPHORE_FILE):
             new_ver = metadata_sync.mirror_archive(
-                sync_host, apache_root, hookenv.local_unit(), LOG,
-                mirror_series, rsync_module=rsync_module)
+                sync_host, apache_root, hookenv.local_unit(), LOG, mirror_series, rsync_module=rsync_module
+            )
 
         if not new_ver:
             LOG('Leader could not gather new metadata', hookenv.WARNING)
             return
         util.update_active_symlink(new_ver)
 
-        LOG('Updating metadata version to {}'.format(new_ver),
-            hookenv.DEBUG)
+        LOG('Updating metadata version to {}'.format(new_ver), hookenv.DEBUG)
         hookenv.relation_set(meta_version=new_ver)
 
     service.unpause()
@@ -206,14 +196,12 @@
     leader_id = hookenv.leader_get(attribute="leader_id")
     # Log the race if it happened:
     if leader_id == hookenv.local_unit():
-        LOG('Leader changed between peer_update_metadata and '
-            '_nonleader_update_metadata', hookenv.WARNING)
+        LOG('Leader changed between peer_update_metadata and ' '_nonleader_update_metadata', hookenv.WARNING)
 
     if leader_id not in rel:
         # Peers can join in any order and the leader may not have joined yet.
         # Log who we think is the leader and return until it joins
-        LOG('Leader {} not yet related, can\'t complete '
-            '_nonleader_update_metadata'.format(leader_id))
+        LOG('Leader {} not yet related, can\'t complete ' '_nonleader_update_metadata'.format(leader_id))
         return
 
     leader_rel = rel[leader_id]
@@ -254,10 +242,8 @@
 
             # Can we connect to the leader?
             leader_hosts = leader_rel.get('ssh_authorized_hosts')
-            if not leader_hosts or \
-                    hookenv.unit_private_ip() not in leader_hosts:
-                LOG('Leader has not added IP to authorized_hosts yet, '
-                    'can not update.')
+            if not leader_hosts or hookenv.unit_private_ip() not in leader_hosts:
+                LOG('Leader has not added IP to authorized_hosts yet, ' 'can not update.')
                 return
 
             # Pull metadata from the leader if it exists and is ready
@@ -268,27 +254,23 @@
                 source = meta_dir + '/'
                 dest = meta_dir
                 try:
-                    rsync_from_peer(source, dest,
-                                    leader_rel.get('private-address'),
-                                    link_dir=active_dir)
+                    rsync_from_peer(source, dest, leader_rel.get('private-address'), link_dir=active_dir)
                 except CalledProcessError:
                     traceback.print_exc()
-                    LOG('Failed to pull metadata from leader; service stopped'
-                        ' until next update from leader.')
+                    LOG('Failed to pull metadata from leader; service stopped' ' until next update from leader.')
                 else:
                     util.update_active_symlink(meta_ver)
                     service.unpause()
 
             # Do nothing. Service is stopped until next update from leader
             else:
-                LOG('Metadata dir does not exist on leader.',
-                    hookenv.DEBUG)
+                LOG('Metadata dir does not exist on leader.', hookenv.DEBUG)
     metadata_sync.clean_metadata_dir(apache_root, LOG)
     LOG('Metadata update complete.')
 
 
 def peer_update_metadata():
-    '''Update the metadata on a clustered peer to the current version.
+    """Update the metadata on a clustered peer to the current version.
 
     If the 'cluster' relationship exists, this will look for the
     current 'meta_version' key on the leader and attempt to
@@ -296,11 +278,13 @@
 
     This function should be called from the cluster-relation-joined,
     cluster-relation-changed, and cluster-relation-departed hooks.
-    '''
+    """
 
-    if not hookenv.is_relation_made('cluster') or \
-            not hookenv.in_relation_hook() or \
-            not hookenv.relation_type() == 'cluster':
+    if (
+        not hookenv.is_relation_made('cluster')
+        or not hookenv.in_relation_hook()
+        or not hookenv.relation_type() == 'cluster'
+    ):
         return
 
     if cluster.is_elected_leader(None):
@@ -315,27 +299,18 @@
 def update_checks(nrpe_config):
     '''Update nagios check for mirror metadata age'''
 
-    service_script = '/'.join((hookenv.charm_dir(),
-                               'files',
-                               'nrpe-external-master',
-                               'check_metadata_age'))
-    metadata_dir = '/'.join((unitdata.kv().get('apache-root'),
-                             'data',
-                             'ubuntu_active'))
-    check_metadata_age_config_path = '/srv/{}/var/check_metadata_age'.format(
-        hookenv.service_name())
+    service_script = '/'.join((hookenv.charm_dir(), 'files', 'nrpe-external-master', 'check_metadata_age'))
+    metadata_dir = '/'.join((unitdata.kv().get('apache-root'), 'data', 'ubuntu_active'))
+    check_metadata_age_config_path = '/srv/{}/var/check_metadata_age'.format(hookenv.service_name())
 
     config = hookenv.config()
     context = {}
     context['crit_age'] = config['sync-age-crit']
     context['warn_age'] = config['sync-age-warn']
-    templating.render('check_metadata_age-config',
-                      check_metadata_age_config_path,
-                      context)
+    templating.render('check_metadata_age-config', check_metadata_age_config_path, context)
 
     nrpe_config.add_check(
         shortname='mirror',
         description='Ubuntu repository cache metadata age',
-        check_cmd=' '.join(
-            (service_script, metadata_dir, check_metadata_age_config_path)),
+        check_cmd=' '.join((service_script, metadata_dir, check_metadata_age_config_path)),
     )

=== modified file 'lib/ubuntu_repository_cache/service.py'
--- lib/ubuntu_repository_cache/service.py	2020-06-03 00:17:42 +0000
+++ lib/ubuntu_repository_cache/service.py	2020-10-06 10:05:01 +0000
@@ -63,27 +63,23 @@
     # environment, it doesn't mean we can support it.
     preinstall_files = glob.glob('exec.d/*/charm-pre-install')
     if preinstall_files:
-        LOG('============================================================',
-            hookenv.CRITICAL)
+        LOG('============================================================', hookenv.CRITICAL)
         LOG('Executing pre-install script(s).', hookenv.CRITICAL)
     for pre in preinstall_files:
         if not os.path.isfile(pre) or not os.access(pre, os.X_OK):
             LOG('Can not execute %s' % pre, hookenv.CRITICAL)
             raise RuntimeError('Pre-install script %s not executable' % pre)
         try:
-            LOG('============================================================',
-                hookenv.CRITICAL)
+            LOG('============================================================', hookenv.CRITICAL)
             LOG('Calling %s' % pre, hookenv.CRITICAL)
-            cmd = (pre)
+            cmd = pre
             subprocess.check_call(cmd)
         except subprocess.CalledProcessError as xcp:
-            LOG('%s failed, retcode %d' % (pre, xcp.returncode),
-                hookenv.CRITICAL)
+            LOG('%s failed, retcode %d' % (pre, xcp.returncode), hookenv.CRITICAL)
             raise RuntimeError('%s failed, retcode %d' % (pre, xcp.returncode))
         else:
             LOG('%s succeeded' % pre, hookenv.CRITICAL)
-            LOG('============================================================',
-                hookenv.CRITICAL)
+            LOG('============================================================', hookenv.CRITICAL)
 
     LOG('Installing services', hookenv.INFO)
     write_status('installing')
@@ -104,9 +100,9 @@
     apache.install()
     squid.install()
     try:
-        subprocess.check_call(['useradd', '--gid', 'www-data',
-                               '--create-home', '--no-user-group', '--shell',
-                               '/bin/bash', 'www-sync'])
+        subprocess.check_call(
+            ['useradd', '--gid', 'www-data', '--create-home', '--no-user-group', '--shell', '/bin/bash', 'www-sync']
+        )
     except subprocess.CalledProcessError as e:
         if e.returncode == 9:  # User already exists.
             pass
@@ -115,8 +111,7 @@
 
     # Make sure a log file is available for the user to write to - this will be
     # use by the cron, run as that user.
-    subprocess.check_call(['install', '-o', 'www-sync', '-d',
-                           util.REPO_SYNC_DIR])
+    subprocess.check_call(['install', '-o', 'www-sync', '-d', util.REPO_SYNC_DIR])
     subprocess.check_call(['touch', util.REPO_SYNC_CRON_LOG])
     subprocess.check_call(['chown', 'www-sync', util.REPO_SYNC_CRON_LOG])
 
@@ -124,7 +119,7 @@
 
 
 def pause():
-    '''Temporarily route metadata requests to a peer (non-leader)
+    """Temporarily route metadata requests to a peer (non-leader)
 
     Use this when the metadata does not exist so that users don't
     find an empty mirror.  This is achieved by using the next peer
@@ -135,7 +130,7 @@
     * takes a long time to stop/start,
     * trashes the in-memory cache when stopped, and
     * can continue serving requests if left running.
-    '''
+    """
 
     # Don't pause on leader, but warn developer of incorrect usage
     # Change servicing of metadata by forwarding requests for
@@ -146,8 +141,7 @@
         util.set_failover()
         render_configs()
     else:
-        LOG('Pause should not be called on the leader, report to support',
-            hookenv.DEBUG)
+        LOG('Pause should not be called on the leader, report to support', hookenv.DEBUG)
 
 
 def unpause():
@@ -188,28 +182,26 @@
 def is_running():
     '''Check if service is running'''
 
-    return apache.service_running() and \
-        squid.service_running()
+    return apache.service_running() and squid.service_running()
 
 
 def service_map():
-    '''Mapping of configuration files to services.
+    """Mapping of configuration files to services.
 
     This is used by charmhelpers.core.host.restart_on_change to
     restart services when configuration files are altered.
-    '''
+    """
 
     return {
         '/etc/squid-deb-proxy/squid-deb-proxy.conf': ['squid-deb-proxy'],
         '/etc/squid-deb-proxy/allowed-networks-src.acl': ['squid-deb-proxy'],
-        ('/etc/squid-deb-proxy/mirror-dstdomain.acl.d/'
-         '99-ubuntu-repository-cache'): ['squid-deb-proxy'],
+        ('/etc/squid-deb-proxy/mirror-dstdomain.acl.d/' '99-ubuntu-repository-cache'): ['squid-deb-proxy'],
         '/etc/apache2/sites-available/archive_ubuntu_com.conf': ['apache2'],
     }
 
 
 def reload_on_change(mapping, restart_on_failure=False):
-    '''Reload services based on configuration files changing
+    """Reload services based on configuration files changing
 
     (Based on charmhelpers.core.host.restart_on_change)
     This function is used as a decorator, for example::
@@ -222,7 +214,8 @@
     In this example, the cinder-api and cinder-volume services
     would be reloaded if /etc/ceph/ceph.conf is changed by the
     ceph_client_changed function.
-    '''
+    """
+
     def wrap(function):
         def wrapped_f(*args):
             checksums = {}
@@ -235,11 +228,11 @@
                     restarts += mapping[path]
             services_list = list(OrderedDict.fromkeys(restarts))
             for service_name in services_list:
-                LOG('Reloading %s service' % service_name,
-                    hookenv.DEBUG)
-                host.service_reload(service_name,
-                                    restart_on_failure=restart_on_failure)
+                LOG('Reloading %s service' % service_name, hookenv.DEBUG)
+                host.service_reload(service_name, restart_on_failure=restart_on_failure)
+
         return wrapped_f
+
     return wrap
 
 
@@ -255,12 +248,12 @@
 
     # Log file rotation
     logrotate_filename = '/etc/logrotate.d/apache2'
-    logrotate_context = {'logrotate_rotate': config['logrotate_rotate'],
-                         'logrotate_count': config['logrotate_count'],
-                         'logrotate_dateext': config['logrotate_dateext'],
-                         }
-    templating.render('logrotate/logrotate.conf.template',
-                      logrotate_filename, logrotate_context, perms=0o644)
+    logrotate_context = {
+        'logrotate_rotate': config['logrotate_rotate'],
+        'logrotate_count': config['logrotate_count'],
+        'logrotate_dateext': config['logrotate_dateext'],
+    }
+    templating.render('logrotate/logrotate.conf.template', logrotate_filename, logrotate_context, perms=0o644)
 
     if not os.path.exists(CONFIG_DIR):
         host.mkdir(CONFIG_DIR)
@@ -280,16 +273,11 @@
         cron_context['RsyncModule'] = config['rsync-module']
         cron_context['Minutes'] = unitdata.kv().get('rsync-minutes')
         cron_context['UnitId'] = hookenv.local_unit()
-        cron_context['UnitPath'] = \
-            '-'.join(('unit', hookenv.local_unit().replace('/', '-')))
+        cron_context['UnitPath'] = '-'.join(('unit', hookenv.local_unit().replace('/', '-')))
         cron_context['MirrorSeries'] = config['mirror-series'].strip()
         cron_context['ConfigPath'] = urc_config_path
-        templating.render('cron/ubuntu-repository-cache_rsync.cron',
-                          cron_filename,
-                          cron_context)
-        templating.render('cron/ubuntu-repository-cache-config',
-                          urc_config_path,
-                          cron_context)
+        templating.render('cron/ubuntu-repository-cache_rsync.cron', cron_filename, cron_context)
+        templating.render('cron/ubuntu-repository-cache-config', urc_config_path, cron_context)
     else:
         try:
             os.stat(cron_filename)
@@ -315,17 +303,14 @@
     mirror.update_checks(nrpe_config)
 
     # Metadata service check
-    service_script = '/'.join((hookenv.charm_dir(),
-                               'files',
-                               'nrpe-external-master',
-                               'check_metadata_service'))
+    service_script = '/'.join((hookenv.charm_dir(), 'files', 'nrpe-external-master', 'check_metadata_service'))
     var_dir = '/'.join(('/srv', hookenv.service_name(), 'var'))
     state_filename = '/'.join((var_dir, hookenv.service_name()))
 
     nrpe_config.add_check(
         shortname='metadata',
         description='Ubuntu repository cache metadata service',
-        check_cmd=' '. join((service_script, state_filename)),
+        check_cmd=' '.join((service_script, state_filename)),
     )
 
     nrpe_config.write()

=== modified file 'lib/ubuntu_repository_cache/squid.py'
--- lib/ubuntu_repository_cache/squid.py	2020-05-07 05:26:37 +0000
+++ lib/ubuntu_repository_cache/squid.py	2020-10-06 10:05:01 +0000
@@ -13,9 +13,7 @@
     unitdata,
 )
 
-from charmhelpers.core.host import (
-    lsb_release
-)
+from charmhelpers.core.host import lsb_release
 
 from . import util
 
@@ -25,40 +23,35 @@
 
 @util.run_as_user('proxy')
 def init_caches():
-    '''Initialize the squid on-disk caches
+    """Initialize the squid on-disk caches
 
     This must be called while the service is stopped and after the
     configuration has been written.
-    '''
+    """
 
     if not unitdata.kv().get('squid-disk-caches'):
-        LOG('No on disk cache directories founds for squid.',
-            hookenv.ERROR)
+        LOG('No on disk cache directories founds for squid.', hookenv.ERROR)
         return
-    subprocess.check_call(['/usr/sbin/squid3', '-N', '-z',
-                           '-f', '/etc/squid-deb-proxy/squid-deb-proxy.conf'])
+    subprocess.check_call(['/usr/sbin/squid3', '-N', '-z', '-f', '/etc/squid-deb-proxy/squid-deb-proxy.conf'])
 
 
 def size_caches():
-    '''Determine the sizes for in-memory/on-disk squid caches
+    """Determine the sizes for in-memory/on-disk squid caches
 
     This must be run at installation time.  Runtime tuning is unsupported.
-    '''
+    """
 
     avail_disk = 0
     for cache in unitdata.kv().get('squid-disk-caches'):
         avail_disk += cache[1]
-    LOG('{}MB of disk cache available for squid.'.format(avail_disk),
-        hookenv.DEBUG)
+    LOG('{}MB of disk cache available for squid.'.format(avail_disk), hookenv.DEBUG)
 
     memory = util.system_total_mem() / 3
     # Estimate of 100MB of overhead for squid
     memory = max(memory - 100, 0)
 
     if memory < 128:
-        LOG('Squid has too little memory ({}MB), '
-            'can not deploy service'.format(memory),
-            hookenv.ERROR)
+        LOG('Squid has too little memory ({}MB), ' 'can not deploy service'.format(memory), hookenv.ERROR)
         raise RuntimeError('Too little system memory for squid deployment')
 
     # Start by giving squid a maximum of 256MB for in-memory cache
@@ -77,10 +70,11 @@
 
     unitdata.kv().set('squid-cache-mem', squid_cache_mem)
     unitdata.kv().set('squid-cache-disk', squid_cache_disk)
-    LOG('Squid sizing complete. In-memory cache: {}MB '
-        'On-disk cache: {}MB'.format(unitdata.kv().get('squid-cache-mem'),
-                                     unitdata.kv().get('squid-cache-disk')),
-        hookenv.INFO)
+    LOG(
+        'Squid sizing complete. In-memory cache: {}MB '
+        'On-disk cache: {}MB'.format(unitdata.kv().get('squid-cache-mem'), unitdata.kv().get('squid-cache-disk')),
+        hookenv.INFO,
+    )
 
 
 def install():
@@ -153,10 +147,10 @@
 
 
 def cache_dirs():
-    '''Generate 'cache_dir' lines for the squid configuration file.
+    """Generate 'cache_dir' lines for the squid configuration file.
 
     Returns a string containing the cache_dir line(s)
-    '''
+    """
     cache_str = ''
     config = hookenv.config()
     max_size = unitdata.kv().get('squid-cache-disk')
@@ -167,9 +161,7 @@
             size = int(min(max_size, free))
 
         max_size -= size
-        cache_str = ''.join((cache_str,
-                             'cache_dir aufs {} {} 16 256\n'.format(path,
-                                                                    size)))
+        cache_str = ''.join((cache_str, 'cache_dir aufs {} {} 16 256\n'.format(path, size)))
     return cache_str
 
 
@@ -185,7 +177,9 @@
     context['Cache_Peers'] = peer_config()
     context['Cache_Hostname'] = hookenv.unit_private_ip()
     if config['squid_snmp']:
-        context['Snmp_Config'] = """acl snmppublic snmp_community public
+        context[
+            'Snmp_Config'
+        ] = """acl snmppublic snmp_community public
                                   snmp_port 3401
                                   snmp_access allow snmppublic localhost
                                   snmp_access deny all
@@ -193,15 +187,13 @@
     else:
         context['Snmp_Config'] = ""
 
-    templating.render('{}/{}.conf'.format(SERVICE, SERVICE),
-                      '/etc/{}/{}.conf'.format(SERVICE, SERVICE),
-                      context)
+    templating.render('{}/{}.conf'.format(SERVICE, SERVICE), '/etc/{}/{}.conf'.format(SERVICE, SERVICE), context)
 
     peer_context = {}
     peer_context['Cache_Sibling_IPs'] = '\n'.join(util.peer_IPs())
-    templating.render('{}/allowed-networks-src.conf'.format(SERVICE),
-                      '/etc/{}/allowed-networks-src.acl'.format(SERVICE),
-                      peer_context)
+    templating.render(
+        '{}/allowed-networks-src.conf'.format(SERVICE), '/etc/{}/allowed-networks-src.acl'.format(SERVICE), peer_context
+    )
 
     dstdomain_context = {}
     # if 99-ubuntu-repository-cache contains a repository already allowed in
@@ -220,7 +212,7 @@
         '^extras\\.ubuntu\\.com$|'
         '\\.extras\\.ubuntu\\.com$|'
         '^changelogs\\.ubuntu\\.com$'
-        )
+    )
     if default_dstdomains.match(config['sync-host']):
         dstdomain_context['Sync_Host'] = ''
     else:
@@ -228,9 +220,9 @@
 
     templating.render(
         '{}/mirror-dstdomain.acl'.format(SERVICE),
-        '/etc/{}/mirror-dstdomain.acl.d/99-ubuntu-repository-cache'.format(
-            SERVICE),
-        dstdomain_context)
+        '/etc/{}/mirror-dstdomain.acl.d/99-ubuntu-repository-cache'.format(SERVICE),
+        dstdomain_context,
+    )
 
 
 def update_checks(nrpe_config):
@@ -240,6 +232,7 @@
     nrpe_config.add_check(
         shortname='squid',
         description='squid serving archive pool',
-        check_cmd=('check_http --hostname localhost --url "/{}/pool/" '
-                   '--string "main/" --expect \"200\\ OK\"').format(path_base),
+        check_cmd=(
+            'check_http --hostname localhost --url "/{}/pool/" ' '--string "main/" --expect \"200\\ OK\"'
+        ).format(path_base),
     )

=== modified file 'lib/ubuntu_repository_cache/storage.py'
--- lib/ubuntu_repository_cache/storage.py	2020-07-13 00:08:07 +0000
+++ lib/ubuntu_repository_cache/storage.py	2020-10-06 10:05:01 +0000
@@ -50,17 +50,14 @@
 
     # Apache serves from www/ and metadata is in data/
     _mkdir(apache_root, owner='www-data', group='www-data', perms=0o775)
-    _mkdir('/'.join((apache_root, 'www')),
-           owner='www-data', group='www-data', perms=0o775)
-    _mkdir('/'.join((apache_root, 'data')),
-           owner='www-data', group='www-data', perms=0o775)
+    _mkdir('/'.join((apache_root, 'www')), owner='www-data', group='www-data', perms=0o775)
+    _mkdir('/'.join((apache_root, 'data')), owner='www-data', group='www-data', perms=0o775)
     # XXX support multi-directory path-base
-    host.symlink('/'.join((apache_root, 'data', 'ubuntu_active')),
-                 '/'.join((apache_root, 'www', config['path-base'])))
+    host.symlink('/'.join((apache_root, 'data', 'ubuntu_active')), '/'.join((apache_root, 'www', config['path-base'])))
 
 
 def _setup_packages_path(primary_mount, secondary_mounts):
-    '''Create the squid cache directorys for package caches.
+    """Create the squid cache directorys for package caches.
 
     The config 'squid-disk-caches' is populated with the path to each
     cache directory and the maximum space available, in MB, for that mount.
@@ -71,7 +68,7 @@
     be sized based on system memory, so some available disk space may
     not be used.  In that case, having the mount used for metadata
     mirrors last would let any additional space be used for that.
-    '''
+    """
 
     squid_disk_caches = []
     for mnt in secondary_mounts:
@@ -90,9 +87,7 @@
     # See https://pastebin.ubuntu.com/p/ftCFNMx947/
     reserve = (20 + 5 + 4) * 1024
     if max_size < reserve:
-        LOG('Less than {}MB disk free @ {} for mirror.'.format(reserve,
-                                                               primary_mount),
-            hookenv.ERROR)
+        LOG('Less than {}MB disk free @ {} for mirror.'.format(reserve, primary_mount), hookenv.ERROR)
     else:
         max_size = (max_size - reserve) * 0.75
         squid_disk_caches.append([squid_cache, max_size])
@@ -101,7 +96,7 @@
 
 
 def _setup_ephemeral(devices=None):
-    '''Formats and mounts ephemeral devices
+    """Formats and mounts ephemeral devices
 
     Each ephemeral device is formated with ext4 and provided a label
     of the format '<service_name>_<#>'
@@ -111,7 +106,7 @@
 
     An fstab entry is added for each device to ensure the device is
     mounted on reboot.
-    '''
+    """
 
     ephemeral_mounts = []
     if not devices:
@@ -135,8 +130,7 @@
         partitions = glob.glob(dev + '*').remove(dev) or []
         for part in partitions:
             if Storage.is_device_mounted(part):
-                LOG('Ephemeral device had a mounted partition %s skipping' %
-                    part, hookenv.ERROR)
+                LOG('Ephemeral device had a mounted partition %s skipping' % part, hookenv.ERROR)
                 continue
 
         if Storage.is_device_mounted(dev):
@@ -166,27 +160,25 @@
         # Add to fstab by label, not device name
         _mkdir(mountpoint, perms=0o775)
         devname = '='.join(('LABEL', label))
-        ftab.add_entry(fstab.Fstab.Entry(devname, mountpoint, 'ext4',
-                                         options=None))
+        ftab.add_entry(fstab.Fstab.Entry(devname, mountpoint, 'ext4', options=None))
         ftab.close()
 
         subprocess.check_call(['mount', mountpoint])
         os.chmod(mountpoint, 0o775)
         ephemeral_mounts.append(mountpoint)
         devno += 1
-    LOG('Ephemeral storage mounted @ {}'.format(ephemeral_mounts),
-        hookenv.DEBUG)
+    LOG('Ephemeral storage mounted @ {}'.format(ephemeral_mounts), hookenv.DEBUG)
     unitdata.kv().set('ephemeral-mounts', ephemeral_mounts)
 
 
 def _mkdir(path, owner='root', group='root', perms=0o555):
-    '''Make directories recursively with a umask=0o000.
+    """Make directories recursively with a umask=0o000.
 
     This storage module makes calls to mkdir repeatedly with permissions
     that include group write permission.  This would be masked by the
     default 0o022 umask.   This simple helper function will clear
     the umask prior to calling host.mkdir and then restore it when done.
-    '''
+    """
 
     prev_umask = os.umask(0o000)
     host.mkdir(path, owner=owner, group=group, perms=perms)
@@ -210,9 +202,7 @@
         return
 
     try:
-        LOG('Adding check for ephemeral storage {}'.format(
-            unitdata.kv().get('ephemeral-mounts')),
-            hookenv.DEBUG)
+        LOG('Adding check for ephemeral storage {}'.format(unitdata.kv().get('ephemeral-mounts')), hookenv.DEBUG)
     except KeyError:
         LOG('No checks added for ephemeral storage', hookenv.DEBUG)
         return
@@ -220,6 +210,5 @@
     nrpe_config.add_check(
         shortname='disks-ephemeral',
         description='disk space on ephemeral volumes',
-        check_cmd='check_disk -w 15 -c 5 -r '
-                  '^/srv/ubuntu-repository-cache/ephemeral/[0-9].*$',
-        )
+        check_cmd='check_disk -w 15 -c 5 -r ' '^/srv/ubuntu-repository-cache/ephemeral/[0-9].*$',
+    )

=== modified file 'lib/ubuntu_repository_cache/tests/test_metadata_sync.py'
--- lib/ubuntu_repository_cache/tests/test_metadata_sync.py	2020-08-11 04:12:28 +0000
+++ lib/ubuntu_repository_cache/tests/test_metadata_sync.py	2020-10-06 10:05:01 +0000
@@ -21,20 +21,22 @@
  a41cb792e56b512948b9dd35d3c974497d84f1ea         47334442 something-else
 """
 
-RELEASE_FILE_WITH_SHA256 = RELEASE_FILE_CONTENT + """
+RELEASE_FILE_WITH_SHA256 = (
+    RELEASE_FILE_CONTENT
+    + """
 SHA256:
  36193e81e070279baaf8adce44305b02c3fd029f6c0f1497d9bd044ab2a633aa 435597291 foo
  e653b6621b1d77144d86421927ae7f9466f9a6b7012fa4b9a51cdf68b333a23a  47334442 bar
 """
+)
 
 
 EXPECTED_FILES_DICT = OrderedDict(
-    [('foo', {'SHA256': '36193e81e070279baaf8adce44305b02c3fd029f6c0f1497d9bd'
-                        '044ab2a633aa',
-      'size': '435597291'}),
-     ('bar', {'SHA256': 'e653b6621b1d77144d86421927ae7f9466f9a6b7012fa4b9a51c'
-                        'df68b333a23a',
-      'size': '47334442'})])
+    [
+        ('foo', {'SHA256': '36193e81e070279baaf8adce44305b02c3fd029f6c0f1497d9bd' '044ab2a633aa', 'size': '435597291'}),
+        ('bar', {'SHA256': 'e653b6621b1d77144d86421927ae7f9466f9a6b7012fa4b9a51c' 'df68b333a23a', 'size': '47334442'}),
+    ]
+)
 
 
 FakeException = namedtuple('FakeException', 'returncode')
@@ -55,30 +57,24 @@
 
 
 class MirrorTestCase(unittest.TestCase):
-
     def test_rsync_sends_rsync_command(self):
         """
         The rsync function executes a system rsync shell with the passed in
         parameters.
         """
+
         def fake_check_output(cmd, stderr):
             self.assertEqual(stderr, subprocess.STDOUT)
-            self.assertEqual(
-                ["/usr/bin/rsync", "-r", "--foo", "--bar", "source", "dest"],
-                cmd)
+            self.assertEqual(["/usr/bin/rsync", "-r", "--foo", "--bar", "source", "dest"], cmd)
             return b"called "  # Note: real check_output returns bytes.
 
         log = InvocationRecorder()
 
         options = ("--foo", "--bar")
-        result = metadata_sync.rsync(
-                "source", "dest", options, log,
-                check_output=fake_check_output)
+        result = metadata_sync.rsync("source", "dest", options, log, check_output=fake_check_output)
 
         self.assertEqual("called", result)  # "rsync" decodes and strips
-        self.assertEqual(
-            [[("/usr/bin/rsync -r --foo --bar source dest",), {}]],
-            log.invocations)
+        self.assertEqual([[("/usr/bin/rsync -r --foo --bar source dest",), {}]], log.invocations)
 
     def test_parse_release_file_no_sha256(self):
         """
@@ -93,9 +89,11 @@
                 temp.write(RELEASE_FILE_CONTENT)
                 temp.flush()
             result = metadata_sync._parse_release_file(temp_dir)
-            expected = {'files': OrderedDict(),
-                        'name': os.path.basename(temp_dir),
-                        'mtime': os.stat(temp_dir + "/Release").st_mtime}
+            expected = {
+                'files': OrderedDict(),
+                'name': os.path.basename(temp_dir),
+                'mtime': os.stat(temp_dir + "/Release").st_mtime,
+            }
             self.assertEqual(expected, result)
         finally:
             shutil.rmtree(temp_dir)
@@ -113,9 +111,11 @@
                 temp.write(RELEASE_FILE_WITH_SHA256)
                 temp.flush()
             result = metadata_sync._parse_release_file(temp_dir)
-            expected = {'name': os.path.basename(temp_dir.strip("/")),
-                        'mtime': os.stat(temp_dir + "/Release").st_mtime,
-                        'files': EXPECTED_FILES_DICT}
+            expected = {
+                'name': os.path.basename(temp_dir.strip("/")),
+                'mtime': os.stat(temp_dir + "/Release").st_mtime,
+                'files': EXPECTED_FILES_DICT,
+            }
             self.assertEqual(expected, result)
         finally:
             shutil.rmtree(temp_dir)
@@ -128,8 +128,7 @@
 
     def test_rsync_should_retry_do_retry(self):
         """Retry for whitelisted exit codes."""
-        retriables = frozenset((
-            5, 6, 10, 11, 12, 13, 14, 20, 21, 22, 23, 24, 25, 30, 35))
+        retriables = frozenset((5, 6, 10, 11, 12, 13, 14, 20, 21, 22, 23, 24, 25, 30, 35))
 
         for i in retriables:
             exe = FakeException(returncode=i)
@@ -144,16 +143,18 @@
         """
         The main function fails should an environment variable be missing.
         """
+
         def noop(*args, **kwargs):
             return "Called"
 
-        env = {"SYNC_HOST": "foo.com",
-               "MIRROR_SERIES": "xenial",
-               "APACHE_ROOT": "/var/www/",
-               "LOCAL_UNIT": "unit/0",
-               "UNIT_PATH": "something"}
-        result = metadata_sync.main(
-            env, InvocationRecorder(), mirror_archive=noop, check_call=noop)
+        env = {
+            "SYNC_HOST": "foo.com",
+            "MIRROR_SERIES": "xenial",
+            "APACHE_ROOT": "/var/www/",
+            "LOCAL_UNIT": "unit/0",
+            "UNIT_PATH": "something",
+        }
+        result = metadata_sync.main(env, InvocationRecorder(), mirror_archive=noop, check_call=noop)
         self.assertEqual("Called", result)
 
     def test_main_calls_juju_run(self):
@@ -161,11 +162,13 @@
         The main() function calls juju run once it determined the meta_ver from
         syncing with upstream.
         """
-        env = {"SYNC_HOST": "foo.com",
-               "MIRROR_SERIES": "xenial",
-               "APACHE_ROOT": "/var/www/",
-               "LOCAL_UNIT": "unit/0",
-               "UNIT_PATH": "something"}
+        env = {
+            "SYNC_HOST": "foo.com",
+            "MIRROR_SERIES": "xenial",
+            "APACHE_ROOT": "/var/www/",
+            "LOCAL_UNIT": "unit/0",
+            "UNIT_PATH": "something",
+        }
 
         def fake_mirror_archive(*args, **kwargs):
             return "some_meta_var"
@@ -173,17 +176,25 @@
         fake_check_call = InvocationRecorder()
 
         result = metadata_sync.main(
-            env, InvocationRecorder(), mirror_archive=fake_mirror_archive,
-            check_call=fake_check_call)
+            env, InvocationRecorder(), mirror_archive=fake_mirror_archive, check_call=fake_check_call
+        )
 
         self.assertEqual("some_meta_var", result)
 
         expected = [
-            [(['juju-run',
-               'unit/0',
-               '/usr/local/sbin/charm-env '
-               '/var/lib/juju/agents/something/charm/hooks/'
-               'ubuntu-repository-cache-sync some_meta_var'],), {}]]
+            [
+                (
+                    [
+                        'juju-run',
+                        'unit/0',
+                        '/usr/local/sbin/charm-env '
+                        '/var/lib/juju/agents/something/charm/hooks/'
+                        'ubuntu-repository-cache-sync some_meta_var',
+                    ],
+                ),
+                {},
+            ]
+        ]
 
         self.assertEqual(expected, fake_check_call.invocations)
 
@@ -201,9 +212,9 @@
         "LOCAL_UNIT": "unit/0",
         "UNIT_PATH": "something",
     }
-    key_combinations = itertools.chain(*[
-        itertools.combinations(full_dict.keys(), n)
-        for n in range(len(full_dict.keys()))])
+    key_combinations = itertools.chain(
+        *[itertools.combinations(full_dict.keys(), n) for n in range(len(full_dict.keys()))]
+    )
 
     def do_test(env):
         assert_raises(KeyError, metadata_sync.main, env, InvocationRecorder())

=== modified file 'lib/ubuntu_repository_cache/tests/test_util.py'
--- lib/ubuntu_repository_cache/tests/test_util.py	2020-08-11 04:12:28 +0000
+++ lib/ubuntu_repository_cache/tests/test_util.py	2020-10-06 10:05:01 +0000
@@ -7,7 +7,6 @@
 
 
 class SemaphoreTest(unittest.TestCase):
-
     def setUp(self):
         self.test_dir = tempfile.mkdtemp()
 
@@ -35,7 +34,6 @@
 
 
 class TouchTest(unittest.TestCase):
-
     def setUp(self):
         self.test_dir = tempfile.mkdtemp()
 

=== modified file 'lib/ubuntu_repository_cache/util.py'
--- lib/ubuntu_repository_cache/util.py	2020-05-07 05:26:37 +0000
+++ lib/ubuntu_repository_cache/util.py	2020-10-06 10:05:01 +0000
@@ -29,19 +29,18 @@
     '''An error raised when the desired semaphore name already exists.'''
 
 
-class FileSemaphore():
-    '''A context manager that creates and deletes semaphores at the given path.
+class FileSemaphore:
+    """A context manager that creates and deletes semaphores at the given path.
 
     It will raise SemaphoreExistsError if the "lock" can't be acquired, and
-    will cleanup after itself on exit.'''
+    will cleanup after itself on exit."""
 
     def __init__(self, filename):
         self.filename = filename
 
     def __enter__(self):
         if os.path.exists(self.filename):
-            raise SemaphoreExistsError(
-                "File '{}' already exists.".format(self.filename))
+            raise SemaphoreExistsError("File '{}' already exists.".format(self.filename))
         touch(self.filename)
 
     def __exit__(self, *args):
@@ -49,9 +48,9 @@
 
 
 def touch(filename):
-    '''Make an empty file at the passed in filename.
+    """Make an empty file at the passed in filename.
 
-    Its modified access time is set to "now".'''
+    Its modified access time is set to "now"."""
     with open(filename, 'a'):
         os.utime(filename, None)
 
@@ -75,11 +74,11 @@
 
 
 def get_failover_host():
-    '''Find the private address of the failover host.
+    """Find the private address of the failover host.
 
     The next highest numbered unit in the cluster relationship is
     choosen as the host for failover.  Its private address is returned.
-    '''
+    """
 
     if not hookenv.is_relation_made('cluster'):
         return None
@@ -98,15 +97,12 @@
 
     # Filter the list to find all units with a higher unit id, will
     # wrap to lowest unit number
-    cluster_ids = [x for x in cluster_ids if x > local_id] or \
-                  [x for x in cluster_ids if x < local_id]
+    cluster_ids = [x for x in cluster_ids if x > local_id] or [x for x in cluster_ids if x < local_id]
     if not cluster_ids:
         return None
 
     failover_unit = '%s/%s' % (hookenv.service_name(), cluster_ids[0])
-    return hookenv.relation_get(attribute='private-address',
-                                unit=failover_unit,
-                                rid=rel_id)
+    return hookenv.relation_get(attribute='private-address', unit=failover_unit, rid=rel_id)
 
 
 def restore_saved_id():
@@ -118,14 +114,15 @@
 
 # Submit MP to include this in charmhelpers.core.host
 def run_as_user(user_name):
-    '''A decorator to run a function as a particular user.
+    """A decorator to run a function as a particular user.
 
     This works as long as the saved uid (see os.getresuid()[2])
     has permission to change the effective to that of the
     desired uid/gid of the provided user name.
 
     The $HOME environment variable is also set to the particular user.
-    '''
+    """
+
     def decorator(function):
         @functools.wraps(function)
         def wrapper(*args, **kwargs):
@@ -155,7 +152,9 @@
                 del os.environ['HOME']
 
             return result
+
         return wrapper
+
     return decorator
 
 
@@ -167,12 +166,12 @@
 
 
 def change_aptsources_url(url='http://archive.ubuntu.com/ubuntu'):
-    '''Change the URL for the current apt sources
+    """Change the URL for the current apt sources
 
     This affects the URL for all sources in /etc/apt/sources.list
     and /etc/apt/sources.list.d/ so care must be taken if the charm
     has added any custom source URLs as it will alter them as well.
-    '''
+    """
     import aptsources.sourceslist
     import aptsources.distro
 
@@ -192,16 +191,15 @@
     ips = []
     for ident in hookenv.relation_ids(reltype=reltype):
         for unit in hookenv.related_units(relid=ident):
-            ips.append(hookenv.relation_get(attribute='private-address',
-                                            unit=unit, rid=ident))
+            ips.append(hookenv.relation_get(attribute='private-address', unit=unit, rid=ident))
     return ips
 
 
 def get_active_metaver():
-    '''Get the metadata version of the active metadata
+    """Get the metadata version of the active metadata
 
     Returns version or None
-    '''
+    """
 
     apache_data = '/'.join((unitdata.kv().get('apache-root'), 'data'))
     path = os.path.realpath('/'.join((apache_data, 'ubuntu_active')))
@@ -212,8 +210,8 @@
 
 
 def update_active_symlink(meta_version, apache_root=None):
-    '''Update the symlink to the active metadata to point to the
-    metadata for meta_version.'''
+    """Update the symlink to the active metadata to point to the
+    metadata for meta_version."""
 
     if apache_root:
         root = apache_root
@@ -231,17 +229,11 @@
 
 
 def remote_path_exists(user, host_ip, path, localuser='www-sync'):
-    '''Use ssh to determine if a remote path exists.
-
-    Remotely execute the stat(1) command on the remote host.'''
-
-    cmd = ('sudo',
-           '-u',
-           localuser,
-           'ssh',
-           '{}@{}'.format(user, host_ip),
-           'stat {}'.format(path)
-           )
+    """Use ssh to determine if a remote path exists.
+
+    Remotely execute the stat(1) command on the remote host."""
+
+    cmd = ('sudo', '-u', localuser, 'ssh', '{}@{}'.format(user, host_ip), 'stat {}'.format(path))
     try:
         subprocess.check_call(cmd)
     except subprocess.CalledProcessError as excp:

=== modified file 'reactive/ubuntu-repository-cache.py'
--- reactive/ubuntu-repository-cache.py	2020-08-11 05:04:02 +0000
+++ reactive/ubuntu-repository-cache.py	2020-10-06 10:05:01 +0000
@@ -82,25 +82,22 @@
         try:
             with util.FileSemaphore(util.SEMAPHORE_FILE):
                 meta_ver = metadata_sync.mirror_archive(
-                    sync_host,
-                    unitdata.kv().get('apache-root'),
-                    hookenv.local_unit(),
-                    LOG,
-                    mirror_series)
+                    sync_host, unitdata.kv().get('apache-root'), hookenv.local_unit(), LOG, mirror_series
+                )
         except util.SemaphoreExistsError:
-            LOG('Another metadata sync seems to be running (semaphore found '
-                'at {}). Bailing out.'.format(util.SEMAPHORE_FILE))
+            LOG(
+                'Another metadata sync seems to be running (semaphore found '
+                'at {}). Bailing out.'.format(util.SEMAPHORE_FILE)
+            )
             raise
 
         if meta_ver:
-            LOG('Initial sync from {} completed ver={}.'.format(sync_host,
-                                                                meta_ver))
+            LOG('Initial sync from {} completed ver={}.'.format(sync_host, meta_ver))
             service.start()
         else:
             LOG('Leader could not gather new metadata', hookenv.WARNING)
     else:
-        LOG('Skipping initial content sync, "sync-on-start" config '
-            'option was not set')
+        LOG('Skipping initial content sync, "sync-on-start" config ' 'option was not set')
 
 
 @reactive.hook('stop')
@@ -116,8 +113,7 @@
     '''Provide hostname/port for the website relationship'''
 
     LOG('Website relation joined for %s' % SERVICE)
-    settings = {'hostname': hookenv.unit_private_ip(),
-                'port': 80}
+    settings = {'hostname': hookenv.unit_private_ip(), 'port': 80}
     hookenv.relation_set(relation_settings=settings)
 
 
@@ -126,8 +122,7 @@
     '''Join a peer cluster relationship'''
 
     LOG('Cluster relation joined for %s' % SERVICE)
-    unison.ssh_authorized_peers(peer_interface='cluster',
-                                user='www-sync', group='www-data')
+    unison.ssh_authorized_peers(peer_interface='cluster', user='www-sync', group='www-data')
     # LP:1770071: Work around charm-helper's unison ownership
     #             https://github.com/juju/charm-helpers/issues/487
     _fix_ssh_ownership(user='www-sync')
@@ -140,8 +135,7 @@
     '''Handle peer cluster relationship changes'''
 
     LOG('Cluster relation changed for %s' % SERVICE)
-    unison.ssh_authorized_peers(peer_interface='cluster',
-                                user='www-sync', group='www-data')
+    unison.ssh_authorized_peers(peer_interface='cluster', user='www-sync', group='www-data')
     # LP:1770071: Work around charm-helper's unison ownership
     #             https://github.com/juju/charm-helpers/issues/487
     _fix_ssh_ownership(user='www-sync')
@@ -154,8 +148,7 @@
     '''Handle peer cluster relationship departures'''
 
     LOG('Cluster relation departed for %s' % SERVICE)
-    unison.ssh_authorized_peers(peer_interface='cluster',
-                                user='www-sync', group='www-data')
+    unison.ssh_authorized_peers(peer_interface='cluster', user='www-sync', group='www-data')
     # LP:1770071: Work around charm-helper's unison ownership
     #             https://github.com/juju/charm-helpers/issues/487
     _fix_ssh_ownership(user='www-sync')
@@ -200,8 +193,7 @@
     if not hookenv.is_leader():
         LOG('leader-elected fired. This is not the leader')
         return
-    LOG('leader-elected fired. This unit is the new leader: {}'.format(
-            hookenv.local_unit()))
+    LOG('leader-elected fired. This unit is the new leader: {}'.format(hookenv.local_unit()))
     hookenv.leader_set(leader_id=hookenv.local_unit())
     mirror.peer_update_metadata()
     service.render_configs()

=== modified file 'tests/util.py'
--- tests/util.py	2020-05-07 05:29:31 +0000
+++ tests/util.py	2020-10-06 10:05:01 +0000
@@ -33,19 +33,19 @@
 
 
 def unit_name(unit):
-    '''
+    """
     Returns the juju unit name for the given amulet unit object.
-    '''
+    """
     return unit.info['unit_name']
 
 
 def send_script(unit, path, script):
-    '''
+    """
     Write out the provided script contents to the specified path and unit.
 
     Writes one line out at a time using ssh since there is no other convenient
     amulet method to do so. Works fine for short scripts.
-    '''
+    """
     unit.ssh('sudo rm -f {}'.format(path))
     for line in script.splitlines():
         command = 'sudo echo \'{}\' >> {}'.format(line, path)
@@ -54,20 +54,22 @@
 
 
 def execute(unit, command):
-    '''
+    """
     Executes a command on the given unit via a wrapper script.
 
     The amulet ssh method provides excessively verbose output on errors.
     This wrapper gives the test more control over the output and result.
-    '''
+    """
     log('INFO: Executing: {}'.format(command))
     unit.ssh('sudo rm -f /tmp/command-runner.result')
     unit.ssh('sudo rm -f /tmp/command-runner.log')
-    runner_template = '\n'.join([
-        '#!/bin/bash',
-        '{} > /tmp/command-runner.log 2>&1',
-        'echo $? > /tmp/command-runner.result',
-    ])
+    runner_template = '\n'.join(
+        [
+            '#!/bin/bash',
+            '{} > /tmp/command-runner.log 2>&1',
+            'echo $? > /tmp/command-runner.result',
+        ]
+    )
     runner_script_path = '/tmp/command-runner.sh'
     runner_script = runner_template.format(command)
     send_script(unit, runner_script_path, runner_script)
@@ -77,43 +79,42 @@
     try:
         return (int(result), output)
     except ValueError:
-        msg = ('Command execution failed on {}:\n'
-               '\texit code: {}\n\toutput: {}'.format(
-                   unit_name(unit), result, output))
+        msg = 'Command execution failed on {}:\n' '\texit code: {}\n\toutput: {}'.format(
+            unit_name(unit), result, output
+        )
         amulet.raise_status(amulet.FAIL, msg=msg)
 
 
 def disable_cron(unit):
-    '''
+    """
     Disables the cron service on the given unit.
-    '''
+    """
     command = 'sudo systemctl stop cron.service'
     (result, output) = execute(unit, command)
     if result:
-        msg = ('Failed to disable cron on {}:\n'
-               '\texit code: {}\noutput: {}'.format(
-                   unit_name(unit), result, output))
+        msg = 'Failed to disable cron on {}:\n' '\texit code: {}\noutput: {}'.format(unit_name(unit), result, output)
         amulet.raise_status(amulet.FAIL, msg=msg)
 
 
 def rotate_cron_sync_log(unit):
-    '''
+    """
     Rotates the LOG_FILE via logrotate.
 
     The end result is an empty LOG_FILE.
-    '''
+    """
     command = 'sudo logrotate -f /etc/logrotate.d/apache2'
     (result, output) = execute(unit, command)
     if result:
         # logrotate can return non-zero even if the log file we care
         # about was rotated
-        log('INFO: Rotating logs on {} return non-zero result (may be ok):\n'
-            '\texit code: {}\noutput: {}'.format(
-                unit_name(unit), result, output))
+        log(
+            'INFO: Rotating logs on {} return non-zero result (may be ok):\n'
+            '\texit code: {}\noutput: {}'.format(unit_name(unit), result, output)
+        )
 
 
 def attempt_rsync(unit):
-    '''
+    """
     Performs an archive sync as specified by the cron file.
 
     This extracts the user, environment variables and command from the unit's
@@ -121,7 +122,7 @@
 
     It would be preferred to let the cron run, but this allows for easier
     extraction of any errors.
-    '''
+    """
     contents = unit.file_contents(CRON_FILE)
     lines = contents.splitlines()
 
@@ -136,33 +137,32 @@
     command = 'sudo -Hu {} {} {}'.format(cron_user, env_vars, cron_command)
     (result, output) = execute(unit, command)
     if result:
-        msg = ('Failed to execute repository sync command on {}\n'
-               '\tresult: {}\n\toutput: {}'.format(
-                   unit_name(unit), result, output))
+        msg = 'Failed to execute repository sync command on {}\n' '\tresult: {}\n\toutput: {}'.format(
+            unit_name(unit), result, output
+        )
         amulet.raise_status(amulet.FAIL, msg=msg)
 
 
 def check_message_count(contents, message, count):
-    '''
+    """
     Check for the requested message in the content.
-    '''
+    """
     found = len([line for line in contents.splitlines() if message in line])
     if count == found:
         log('PASS: "{}" found {} times'.format(message, count))
     else:
-        msg = 'FAIL: "{}" found {} times, expected {}'.format(
-            message, found, count)
+        msg = 'FAIL: "{}" found {} times, expected {}'.format(message, found, count)
         amulet.raise_status(amulet.FAIL, msg=msg)
 
 
 def test_url(url, waitsec=30):
-    '''Request a url and return the contents.
+    """Request a url and return the contents.
 
     Return:
         response on success,
         None on timeout,
         Raise exception for all other failures
-    '''
+    """
 
     try:
         page = requests.get(url, timeout=waitsec)
@@ -174,9 +174,9 @@
 
 
 def check_metadata_is_active(unit):
-    '''
+    """
     Checks that the synced metadata is available over http.
-    '''
+    """
     page = test_url('http://{}/ubuntu'.format(unit.info['public-address']))
     if page is None:
         log('FAIL: Timeout checking metadata on {}'.format(unit_name(unit)))
@@ -186,11 +186,10 @@
 
 
 def check_pool_data_is_active(unit):
-    '''
+    """
     Checks that the squid cached pool data is available over http.
-    '''
-    page = test_url('http://{}/ubuntu/pool'.format(
-        unit.info['public-address']))
+    """
+    page = test_url('http://{}/ubuntu/pool'.format(unit.info['public-address']))
     if page is None:
         log('FAIL: Timeout checking pool data on {}'.format(unit_name(unit)))
         return