Merge ~nick-moffitt/ubuntu-mirror-charm:xinetd into ubuntu-mirror-charm:master

[Nick Moffitt]

Allow rsync on xinetd instead of systemd RT#128036

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

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

[Nick Moffitt (nick-moffitt)]

Most of this comes from https://git.launchpad.net/ubuntu-mirror-charm/commit/?id=32ee49e93ef57fb0af74b6020eb7f12fc7903889 but I have added a flag to let you switch to xinetd on post-15.04 systems.

[David Lawson (deej)]

LGTM

review: Approve

[Tom Haddon (mthaddon)]

We've discussed some re-ordering and adding unit test coverage for this change, so I'll take another look once you've had a chance to address those.

[Tom Haddon (mthaddon)]

LGTM, thx

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 80397809817f1fb5844c463e72e504f03e520274

diff --git a/config.yaml b/config.yaml
index dccc75f..f2b4616 100644
--- a/config.yaml
+++ b/config.yaml
@@ -668,6 +668,10 @@ options:
     default: "/var/log/rsyncd"
     type: string
     description: "Rsync log directory"
+  rsync_use_xinetd:
+    default: false
+    type: boolean
+    description: "Whether to launch rsyncd from xinetd (if true) or systemd (if false)."
   apache_logdir:
     default: "/var/log/apache2"
     type: string
diff --git a/hooks/Config.py b/hooks/Config.py
index 95c1ff2..03f840a 100755
--- a/hooks/Config.py
+++ b/hooks/Config.py
@@ -281,6 +281,9 @@ class Config:
     def rsyncd_dir(self):
         return "/etc/rsync-juju.d"
 
+    def rsync_use_xinetd(self):
+        return config("rsync_use_xinetd")
+
     def script_dir(self):
         return str(config("script_dir"))
 
diff --git a/hooks/hooks.py b/hooks/hooks.py
index 5bf370c..f5f9339 100755
--- a/hooks/hooks.py
+++ b/hooks/hooks.py
@@ -422,11 +422,7 @@ def configure_rsync_server(conf, hostname):
 
     # Write the motd file
     mkdir(os.path.dirname(motdfile))
-    if os.path.isfile(motdfile):
-        os.unlink(motdfile)
-    with open(motdfile, "w") as f:
-        f.write(conf.rsync_motd())
-    os.chmod(motdfile, 0o444)
+    write_file(motdfile, conf.rsync_motd(), perms=0o444)
 
     # Make sure the logdir exists
     mkdir(tmpl_data["logdir"])
@@ -437,9 +433,13 @@ def configure_rsync_server(conf, hostname):
     file_from_template("rsync-base-cfg.tmpl", "/etc/rsyncd.conf", tmpl_data)
     file_from_template("rsync-mirrors-cfg.tmpl", os.path.join(conf.rsyncd_dir(), "010-ubuntu-mirror.conf"), tmpl_data)
 
+    # xinetd is opt-in, now.
+    if conf.rsync_use_xinetd():
+        file_from_template("rsync-default.tmpl", "/etc/default/rsync", tmpl_data)
+        file_from_template("rsync-xinetd.tmpl", "/etc/xinetd.d/rsync", tmpl_data)
     # Need to tell systemd to enable rsync and then start it
     # but only in 15.04 or greater per https://wiki.ubuntu.com/SystemdForUpstartUsers
-    if float(platform.linux_distribution()[1]) >= 15.04:
+    elif float(platform.linux_distribution()[1]) >= 15.04:
         # We disable rsync and run rsync over systemd sockets to allow limiting
         # connections per source/IP
         check_call('systemctl disable rsync'.split())
@@ -453,6 +453,8 @@ def configure_rsync_server(conf, hostname):
         check_call('systemctl daemon-reload'.split())
         check_call('systemctl enable rsyncd.socket'.split())
         check_call('systemctl start rsyncd.socket'.split())
+    # pre-15.04 installations will need to explicitly turn on xinetd,
+    # or continue with previous upstart behaviours.
 
     log("CHARM: Finished configuring rsync server")
 
diff --git a/templates/rsync-default.tmpl b/templates/rsync-default.tmpl
new file mode 100644
index 0000000..0cf560c
--- /dev/null
+++ b/templates/rsync-default.tmpl
@@ -0,0 +1,4 @@
+RSYNC_ENABLE=xinetd
+RSYNC_CONFIG_FILE=/etc/rsyncd.conf
+RSYNC_OPTS=''
+RSYNC_NICE=''
diff --git a/templates/rsync-xinetd.tmpl b/templates/rsync-xinetd.tmpl
new file mode 100644
index 0000000..3910ca9
--- /dev/null
+++ b/templates/rsync-xinetd.tmpl
@@ -0,0 +1,12 @@
+service rsync
+{
+        socket_type     = stream
+        bind            = ::
+        wait            = no
+        user            = root
+        nice            = 5
+        server          = /usr/bin/rsync
+        server_args     = --daemon
+        instances       = ${max_connections}
+        per_source      = ${max_connections_per_source}
+}
diff --git a/tests/unit/test_charm.py b/tests/unit/test_charm.py
index 1622eb1..b92bd34 100644
--- a/tests/unit/test_charm.py
+++ b/tests/unit/test_charm.py
@@ -80,6 +80,24 @@ MERGED_TRIGGERS = {
 
 MERGEABLE_TRIGGERS_SSH_AUTHORIZED_KEYS = 'no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty,command="( /srv/ubuntu-mirror/bin/mirror-1stage.sh releases ; /srv/ubuntu-mirror/bin/mirror-1stage.sh cdimage ) &",from="91.189.90.151,91.189.89.127,10.22.96.61,10.22.96.161" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA7TIXsws/s48o4N1MA+TpaudHS8XVF79JujYQGTumroZZqbsr04lbg1FaJ9HyS9P31e8lP2bmB5rexJaMyfAxDTV+DtrHXmeLi/XcGSOXoliOa/j3eQmdZyYme9z+Tfp8s3S6nxuDP3BRKkOuIzOPgPO5fr8AH7y83v3fyHi+H0sbm6agX2b+xV9oP8+DEgSxPNfZEVTgpdJ7/ULwAl68mWQW0w6VTVx0CMYF+cvcorcZMGmy+THzk8WH2XRalA5HqeiBtS7vJ+yFHJ5WbQOEUeR6gHRcrogR4Yd10eFWUNAFyvt53zF7W91PEgnJWjcCUN/uctybAFSgDK1UB6TPkQ== cjwatson@little\n'  # noqa: E501
 
+XINETD_CONFIG = {
+    'rsync_use_xinetd': True,
+    'role_map': json.dumps({
+        'localhost': ['cdimage', 'releases'],
+    })
+}
+
+SYSTEMD_CONFIG = {
+    'rsync_use_xinetd': False,
+    'role_map': json.dumps({
+        'localhost': ['cdimage', 'releases'],
+    })
+}
+JUJU_HEADER = """#-------------------------------------------------#
+# This file is Juju managed - do not edit by hand #
+#-------------------------------------------------#
+"""
+
 
 class TestUbuntuMirrorCharm(unittest.TestCase):
     def setUp(self):
@@ -252,6 +270,96 @@ class TestUbuntuMirrorCharm(unittest.TestCase):
             perms=0o444,
         )
 
+    # Cheetah warns about using the Python version of NameMapper, so
+    # we ignore it here.  Matching more closely by the message doesn't
+    # seem to work, probably because it begins with a newline and
+    # Python's warnings matching code anchors the message regexp.
+    @pytest.mark.filterwarnings("ignore::UserWarning:Cheetah")
+    @patch('hooks.charm_dir')
+    @patch('hooks.check_call')
+    @patch('hooks.mkdir')
+    @patch('hooks.write_file')
+    @patch('hooks.os.path.isfile')
+    @patch('hooks.os.chmod')
+    @patch('shutil.copyfile')
+    @patch('platform.linux_distribution')
+    @patch('Config.config')
+    def test_configure_rsync_server(self, _config, _distro, _copyfile, _chmod,
+                                    _isfile, _write_file, _mkdir, _check_call, _charm_dir):
+        _distro.return_value = ('Ubuntu', '20.04', 'focal')
+        _mkdir.return_value = None
+        _isfile.return_value = False
+        _charm_dir.return_value = "."
+        config = CallableDict(self.default_config)
+        config.update(MERGEABLE_TRIGGERS_CONFIG)
+        config.update(SYSTEMD_CONFIG)
+        _config.side_effect = config  # i.e. we want our CallableDict to supply the charm config
+        conf = Config.Config()
+
+        hooks.configure_rsync_server(conf, 'localhost')
+
+        self.assertEqual(_write_file.call_count, 4)
+        _write_file.assert_any_call("/etc/rsyncd/motd", "This is an Ubuntu mirror - treat it kindly\n", perms=0o444)
+        _write_file.assert_any_call("/etc/systemd/system/rsyncd.socket",
+                                    JUJU_HEADER + """[Unit]
+Description=rsync daemon (socket)
+Conflicts=rsyncd.service
+
+[Socket]
+ListenStream=873
+Accept=yes
+MaxConnections=65
+MaxConnectionsPerSource=5
+KeepAlive=true
+
+[Install]
+WantedBy=sockets.target
+""", perms=0o444)
+
+        _copyfile.assert_called_with("./files/rsyncd-systemd.service", "/etc/systemd/system/rsyncd@.service")
+        _check_call.assert_called_with(['systemctl', 'start', 'rsyncd.socket'])
+
+    # Cheetah warns about using the Python version of NameMapper, so
+    # we ignore it here.  Matching more closely by the message doesn't
+    # seem to work, probably because it begins with a newline and
+    # Python's warnings matching code anchors the message regexp.
+    @pytest.mark.filterwarnings("ignore::UserWarning:Cheetah")
+    @patch('hooks.charm_dir')
+    @patch('hooks.check_call')
+    @patch('hooks.mkdir')
+    @patch('hooks.write_file')
+    @patch('hooks.os.path.isfile')
+    @patch('hooks.os.chmod')
+    @patch('Config.config')
+    def test_xinetd_rsync_server(self, _config, _chmod, _isfile, _write_file, _mkdir, _check_call, _charm_dir):
+        _mkdir.return_value = None
+        _isfile.return_value = False
+        _charm_dir.return_value = "."
+        config = CallableDict(self.default_config)
+        config.update(MERGEABLE_TRIGGERS_CONFIG)
+        config.update(XINETD_CONFIG)
+        _config.side_effect = config  # i.e. we want our CallableDict to supply the charm config
+        conf = Config.Config()
+
+        hooks.configure_rsync_server(conf, 'localhost')
+        _write_file.assert_any_call("/etc/rsyncd/motd", "This is an Ubuntu mirror - treat it kindly\n", perms=0o444)
+        self.assertEqual(_write_file.call_count, 5)  # We render the two
+        _check_call.assert_not_called()  # No systemctl commands are run
+        _write_file.assert_any_call("/etc/xinetd.d/rsync",
+                                    JUJU_HEADER + """service rsync
+{
+        socket_type     = stream
+        bind            = ::
+        wait            = no
+        user            = root
+        nice            = 5
+        server          = /usr/bin/rsync
+        server_args     = --daemon
+        instances       = 65
+        per_source      = 5
+}
+""", perms=0o444)
+
     def test_ensure_symlink(self):
         try:
             tmpdir = mkdtemp()  # Python 2 doesn't have tempfile.TemporaryDirectory