Merge lp:~canonical-is-sa/charms/trusty/elasticsearch/trunk into lp:charms/trusty/elasticsearch

[Michael Foley]

Add data relations for using block-storage-broker.

[Michael Nelson (michael.nelson)]

Thanks Michael. Sorry for the delay, I've just ran the existing tests with this branch to ensure everything works as normal without block storage, and will be testing the blockstorage with a deployment.

review: Approve

=== added symlink 'hooks/data-relation-changed'
=== target is u'hooks.py'
=== added symlink 'hooks/data-relation-departed'
=== target is u'hooks.py'
=== added symlink 'hooks/data-relation-joined'
=== target is u'hooks.py'
=== modified file 'hooks/hooks.py'
--- hooks/hooks.py	2014-07-08 13:38:52 +0000
+++ hooks/hooks.py	2015-05-25 04:21:12 +0000
@@ -5,13 +5,21 @@
 import charmhelpers.contrib.ansible
 import charmhelpers.payload.execd
 import charmhelpers.core.host
+from charmhelpers.core import hookenv
+import os
+import shutil
 
+mountpoint = '/srv/elasticsearch'
 
 hooks = charmhelpers.contrib.ansible.AnsibleHooks(
     playbook_path='playbook.yaml',
     default_hooks=[
         'config-changed',
         'cluster-relation-joined',
+        'data-relation-joined',
+        'data-relation-changed',
+        'data-relation-departed',
+        'data-relation-broken',
         'peer-relation-joined',
         'peer-relation-departed',
         'nrpe-external-master-relation-changed',
@@ -39,5 +47,52 @@
         '/usr/share/ansible')
 
 
[e-mail]('data-relation-joined', 'data-relation-changed')
+def data_relation():
+    if hookenv.relation_get('mountpoint') == mountpoint:
+        # Other side of relation is ready
+        migrate_to_mount(mountpoint)
+    else:
+        # Other side not ready yet, provide mountpoint
+        hookenv.log('Requesting storage for {}'.format(mountpoint))
+        hookenv.relation_set(mountpoint=mountpoint)
+
+
[e-mail]('data-relation-departed', 'data-relation-broken')
+def data_relation_gone():
+    hookenv.log('Data relation no longer present, stopping elasticsearch.')
+    charmhelpers.core.host.service_stop('elasticsearch')
+
+
+def migrate_to_mount(new_path):
+    """Invoked when new mountpoint appears. This function safely migrates
+    elasticsearch data from local disk to persistent storage (only if needed)
+    """
+    old_path = '/var/lib/elasticsearch'
+    if os.path.islink(old_path):
+        hookenv.log('{} is already a symlink, skipping migration'.format(
+            old_path))
+        return True
+    # Ensure our new mountpoint is empty. Otherwise error and allow
+    # users to investigate and migrate manually
+    files = os.listdir(new_path)
+    try:
+        files.remove('lost+found')
+    except ValueError:
+        pass
+    if files:
+        raise RuntimeError('Persistent storage contains old data. '
+                           'Please investigate and migrate data manually '
+                           'to: {}'.format(new_path))
+    os.chmod(new_path, 0700)
+    charmhelpers.core.host.service_stop('elasticsearch')
+    charmhelpers.core.host.rsync(os.path.join(old_path, ''),  # Ensure we have trailing slashes
+        os.path.join(new_path, ''),
+        options=['--archive'])
+    shutil.rmtree(old_path)
+    os.symlink(new_path, old_path)
+    charmhelpers.core.host.service_start('elasticsearch')
+
+
 if __name__ == "__main__":
     hooks.execute(sys.argv)
 
=== modified file 'metadata.yaml'
--- metadata.yaml	2014-09-11 18:34:45 +0000
+++ metadata.yaml	2015-05-25 04:21:12 +0000
@@ -16,3 +16,6 @@
   nrpe-external-master:
      interface: nrpe-external-master
      scope: container
+  data:
+    interface: block-storage
+    scope: container
 
=== modified file 'playbook.yaml'
--- playbook.yaml	2014-10-31 03:43:31 +0000
+++ playbook.yaml	2015-05-25 04:21:12 +0000
@@ -60,3 +60,13 @@
         cluster-name={{ cluster_name }}
         host={{ ansible_default_ipv4.address }}
         port=9200
+
+    # A bug in the ansible hooks() helper requires at least
+    # one task to be tagged.
+    - name: Empty task to keep ansible helper satisfied.
+      debug: msg="Noop ansible task."
+      tags:
+        - data-relation-joined
+        - data-relation-changed
+        - data-relation-departed
+        - data-relation-broken
 
=== modified file 'roles/nrpe/tasks/main.yml'
--- roles/nrpe/tasks/main.yml	2014-04-08 13:25:50 +0000
+++ roles/nrpe/tasks/main.yml	2015-05-25 04:21:12 +0000
@@ -7,6 +7,7 @@
     owner: nagios
     group: nagios
     mode: 0644
+  when: "'nagios_hostname' in current_relation"
 
 - name: Write nagios check service definition for export.
   tags:
@@ -17,9 +18,11 @@
     owner: nagios
     group: nagios
     mode: 0644
+  when: "'nagios_hostname' in current_relation"
 
 - name: Trigger nrpe-external-master-relation-changed to restart.
   tags:
     - nrpe-external-master-relation-changed
   command: >
     relation-set timestamp={{ ansible_date_time.iso8601_micro }}
+  when: "'nagios_hostname' in current_relation"