Add backup action

Add a new action to backup the pxc database on a unit.

Backups by default are stored in /opt/backups/mysql and can
optionally be compressed and done as incremental backups.

Change-Id: I5c6ab9fd8be7cb6cdb2a26e849ec0b22d8d4f9a6

actions.yaml

@@ -1,4 +1,20 @@
 pause:
   description: Pause the MySQL service.
 resume:
-  description: Resume the MySQL service.
+  description: Resume the MySQL service.
+backup:
+  description: Full database backup
+  params:
+    basedir:
+      type: string
+      default: "/opt/backups/mysql"
+      description: The base directory for backups
+    compress:
+      type: boolean
+      default: false
+      description: Whether or not to compress the backup
+    incremental:
+      type: boolean
+      default: false
+      description: Make an incremental database backup
+

actions/actions.py

@@ -2,11 +2,20 @@
 
 import os
 import sys
+import subprocess
+import traceback
+from time import gmtime, strftime
 
 from charmhelpers.core.host import service_pause, service_resume
-from charmhelpers.core.hookenv import action_fail, status_set
-from percona_utils import assess_status
+from charmhelpers.core.hookenv import (
+    action_get,
+    action_set,
+    action_fail,
+    status_set,
+    config,
+)
 
+from percona_utils import assess_status
 
 MYSQL_SERVICE = "mysql"
 
@@ -32,9 +41,45 @@ def resume(args):
     assess_status()
 
 
+def backup():
+    basedir = (action_get("basedir")).lower()
+    compress = (action_get("compress"))
+    incremental = (action_get("incremental"))
+    sstpw = config("sst-password")
+    optionlist = []
+
+    # innobackupex will not create recursive dirs that do not already exist,
+    # so help it along
+    if not os.path.exists(basedir):
+        os.makedirs(basedir)
+
+    # Build a list of options to pass to innobackupex
+    if compress is "true":
+        optionlist.append("--compress")
+
+    if incremental is "true":
+        optionlist.append("--incremental")
+
+    try:
+        subprocess.check_call(
+            ['innobackupex', '--compact', '--galera-info', '--rsync',
+             basedir, '--user=sstuser', '--password=' + sstpw] + optionlist)
+        action_set({
+            'time-completed': (strftime("%Y-%m-%d %H:%M:%S", gmtime())),
+            'outcome': 'Success'}
+        )
+    except subprocess.CalledProcessError as e:
+        action_set({
+            'time-completed': (strftime("%Y-%m-%d %H:%M:%S", gmtime())),
+            'output': e.output,
+            'return-code': e.returncode,
+            'traceback': traceback.format_exc()})
+        action_fail("innobackupex failed, you should log on to the unit"
+                    "and check the status of the database")
+
 # A dictionary of all the defined actions to callables (which take
 # parsed arguments).
-ACTIONS = {"pause": pause, "resume": resume}
+ACTIONS = {"pause": pause, "resume": resume, "backup": backup}
 
 
 def main(args):