puppet: Add script for doing Postgres base backups and purging old backups

(imported from commit 93a92729b2e964e054aa1af7bcb8a0bae3fd1b33)

servers/puppet/modules/humbug/files/postgresql/pg_backup_and_purge.py

@@ -0,0 +1,45 @@
+#!/usr/bin/python
+
+import subprocess
+import sys
+import logging
+import dateutil.parser
+import pytz
+from datetime import datetime, timedelta
+
+logger = logging.getLogger(__name__)
+
+def run(args, dry_run=False):
+    if dry_run:
+        print "Would have run: " + " ".join(args)
+        return ""
+
+    p = subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
+                         stderr=subprocess.PIPE)
+    stdout, stderr = p.communicate()
+    if p.returncode:
+        logger.error("Could not invoke %s\nstdout: %s\nstderror: %s"
+                     % (args[0], stdout, stderr))
+        sys.exit(1)
+    return stdout
+
+# Only run if we're the master
+if run(['psql', '-t', '-c', 'select pg_is_in_recovery()']).strip() != 'f':
+    sys.exit(0)
+
+run(['env-wal-e', 'backup-push', '/var/lib/postgresql/9.1/main'])
+
+backups = {}
+lines = run(['env-wal-e', 'backup-list']).split("\n")
+for line in lines[1:]:
+    if line:
+        backup_name, date, _, _ = line.split()
+        backups[dateutil.parser.parse(date)] = backup_name
+
+one_month_ago = datetime.now(tz=pytz.utc) - timedelta(days=30)
+for date in sorted(backups.keys(), reverse=True):
+    if date < one_month_ago:
+        run(['env-wal-e', 'delete', '--confirm', 'before', backups[date]])
+        # Because we're going from most recent to least recent, we
+        # only have to do one delete operation
+        break

servers/puppet/modules/humbug/manifests/postgres-common.pp

@@ -3,7 +3,7 @@ class humbug::postgres-common {
 
   $postgres_packages = [ "postgresql-9.1", "pgtune", "python-boto",
                          "python-argparse", "python-gevent",
-                         "lzop", "pv", "hunspell-en-us"]
+                         "lzop", "pv", "hunspell-en-us", "python-dateutil"]
   package { $postgres_packages: ensure => "installed" }
 
   exec {"pip_wal-e":
@@ -21,6 +21,15 @@ class humbug::postgres-common {
     source => "puppet:///modules/humbug/postgresql/env-wal-e",
   }
 
+  file { "/usr/local/bin/pg_backup_and_purge.py":
+    ensure => file,
+    owner => "root",
+    group => "postgres",
+    mode => 754,
+    source => "puppet:///modules/humbug/postgresql/pg_backup_and_purge.py",
+    require => File["/usr/local/bin/env-wal-e"],
+  }
+
   file { "/etc/postgresql/9.1/main/pg_hba.conf":
     require => Package["postgresql-9.1"],
     ensure => file,