Merge lp:~abentley/charms/precise/charmworld/multi-mongo into lp:~juju-jitsu/charms/precise/charmworld/trunk

[Aaron Bentley]

Allow multiple mongodb instances

Change functionality of write_config so that it directly interrogates the
environment to determine the juju hosts, instead of accepting commandline
parameters or reading previous config. Use mongo.url setting instead of
host/port, and stop setting session.secret (it's now unused). write_config
moves into scripts/ partly for cleanliness and partly to access charmsupport.

With this change to write_config, config-changed now handles db relation
changes as well as setting changes, so invoke it in every db relation hook
(except join, since -changed will follow join). database-relation-changed is
now essentially a wrapper to ensure that ingest is run when a database becomes
available.

Flatten the refresh function back into the body of config-changed, since it
would be invoked unconditionally.

Delete ~webops_deploy/charmworld on install if present, since it may
contain incorrect or invalid config data.

https://codereview.appspot.com/7314102/

[j.c.sackett (jcsackett)]

On 2013/02/14 20:27:24, abentley wrote:
> Please take a look.

lgtm.

https://codereview.appspot.com/7314102/

=== modified file 'common'
--- common	2013-02-07 21:09:02 +0000
+++ common	2013-02-14 20:27:37 +0000
@@ -4,6 +4,11 @@
 project_dir="$webops_home/charmworld"
 CONFIG_FILE="$project_dir/production.ini"
 configure(){
-  ./write_config.py $project_dir/default.ini production_overrides.ini\
-      $CONFIG_FILE "$@"
+  scripts/write_config.py $project_dir/default.ini production_overrides.ini\
+      $CONFIG_FILE
+}
+maybe_rmtree(){
+  if [ -d $1 ]; then
+      rm $1 -R
+  fi
 }

=== modified file 'hooks/config-changed'
--- hooks/config-changed	2013-02-12 18:49:31 +0000
+++ hooks/config-changed	2013-02-14 20:27:37 +0000
@@ -12,6 +12,8 @@
 fi
 
 
+hooks/stop || true
+
 if [ -z "$source_url" ]; then
     exit 0
 fi
@@ -35,28 +37,27 @@
     cd $charm_dir
 }
 
-
-refresh(){
-    configure
-    chown webops_deploy.webops_deploy $project_dir -R
-    if grep -E 'mongo.host = .+' $CONFIG_FILE; then
-        cd $project_dir
-        INI=$CONFIG_FILE bin/migrations upgrade
-        cd $charm_dir
-        hooks/start
-    fi
-}
-
-
 juju-log "Disable ingest..."
 rm -f /etc/cron.d/charmworld
-hooks/stop || true
 if [ "$source_url" != "$current_source_url" ]; then
     update_source
 elif [ "$revno" -ge 0 -a $revno != $(bzr revno $project_dir) ]; then
     update_source
 fi
-refresh
+configure
+chown webops_deploy.webops_deploy $project_dir -R
+
+# nagios_context may have changed.
+scripts/update-nrpe.py
+if grep -E 'mongo.url = .+' $CONFIG_FILE; then
+    cd $project_dir
+    su charmworld -c "INI=$CONFIG_FILE bin/migrations upgrade --init"
+    cd $charm_dir
+    hooks/start
+else
+    # avoid setting up ingest if no db available.
+    exit 0
+fi
 
 interval=`config-get execute-ingest-every`
 : ${interval:-0}
@@ -89,5 +90,4 @@
 EOF
 
 fi
-# nagios_context may have changed.
-scripts/update-nrpe.py
+

=== modified file 'hooks/database-relation-broken'
--- hooks/database-relation-broken	2013-01-29 15:32:47 +0000
+++ hooks/database-relation-broken	1970-01-01 00:00:00 +0000
@@ -1,7 +0,0 @@
-#!/bin/bash
-set -eux
-
-hooks/stop || true
-source common
-
-configure '' ''

=== target is u'config-changed'
=== modified file 'hooks/database-relation-changed'
--- hooks/database-relation-changed	2013-02-07 21:09:02 +0000
+++ hooks/database-relation-changed	2013-02-14 20:27:37 +0000
@@ -3,31 +3,26 @@
 source common
 set -x
 
-DB_HOST=`relation-get private-address`
 HOME=$webops_home
 
-if [ -z "$DB_HOST" ]; then
-    juju-log "Waiting for handshake from mongodb"
+set +e
+grep -E 'mongo.url = .+' $CONFIG_FILE
+had_url=$?
+set -e
+
+hooks/config-changed
+
+if ! grep -E 'mongo.url = [^ ]+' $CONFIG_FILE; then
     exit 0
 fi
 
-if [ ! -f "$CONFIG_FILE" ]; then
-    hooks/config-changed
+if [ $had_url != 0 ]; then
+    juju-log "Hey, we're ingesting over here. This WILL take a while."
+    # Perform an initial ingest
+    su charmworld -c "INI=$CONFIG_FILE HOME=$charmworld_home \
+      LOGDIR=$log_dir PYTHON_BIN=$project_dir/bin/python \
+      $project_dir/scripts/ingest"
 fi
-
-relation_port=`relation-get port`
-DB_PORT=${relation_port:-27017}
-
-configure $DB_HOST $DB_PORT
-
-su charmworld -c "export INI=$CONFIG_FILE; $project_dir/bin/migrations upgrade --init"
-
-juju-log "Hey, we're ingesting over here. This WILL take a while."
-# Perform an initial ingest
-su charmworld -c "INI=$CONFIG_FILE HOME=$charmworld_home \
-  LOGDIR=$log_dir PYTHON_BIN=$project_dir/bin/python \
-  $project_dir/scripts/ingest"
-
 open-port 80
 
 source hooks/restart

=== added symlink 'hooks/database-relation-departed'
=== target is u'config-changed'
=== modified file 'hooks/install'
--- hooks/install	2013-02-07 21:09:02 +0000
+++ hooks/install	2013-02-14 20:27:37 +0000
@@ -34,3 +34,4 @@
 install -o charmworld -g charmworld -m 0755 -d $charmworld_home/var/charms
 $INSTALL scripts/run-write-errors $webops_home
 python scripts/gen_deploymgr.py
+maybe_rmtree $project_dir

=== modified file 'hooks/upgrade-charm'
--- hooks/upgrade-charm	2013-02-07 21:09:02 +0000
+++ hooks/upgrade-charm	2013-02-14 20:27:37 +0000
@@ -1,15 +1,12 @@
 #!/bin/bash
-set -eux
+set -eu
+source common
+set -x
 
 hooks/stop || true
 hooks/install
-maybe_rm(){
-  if [ -d $1 ]; then
-      rm $1 -R
-  fi
-}
-maybe_rm ~ubuntu/charmworld
-maybe_rm ~ubuntu/var
+maybe_rmtree ~ubuntu/charmworld
+maybe_rmtree ~ubuntu/var
 hooks/config-changed
 hooks/restart
 maybe_rm ~ubuntu/shhh.py

=== modified file 'production_overrides.ini'
--- production_overrides.ini	2013-02-12 18:30:49 +0000
+++ production_overrides.ini	2013-02-14 20:27:37 +0000
@@ -5,7 +5,6 @@
 mongo.host =
 mongo.port =
 mongo.url =
-session.secret =
 
 [server:main]
 port = 6543

=== modified file 'revision'
--- revision	2013-02-13 19:45:57 +0000
+++ revision	2013-02-14 20:27:37 +0000
@@ -1,1 +1,1 @@
-24
+25

=== renamed file 'write_config.py' => 'scripts/write_config.py'
--- write_config.py	2013-01-29 15:45:19 +0000
+++ scripts/write_config.py	2013-02-14 20:27:37 +0000
@@ -1,16 +1,12 @@
 #!/usr/bin/env python
 
-from ConfigParser import ConfigParser, NoSectionError
-from random import getrandbits
+from ConfigParser import ConfigParser
+import json
+import subprocess
 import sys
 
-
-def update_config(parser, items):
-    configurable = set(['session.secret', 'mongo.host', 'mongo.port'])
-    for key, value in items:
-        if key not in configurable:
-            continue
-        parser.set('app:main', key, value)
+from charmsupport.hookenv import related_units
+from charmsupport.hookenv import relation_ids
 
 
 def read_config(files):
@@ -19,33 +15,56 @@
     return new_config
 
 
-def write_new_config(changes, default, override, target):
+def write_new_config(mongo_url, default, override, target):
     new_config = read_config([default, override])
-    old_config = read_config(target)
-    try:
-        update_config(new_config, old_config.items('app:main', raw=True))
-    except NoSectionError:
-        pass
-    update_config(new_config, changes)
-    if new_config.get('app:main', 'session.secret') == '':
-        new_config.set('app:main', 'session.secret', str(getrandbits(32)))
+    new_config.set('app:main', 'mongo.url', mongo_url)
     with open(target, 'w') as output:
         new_config.write(output)
 
 
+def get_relation_id_data(relation_id, unit):
+    """Return a dictionary containing relation settings.
+
+    :param relation_id: The relation id specifying the relation.
+    :param unit: The name of the unit participating in the relation.
+    """
+    cmd = ['relation-get', '--format=json', '-r', relation_id, '-', unit]
+    return json.loads(subprocess.check_output(cmd))
+
+
+def get_mongo_url():
+    """Use the 'database' relation settings to build a mongodb url.
+
+    If mongodb units are present, return an empty string.
+    """
+    host_ports = []
+    replset = None
+    for relation_id in relation_ids('database'):
+        for unit in related_units(relation_id):
+            relation_data = get_relation_id_data(relation_id, unit)
+            # Consider configuration incomplete until port is supplied.
+            if relation_data is None or 'port' not in relation_data:
+                continue
+            if replset is None:
+                replset = relation_data['replset']
+            # All units should be members of the same replication set.
+            elif replset != relation_data['replset']:
+                raise AssertionError('DB instances are from different sets!')
+            host_ports.append(
+                '%(private-address)s:%(port)s' % relation_data)
+    if len(host_ports) == 0:
+        return ''
+    return 'mongodb://%s/?replicaSet=%s' % (','.join(host_ports), replset)
+
+
 class UsageError(Exception):
     """An error triggered by incorrect usage"""
 
 
 def main():
     if len(sys.argv) < 4:
-        raise UsageError('Usage: %s DEFAULTS OVERRIDES TARGET [HOST [PORT]]')
-    changes = {}
-    if len(sys.argv) > 4:
-        changes['mongo.host'] = sys.argv[4]
-    if len(sys.argv) > 5:
-        changes['mongo.port'] = sys.argv[5]
-    parser = write_new_config(changes.items(), default=sys.argv[1],
+        raise UsageError('Usage: %s DEFAULTS OVERRIDES TARGET')
+    parser = write_new_config(get_mongo_url(), default=sys.argv[1],
                               override=sys.argv[2], target=sys.argv[3])