Merge lp:~kim0/pyjuju/fix-mysql-example-formula-publish-details-precreated-databases into lp:pyjuju

[Ahmed Kamal]

Fixing for formula for saving service DB passwords, and publishing them to new service units

[Gustavo Niemeyer (niemeyer)]

This looks like a good interim solution, thanks!

The proper way is actually to use a database named after the relation id,
and then create a new database on every new relation id we get. The
problem is that we currently don't offer such a relation id for the hooks,
so this will do for now.

review: Approve

=== modified file 'examples/mysql/hooks/db-relation-joined'
--- examples/mysql/hooks/db-relation-joined	2011-05-03 08:54:13 +0000
+++ examples/mysql/hooks/db-relation-joined	2011-06-03 20:01:15 +0000
@@ -2,6 +2,11 @@
 
 set -eu # -x for verbose logging to ensemble debug-log
 
+# XXX The local hostname should be provided by Ensemble itself in a
+# future release, so as to remove the dependency of the formula on the
+# cloud provider (EC2 in this case)
+hostname=`curl http://169.254.169.254/latest/meta-data/local-hostname`
+
 # Get the mysql password that was generated by the install hook
 password=`cat /var/lib/ensemble/mysql.passwd`
 
@@ -13,18 +18,19 @@
 existing_databases=`mysql --password="$password" --silent --execute 'show databases'`
 for db in $existing_databases; do
     if [ "$db" = "$service" ] ; then
-        ensemble-log "Database already exists, exiting"
+        ensemble-log "Database already exists, publishing details and exiting"
+        service_password=`cat /var/lib/ensemble/$service.passwd`
+        # Save these settings on the relation; this will trigger the remote
+        # service unit
+        relation-set database="$service" user="$service" password="$service_password" host="$hostname"
         exit 0 # database already exists
     fi
 done
 
 # Generate a strong password for the database, using /dev/urandom
 service_password=`pwgen 10 1`
-
-# XXX The local hostname should be provided by Ensemble itself in a
-# future release, so as to remove the dependency of the formula on the
-# cloud provider (EC2 in this case)
-hostname=`curl http://169.254.169.254/latest/meta-data/local-hostname`
+# Store service password, new service units of same service would need it
+echo $service_password >> /var/lib/ensemble/$service.passwd
 
 # Create new database and corresponding security settings
 ensemble-log "Creating new database and corresponding security settings"