charm-rabbitmq-server/hooks/rabbitmq-relations

#!/bin/bash
#
#    rabbitmq-relations - relations to be used by formula, referenced
#                         via symlink
#
#    Copyright (C) 2011  Canonical Ltd.
#    Author: Adam Gandelman <adam.gandelman@canonical.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

set -e

CHARM_DIR=$(dirname $0)
ARG0=${0##*/}

if [[ -e $CHARM_DIR/rabbitmq-common ]] ; then
  . $CHARM_DIR/rabbitmq-common
else
  juju-log "rabbitmq-server: ERROR Could not load $CHARM_DIR/rabbitmq-common"
  exit 1
fi

juju-log "rabbitmq-server: Firing hook $ARG0."

function install_hook() {
  [[ ! `which pwgen` ]] && apt-get -y install pwgen
  DEBIAN_FRONTEND=noninteractive apt-get -qqy \
    install --no-install-recommends rabbitmq-server
  rc=$?
  service rabbitmq-server stop
  open-port 5672/tcp
}

function amqp_changed() {
  # Connecting clients should request a username and vhost.
  # In reponse, we generate a password for new users,
  # grant the user access on the default vhost "/",
  # and tell it where to reach us.

  # Skip managing rabbit queue config unless we are the
  # lowest numbered unit in the service cluster.
  local local_unit_id=$(echo $JUJU_UNIT_NAME | cut -d/ -f2)
  local remote_unit_id=""
  for relid in $(relation-ids cluster) ; do
    for unit in $(relation-list -r "$relid") ; do
      remote_unit_id="$(echo $unit | cut -d/ -f2)"
      if [[ "$local_unit_id" -gt "$remote_unit_id" ]]; then
        juju-log "amqp_changed(): Deferring amqp_changed to leader."
        exit 0
      fi
    done
  done

  local rabbit_user=`relation-get username`
  local vhost=`relation-get vhost`
  if [[ -z "$rabbit_user" ]] || [[ -z "$vhost" ]] ; then
    juju-log "rabbitmq-server: rabbit_user||vhost not yet received from peer."
    exit 0
  fi
  local passwd_file="/var/lib/juju/$rabbit_user.passwd"
  local password=""
  if [[ -e $passwd_file ]] ; then
    password=$(cat $passwd_file)
  else
    password=$(pwgen 10 1)
    echo $password >$passwd_file
    chmod 0400 $passwd_file
  fi
  if ! vhost_exists "$vhost" ; then
    juju-log "rabbitmq-server: Creating vhost $vhost"
    create_vhost "$vhost"
  fi
  if ! user_exists "$rabbit_user" ; then
    juju-log "rabbitmq-server: Creating user $rabbit_user"
    user_create "$rabbit_user" "$password" "$vhost" admin || exit 1
  else
    juju-log "rabbitmq-server: user $rabbit_user already exists."
  fi
  local remote_host="$(relation-get private-address)"
  juju-log "rabbitmq-server: Returning credentials for $rabbit_user@$remote_host"
  relation-set password="$password"

  if is_clustered ; then
    relation-set clustered="true" vip="$(config-get vip)"
  fi
}

function cluster_joined {
  local remote_unit_id=$(echo $JUJU_REMOTE_UNIT | cut -d/ -f2)
  local local_unit_id=$(echo $JUJU_UNIT_NAME | cut -d/ -f2)
  [[ $local_unit_id -gt $remote_unit_id ]] && echo "Relation greater" && exit 0
  if [[ ! -e $ERLANG_COOKIE ]] ; then
    juju-log "rabbitmq-server: ERROR Could not find cookie at $ERLANG_COOKIE"
    exit 1
  fi
  relation-set cookie="$(cat $ERLANG_COOKIE)" host="$(hostname)"
}

function cluster_changed {
  local remote_unit_id=$(echo $JUJU_REMOTE_UNIT | cut -d/ -f2)
  local local_unit_id=$(echo $JUJU_UNIT_NAME | cut -d/ -f2)

  [[ $local_unit_id -lt $remote_unit_id ]] && echo "Relation lesser" && exit 0

  local remote_host=$(relation-get host)
  local cookie_value=$(relation-get cookie)

  [[ -z "$remote_host" ]] || [[ -z "$cookie_value" ]] && \
    juju-log "rabbimtq-server: remote_host||cookie_value not yet set." &&
    exit 0

  # Sync the erlang cookie to that of remote host.
  service rabbitmq-server stop
  echo -n "$cookie_value" > $ERLANG_COOKIE
  service rabbitmq-server start

  # Configure clustering.
  # rabbitmq apparently does not like FQDNs.
  local short_host=$(echo $remote_host | sed -e 's/\./ /g' | awk '{ print $1 }')
  local cur_vers=$(rabbit_version)
  local cluster_cmd="cluster"
  if dpkg --compare-versions "$cur_vers" ge "3.0.1-1" ; then
    cluster_cmd="join_cluster"
  fi
  if ! rabbitmqctl cluster_status | grep -q "rabbit@$short_host" ; then
    juju-log "Clustering with new rabbitmq peer @ $short_host."
    rabbitmqctl stop_app
    rabbitmqctl $cluster_cmd rabbit@$short_host
    rabbitmqctl start_app
  else
    juju-log "Already clustered with rabbitmq peer @ $short_host."
  fi
}

function ha_joined() {
  local corosync_bindiface=`config-get ha-bindiface`
  local corosync_mcastport=`config-get ha-mcastport`
  local vip=`config-get vip`
  local vip_iface=`config-get vip_iface`
  local vip_cidr=`config-get vip_cidr`
  if [ -n "$vip" ] && [ -n "$vip_iface" ] && \
     [ -n "$vip_cidr" ] && [ -n "$corosync_bindiface" ] && \
     [ -n "$corosync_mcastport" ]; then
    # TODO: This feels horrible but the data required by the hacluster
    # charm is quite complex and is python ast parsed.
    resources="{
'res_rabbitmq_vip':'ocf:heartbeat:IPaddr2'
}"
    resource_params="{
'res_rabbitmq_vip': 'params ip=\"$vip\" cidr_netmask=\"$vip_cidr\" nic=\"$vip_iface\"'
}"
    relation-set corosync_bindiface=$corosync_bindiface \
      corosync_mcastport=$corosync_mcastport \
      resources="$resources" resource_params="$resource_params"
  else
    juju-log "Insufficient configuration data to configure hacluster"
    exit 1
  fi
}

function ha_changed() {
  # we may now be clustered, advertise our vip to clients if so.
  if is_clustered ; then
    local vip="$(config-get vip)"
    juju-log "$CHARM - ha_changed(): We are now HA clustered. "\
             "Advertising our VIP ($vip) to all AMQP clients."
    for rid in $(relation-ids amqp) ; do
        relation-set -r $rid clustered="true" vip="$vip"
    done
  fi
}

case $ARG0 in
  "install") install_hook ;;
  "start") service rabbitmq-server status || service rabbitmq-server start ;;
  "stop") service rabbitmq-server status && service rabbitmq-server stop ;;
  "amqp-relation-joined") exit 0 ;;
  "amqp-relation-changed") amqp_changed ;;
  "cluster-relation-joined") cluster_joined ;;
  "cluster-relation-changed") cluster_changed ;;
  "ha-relation-joined") ha_joined ;;
  "ha-relation-changed") ha_changed ;;
esac

rc=$?
juju-log "rabbitmq-server: Hook $ARG0 complete. Exiting $rc"
exit $rc