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• Shared db relation joined

#!/bin/bash
#
# Create relations between a shared database to many peers.
# Join does nothing.   Peer requests access to $DATABASE from $REMOTE_HOST.
# It's up to the hooks to ensure database exists, peer has access and
# clean up grants after a broken/departed peer (TODO)
#
# Author: Adam Gandelman <adam.gandelman@canonical.com>

set -ue

FORMULA_DIR=$(dirname $0)

if [[ -e $FORMULA_DIR/shared-db-common ]] ; then
  . $FORMULA_DIR/shared-db-common
else
  juju-log "mysql - shared-db: ERROR Could not load $FORMULA_DIR/shared-db-common"
fi

shared-db_changed() {
  juju-log "mysql - shared-db: Relation CHANGED"

  DATABASE=`relation-get database`
  DB_USER=`relation-get username`
  REMOTE_HOST=`relation-get hostname`
  PASSWD_FILE="/var/lib/juju/mysql-$DB_USER.passwd"

  # peer not ready, exit 0 and wait.
  [[ -z $DATABASE ]] || [[ -z $REMOTE_HOST ]] || [[ -z $DB_USER ]] \
    && echo "DATABASE||REMOTE_HOST||DB_USER not set. Peer not ready?" && exit 0

  # to be used for GRANTs
  # if the remote unit is actually placed on the same system,
  # it'll need a grant for a user connecting from 127.0.0.1
  local_hostname=$(hostname -f)
  if [[ $REMOTE_HOST != $local_hostname ]] ; then
    REMOTE_IP=$(dig +search +short $REMOTE_HOST)
  else
    REMOTE_IP="127.0.0.1"
  fi

  if [[ ! -e $PASSWD_FILE ]] ; then
    PASSWORD=$(pwgen -s 16)
    echo $PASSWORD >$PASSWD_FILE
  else
    PASSWORD=$(cat $PASSWD_FILE)
  fi

  if ! database_exists ; then
    juju-log "mysql - shared db: Creating database $DATABASE"
    create_database || exit 1
    echo "Done"
  fi
  if ! grant_exists ; then
    juju-log "mysql - shared-db: Granting $DB_USER@$REMOTE_HOST access to $DATABASE"
    create_grant || exit 1
  fi
  relation-set db_host=$(hostname -f) password=$PASSWORD
  juju-log "mysql - shared-db: Returning access to $DATABASE to $DB_USER@$REMOTE_HOST."
}

RELATION_ACTION=${0##*/shared-db-relation-}
juju-log "HOOK: shared-db-relation-$RELATION_ACTION fired."

case $RELATION_ACTION in
  "joined") exit 0 ;; # do nothing on join, wait for peer to request access
  "changed") shared-db_changed ;;
  *) exit 0 ;;
esac