0k-charms/postgres/hooks/schedule_command-relation-joined

#!/bin/bash

## When writing relation script, remember:
##  - they should be idempotents
##  - they can be launched while the dockers is already up
##  - they are launched from the host
##  - the target of the link is launched first, and get a chance to ``relation-set``
##  - both side of the scripts get to use ``relation-get``.

set -e

## XXXvlab: should use container name here so that it could support
## multiple postgres
label=pg-backup-$SERVICE_NAME
DST=$CONFIGSTORE/$TARGET_CHARM_NAME/etc/cron/$label
schedule=$(relation-get schedule)

if ! echo "$schedule" | egrep '^\s*(([0-9/,*-]+\s+){4,4}[0-9/,*-]+|@[a-z]+)\s*$' >/dev/null 2>&1; then
    err "Unrecognized schedule '$schedule'."
    exit 1
fi

## XXXvlab: how is this meant to works if there's multiples postgres (about PGHOST=?) ?
## Warning: using '\' in heredoc will be removed in the final cron file, which
##   is totally wanted: cron does not support multilines.

exclude_dbs=$(relation-get exclude-dbs 2>/dev/null) || true
exclude_dbs=$(echo "$exclude_dbs" | shyaml get-values 2>/dev/null | xargs echo) || true

## Warning: 'docker -v' will use HOST directory even if launched from
##   'cron' container.
file_put "$DST" <<EOF
$schedule     root  lock $label -D -p 10 -c "\
    docker run --rm \
        -e PGHOST=\$POSTGRES_PORT_5432_TCP_ADDR \
        -e exclude_dbs=\"$exclude_dbs\" \
        -v /root/.pgpass:/root/.pgpass \
        -v \"$BASE_CHARM_PATH/resources/bin/pg-backup:/usr/sbin/pg-backup\" \
        -v \"$SERVICE_DATASTORE/var/backups/pg:/var/backups/pg\" \
        --entrypoint pg-backup \
        \"$DOCKER_BASE_IMAGE\"" 2>&1 | ts '\%F \%T \%Z' >> /var/log/cron/pg-backup_script.log
EOF
chmod +x "$DST"

config-add "\
$MASTER_TARGET_CHARM_NAME:
  links:
    - $MASTER_BASE_CHARM_NAME
"