setup-replication.sh

#!/usr/bin/env bash

source /env-data.sh

# This script will setup slave instance to use standby replication

# Adapted from https://github.com/DanielDent/docker-postgres-replication
# To set up replication
if [[ "$DESTROY_DATABASE_ON_RESTART" =~ [Tt][Rr][Uu][Ee] ]]; then
	echo "Destroy initial database, if any."
	rm -rf $DATADIR
fi

mkdir -p $DATADIR
chown -R postgres:postgres $DATADIR
chmod -R 700 $DATADIR

# No content yet - but this is a slave database
until ping -c 1 -W 1 ${REPLICATE_FROM}
do
	echo "Waiting for master to ping..."
	sleep 1s
done

if [[ "$DESTROY_DATABASE_ON_RESTART" =~ [Tt][Rr][Uu][Ee] ]]; then
	echo "Get initial database from master"

	chown -R postgres:postgres $(getent passwd postgres  | cut -d: -f6)
	su - postgres -c "echo \"${REPLICATE_FROM}:${REPLICATE_PORT}:*:${POSTGRES_USER}:${POSTGRES_PASS}\" > ~/.pgpass"
	su - postgres -c "chmod 0600 ~/.pgpass"

	until su - postgres -c "${PG_BASEBACKUP} -X stream -h ${REPLICATE_FROM} -p ${REPLICATE_PORT} -D ${DATADIR} -U ${POSTGRES_USER} -vP -w"
	do
		echo "Waiting for master to connect..."
		sleep 1s
		if [ "$(ls -A $DATADIR)" ]; then
			echo "Need empty folder. Cleaning directory..."
			rm -rf $DATADIR/*
		fi
	done
fi

# Setup recovery.conf, a configuration file for slave
cat > ${DATADIR}/recovery.conf <<EOF
standby_mode = on
primary_conninfo = 'host=${REPLICATE_FROM} port=${REPLICATE_PORT} user=${POSTGRES_USER} password=${POSTGRES_PASS} sslmode=${PGSSLMODE}'
trigger_file = '${PROMOTE_FILE}'
EOF
# Setup permissions. Postgres won't start without this.
chown postgres ${DATADIR}/recovery.conf
chmod 600 ${DATADIR}/recovery.conf

# Promote to master if desired
if [ ! -z "$PROMOTE_MASTER" ]; then
	touch $PROMOTE_FILE
fi