Run a command against a PostgreSQL DB installed and started on demand using Docker

with-docker-db.sh

#!/bin/bash -e

image=mdillon/postgis:9.6-alpine
container_name=my-app-postgresql

if [ -z "$1" ]; then
    echo "Run command with a dockerised PostgreSQL DB.

usage: $(basename "$0") command

The various PG* environment variables are set so that if command uses
them - as postgresql's tools and most libpq-based programs do - then
they will automatically use this DB." >&2
    exit 1
fi

export PGPASSWORD=bananapancakes
export PGPORT=15432
export PGUSER=postgres
export PGHOST=localhost

trace() { echo "$*" >&1; }

trace "Starting Dockerised DB"
if docker container inspect $container_name >/dev/null 2>&1; then
    trace "* Using existing container"
    docker container start $container_name >/dev/null
else
    trace "* Creating fresh container"
    docker run --name $container_name -p $PGPORT:5432 -e POSTGRES_PASSWORD=$PGPASSWORD -d $image >/dev/null
fi

cleanup() {
    trace "Stopping Dockerised DB"
    docker container stop "$container_name" >/dev/null;
}

trap cleanup EXIT

check_count=0
while ! psql -c 'select 1' >/dev/null 2>&1; do
    check_count=$(( check_count + 1 ))
    if [[ $check_count -eq 10 ]]; then
        trace "Timed out waiting for port to be opened."
        exit 1
    fi
    trace "* Waiting for DB to be available"
    sleep 1
done

"$@"