Run an ephemeral Postgres container and connect to it

psqltmp

#!/bin/bash
set -Eeu -o pipefail

PG_VERSION="${PG_VERSION:-9.6-alpine}"

psqltmp() {
  (
  set -Eeu -o pipefail

  local _pgcmd
  if [ -n "${1:-}" ]; then
    _pgcmd="${1}"
  elif command -v pgcli >/dev/null 2>&1; then
    _pgcmd=pgcli
  else
    _pgcmd=psql
  fi

  local POSTGRES_USER POSTGRES_PASSWORD
  POSTGRES_USER=localuser
  POSTGRES_PASSWORD=password
  export POSTGRES_USER POSTGRES_PASSWORD

  # Create a docker container for the DB.
  local _container_id
  _container_id="$(docker run -dP -e POSTGRES_USER -e POSTGRES_PASSWORD postgres:"${PG_VERSION}")"

  # When done, remove the container.
  trap 'docker rm -f "${_container_id}" >/dev/null' EXIT

  # Get the bound localhost port corresponding to the standard 5432 postgres port of the container.
  local _pg_port _pg_uri
  _pg_port="$(docker inspect "${_container_id}" -f '{{index .NetworkSettings.Ports "5432/tcp" 0 "HostPort"}}')"
  _pg_uri="postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@127.0.0.1:${_pg_port}"

  # Wait for DB to start.
  while ! psql -q "${_pg_uri}" -c 'SELECT 1' >/dev/null 2>&1; do printf . >&2; sleep 0.1; done;
  printf '\n'

  echo "${_pg_uri}"
  ${_pgcmd} "${_pg_uri}"
  )
}
psqltmp "$@"