PostgreSQL

Here is one example of running posgres.

#
# Sample Vagga configuration for running PostgreSQL server
#

containers:
  ubuntu:
    setup:
    - !Ubuntu xenial
    # Use fixed user id and group id for postgres, because in some cases
    # we may need to upgrade (rebuild) a postgres container, but keep the data
    # on a `!Persistent` volume still usable. User ids in ubuntu packages are
    # not guaranteed to be same on every installation.
    #
    # The command-lines are from the postgres-common package except
    # added --uid 200 --gid 200
    - !Sh |
        addgroup --system --gid 200 postgres
        adduser --uid 200 --system --home /data --no-create-home \
            --shell /bin/bash --group --gecos "PostgreSQL administrator" \
            postgres
    - !Install [postgresql-9.5]
    - !EnsureDir /data
    environ:
      PG_PORT: 5433   # Port of host to use
      PG_DB: vagga
      PGDATA: /data
      PG_BIN: /usr/lib/postgresql/9.5/bin
    volumes:
      /data: !Persistent
        name: postgres
        owner-uid: 200
        owner-gid: 200
        init-command: _pg-init
      /run: !Tmpfs
        subdirs:
          postgresql: { mode: 0o777 }  # until we have user, group options

commands:

  _pg-init: !Command
    description: Init postgres database
    container: ubuntu
    user-id: 200
    group-id: 200
    run: |
      set -ex
      ls -la /data
      $PG_BIN/pg_ctl initdb
      $PG_BIN/pg_ctl -w -o '-F --port=$PG_PORT -k /tmp' start
      $PG_BIN/createuser -h 127.0.0.1 -p $PG_PORT vagga
      $PG_BIN/createdb -h 127.0.0.1 -p $PG_PORT $PG_DB -O vagga

      # init schema usually schema shouldn't be inline here, but contained
      # in a separate file
      psql postgres://vagga:vagga@127.0.0.1:$PG_PORT/$PG_DB <<ENDSQL
      CREATE TABLE random_stuff (x TEXT);
      ENDSQL

      $PG_BIN/pg_ctl stop

  postgres: &postgres !Command
    description: Run postgres database
    container: ubuntu
    user-id: 200
    group-id: 200
    run: |
      trap "$PG_BIN/pg_ctl -w stop; trap - INT; kill -INT $$" INT
      $PG_BIN/pg_ctl -w -o '-F --port=$PG_PORT -k /tmp' start
      sleep infinity

  psql: &psql !Command
    description: Run postgres shell
    container: ubuntu
    run: |
      psql -U vagga postgres://$PG_USER:$PG_PASSWORD@127.0.0.1:$PG_PORT/$PG_DB

  run: !Supervise
    description: Run both postgres and shell
    children:
      postgres: *postgres
      psql: *psql

There is a more complicated example of postgres with alembic migrations