IMAGE postgres
LAYER shared/alpine3.9
LAYER postgres/postgres

RUN EOF
    # Modify OS user (which will be picked up later by apk add)
    sed -i 's/postgres:x:70:70/postgres:x:5432:5432/' /etc/passwd
    sed -i 's/postgres:x:70/postgres:x:5432/' /etc/group

    # Install PostgreSQL + PostGIS
    apk --no-cache add postgresql postgresql-contrib postgis

    # Create socket directory 
    mkdir /run/postgresql
    chown postgres:postgres /run/postgresql
EOF

MOUNT DIR /srv/postgres/data var/lib/postgresql

USER 5432 5432
CMD postgres -D /var/lib/postgresql