Presentation support for https://docs.google.com/presentation/d/1InNLrWKupzii959L6DzogocDSkv7n4e007wytGLXGHI/edit#slide=id.g225cc96baa_0_61

db_pack.sh

#!/bin/sh
set -e

echo "Packing data folder: " $PGDATA

cd /zdata/
tar -cf backup.tar -C $PGDATA ./
sync
rm -rf $PGDATA/*

echo "Pack & clean finished successfully."

db_run.sh

#!/bin/sh

set -e

if [ ! -f "$PGDATA/PG_VERSION" ]; then
    echo "Restoring $PGDATA ..."
    tar -xf /zdata/backup.tar -C $PGDATA
    #chown -R postgres:postgres "$PGDATA"
    sync
    echo "Done."
else
    echo "$PGDATA was already there, skipping restore."
fi

echo "Launching command: $@ ..."
if [ "$1" = 'postgres' ]; then
    gosu postgres "$@"
else
    exec "$@"
fi

db_setup.sh

#!/bin/sh
set -e

if [ ! -d "$PGDATA" ]; then
    mkdir -p ${PGDATA}
fi
chown -R postgres:postgres "$PGDATA"

gosu postgres initdb
sed -ri "s/^#(listen_addresses\s*=\s*)\S+/\1'*'/" "$PGDATA"/postgresql.conf

: ${POSTGRES_USER:=$POSTGRES_USER}
: ${POSTGRES_DB:=$POSTGRES_DB}

if [ "$POSTGRES_PASSWORD" ]; then
  pass="PASSWORD '$POSTGRES_PASSWORD'"
  authMethod=md5
else
  echo "==============================="
  echo "!!! Use \$POSTGRES_PASSWORD env var to secure your database !!!"
  echo "==============================="
  pass=
  authMethod=trust
fi
echo

createSql="CREATE DATABASE $POSTGRES_DB;"
echo $createSql | gosu postgres postgres --single -jE
echo

op=CREATE

userSql="$op USER $POSTGRES_USER WITH SUPERUSER $pass;"
echo $userSql | gosu postgres postgres --single -jE
echo

# internal start of server in order to allow set-up using psql-client
# does not listen on TCP/IP and waits until start finishes
gosu postgres pg_ctl -D "$PGDATA" \
    -o "-c listen_addresses=''" \
    -w start
echo

cd ./data-scripts.d/
for f in *; do
        case "$f" in
            *.sql) echo "$0: running $f"; psql --quiet --username "$POSTGRES_USER" --dbname "$POSTGRES_DB" --file="$f" &> /dev/null;;
            *)     echo "$0: ignoring $f" ;;
        esac
        echo
done
cd ../
sync

gosu postgres pg_ctl -D "$PGDATA" -m fast -w stop

{ echo; echo "host all all 0.0.0.0/0 $authMethod"; } >> "$PGDATA"/pg_hba.conf
sync

Dockerfile for pre-populated databases

# source: https://github.com/kiasaki/docker-alpine-postgres
FROM alpine

RUN echo "@edge http://nl.alpinelinux.org/alpine/edge/main" >> /etc/apk/repositories && \
    apk update && \
    apk add curl "libpq@edge<9.7" "postgresql-client@edge<9.7" "postgresql@edge<9.7" "postgresql-contrib@edge<9.7" && \
    curl -o /usr/local/bin/gosu -sSL "https://github.com/tianon/gosu/releases/download/1.2/gosu-amd64" && \
    chmod +x /usr/local/bin/gosu && \
    apk del curl && \
    rm -rf /var/cache/apk/*

ENV LANG en_US.utf8
ENV PGDATA /var/lib/postgresql/data/

ENV POSTGRES_DB datastore
ENV POSTGRES_USER docker
ENV POSTGRES_PASSWORD letmein

RUN mkdir -p /opt/setup/data-scripts.d/
RUN mkdir -p /zdata/
COPY ./data-scripts.d/* /opt/setup/data-scripts.d/

WORKDIR /opt/setup/
COPY db-setup.sh /opt/setup/
COPY db-pack.sh /opt/setup/
COPY db-run.sh /opt/setup/

RUN ./db-setup.sh
RUN ./db-pack.sh

VOLUME $PGDATA

EXPOSE 5432

ENTRYPOINT [ "/opt/setup/db-run.sh" ]

CMD [ "postgres" ]