A better wait-for-postgres.sh

wait-for-postgres.sh

#!/bin/bash -e
# wait-for-postgres.sh
# Adapted from https://docs.docker.com/compose/startup-order/

# Expects the necessary PG* variables.

until psql -c '\l'; do
  echo >&2 "$(date +%Y%m%dt%H%M%S) Postgres is unavailable - sleeping"
  sleep 1
done
echo >&2 "$(date +%Y%m%dt%H%M%S) Postgres is up - executing command"

exec ${@}

You will need to install the "postgresql-client" package for these commands to be available in the webapp.

The included pg_isready command achieves the same as above without the retry limit.

See the complete config using this technique here.

A simplified Dockerfile is shown below. You will need to include a pgsql link for hostname in docker-compose.yml.

FROM openjdk:11

RUN apt-get update && apt-get install -y procps curl net-tools telnet
RUN apt-get install -y postgresql-client

#other things

COPY build/libs/app-0.0.1.war app.war

EXPOSE 8080

CMD until pg_isready --host=pgsql; do sleep 1; done \
    && java -jar app.war

For the above script replace the CMD with :

CMD wait-for-postgres.sh && java -jar app.war