Postgres Docker image with Flyway migrations for integration testing

Here's how you set up a Docker image of a PostgreSQL database with migrations (and possibly test data) applied by Flyway - often for integration testing.

Source on GitHub

Assume the following folder structure:

sql/
  V1__foo.sql
  V2__bar.sql
  V3__baz.sql
20_flyway.sh
Dockerfile
flyway.conf

Ensure to do a sudo chmod a+x 20_flyway.sh. The content of the shell script:

#!/bin/bash
set -o errexit
set -o pipefail
set -o nounset

flyway -jdbcProperties.socketFactory='org.newsclub.net.unix.AFUNIXSocketFactory$FactoryArg' -jdbcProperties.socketFactoryArg=/var/run/postgresql/.s.PGSQL.5432 -jdbcProperties.sslMode=disable migrate

Order of things is important, don't try to change anything.

We must switch out the class responsible for connecting to Postgres because during the startup of the temporary database, only unix sockets (not TCP) are available. For this purpose, we will later download a specific driver.

The flyway.conf I'm going to use is unspectacular:

flyway.locations=filesystem:sql
flyway.url=jdbc:postgresql://:5432/platform
flyway.password=admin
flyway.user=admin
flyway.connectRetries=60

And finally the Dockerfile:

# I'll use PostGIS as base image but you can also do this with the official one.
FROM postgis/postgis:13-master

# We download Flyway and install it, nothing special.
ADD https://repo1.maven.org/maven2/org/flywaydb/flyway-commandline/9.15.0/flyway-commandline-9.15.0-linux-x64.tar.gz /flyway.tar.gz
RUN tar xvf /flyway.tar.gz
RUN mv flyway-9.15.0 flyway
RUN chmod +x /flyway/flyway
RUN ln -s /flyway/flyway /usr/local/bin/flyway

# We download the driver for unix sockets and place it in Flyway's driver folder.
ADD https://github.com/kohlschutter/junixsocket/releases/download/junixsocket-2.6.2/junixsocket-dist-2.6.2-bin.tar.gz /junixsocket.tar.gz
RUN tar xvf /junixsocket.tar.gz
RUN mv /junixsocket-dist-2.6.2/lib/junixsocket-common-2.6.2.jar /flyway/drivers/junixsocket-common-2.6.2.jar
RUN mv /junixsocket-dist-2.6.2/lib/junixsocket-native-common-2.6.2.jar /flyway/drivers/junixsocket-native-common-2.6.2.jar

# We copy the script to the `docker-entrypoint-initdb.d`.
# Shell scripts in this folder will get executed on startup.
# Do mind the integer prefix of the file if order is important.
# I prefixed it with `20` because PostGIS uses `10` and my SQL relies on it.
COPY 20_flyway.sh /docker-entrypoint-initdb.d/20_flyway.sh
RUN chmod +x /docker-entrypoint-initdb.d/20_flyway.sh

# Copy Flyway configuration
COPY flyway.conf /flyway.conf

# Copy SQL files
COPY sql /sql

For building and running nothing special is required:

docker build . -t foobar
docker run -e POSTGRES_USER=admin -e POSTGRES_PASSWORD=admin -e POSTGRES_DB=platform -p 5432:5432 foobar