Flyway docker image

What is Flyway?

Flyway is an open source database migration tool. It strongly favors simplicity and convention over configuration.

It is based around 6 basic commands: Migrate, Clean, Info, Validate, Baseline and Repair.

Migrations can be written in SQL (database-specific syntax (such as PL/SQL, T-SQL, ...) is supported) or Java (for advanced data transformations or dealing with LOBs).

It has a Command-line client, a Java API (also works on Android) for migrating the database on application startup, a Maven plugin, Gradle plugin, SBT plugin and Ant tasks.

Plugins are available for Spring Boot, Dropwizard, Grails, Play, Griffon, Grunt, Ninja and more.

Supported databases are Oracle, SQL Server, SQL Azure, DB2, DB2 z/OS, MySQL (including Amazon RDS), MariaDB, Google Cloud SQL, PostgreSQL (including Amazon RDS and Heroku), Redshift, Vertica, H2, Hsql, Derby, SQLite, SAP HANA, solidDB, Sybase ASE and Phoenix.

Usage

How to use this image

To run a schema migration, you have to mount the folder containing migration scripts in a volume under /flyway/sql.

Assuming your DB is a PostgreSQL Database, running a schema migration is simple as this:

docker run --rm \
  -v ${PWD}:/flyway/sql 
  teviotia/flyway \
  -user=postgres \
  -password=password \
  -url=jdbc:postgresql://postgres/postgres \
  migrate

Waiting for the DB

It is common when using tools like Docker Compose to depend on services in other linked containers, however often relying on links is not enough - whilst the container itself may have started, the service(s) within it may not yet be ready.

That's typically the case when we use Docker Compose to run migration on a DB managed in a container. Whilst the container itself may have started, the database service is not reachable immediately, so the database migration might fail.

Unfortunately with Postgres even a tcp polling solution such as Dockerize fails, because the database starts listening on the port before it is ready to accept connections.

That's why this image provides an exponentially backing off bash function to allow retrying until success. By default it will try 7 times over the course of about 16 seconds in total.

Here is a sample using PostgreSQL:

version: '3'

services:

  # Database
  db:
    image: postgres:9.6.3
    ports:
      - 5432:5432
    environment:
      POSTGRES_PASSWORD: password

  # Database Schema migration
  schema:
    image: teviotia/flyway
    entrypoint: with_backoff
    command: >
      flyway
      -user=postgres
      -password=password
      -url=jdbc:postgresql://db/postgres
      migrate
    volumes:
      - "./db:/flyway/sql"
    depends_on:
      - db

Build

This project is built by Circle CI at https://circleci.com/gh/Mahoney/docker-flyway.

License

All the code contained in this repository, unless explicitly stated, is licensed under ISC license.

A copy of the license can be found inside the LICENSE file.

Attribution

Forked from bandsintown/docker-flyway.

Backoff script adapted from https://coderwall.com/p/--eiqg/exponential-backoff-in-bash

Mahoney / docker-flyway