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Last pushed: a year ago
Short Description
Go goose migrations docker container
Full Description

Docker Goose

Docker image with Golang Goose Database migration tool

Why

Quite a few times I use Docker to setup the entire development environment of a project; some of them require migrations and I sometimes use Goose for them, so I needed a docker image which allows to run Goose migrations on the database docker container.

So this docker imaged cover those personal needs.

Hang on!, there are a few of Goose Docker images, why another one?

Because the ones that I found in 3 Google searches didn't fit to my needs:

  • jeffutter/goose: I defines an ENTRYPOINT, so I cannot rewrite the command to run (goose) with environment variables which are resolved inside the container; see ENTTRYPOINT issue
  • shopkeep/goose: I don't want to build an image each time that I have to run a new migration, besides it only supports Postgres, it's a bit heavy image and it has the same ENTRYPOINT of the one above

ENTRYPOINT issue

Dockerfile can define an ENTRYPOINT, which is useful for containers which run a command, which is the case here, but I needed to run a command with an environment variable which part of its values are values of other variables available inside of the container.

docker run --entrypoint ... allow to set the ENTRYPOINT rewriting the value set in the Dockerfile however however the string it isn't "interpreted" by the container shell, so the problem is the same.

To understand what I'm saying, let's see the specific case which I had to deal

  • I use a Makefile to create simple targets to run commands.
  • The database run as any other container, in this case the official Posgres Image, and let's set postgres as a container name
  • Because I use a Makefile, I set values of POSTGRES_USER and the rest of the environments variables used by the Postgres image into it.
  • I want to have a Makefile target which allows me to run Goose migrations on Posgres container and I don't want to hardcode docker IP post, etc., so I link Postgres container with Goose container, hence I have to execute
    docker run --rm --link postgres:postgres -v $(realpath db):/db ifraixedes/goose sh -c 'DB_URL=postgres://$(DB_USER):$(DB_PWD)@$$POSTGRES_PORT_5432_TCP_ADDR:$$POSTGRES_PORT_5432_TCP_PORT/$(DB_NAME)?sslmode=disable, where those $(..) variables are defined in the Makefile and used by the the other targets which do something with Postgres container (e.g. Running the Postgres image) and the $$.. are the variables defined inside of the Docker container and you probably already know are set due the linked Postgres container (--link ...)
  • Then when that command is run, DB_URL is set as an environment variable and inside of Goose configuration file (dbconf.yml) I can use it to define the connection (open: $DB_URL) and Goose run the migrations as expected

Running the same command (sh -c ...) but set as ENTRYPOINT (--entrypoint), the $$.. environment variables aren't interpeted, so it doesn't work

License

MIT, read LICENSE file for more information.

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ifraixedes
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