migrate-exp

Go database migration experiments.
The sample code contains simple examples on how golang-migrate/migrate can be used to automate version control for databases. MySQL was used to perform this task.

Requirements

• Go 1.13 or later (any version with go modules should work too)
• docker
• docker-compose

Instructions

cd into 0dev and run make up-docker to setup initial mysql database.
make clean-docker can be used to clean up docker containers when you are done.
Do check the Makefiles for useful commands.

Documentation

In the cmd there are two projects

• multiple
• single

The key difference is how the migrations scripts are written.
In multiple there are multiple statements in a single file. To achieve this, the flag multiStatements has to be enabled. Enabling this feature, comes with some risk. To mitigate this risk, a second connection is opened just to run the migrations and then close immediately after.

Migrate and Up are the 2 functions that are most suitable for version control.
In the example, I have chosen to use Up instead of Migrate because when building docker images to be deployed on k8, the Down scripts will not be available in an older image.

If the migration scripts are injected into the service via an external storage(ie: volume)
Migrate would be a better solution and provide more autonomy to the service upon rollbacks.