Postgres in Docker is great. If you mount a folder to /docker-entrypoint-initdb.d/ within the container, all .sh and .sql files will be executed. This is great! And it will only run if there is no existing database data volume, so its perfect for seeding databases.
A problem I ran into is that Postgres runs this during startup, which by default can't be detected by a CD pipeline, and the database cannot be connected until these scripts have completed. Lots of people have had trouble with this.
I used a Grep Timer to watch the logs for the 2 success messages and block the pipeline.