Extending the application

The base-images/db-mysql-fdw image is provided to build a Sparrow-compatible PostGIS image with the MySQL foreign data wrapper extension (for connecting with external MySQL databases). This functionality is not enabled by default because it adds ~700 Mb to the installed size of Sparrow and will not be necessary for most setups. However, it can be enabled with two steps: first, build the appropriate Docker image with sparrow build db-mysql-fdw. Then override the db portion of the docker-compose.yaml file with the new image definition: 1., create an overrides file (e.g. docker-compose.overrides.yaml with the following contents:

version: "3.4"
services:
db:
image: sparrowdata/db-mysql-fdw:1.0
  1. reference this overrides file with the SPARROW_COMPOSE_OVERRIDES environment variable in your config file, e.g.
SPARROW_COMPOSE_OVERRIDES=(<path>/<to>/docker-compose-overrides.yaml)

This will update the Sparrow configuration transparently to use the new image in place of the default.

Once the image builds, you can run CREATE EXTENSION mysql_fdw in the sparrow database, or add this command to your SPARROW_INIT_SQL file.