chore: replace datalayer ids with uuids

[davidbgk]

• Use UUIDs rather than default IDs
• Create migrations
• Update the URLs
• Update the tests
• Do the uuid4 generation with SQL directly
• Add a test to ensure old layers are still available trough the API
• Ensure datalayer versioning still works when migrating an already existing map with layers
• Get the constraint name (relevant stack overflow)
• Migrate existing datalayers when using a local remoteURL
• Make the migration reversible
• Rename datalayer.id to datalayer.old_id

Resources

• https://docs.djangoproject.com/en/5.0/howto/writing-migrations/#migrations-that-add-unique-fields
• https://blog.hexack.fr/en/change-the-primary-key-of-a-django-model.html

[almet]

I've successfully migrated my local database with UUIDs, with the updated branch here.

(edit: ruff formated everything)

[almet]

I wonder if this will work on other systems, as the constraints seems to be named uniquely on different installs.

[yohanboniface]

👍

[almet]

Here is the generated SQL when running the migrations

ALTER TABLE "umap_datalayer" ALTER COLUMN "uuid" DROP DEFAULT
UPDATE umap_datalayer SET uuid = gen_random_uuid()
DO $$
BEGIN
    EXECUTE 'ALTER TABLE umap_datalayer DROP CONSTRAINT ' || (
        SELECT indexname
        FROM pg_indexes
        WHERE tablename = 'umap_datalayer' AND indexname LIKE '%pk%'
    );
END $$;

ALTER TABLE "umap_datalayer" ALTER COLUMN "id" DROP IDENTITY IF EXISTS
ALTER TABLE "umap_datalayer" ALTER COLUMN "id" TYPE integer, ALTER COLUMN "id" DROP NOT NULL
DROP INDEX IF EXISTS "umap_datalayer_id_5f429f28_like"
ALTER TABLE "umap_datalayer" RENAME COLUMN "id" TO "old_id"
ALTER TABLE "umap_datalayer" ALTER COLUMN "uuid" SET DEFAULT '135add95-f480-4467-9eba-84c7e1827785'::uuid
UPDATE "umap_datalayer" SET "uuid" = '7563076e-f4ed-4f91-886e-f20e73165c1c'::uuid WHERE "uuid" IS NULL; SET CONSTRAINTS ALL IMMEDIATE
ALTER TABLE "umap_datalayer" ALTER COLUMN "uuid" SET NOT NULL
ALTER TABLE "umap_datalayer" ADD CONSTRAINT "umap_datalayer_uuid_5cb47aed_pk" PRIMARY KEY ("uuid")
ALTER TABLE "umap_datalayer" ALTER COLUMN "uuid" DROP DEFAULT

[yohanboniface]

🎉