postgresql.svg was never in the registry's icons/, so serverkit.ai
answered 404 and the catalog fell back to a built-in icon. The logo
the registry publishes is postgres.svg.
The third deferred item. An extension installs INTO a running engine rather than
getting its own container, so it lives in its own namespace:
`backend/templates/extensions/<id>.yaml` with a top-level `extension:` block,
discovered by the same operator-wins two-directory scan the app templates use.
Dropping a YAML in makes it available with no code change, and a test pins that.
Not nested inside the engine template, because pgvector applies to any
PostgreSQL-speaking engine rather than to `postgresql.yaml` — nesting would force
duplication per host. Not a third `kind:` in the app catalog either: an
extension has no compose, port or volume and produces no Application, so every
consumer of `list_all_templates` would have had to learn to skip it.
The hard part is not the SQL. `CREATE EXTENSION vector` is valid and fails on
stock `postgres:16` with "could not open extension control file", because that
image does not ship the library. Two layers, and the statement is never sent
speculatively: an extension declares which images provide it, so a listing marks
an instance unsupported BEFORE anything is clicked; then at install
`pg_available_extensions` is queried first and a negative answer is a 409 with a
remedy, not an attempt. The live probe overrules the image name in both
directions — a private `registry.internal/ops/pg-with-vector` is allowed, and a
`pgvector/pgvector` tag that does not actually carry the library is still
refused.
ServerKit does not recreate a container behind the operator's back. The remedy
instead names an engine template that IS capable, found by matching the
extension's images against each engine template's compose — hence
`postgresql-pgvector.yaml`. TimescaleDB deliberately ships no bundled host and
says so rather than implying one exists.
Compatibility also needed correcting mid-build: matching on wire protocol alone
claimed CockroachDB could host pgvector. It answers on pgwire and cannot load a
single extension. Engines opt in with `engine.extensions: true`, which excludes
it without any Python naming it.
Two fixes fell out. `DatabaseService` had no psql twin of `docker_mysql_execute`
— `managed_db_user_service` carried a private copy with a comment saying as
much; there is now one implementation and it delegates. And that twin sets
`ON_ERROR_STOP=1`, without which psql reports SUCCESS for a statement the server
rejected.
57 tests, covering the zero-code-change property, compatibility, the image
problem in both probe directions, admin gating, and refusals that must not
execute anything.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Juan Denis