New DB connections on every inspect page refresh

[zhuojg]

I'm encountering an issue during local development when using @workflow/world-postgres.

The Postgres Docker container eventually throws an error:

FATAL: sorry, too many clients already

I am using following commands to start inspect server:
WORKFLOW_TARGET_WORLD="@workflow/world-postgres" WORKFLOW_POSTGRES_URL="postgresql://postgres:mysecretpassword@127.0.0.1/postgres" npx workflow inspect runs --web

When I inspect the active database connections with:

SELECT * FROM pg_stat_activity;

I notice that each time I refresh the web page, new database connections are created and never reused. The duplicate connections can be observed from this screenshot. And everytime I refresh the page, more connections will appear.

After digging into the code, it appears that the server action in
packages/web-shared/src/api/workflow-server-actions.ts — specifically the getWorldFromEnv function — always creates a new world instance without any caching. As a result, each page refresh spawns a new world instance and eventually exhausts available DB connections.

If this assessment is correct, I'm happy to work on a fix.

[VaguelySerious]

Hi @zhuojg, this assessment looks right. We have a module-level cache packages/core/src/runtime/world.ts, which wasn't used in workflow-server-actions.ts because it doesn't cache-bust if the relevant environment variables change, and also can't in the case of third-party worlds that use unknown env variables.

The solution for this the problem at hand would likely be to cache the world workflow-server-actions.ts by the envMap being passed. If you want to take a shot at this, that would be very welcome!

[zhuojg]

Hi @zhuojg, this assessment looks right. We have a module-level cache packages/core/src/runtime/world.ts, which wasn't used in workflow-server-actions.ts because it doesn't cache-bust if the relevant environment variables change, and also can't in the case of third-party worlds that use unknown env variables.

The solution for this the problem at hand would likely be to cache the world workflow-server-actions.ts by the envMap being passed. If you want to take a shot at this, that would be very welcome!

Thanks for the clarification above — I’ve addressed the issue in this PR.
Let me know if anything needs adjustment.