Pub/Sub and Eventarc triggers store fully-qualified resource paths as user_id, making sessions unqueryable via REST API

[eliasecchig]

Summary

The Pub/Sub and Eventarc trigger handlers use raw resource identifiers as user_id when creating sessions. These identifiers contain slashes, which makes the resulting sessions difficult to query via the ADK's REST session APIs.

Details

In trigger_routes.py:414, the Pub/Sub handler sets:

user_id = req.subscription or "pubsub-caller"

Pub/Sub push deliveries always send the fully-qualified subscription path:

projects/my-project/subscriptions/my-sub

Similarly, the Eventarc handler at trigger_routes.py:480 sets:

user_id = req.source or request.headers.get("ce-source") or "eventarc-caller"

Eventarc sources look like //pubsub.googleapis.com/projects/my-project/topics/my-topic.

These values are used as user_id when creating sessions. Sessions are created and stored successfully, but retrieving them via the session list endpoint at adk_web_server.py:1347 is not possible because user_id is a URL path parameter:

GET /apps/{app_name}/users/{user_id}/sessions

ASGI/Starlette decodes %2F → / before routing, so a user_id containing slashes causes the request to 404 or match the wrong route.

Suggested fix

Replace slashes with a safe delimiter (--) to preserve the full resource path while keeping the user_id queryable:

# Pub/Sub: "projects/p/subscriptions/my-sub" → "projects--p--subscriptions--my-sub"
subscription = req.subscription or "pubsub-caller"
user_id = subscription.replace("/", "--")

# Eventarc: "//pubsub.googleapis.com/projects/p/topics/t" → "pubsub.googleapis.com--projects--p--topics--t"
source = req.source or request.headers.get("ce-source") or "eventarc-caller"
user_id = source.strip("/").replace("/", "--")

This keeps the full resource identity intact, avoids information loss, and produces user_id values that are safe to use in URL path parameters.

Workaround

Add ASGI middleware to normalize the subscription field in the request body before it reaches the trigger handler.