Slack Bridge (via Slack App) not working but Legacy API works in one way (from RocketChat to Slack)

[tamasgal]

Description:

We struggle to get the Slack bridge running using the recommended Slack App (cf. #30630). The Slack application works fine according to the Slack testing tools but none of the messages are sent/received on either sides.

We also tried the Legacy API and we are able to see messages on Slack (sent from RocketChat) but no messages on the RocketChat side (when sent from Slack).

Is there any way to debug this? The logs are pretty silent on both sides.

We configured everything as described in #30630 and again, the Slack app testing tool successfully communicates with the app on Slack and test messages are arriving.

We have an HTTP/HTTPS load balancer in front of the RocketChat instance. Is there any other socket communication needed maybe?

We are kind of clueless...

Steps to reproduce:

(create the Slack app as described in #30630)

1. Enable Slack Bridge
2. Make sure "Legacy API" is turned OFF
3. Enter the "Signing Secret" of the Slack app
4. Enter the "App Token" of the Slack app under "App Tokens"
5. Enable sending messages in both ways

Expected behavior:

Slack bridge mirrors messages in both ways.

Actual behavior:

No messages are mirrored.

Server Setup Information:

• Version of Rocket.Chat Server: 6.7.0
• Operating System: Debian 22
• Deployment Method: Docker (in a Swarm, behind an HAProxy load balancer)
• Number of Running Instances: 1
• DB Replicaset Oplog:
• NodeJS Version: v14.21.3
• MongoDB Version: 4.4.15 / wiredTiger (oplog Enabled)

Client Setup Information

• Desktop App or Browser Version:
• Operating System:

Additional context

Relevant logs:

[tamasgal]

The missing ingredient was giving app-level token in slack enough permissions.

authorizations:read -> connections:write, authorizations:read

One issue remains: whatever channels are put in SlackBridge Out Channels, those disappear when the settings are opened again. But the connections remain functional.

Another issue: "SlackBridge Out All" lets all users on the IceCube side join all channels on the RocketChat side, no matter if the channels exist on both sides or not. That caused a lot of confusion.