Outgoing webhook not launched after an Incoming Webhook is called

[nabilgasri]

Hi everyone!

Summary

Mattermost does not lauch an outgoing webhook after an incoming webhook is called.

Steps to reproduce

1- Create a public channel "test_outgoing"
2- Create an incoming webhook inside the team holding the test_outgoing channel.
3- Create an outgoing webhook. bind it the the channel test_outgoing. example a webhook starting a jenkins build.
4- Send a message to the test_outgoing channel using the "incoming_webhook"

Expected behavior

The outgoing webhook is launched (jenkins build starts)

[amyblais]

@nabilgasri What Mattermost server version are you on? What OS and version are you using? Do you see any errors in server logs or developer console?

[nabilgasri]

@amyblais
There is no errors on the server side.
I reproduced the bug locally with the mattermost-preview docker image. Here how I did:

1. run mattermost-preview as explained on the documentation

docker run --name mattermost-preview -d --publish 8065:8065 --add-host dockerhost:127.0.0.1 mattermost/mattermost-preview

2. create a Team and a webhook channel named test_webhook

3. create an incoming webhook test_incoming_webhook

4. create an outgoing webhook test_outgoing_webhook, set "http://host_ip/test_in_out_webhhok" as a callback url

5. go to http://localhost:8065/admin_console/environment/developer and add the http://host_ip to "Allow untrusted internal connections to:" section

6. run an ngninx server:
   docker run --name ngx-docker -p 80:80 --rm -d nginx

7. write manually a message on the web page of the channel => logs on nginx show a call to /test_in_out_webhhok

8. send a message th the incoming webhook
   curl -i -X POST --data-urlencode 'payload={"text": "Hello, this is some text\nThis is more text. :tada:"}' http://localhost:8065/hooks/$hook_id => should have the same erroe as on step 7.

Hope it helps finding the root cause.

[amyblais]

@DHaussermann @mickmister Is this something you're able to help test if this is a bug?

[mickmister]

@nabilgasri It looks like incoming webhooks have never supported the use case of sending to an outgoing webhook. I've created a ticket here for investigation https://mattermost.atlassian.net/browse/MM-31208