Jenkins slack plugin: response 400 - but "test connection" works ok

Using Jenkins
1

Hi

I am trying to send slack notifications from jenkins. I installed the most recent version of the slack plugin. My (related) configuration as code is

credentials:
  system:
    domainCredentials:
    - credentials:
      - string:
          description: "Adzuna Slack Token"
          id: "slack-token"
          scope: GLOBAL
          secret: "{foo}"
jenkins:
  crumbIssuer: "strict"
unclassified:
  slackNotifier:
    botUser: false
    sendAsText: false
    teamDomain: "team-foo"
    tokenCredentialId: "slack-token"

I tested through “Dashboard → Manage Jenkins → System → Slack → Test connection”. It says “success” and it does send a message to slack

However, from my pipeline console output says

...
Slack Send Pipeline step running, values are - baseUrl: <empty>, teamDomain: team-foo, channel: null, color: danger, botUser: false, tokenCredentialId: slack-token, notifyCommitters: false, iconEmoji: <empty>, username: <empty>, timestamp: <empty>
ERROR: Slack notification failed. See Jenkins logs for details.
...

and jenkis logs say:

Jul 06 10:32:20 jenkins-controller jenkins[3259]: 2023-07-06 10:32:20.599+0000 [id=3008]        WARNING        j.p.slack.StandardSlackService#postToSlack: Slack post may have failed. Response: null
Jul 06 10:32:20 jenkins-controller jenkins[3259]: 2023-07-06 10:32:20.600+0000 [id=3008]        WARNING        j.p.slack.StandardSlackService#postToSlack: Response Code: 400

Any ideas would be helpful. Let me know if I can provide more info

PS without the Strict Crumb Issuer Plugin I was getting a warning and a 403. So I followed the instructions in the log file (Improved CSRF protection link), and installed it with the default configuration, Hope this wasn’t a red herring.

Jul 06 10:30:45 jenkins-controller jenkins[3259]: 2023-07-06 10:30:45.565+0000 [id=475]        INFO        o.j.p.s.StrictCrumbIssuer#validateCrumb: Invalid crumb found in the request
Jul 06 10:30:45 jenkins-controller jenkins[3259]: 2023-07-06 10:30:45.566+0000 [id=475]        WARNING        hudson.security.csrf.CrumbFilter#doFilter: Found invalid crumb 2c346e60bc7344ddbe137e316e3df8b8e7c0dadaf63dfe3aa6b769c330dcb067. If you are calling this URL with a script, please use the API Token instead. More information: https://www.jenkins.io/redirect/crumb-cannot-be-used-for-script
Jul 06 10:30:45 jenkins-controller jenkins[3259]: 2023-07-06 10:30:45.568+0000 [id=475]        WARNING        hudson.security.csrf.CrumbFilter#doFilter: No valid crumb was included in request for /ajaxExecutors by adzuna. Returning 403.
2

Forgot to mention I use

  • Jenkins 2.401.2
  • slack plugin Version 664.vc9a_90f8b_c24a_ (I understand this is the latest)

Clarification: I saw this Slack response code 400, message null, when using blocks · Issue #623 · jenkinsci/slack-plugin · GitHub

  • I don’t have blocks in my jenkinsfile a
  • I am using the jenkins-ci slack app

The installation instructions say that I should be using the jenkins-ci slack app, but I can also use another slack app? I am unsure

I also increased the log verbosity. I got this at the logs (but it doesn’t reveal anything to me at least)

Jul 08, 2023 10:09:16 AM FINE jenkins.plugins.slack.StandardSlackService
Posting: to null on foo:  {"attachments":[{"fallback":"Build failed - 2 in repo_foo/branch_foo (<http://jenkins-controller.example.com/job/repo_foo/job/branch_foo/2/|Open>)","color":"danger","fields":[{"short":false,"value":"Build failed - 2 in repo_foo/branch_foo (<http://jenkins-controller.example.com/job/repo_foo/job/branch_foo/2/|Open>)"}],"mrkdwn_in":["pretext","text","fields"]}],"link_names":"1","unfurl_links":"true","unfurl_media":"true","channel":"null","as_user":"true"}

Jul 08, 2023 10:09:16 AM WARNING jenkins.plugins.slack.StandardSlackService postToSlack
Slack post may have failed. Response: null

Jul 08, 2023 10:09:16 AM WARNING jenkins.plugins.slack.StandardSlackService postToSlack
Response Code: 400

Moreover, testing the slack connection through the web UI still works

image
image1802×762 36.8 KB

and the relevant logs

Jul 08, 2023 10:14:18 AM FINE jenkins.plugins.slack.StandardSlackService
Posting: to  on foo:  {"attachments":[{"fallback":"Slack/Jenkins plugin: you're all set on http://jenkins-controller.example.com/","color":"good","fields":[{"short":false,"value":"Slack/Jenkins plugin: you're all set on http://jenkins-controller.example.com/"}],"mrkdwn_in":["pretext","text","fields"]}],"link_names":"1","unfurl_links":"true","unfurl_media":"true","channel":"","as_user":"true"}
Jul 08, 2023 10:14:18 AM FINE jenkins.plugins.slack.StandardSlackService
Posting succeeded
3

Hello @vkatsikaros ,
Did you find any solution for this problem? I’m facing the exact issue now with Jenkins 2.4.6 as well.
It’s been one year and no one has ever replied to this post yet.

If this information helps, I’ve deployed Jenkins using jenkins.war inside Ubuntu 24.04 VirtualBox virtual machine.

Please someone let me know what’s going on here.

Thank you.