Pipeline duration is always 00:00 in Slack notifications

Summary

Build pipeline duration is always 00:00 in Slack notifications

Steps to reproduce

I am using Jenkins for the build and updateGitlabCommitStatus from the gitlab jenkins plugin to notify GitLab when the build starts and completes. The project has Slack notifications enabled for pipelines.

What is the current bug behavior?

When the build completes, the Slack notification says "Pipeline ... passed in 00:00". However, on the jobs tab of the CI/CD pipelines page on GitLab shows the correct duration.

What is the expected correct behavior?

The Slack notification contains the same duration that is displayed on the pipelines page.

Relevant logs and/or screenshots

This issue seems to be similar to gitlab-ce#22660. One of the comments on that issue asked the reporter to get the started_at, finished_at and pipeline.duration of a GenericCommitStatus. Here is the output for one of my recent pipeline jobs

irb(main):010:0> status.started_at # => ?
=> Wed, 31 Oct 2018 14:47:35 UTC +00:00
irb(main):011:0> status.finished_at # => ?
=> Wed, 31 Oct 2018 14:51:45 UTC +00:00
irb(main):012:0> status.pipeline.duration # => ?
=> 0

Results of GitLab environment info

Expand for output related to GitLab environment info 
System information
System:		Ubuntu 18.04
Current User:	git
Using RVM:	no
Ruby Version:	2.4.5p335
Gem Version:	2.7.6
Bundler Version:1.16.2
Rake Version:	12.3.1
Redis Version:	3.2.12
Git Version:	2.18.1
Sidekiq Version:5.2.1
Go Version:	unknown


GitLab information
Version:	11.4.4
Revision:	2e8fd64ba68
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	postgresql
URL:		XXX
HTTP Clone URL:	XXX
SSH Clone URL:	XXX
Using LDAP:	yes
Using Omniauth:	yes
Omniauth Providers: azure_oauth2


GitLab Shell
Version:	8.3.3
Repository storage paths:
  • default: /var/opt/gitlab/git-data/repositories Hooks: /opt/gitlab/embedded/service/gitlab-shell/hooks Git: /opt/gitlab/embedded/bin/git