Scope

• Change button to "Show More"
• Only show the next 64k log page
  • never inject the whole log
• Investigate how we can more efficiently render items "cooperatively" (yielding) vs handling/parsing as one big chunk

Summary
When building from a Jenkinsfile which includes a stage that runs "cat /var/log/jenkins/jenkins.log," displaying the output of that shell step can cause browser performance to degrade noticably. Sometimes this will result in Chrome prompting the user to kill the tab altogether because it's gone unresponsive.

Steps to recreate:
1. Create a Pipeline, using GitHub, which uses a Declarative Pipeline Jenkinsfile.
2. This Jenkinsfile should include a stage which includes the following:

        stage("I won a hat this weekend") {
            steps {
                echo "It was a very expensive hat."
                sh 'cat /var/log/jenkins/jenkins.log'
            }
        }

3. Run the build and allow it to complete.
4. Go to the stage which has the shell step which cats the Jenkins log.
5. Click on the Step which has the log file in it. In this screenshot, it's the second step, labeled as Shell Script:

6. Notice that after clicking on it, you'll see a very long log. There are 2258 lines being shown at present. At the top there's a button that says "Show complete log"


7. Click "Show complete log." In MS Edge, you'll get a thin blue line, and eventually, the tab will show as "Not responding." I was unable to get the screenshot to display the error message, I guess because when it was displaying it, the entire browser kind of went out to lunch. CPU fans spun up A LOT as well.