Build history and logs in Jenkins - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print the last build number in Jenkins pipeline.

Jenkins

echo "Last build number is: [1]"

Drag options to blanks, or click blank then click option'

AcurrentBuild.number

Bbuild.number

ClastBuild.number

Dbuilds.number

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'build.number' which is undefined in pipeline context.

In Jenkins pipeline, currentBuild.number gives the current build number.

2fill in blank

medium

Complete the code to archive the build logs as artifacts in Jenkins pipeline.

Jenkins

archiveArtifacts artifacts: '[1]', fingerprint: true

Drag options to blanks, or click blank then click option'

Abuild.log

B**/build.log

Clogs/build.log

D**/logs/*.log

Attempts:

3 left

💡 Hint

Common Mistakes

Using a single file name which may not match all logs.

The pattern **/logs/*.log archives all log files inside any 'logs' folder.

3fill in blank

hard

Fix the error in the code to get the build duration in seconds.

Jenkins

def duration = currentBuild.[1] / 1000

Drag options to blanks, or click blank then click option'

Aduration

BdurationInMillis

CtimeMillis

DbuildDuration

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'duration' which is not a property of currentBuild.

currentBuild.durationInMillis holds the build duration in milliseconds.

4fill in blank

hard

Fill both blanks to filter build logs for errors and save them.

Jenkins

def errors = sh(script: 'grep [1] build.log', returnStdout: true).trim()
writeFile file: 'errors.txt', text: [2]

Drag options to blanks, or click blank then click option'

A"ERROR"

Berrors

C"WARNING"

Derrors.trim()

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'WARNING' instead of 'ERROR' for filtering.

Use grep "ERROR" to find error lines and save the variable errors to file.

5fill in blank

hard

Fill all three blanks to create a map of build numbers to their result status.

Jenkins

def buildResults = [[1]: [2] for build in currentBuild.rawBuild.project.builds if build.number > [3]]

Drag options to blanks, or click blank then click option'

Abuild.number

Bbuild.result.toString()

C10

Dbuild.status

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'build.status' which is not a valid property.

Use build.number as key, build.result.toString() as value, and filter builds with number greater than 10.

Practice

1. What does the Build History section in Jenkins primarily show?

easy

A. The configuration settings of the Jenkins server

B. The detailed logs of the current build

C. A list of past builds with their results and status

D. The list of users who accessed Jenkins

Solution

1. Step 1: Understand the purpose of Build History

   The Build History section shows a timeline of previous builds with their success or failure status.

2. Step 2: Differentiate from build logs and settings

   Build logs show detailed steps, not the summary list. Configuration and user lists are separate sections.

3. Final Answer:

   A list of past builds with their results and status -> Option C

4. Quick Check:

   Build History = past build results [OK]

Hint: Build History = summary of past builds, not logs [OK]

Common Mistakes:

• Confusing Build History with build logs
• Thinking Build History shows Jenkins settings
• Assuming Build History lists users

2. Which Jenkins UI element do you click to view the detailed logs of a specific build?

easy

A. The build number link in Build History

B. The 'Configure' button on the job page

C. The 'New Item' button on the dashboard

D. The 'Manage Jenkins' link

Solution

1. Step 1: Identify where build logs are accessed

   Clicking the build number in Build History opens that build's details including logs.

2. Step 2: Exclude unrelated UI elements

   'Configure' edits job settings, 'New Item' creates jobs, 'Manage Jenkins' is for admin tasks.

3. Final Answer:

   The build number link in Build History -> Option A

4. Quick Check:

   Build logs accessed via build number link [OK]

Hint: Click build number in history to see logs [OK]

Common Mistakes:

• Clicking 'Configure' instead of build number
• Trying 'New Item' to see logs
• Using 'Manage Jenkins' for build logs

3. Given a Jenkins job with three builds: #1 (SUCCESS), #2 (FAILURE), #3 (SUCCESS). What will the Build History show after build #3 completes?

medium

A. Build #3 FAILURE, Build #2 SUCCESS, Build #1 FAILURE

B. Build #1 SUCCESS, Build #2 FAILURE, Build #3 SUCCESS

C. Build #2 FAILURE only

D. Build #3 SUCCESS, Build #2 FAILURE, Build #1 SUCCESS

Solution

1. Step 1: Understand Build History order

   Build History lists builds in reverse order: newest first.

2. Step 2: Match build statuses and order

   Build #3 is latest and successful, then #2 failed, then #1 successful.

3. Final Answer:

   Build #3 SUCCESS, Build #2 FAILURE, Build #1 SUCCESS -> Option D

4. Quick Check:

   Newest builds appear first in history [OK]

Hint: Build History shows newest builds first [OK]

Common Mistakes:

• Reading builds oldest to newest
• Mixing up build statuses
• Assuming only failed builds show

4. You try to view build logs but see an empty page. What is the most likely cause?

medium

A. You clicked the wrong build number

B. The build has not started or produced logs yet

C. Jenkins server is offline

D. You lack permission to view logs

Solution

1. Step 1: Consider build status and logs availability

   If the build is queued or just started, logs may be empty.

2. Step 2: Exclude other causes

   Wrong build number still shows logs if build exists; server offline shows error; permission issues show access denied.

3. Final Answer:

   The build has not started or produced logs yet -> Option B

4. Quick Check:

   Empty logs usually mean build not started [OK]

Hint: Empty logs = build not started or no output yet [OK]

Common Mistakes:

• Assuming server offline causes empty logs
• Thinking wrong build number shows empty logs
• Ignoring permission errors

5. You want to analyze why a Jenkins build failed by checking logs but the logs are very long. Which Jenkins feature helps you quickly find errors in the logs?

hard

A. The 'Console Output' search box to filter keywords

B. The 'Build History' to rerun the build

C. The 'Configure' page to edit build steps

D. The 'Manage Jenkins' to restart the server

Solution

1. Step 1: Identify how to search logs

   Jenkins Console Output page often has a search/filter box to find keywords like 'error'.

2. Step 2: Exclude unrelated features

   Build History shows past builds but no search; Configure edits jobs; Manage Jenkins is for admin tasks.

3. Final Answer:

   The 'Console Output' search box to filter keywords -> Option A

4. Quick Check:

   Use Console Output search to find errors fast [OK]

Hint: Use Console Output search box to find errors fast [OK]

Common Mistakes:

• Trying to find errors via Build History
• Editing job instead of checking logs
• Restarting Jenkins unnecessarily