Branch discovery configuration in Jenkins - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable branch discovery in Jenkins Multibranch Pipeline.

Jenkins

branchSources {
  git {
    id('1234')
    remote('https://github.com/example/repo.git')
    [1]
  }
}

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

AbranchDiscovery { strategyId(2) }

BbranchDiscovery { strategyId(1) }

CbranchDiscovery { strategyId(3) }

DbranchDiscovery { strategyId(4) }

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong strategyId disables branch discovery.

The branchDiscovery { strategyId(2) } enables discovering all branches.

2fill in blank

medium

Complete the code to configure Jenkins to discover pull requests from origin.

Jenkins

branchSources {
  git {
    id('5678')
    remote('https://github.com/example/repo.git')
    pullRequestDiscovery {
      [1]
    }
  }
}

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

AstrategyId(2)

BstrategyId(1)

CstrategyId(3)

DstrategyId(4)

Attempts:

3 left

💡 Hint

Common Mistakes

Using strategyId for fork PRs instead of origin PRs.

Strategy ID 3 discovers pull requests from origin repository only.

3fill in blank

hard

Fix the error in the branch discovery configuration to correctly discover branches.

Jenkins

branchSources {
  git {
    id('91011')
    remote('https://github.com/example/repo.git')
    branchDiscovery {
      [1]
    }
  }
}

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

AstrategyId(0)

BstrategyId(5)

CstrategyId(1)

DstrategyId(2)

Attempts:

3 left

💡 Hint

Common Mistakes

Using invalid strategyId causes Jenkins to ignore branches.

Strategy ID 2 is the correct value to discover all branches.

4fill in blank

hard

Fill both blanks to configure Jenkins to discover branches and pull requests from forks.

Jenkins

branchSources {
  git {
    id('121314')
    remote('https://github.com/example/repo.git')
    branchDiscovery {
      [1]
    }
    pullRequestDiscovery {
      [2]
    }
  }
}

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

AstrategyId(2)

BstrategyId(1)

CstrategyId(4)

DstrategyId(3)

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up strategy IDs for branch and PR discovery.

Use strategyId 2 for branch discovery and strategyId 4 for pull requests from forks.

5fill in blank

hard

Fill all three blanks to configure Jenkins Multibranch Pipeline for branch discovery, origin PRs, and fork PRs.

Jenkins

branchSources {
  git {
    id('151617')
    remote('https://github.com/example/repo.git')
    branchDiscovery {
      [1]
    }
    pullRequestDiscovery {
      strategyId([2])
    }
    pullRequestDiscovery {
      strategyId([3])
    }
  }
}

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

AstrategyId(2)

B3

C4

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing strategy IDs for origin and fork PRs.

Branch discovery uses strategyId 2. Pull request discovery uses strategyId 3 for origin PRs and 4 for fork PRs.

Practice

1.

What is the main purpose of branch discovery in Jenkins?

easy

A. To merge branches automatically before building

B. To manually select branches for building

C. To automatically find and build all branches in a repository

D. To delete old branches from the repository

Solution

1. Step 1: Understand branch discovery concept

   Branch discovery is designed to find all branches automatically in a source code repository.

2. Step 2: Identify the purpose in Jenkins

   Jenkins uses branch discovery to keep builds updated without manual intervention.

3. Final Answer:

   To automatically find and build all branches in a repository -> Option C

4. Quick Check:

   Branch discovery = automatic branch finding [OK]

Hint: Branch discovery means Jenkins finds branches automatically [OK]

Common Mistakes:

• Thinking branch discovery requires manual branch selection
• Confusing branch discovery with branch deletion
• Assuming branch discovery merges branches

2.

Which strategyId value in Jenkins branch discovery configuration finds all branches including PRs?

easy

A. 4

B. 2

C. 1

D. 3

Solution

1. Step 1: Recall strategyId meanings

   In Jenkins, strategyId 3 means discover all branches including pull requests.

2. Step 2: Match strategyId to description

   StrategyId 1 is for only branches, 2 is for branches and PRs from origin, 3 includes all branches and PRs, 4 is for PRs only.

3. Final Answer:

   3 -> Option D

4. Quick Check:

   strategyId 3 = all branches + PRs [OK]

Hint: strategyId 3 includes all branches and PRs [OK]

Common Mistakes:

• Confusing strategyId 1 with including PRs
• Using strategyId 4 which only finds PRs
• Assuming strategyId 2 includes PRs

3.

Given this Jenkins branch discovery snippet:

{"strategyId": 1}

Which branches will Jenkins discover?

medium

A. Only branches that are not pull requests

B. All branches including pull requests

C. Only pull request branches

D. No branches will be discovered

Solution

1. Step 1: Understand strategyId 1 meaning

   StrategyId 1 means discover only branches, excluding pull requests.

2. Step 2: Apply to the snippet

   The snippet uses strategyId 1, so Jenkins finds only normal branches, not PRs.

3. Final Answer:

   Only branches that are not pull requests -> Option A

4. Quick Check:

   strategyId 1 = branches only [OK]

Hint: strategyId 1 excludes PRs, finds only branches [OK]

Common Mistakes:

• Assuming strategyId 1 includes PRs
• Thinking strategyId 1 finds no branches
• Confusing strategyId 1 with strategyId 3

4.

You configured Jenkins with {"strategyId": 5} for branch discovery. What is the likely result?

medium

A. Jenkins discovers all branches and PRs correctly

B. Jenkins throws a configuration error or ignores the setting

C. Jenkins discovers only pull requests

D. Jenkins discovers no branches but builds anyway

Solution

1. Step 1: Check valid strategyId values

   Valid strategyId values are 1, 2, 3, and 4. 5 is invalid.

2. Step 2: Predict Jenkins behavior on invalid strategyId

   Jenkins will likely throw an error or ignore the invalid value, causing no discovery.

3. Final Answer:

   Jenkins throws a configuration error or ignores the setting -> Option B

4. Quick Check:

   Invalid strategyId = error or ignore [OK]

Hint: Use only valid strategyId 1-4 to avoid errors [OK]

Common Mistakes:

• Assuming strategyId 5 works like 3 or 4
• Expecting Jenkins to discover branches anyway
• Ignoring configuration errors

5.

You want Jenkins to build only branches that start with feature/ and ignore others. Which branch discovery configuration should you use?

hard

A. Use {"strategyId": 1} with an additional branch filter for feature/*

B. Use {"strategyId": 3} without any filters

C. Use {"strategyId": 2} and disable branch filtering

D. Use {"strategyId": 4} with a filter for feature/*

Solution

1. Step 1: Choose strategyId for branches only

   StrategyId 1 discovers only branches (excluding PRs), suitable for filtering branches.

2. Step 2: Apply branch filter for prefix

   Adding a filter for branches starting with 'feature/' limits builds to those branches only.

3. Final Answer:

   Use {"strategyId": 1} with an additional branch filter for feature/* -> Option A

4. Quick Check:

   strategyId 1 + filter = feature branches only [OK]

Hint: Combine strategyId 1 with branch filter for prefix [OK]

Common Mistakes:

• Using strategyId 3 without filters builds all branches and PRs
• Disabling filters causes all branches to build
• Using strategyId 4 only finds PRs, not branches