Environment variables access in Jenkins - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to access the environment variable named 'HOME' in a Jenkins pipeline.

Jenkins

echo "Home directory is: $[1]"

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

AHOME_DIR

Bhome

Cenv.HOME

DHOME

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase variable names like $home

Using incorrect syntax like env.HOME without proper context

In Jenkins pipeline scripts, environment variables can be accessed using the $ sign followed by the variable name in uppercase, like $HOME.

2fill in blank

medium

Complete the code to print the environment variable 'BUILD_NUMBER' inside a Jenkins pipeline script.

Jenkins

echo "Build number is: $[1]"

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

ABUILD_NUMBER

Benv.BUILD_NUMBER

Cbuild_number

DBuildNumber

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase variable names

Trying to access variables as env.BUILD_NUMBER without proper syntax

Jenkins environment variables are uppercase and accessed with $ followed by the variable name, so $BUILD_NUMBER is correct.

3fill in blank

hard

Fix the error in accessing the environment variable 'PATH' in this Jenkins pipeline snippet.

Jenkins

echo "System path: $[1]"

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

APATH

Bpath

Cenv.PATH

D$PATH

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'env.PATH' which is not valid in shell steps

Using lowercase 'path' which is not recognized

In Jenkins pipeline shell steps, environment variables are accessed with $ followed by the variable name in uppercase without 'env.' prefix.

4fill in blank

hard

Fill both blanks to correctly access environment variables 'USER' and 'WORKSPACE' in a Jenkins pipeline script.

Jenkins

echo "User: $[1], Workspace: $[2]"

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

AUSER

Buser

CWORKSPACE

Dworkspace

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase variable names

Mixing uppercase and lowercase incorrectly

Environment variables in Jenkins are uppercase and accessed with $ followed by the variable name, so $USER and $WORKSPACE are correct.

5fill in blank

hard

Fill all three blanks to create a map of environment variables 'BRANCH_NAME', 'JOB_NAME', and 'BUILD_ID' in a Jenkins pipeline Groovy script.

Jenkins

def envMap = [branch: env.[1], job: env.[2], build: env.[3]]

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

ABRANCH_NAME

BJOB_NAME

CBUILD_ID

DBUILD_NUMBER

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase variable names

Using wrong variable names like BUILD_NUMBER instead of BUILD_ID

In Jenkins pipeline Groovy scripts, environment variables are accessed via 'env.VARIABLE_NAME' with uppercase names like BRANCH_NAME, JOB_NAME, and BUILD_ID.

Practice

1. In a Jenkins Pipeline script, how do you access an environment variable named BUILD_NUMBER?

easy

A. Using BUILD_NUMBER directly without prefix

B. Using env.BUILD_NUMBER

C. Using getEnv('BUILD_NUMBER')

D. Using $BUILD_NUMBER inside the script block

Solution

1. Step 1: Understand Jenkins environment variable access

   Jenkins Pipeline exposes environment variables via the env object.

2. Step 2: Access the variable using the correct syntax

   You access BUILD_NUMBER as env.BUILD_NUMBER in the script.

3. Final Answer:

   Using env.BUILD_NUMBER -> Option B

4. Quick Check:

   env.VARIABLE_NAME = correct access [OK]

Hint: Always prefix environment variables with env. in Jenkins [OK]

Common Mistakes:

• Trying to use variable name without env prefix
• Using shell-style $VARIABLE inside Groovy script
• Calling non-existent getEnv() method

2. Which of the following is the correct syntax to print the environment variable JOB_NAME in a Jenkins Pipeline script block?

easy

A. println("JOB_NAME")

B. echo $JOB_NAME

C. println(env.JOB_NAME)

D. print(JOB_NAME)

Solution

1. Step 1: Identify the correct way to print env variables in Groovy script

   In Jenkins Pipeline Groovy scripts, use println(env.VARIABLE) to print environment variables.

2. Step 2: Check each option

   println("JOB_NAME") prints the string "JOB_NAME" literally. echo $JOB_NAME uses shell syntax, invalid in Groovy. print(JOB_NAME) attempts to print JOB_NAME directly, but it's not available in Groovy scope without env prefix.

3. Final Answer:

   println(env.JOB_NAME) -> Option C

4. Quick Check:

   Use println(env.VARIABLE) to print env vars in script [OK]

Hint: Use println(env.VARIABLE) inside script blocks [OK]

Common Mistakes:

• Using shell syntax like $VARIABLE inside Groovy
• Printing variable name as string instead of value
• Trying to access variables without env. prefix

3. Given this Jenkins Pipeline snippet:

pipeline {
  agent any
  stages {
    stage('Print Env') {
      steps {
        script {
          echo "Branch is: ${env.BRANCH_NAME}"
        }
      }
    }
  }
}

What will be the output if the environment variable BRANCH_NAME is set to feature-123?

medium

A. Branch is: feature-123

B. Branch is: ${env.BRANCH_NAME}

C. Branch is: BRANCH_NAME

D. Error: BRANCH_NAME not found

Solution

1. Step 1: Understand string interpolation in Jenkins Pipeline

   Using double quotes with ${env.BRANCH_NAME} interpolates the variable value.

2. Step 2: Substitute the environment variable value

   Since BRANCH_NAME is set to "feature-123", the output will be "Branch is: feature-123".

3. Final Answer:

   Branch is: feature-123 -> Option A

4. Quick Check:

   Double quotes + ${env.VAR} = variable value [OK]

Hint: Use double quotes and ${env.VAR} for variable interpolation [OK]

Common Mistakes:

• Using single quotes which prevent interpolation
• Printing variable name literally without ${}
• Assuming env variables are undefined

4. You wrote this Jenkins Pipeline snippet:

pipeline {
  agent any
  environment {
    MY_VAR = 'hello'
  }
  stages {
    stage('Test') {
      steps {
        script {
          echo env.MY_VAR
        }
      }
    }
  }
}

But the output is empty. What is the likely cause?

medium

A. The environment block syntax is incorrect; use MY_VAR='hello' with quotes and no spaces around =

B. Environment variables must be accessed as env['MY_VAR'] not env.MY_VAR

C. The environment variable was not set correctly; use MY_VAR='hello' without spaces

D. You cannot access environment variables inside script blocks

Solution

1. Step 1: Check environment block syntax

   In Jenkins Pipeline, environment variables must be assigned with no spaces around = and values in quotes, like MY_VAR='hello'.

2. Step 2: Identify the syntax error in the snippet

   The snippet uses MY_VAR = 'hello' with spaces around = which is invalid and causes the variable not to be set.

3. Final Answer:

   The environment block syntax is incorrect; use MY_VAR='hello' with quotes and no spaces around = -> Option A

4. Quick Check:

   Use no spaces around = in environment block [OK]

Hint: No spaces around = in environment block assignments [OK]

Common Mistakes:

• Adding spaces around = in environment variable assignment
• Trying to access env vars incorrectly
• Assuming script block can't access env vars

5. You want to pass a secret API key stored as an environment variable API_KEY to a shell command in Jenkins Pipeline. Which is the best way to do this securely?

hard

A. Use sh "curl -H 'Authorization: Bearer $API_KEY' https://api.example.com"

B. Use sh(script: "curl -H 'Authorization: Bearer ${env.API_KEY}' https://api.example.com")

C. Use sh(script: "curl -H 'Authorization: Bearer $API_KEY' https://api.example.com", environment: [API_KEY: env.API_KEY])

D. Use Jenkins credentials binding plugin to inject API_KEY and access it as env.API_KEY inside sh

Solution

1. Step 1: Understand secure handling of secrets in Jenkins

   Secrets like API keys should be stored in Jenkins credentials and injected securely, not hardcoded or exposed in logs.

2. Step 2: Use credentials binding plugin

   This plugin injects secrets as environment variables during the build, accessible as env.API_KEY inside sh without exposing them in logs.

3. Final Answer:

   Use Jenkins credentials binding plugin to inject API_KEY and access it as env.API_KEY inside sh -> Option D

4. Quick Check:

   Use credentials plugin for secrets, not plain env vars [OK]

Hint: Use Jenkins credentials plugin for secrets, not plain env vars [OK]

Common Mistakes:

• Passing secrets directly in shell commands risking exposure
• Using string interpolation exposing secrets in logs
• Not using Jenkins credentials plugin for sensitive data