Environment directive in Jenkins - Step-by-Step Execution

Process Flow - Environment directive

Start Pipeline

↓

Read environment directive

↓

Set environment variables

↓

Run pipeline steps with env vars

↓

Pipeline completes

The pipeline starts, reads the environment directive to set variables, then runs steps using those variables.

Execution Sample

Jenkins

pipeline {
  environment {
    GREETING = 'Hello'
    TARGET = 'World'
  }
  stages {
    stage('Example') {
      steps {
        echo "${GREETING}, ${TARGET}!"
      }
    }
  }
}

This Jenkins pipeline sets two environment variables and prints a greeting using them.

Process Table

Step	Action	Environment Variables Set	Output
1	Start pipeline	None yet	No output
2	Read environment directive	GREETING='Hello', TARGET='World'	No output
3	Run stage 'Example' steps	GREETING='Hello', TARGET='World'	Prints: Hello, World!
4	Pipeline completes	Environment variables cleared	Pipeline finished successfully

💡 Pipeline ends after all stages run with environment variables available

Status Tracker

Variable	Start	After Step 2	After Step 3	Final
GREETING	undefined	'Hello'	'Hello'	undefined
TARGET	undefined	'World'	'World'	undefined

Key Moments - 2 Insights

Why do environment variables disappear after the pipeline finishes?

Environment variables set in the environment directive exist only during the pipeline run (see execution_table step 4). After completion, Jenkins cleans up the environment.

Can I use environment variables in all stages once set in the environment directive?

Yes, environment variables set in the environment directive are available in all stages and steps (see execution_table step 3).

Visual Quiz - 3 Questions

Look at the execution table, at which step are the environment variables first set?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Check the 'Environment Variables Set' column in the execution_table rows

According to the variable tracker, what is the value of GREETING after step 3?

A 'Hello'

B 'World'

C undefined

D null

💡 Hint

Look at the 'GREETING' row and 'After Step 3' column in variable_tracker

If you add a new variable in the environment directive, when will it be available?

A Only in the first stage

B In all stages and steps during the pipeline run

C Only after the pipeline finishes

D Only in the last stage

💡 Hint

Refer to key_moments about variable availability and execution_table step 3

Concept Snapshot

Jenkins environment directive sets variables for the entire pipeline run.
Syntax: environment { VAR = 'value' }
Variables are available in all stages and steps.
They exist only during pipeline execution.
Use ${VAR} to access them in steps.

Full Transcript

This visual execution shows how Jenkins pipeline uses the environment directive. The pipeline starts with no environment variables. Then it reads the environment directive and sets GREETING to 'Hello' and TARGET to 'World'. These variables are available in all stages and steps, as shown when the example stage prints 'Hello, World!'. After the pipeline finishes, the environment variables are cleared. This helps keep variables scoped to the pipeline run only. Beginners often wonder why variables disappear after the run or if variables are available everywhere. This trace clarifies those points by showing variable states and pipeline steps.