Webhook triggers from GitHub/GitLab in Jenkins - Step-by-Step Execution

Process Flow - Webhook triggers from GitHub/GitLab

Code pushed to GitHub/GitLab

↓

Webhook sends HTTP POST to Jenkins

↓

Jenkins receives webhook

↓

Jenkins matches webhook to job trigger

↓

Jenkins starts the job

↓

Job runs build/test/deploy steps

↓

Job completes and reports status

When code is pushed, GitHub/GitLab sends a webhook to Jenkins, which triggers the matching job to run automatically.

Execution Sample

Jenkins

pipeline {
  agent any
  triggers {
    githubPush()
  }
  stages {
    stage('Build') { steps { echo 'Building...' } }
  }
}

This Jenkins pipeline triggers automatically when GitHub sends a push webhook, then runs the Build stage.

Process Table

Step	Event	Jenkins Action	Job Status	Output
1	Code pushed to GitHub	Webhook sent to Jenkins	N/A	HTTP POST sent
2	Jenkins receives webhook	Matches job trigger	N/A	Trigger matched: githubPush()
3	Job starts	Build stage runs	Running	Echo: Building...
4	Job completes	Reports success	Success	Build finished successfully
5	Waiting for next webhook	Idle	Idle	Ready for next push

💡 Job completes after build stage, Jenkins waits for next webhook event

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
Webhook Received	False	True	True	True	True	False
Job Status	Idle	Idle	Triggered	Running	Success	Idle

Key Moments - 3 Insights

Why does Jenkins start the job only after receiving the webhook?

Because Jenkins waits for the webhook HTTP POST from GitHub/GitLab to know when to trigger the job, as shown in execution_table step 2.

What happens if the webhook does not match any job trigger?

Jenkins ignores the webhook and does not start any job, so the job status stays Idle, as no trigger matched in step 2.

Why is the job status 'Running' during the build stage?

Because Jenkins is actively executing the build steps after trigger, as shown in step 3 where the job status changes to Running.

Visual Quiz - 3 Questions

Look at the execution table, what is the job status at step 3?

A Running

B Success

C Idle

D Triggered

💡 Hint

Check the 'Job Status' column in execution_table row for step 3

At which step does Jenkins match the webhook to the job trigger?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look at the 'Jenkins Action' column in execution_table to find when matching happens

If the webhook was never received, what would the final job status be?

A Running

B Success

C Idle

D Triggered

💡 Hint

Refer to variable_tracker for 'Webhook Received' and 'Job Status' changes

Concept Snapshot

Webhook triggers from GitHub/GitLab:
- GitHub/GitLab sends HTTP POST webhook on code push
- Jenkins listens and matches webhook to job triggers
- Matching triggers start Jenkins jobs automatically
- Jobs run build/test/deploy stages
- Jenkins reports job status after completion

Full Transcript

When a developer pushes code to GitHub or GitLab, these platforms send a webhook, which is a simple HTTP POST message, to Jenkins. Jenkins listens for these webhooks and checks if any job is configured to trigger on such events. If a match is found, Jenkins starts the job automatically. The job runs its defined stages like build or test. After the job finishes, Jenkins reports the status and waits for the next webhook. This process automates running jobs right after code changes without manual intervention.