Create Trigger

Generate Harness Trigger YAML and push to Harness via MCP.

Instructions

1. Identify trigger type - Webhook (Git events), Scheduled (cron), Artifact (registry updates), or Manifest (Helm chart updates)
2. Configure conditions - Branch filters, payload conditions, cron expression, or artifact path
3. Generate YAML using the templates below, referencing the target pipeline
4. Create via MCP using harness_create with resource_type trigger
5. Verify webhook registration - For webhook triggers, confirm the webhook is registered in the Git provider

Trigger Types

• Webhook - GitHub, GitLab, Bitbucket, Azure Repos, Custom
• Scheduled - Cron-based scheduling
• Artifact - Docker Hub, ECR, GCR, ACR, Nexus
• Manifest - Helm chart updates

Webhook Trigger (GitHub)

trigger:
  name: PR Trigger
  identifier: pr_trigger
  orgIdentifier: default
  projectIdentifier: my_project
  pipelineIdentifier: ci_pipeline
  source:
    type: Webhook
    spec:
      type: Github
      spec:
        type: PullRequest
        spec:
          connectorRef: github_connector
          autoAbortPreviousExecutions: true
          payloadConditions:
            - key: targetBranch
              operator: Equals
              value: main
          headerConditions: []
          jexlCondition: ""
          actions:
            - Open
            - Reopen
            - Synchronize
  inputYaml: |
    pipeline:
      identifier: ci_pipeline
      properties:
        ci:
          codebase:
            build:
              type: PR
              spec:
                number: <+trigger.prNumber>

GitHub Event Types

• Push - Code pushed to branch
• PullRequest - PR events (Open, Close, Reopen, Synchronize, Edit)
• IssueComment - PR comments (Create, Edit, Delete)
• Release - Release events (Create, Publish, Edit)

Webhook Trigger (GitLab)

trigger:
  name: GitLab Push
  identifier: gitlab_push
  pipelineIdentifier: ci_pipeline
  source:
    type: Webhook
    spec:
      type: Gitlab
      spec:
        type: Push
        spec:
          connectorRef: gitlab_connector
          payloadConditions:
            - key: ref
              operator: Contains
              value: main

Scheduled (Cron) Trigger

trigger:
  name: Nightly Build
  identifier: nightly_build
  orgIdentifier: default
  projectIdentifier: my_project
  pipelineIdentifier: ci_pipeline
  source:
    type: Scheduled
    spec:
      type: Cron
      spec:
        expression: "0 2 * * *"    # 2 AM daily
  inputYaml: |
    pipeline:
      identifier: ci_pipeline
      properties:
        ci:
          codebase:
            build:
              type: branch
              spec:
                branch: main

Cron format: <minute> <hour> <day-of-month> <month> <day-of-week>

Artifact Trigger (Docker Registry)

trigger:
  name: New Image Trigger
  identifier: new_image
  pipelineIdentifier: deploy_pipeline
  source:
    type: Artifact
    spec:
      type: DockerRegistry
      spec:
        connectorRef: dockerhub
        imagePath: myorg/myimage
        tag: <+trigger.artifact.build>
  inputYaml: |
    pipeline:
      identifier: deploy_pipeline
      stages:
        - stage:
            identifier: deploy
            spec:
              service:
                serviceRef: my_service

Artifact Source Types

• DockerRegistry - Docker Hub
• Ecr - AWS ECR
• Gcr - Google Container Registry
• Acr - Azure Container Registry
• Nexus3Registry - Nexus
• AmazonS3 - S3 artifacts

Creating via MCP

Call MCP tool: harness_create
Parameters:
  resource_type: "trigger"
  org_id: "<organization>"
  project_id: "<project>"
  body: <trigger YAML>

To list existing triggers:

Call MCP tool: harness_list
Parameters:
  resource_type: "trigger"
  org_id: "<organization>"
  project_id: "<project>"

Payload Conditions

Filter triggers by webhook payload:

payloadConditions:
  - key: targetBranch
    operator: Equals        # Equals, NotEquals, In, NotIn, StartsWith, EndsWith, Contains, Regex
    value: main
  - key: sourceBranch
    operator: StartsWith
    value: feature/

Common keys: sourceBranch, targetBranch, ref, action, tag

Examples

• “Create a GitHub PR trigger for CI” - Webhook trigger with PullRequest type
• “Set up nightly builds at 2 AM” - Scheduled trigger with cron
• “Trigger deploy when new Docker image is pushed” - Artifact trigger with DockerRegistry
• “Create a release trigger for tags” - Webhook with Push type, tag filter

Performance Notes

• Verify payload conditions match actual webhook payloads from the Git provider.
• For cron triggers, double-check the expression — cron uses UTC timezone.
• Confirm the target pipeline identifier and inputYaml match the pipeline’s expected inputs.

Troubleshooting

Trigger Not Firing

• Verify webhook is registered in Git provider
• Check payload conditions match actual payload
• Ensure connector has correct permissions
• Test with harness_get on the trigger to verify config

Duplicate Executions

• Enable autoAbortPreviousExecutions for PR triggers
• Check for overlapping trigger conditions

Cron Not Running

• Verify cron expression syntax (5 fields, UTC timezone)
• Check pipeline identifier is correct
• Ensure trigger is enabled