Approvals and Human Input

Lesson 9 of 10 · 3 minutes

Some steps should wait for a person: a review before a release, or a choice only a person can make. The run pauses as Waiting and continues when someone responds in the Web UI.

The workflow

curl -fsSLO https://docs.dagu.sh/tutorial/dags/tutorial-09-approvals.yaml

# Dagu tutorial, lesson 9: https://docs.dagu.sh/tutorial/approvals
description: Pause for a review and ask a person for input
type: graph

steps:
  - id: build
    run: echo "Built release 1.4.0"
    approval:
      prompt: Check the build output, then approve the release

  - id: choose_target
    action: human.task
    with:
      prompt: Where should release 1.4.0 go?
      form:
        type: object
        properties:
          environment:
            type: string
            enum: [staging, production]
        required: [environment]
    depends: build

  - id: deploy
    run: echo "Deploying 1.4.0 to ${steps.choose_target.outputs.environment}"
    depends: choose_target

• approval on build pauses the run after the step succeeds, until someone approves its output.
• action: human.task pauses for a form. form describes the fields as a JSON schema. Here, environment must be one of two values.
• ${steps.choose_target.outputs.environment} reads the answer. Every form field becomes an output of the task.

Watch it run

5.6s / 5.6sSucceeded

deployrunSucceeded

Deploying 1.4.0 to production

A recorded run of this lesson's DAG. Select a step to see its log.

The run waits twice: for the approval of build, then for the form. In this recording, a reviewer approved the build and picked production.

Run it yourself

1. In the Web UI, open tutorial-09-approvals and select Start. build runs, then the run shows Waiting.
2. Select Open actions on the canvas, or open Activity → Actions. Review the output of build and select Approve.
3. The form for choose_target appears in the same tab. Pick an environment and submit it.
4. deploy runs and prints the environment you picked.

A waiting run holds no process or worker slot, so it can wait for as long as the review takes.

Try it

1. Start another run and select the reject button in the workflow bar while it waits. How does the run end?
2. Add a second form field, notify, of type: boolean, and print it in deploy.

Answers

1. As Rejected. The steps after the rejected one do not run.
2. Add the property to form, then read it like any other output:

type: graph

steps:
  - id: choose_target
    action: human.task
    with:
      prompt: Where should release 1.4.0 go?
      form:
        type: object
        properties:
          environment:
            type: string
            enum: [staging, production]
          notify:
            type: boolean
            default: true
        required: [environment]

  - id: deploy
    run: echo "Deploying to ${steps.choose_target.outputs.environment}, notify=${steps.choose_target.outputs.notify}"
    depends: choose_target

Go deeper: Human-in-the-loop →