Your First Workflow

Lesson 1 of 10 · 4 minutes

A workflow is a YAML file with a list of steps. Each step runs a command, and depends says which steps must finish before it starts.

The workflow

curl -fsSLO https://docs.dagu.sh/tutorial/dags/tutorial-01-first-workflow.yaml

# Dagu tutorial, lesson 1: https://docs.dagu.sh/tutorial/first-workflow
description: Four steps; lint and test run in parallel
type: graph

steps:
  - id: checkout
    run: echo "Fetched the source code"

  - id: lint
    run: sleep 1 && echo "Lint passed"
    depends: checkout

  - id: test
    run: sleep 2 && echo "12 tests passed"
    depends: checkout

  - id: package
    run: echo "Packaged app.tar.gz"
    depends: [lint, test]

• id names a step. Other steps refer to it by this name.
• run is the shell command the step runs.
• depends lists the steps that must succeed first. lint and test both wait for checkout, and package waits for both of them.
• type: graph is the default. Steps that do not depend on each other run in parallel, so lint and test start together.

Watch it run

2.2s / 2.2sSucceeded

packagerunSucceeded

Packaged app.tar.gz

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

lint and test start at the same time. package starts only after the slower test finishes.

Run it yourself

dagu start tutorial-01-first-workflow.yaml

The command prints each step with its status and output, then the result. To run it from the Web UI instead, open Workflows, select tutorial-01-first-workflow, and select Start.

Before running a workflow you just edited, check it without running anything:

dagu validate tutorial-01-first-workflow.yaml

Try it

1. Make test fail by changing its command to exit 1, then run the workflow again. What happens to package?
2. Remove depends: checkout from lint. When does lint start now?

Answers

1. The run fails, and package ends as Aborted without running. A step starts only when every step it depends on has succeeded.
2. Immediately, at the same time as checkout. A step without depends has nothing to wait for. To run every step in the order written, without depends, set type: chain instead of type: graph.

Go deeper: Workflow basics →