Log

Write a message to stdout without running a shell command. Use action: log.write for progress markers, status messages, and values you want to expose in the DAG run log without wrapping echo in a shell step.

Basic Usage

params:
  - ENVIRONMENT: production

steps:
  - id: announce
    action: log.write
    with:
      message: "Deploying to ${ENVIRONMENT}"

The step writes this line to stdout:

Deploying to production

If message does not end with a newline, Dagu appends one.

Configuration

Field	Type	Required	Description
message	string	Yes	Message to write to stdout. Supports Dagu variable substitution.

log.write only accepts with.message. Other with fields are rejected during validation.

Variables

message is evaluated like other executor configuration fields, so it can reference params, DAG environment variables, secrets, and outputs from previous steps.

type: graph

params:
  - ENVIRONMENT: staging

steps:
  - id: version
    run: git rev-parse --short HEAD
    output: VERSION

  - id: announce
    depends: version
    action: log.write
    with:
      message: "Deploying ${VERSION} to ${ENVIRONMENT}"

Capturing Output

Because log writes to stdout, you can capture the message with output: and reuse it later.

type: graph

params:
  - VERSION: v1.2.3

steps:
  - id: release_line
    action: log.write
    with:
      message: "release=${VERSION}"
    output: RELEASE_LINE

  - id: use_release_line
    depends: release_line
    run: printf '%s\n' "${RELEASE_LINE}"

When to Use log

Use log.write when the step only needs to emit text. Use run when you need shell features such as pipelines, redirects, command substitution, or conditional logic.

log.write does not support shell commands or scripts.