commands.md

:: Commands

The core toolkit package offers a number of convenience functions for setting results, logging, registering secrets and exporting variables across actions. Sometimes, however, its useful to be able to do these things in a script or other tool.

To allow this, we provide a special :: syntax which, if logged to stdout on a new line, will allow the runner to perform special behavior on your commands. The following commands are all supported:

Set an environment variable

To set an environment variable for future out of process steps, use ::set-env:

echo "::set-env name=FOO::BAR"

Running $FOO in a future step will now return BAR

This is wrapped by the core exportVariable method which sets for future steps but also updates the variable for this step

export function exportVariable(name: string, val: string): void {}

PATH Manipulation

To prepend a string to PATH, use ::addPath:

echo "::add-path::BAR"

Running $PATH in a future step will now return BAR:{Previous Path};

This is wrapped by the core addPath method:

export function addPath(inputPath: string): void {}

Set outputs

To set an output for the step, use ::set-output:

echo "::set-output name=FOO::BAR"

Running steps.[step-id].outputs.FOO in your Yaml will now give you BAR

steps:
  - name: Set the value
    id: step_one
    run: echo "::set-output name=FOO::BAR"
  - name: Use it
    run: echo ${{ steps.step_one.outputs.FOO }}

This is wrapped by the core setOutput method:

export function setOutput(name: string, value: string): void {}

Register a secret

If a script or action does work to create a secret at runtime, it can be registered with the runner to be masked in logs.

To mask a value in the logs, use ::add-mask:

echo "::add-mask::mysecretvalue"

This is wrapped by the core setSecret method

function setSecret(secret: string): void {}

Now, future logs containing BAR will be masked. E.g. running echo "Hello FOO BAR World" will now print Hello FOO **** World.

WARNING The add-mask and setSecret commands only support single line secrets. To register a multiline secrets you must register each line individually otherwise it will not be masked.

WARNING Do not mask short values if you can avoid it, it could render your output unreadable (and future steps' output as well). For example, if you mask the letter l, running echo "Hello FOO BAR World" will now print He*********o FOO BAR Wor****d

Group and Ungroup Log Lines

Emitting a group with a title will instruct the logs to create a collapsable region up to the next ungroup command.

echo "::group::my title"   
echo "::endgroup::"

This is wrapped by the core methods:

function startGroup(name: string): void {}
function endGroup(): void {}

Problem Matchers

Problems matchers can be used to scan a build's output to automatically surface lines to the user that matches the provided pattern. A file path to a .json Problem Matcher must be provided. See Problem Matchers for more information on how to define a Problem Matcher.

echo "::add-matcher::eslint-compact-problem-matcher.json"   
echo "::remove-matcher owner=eslint-compact::"

add-matcher takes a path to a Problem Matcher file remove-matcher removes a Problem Matcher by owner

Save State

Save state to be used in the corresponding wrapper (finally) post job entry point.

echo "::save-state name=FOO::foovalue"

Log Level

Finally, there are several commands to emit different levels of log output:

log level	example usage
debug	echo "::debug::My debug message"
warning	echo "::warning::My warning message"
error	echo "::error::My error message"

Command Prompt

CMD processes the " character differently from other shells when echoing. In CMD, the above snippets should have the " characters removed in order to correctly process. For example, the set output command would be:

echo ::set-output name=FOO::BAR