About YAML syntax for GitHub Actions
All actions require a metadata file. The metadata filename must be either action.yml
or action.yaml
. The data in the metadata file defines the inputs, outputs, and runs configuration for your action.
Action metadata files use YAML syntax. If you're new to YAML, you can read Learn YAML in five minutes.
name
Required The name of your action. GitHub displays the name
in the Actions tab to help visually identify actions in each job.
author
Optional The name of the action's author.
description
Required A short description of the action.
inputs
Optional Input parameters allow you to specify data that the action expects to use during runtime. GitHub stores input parameters as environment variables. We recommend using lowercase input ids.
Example: Specifying inputs
This example configures two inputs: num-octocats
and octocat-eye-color
. The num-octocats
input is not required and will default to a value of 1
. octocat-eye-color
is required and has no default value.
Note
Actions using required: true
will not automatically return an error if the input is not specified.
Workflow files that use this action can use the with
keyword to set an input value for octocat-eye-color
. For more information about the with
syntax, see Workflow syntax for GitHub Actions.
inputs:
num-octocats:
description: 'Number of Octocats'
required: false
default: '1'
octocat-eye-color:
description: 'Eye color of the Octocats'
required: true
When you specify an input, GitHub creates an environment variable for the input with the name INPUT_<VARIABLE_NAME>
. The environment variable created converts input names to uppercase letters and replaces spaces with _
characters.
If the action is written using a composite, then it will not automatically get INPUT_<VARIABLE_NAME>
. With composite actions you can use inputs
Accessing contextual information about workflow runs to access action inputs.
To access the environment variable in a Docker container action, you must pass the input using the args
keyword in the action metadata file. For more information about the action metadata file for Docker container actions, see Creating a Docker container action.
For example, if a workflow defined the num-octocats
and octocat-eye-color
inputs, the action code could read the values of the inputs using the INPUT_NUM-OCTOCATS
and INPUT_OCTOCAT-EYE-COLOR
environment variables.
inputs.<input_id>
Required A string
identifier to associate with the input. The value of <input_id>
is a map of the input's metadata. The <input_id>
must be a unique identifier within the inputs
object. The <input_id>
must start with a letter or _
and contain only alphanumeric characters, -
, or _
.
inputs.<input_id>.description
Required A string
description of the input parameter.
inputs.<input_id>.required
Optional A boolean
to indicate whether the action requires the input parameter. Set to true
when the parameter is required.
inputs.<input_id>.default
Optional A string
representing the default value. The default value is used when an input parameter isn't specified in a workflow file.
inputs.<input_id>.deprecationMessage
Optional If the input parameter is used, this string
is logged as a warning message. You can use this warning to notify users that the input is closing down and mention any alternatives.
outputs
for Docker container and JavaScript actions
Optional Output parameters allow you to declare data that an action sets. Actions that run later in a workflow can use the output data set in previously run actions. For example, if you had an action that performed the addition of two inputs (x + y = z), the action could output the sum (z) for other actions to use as an input.
Outputs are Unicode strings, and can be a maximum of 1 MB. The total of all outputs in a workflow run can be a maximum of 50 MB.
If you don't declare an output in your action metadata file, you can still set outputs and use them in a workflow. For more information on setting outputs in an action, see Workflow commands for GitHub Actions.
Example: Declaring outputs for Docker container and JavaScript actions
outputs:
sum: # id of the output
description: 'The sum of the inputs'
outputs.<output_id>
Required A string
identifier to associate with the output. The value of <output_id>
is a map of the output's metadata. The <output_id>
must be a unique identifier within the outputs
object. The <output_id>
must start with a letter or _
and contain only alphanumeric characters, -
, or _
.
outputs.<output_id>.description
Required A string
description of the output parameter.
outputs
for composite actions
Optional outputs
use the same parameters as outputs.<output_id>
and outputs.<output_id>.description
(see outputs
for Docker container and JavaScript actions), but also includes the value
token.
Outputs are Unicode strings, and can be a maximum of 1 MB. The total of all outputs in a workflow run can be a maximum of 50 MB.
Example: Declaring outputs for composite actions
outputs:
random-number:
description: "Random number"
value: ${{ steps.random-number-generator.outputs.random-id }}
runs:
using: "composite"
steps:
- id: random-number-generator
run: echo "random-id=$(echo $RANDOM)" >> $GITHUB_OUTPUT
shell: bash
outputs.<output_id>.value
Required The value that the output parameter will be mapped to. You can set this to a string
or an expression with context. For example, you can use the steps
context to set the value
of an output to the output value of a step.
For more information on how to use context syntax, see Accessing contextual information about workflow runs.
runs
Required Specifies whether this is a JavaScript action, a composite action, or a Docker container action and how the action is executed.
runs
for JavaScript actions
Required Configures the path to the action's code and the runtime used to execute the code.
Example: Using Node.js v20
runs:
using: 'node20'
main: 'main.js'
runs.using
for JavaScript actions
Required The runtime used to execute the code specified in main
.
- Use
node20
for Node.js v20.
runs.main
Required The file that contains your action code. The runtime specified in using
executes this file.
runs.pre
Optional Allows you to run a script at the start of a job, before the main:
action begins. For example, you can use pre:
to run a prerequisite setup script. The runtime specified with the using
syntax will execute this file. The pre:
action always runs by default but you can override this using runs.pre-if
.
In this example, the pre:
action runs a script called setup.js
:
runs:
using: 'node20'
pre: 'setup.js'
main: 'index.js'
post: 'cleanup.js'
runs.pre-if
Optional Allows you to define conditions for the pre:
action execution. The pre:
action will only run if the conditions in pre-if
are met. If not set, then pre-if
defaults to always()
. In pre-if
, status check functions evaluate against the job's status, not the action's own status.
Note that the step
context is unavailable, as no steps have run yet.
In this example, cleanup.js
only runs on Linux-based runners:
pre: 'cleanup.js'
pre-if: runner.os == 'linux'
runs.post
Optional Allows you to run a script at the end of a job, once the main:
action has completed. For example, you can use post:
to terminate certain processes or remove unneeded files. The runtime specified with the using
syntax will execute this file.
In this example, the post:
action runs a script called cleanup.js
:
runs:
using: 'node20'
main: 'index.js'
post: 'cleanup.js'
The post:
action always runs by default but you can override this using post-if
.
runs.post-if
Optional Allows you to define conditions for the post:
action execution. The post:
action will only run if the conditions in post-if
are met. If not set, then post-if
defaults to always()
. In post-if
, status check functions evaluate against the job's status, not the action's own status.
For example, this cleanup.js
will only run on Linux-based runners:
post: 'cleanup.js'
post-if: runner.os == 'linux'
runs
for composite actions
Required Configures the path to the composite action.
runs.using
for composite actions
Required You must set this value to 'composite'
.
runs.steps
Required The steps that you plan to run in this action. These can be either run
steps or uses
steps.
runs.steps[*].run
Optional The command you want to run. This can be inline or a script in your action repository:
runs:
using: "composite"
steps:
- run: ${{ github.action_path }}/test/script.sh
shell: bash
Alternatively, you can use $GITHUB_ACTION_PATH
:
runs:
using: "composite"
steps:
- run: $GITHUB_ACTION_PATH/script.sh
shell: bash
For more information, see Accessing contextual information about workflow runs.
runs.steps[*].shell
Optional The shell where you want to run the command. You can use any of the shells listed in Workflow syntax for GitHub Actions. Required if run
is set.
runs.steps[*].if
Optional You can use the if
conditional to prevent a step from running unless a condition is met. You can use any supported context and expression to create a conditional.
When you use expressions in an if
conditional, you can, optionally, omit the ${{ }}
expression syntax because GitHub Actions automatically evaluates the if
conditional as an expression. However, this exception does not apply everywhere.
You must always use the ${{ }}
expression syntax or escape with ''
, ""
, or ()
when the expression starts with !
, since !
is reserved notation in YAML format. For example:
if: ${{ ! startsWith(github.ref, 'refs/tags/') }}
For more information, see Evaluate expressions in workflows and actions.
Example: Using contexts
This step only runs when the event type is a pull_request
and the event action is unassigned
.
steps:
- run: echo This event is a pull request that had an assignee removed.
if: ${{ github.event_name == 'pull_request' && github.event.action == 'unassigned' }}
Example: Using status check functions
The my backup step
only runs when the previous step of a composite action fails. For more information, see Evaluate expressions in workflows and actions.
steps:
- name: My first step
uses: octo-org/action-name@main
- name: My backup step
if: ${{ failure() }}
uses: actions/[email protected]
runs.steps[*].name
Optional The name of the composite step.
runs.steps[*].id
Optional A unique identifier for the step. You can use the id
to reference the step in contexts. For more information, see Accessing contextual information about workflow runs.
runs.steps[*].env
Optional Sets a map
of environment variables for only that step. If you want to modify the environment variable stored in the workflow, use echo "{name}={value}" >> $GITHUB_ENV
in a composite step.
runs.steps[*].working-directory
Optional Specifies the working directory where the command is run.
runs.steps[*].uses
Optional Selects an action to run as part of a step in your job. An action is a reusable unit of code. You can use an action defined in the same repository as the workflow, a public repository, or in a published Docker container image.
We strongly recommend that you include the version of the action you are using by specifying a Git ref, SHA, or Docker tag number. If you don't specify a version, it could break your workflows or cause unexpected behavior when the action owner publishes an update.
- Using the commit SHA of a released action version is the safest for stability and security.
- Using the specific major action version allows you to receive critical fixes and security patches while still maintaining compatibility. It also assures that your workflow should still work.
- Using the default branch of an action may be convenient, but if someone releases a new major version with a breaking change, your workflow could break.
Some actions require inputs that you must set using the with
keyword. Review the action's README file to determine the inputs required.
runs:
using: "composite"
steps:
# Reference a specific commit
- uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
# Reference the major version of a release
- uses: actions/checkout@v4
# Reference a specific version
- uses: actions/[email protected]
# Reference a branch
- uses: actions/checkout@main
# References a subdirectory in a public GitHub repository at a specific branch, ref, or SHA
- uses: actions/aws/ec2@main
# References a local action
- uses: ./.github/actions/my-action
# References a docker public registry action
- uses: docker://gcr.io/cloud-builders/gradle
# Reference a docker image published on docker hub
- uses: docker://alpine:3.8
runs.steps[*].with
Optional A map
of the input parameters defined by the action. Each input parameter is a key/value pair. For more information, see Example: Specifying inputs.
runs:
using: "composite"
steps:
- name: My first step
uses: actions/hello_world@main
with:
first_name: Mona
middle_name: The
last_name: Octocat
runs
for Docker container actions
Required Configures the image used for the Docker container action.
Example: Using a Dockerfile in your repository
runs:
using: 'docker'
image: 'Dockerfile'
Example: Using public Docker registry container
runs:
using: 'docker'
image: 'docker://debian:stretch-slim'
runs.using
for Docker container actions
Required You must set this value to 'docker'
.
runs.pre-entrypoint
Optional Allows you to run a script before the entrypoint
action begins. For example, you can use pre-entrypoint:
to run a prerequisite setup script. GitHub Actions uses docker run
to launch this action, and runs the script inside a new container that uses the same base image. This means that the runtime state is different from the main entrypoint
container, and any states you require must be accessed in either the workspace, HOME
, or as a STATE_
variable. The pre-entrypoint:
action always runs by default but you can override this using runs.pre-if
.
The runtime specified with the using
syntax will execute this file.
In this example, the pre-entrypoint:
action runs a script called setup.sh
:
runs:
using: 'docker'
image: 'Dockerfile'
args:
- 'bzz'
pre-entrypoint: 'setup.sh'
entrypoint: 'main.sh'
runs.image
Required The Docker image to use as the container to run the action. The value can be the Docker base image name, a local Dockerfile
in your repository, or a public image in Docker Hub or another registry. To reference a Dockerfile
local to your repository, the file must be named Dockerfile
and you must use a path relative to your action metadata file. The docker
application will execute this file.
runs.env
Optional Specifies a key/value map of environment variables to set in the container environment.
runs.entrypoint
Optional Overrides the Docker ENTRYPOINT
in the Dockerfile
, or sets it if one wasn't already specified. Use entrypoint
when the Dockerfile
does not specify an ENTRYPOINT
or you want to override the ENTRYPOINT
instruction. If you omit entrypoint
, the commands you specify in the Docker ENTRYPOINT
instruction will execute. The Docker ENTRYPOINT
instruction has a shell form and exec form. The Docker ENTRYPOINT
documentation recommends using the exec form of the ENTRYPOINT
instruction.
For more information about how the entrypoint
executes, see Dockerfile support for GitHub Actions.
runs.post-entrypoint
Optional Allows you to run a cleanup script once the runs.entrypoint
action has completed. GitHub Actions uses docker run
to launch this action. Because GitHub Actions runs the script inside a new container using the same base image, the runtime state is different from the main entrypoint
container. You can access any state you need in either the workspace, HOME
, or as a STATE_
variable. The post-entrypoint:
action always runs by default but you can override this using runs.post-if
.
runs:
using: 'docker'
image: 'Dockerfile'
args:
- 'bzz'
entrypoint: 'main.sh'
post-entrypoint: 'cleanup.sh'
runs.args
Optional An array of strings that define the inputs for a Docker container. Inputs can include hardcoded strings. GitHub passes the args
to the container's ENTRYPOINT
when the container starts up.
The args
are used in place of the CMD
instruction in a Dockerfile
. If you use CMD
in your Dockerfile
, use the guidelines ordered by preference:
- Document required arguments in the action's README and omit them from the
CMD
instruction. - Use defaults that allow using the action without specifying any
args
. - If the action exposes a
--help
flag, or something similar, use that to make your action self-documenting.
If you need to pass environment variables into an action, make sure your action runs a command shell to perform variable substitution. For example, if your entrypoint
attribute is set to "sh -c"
, args
will be run in a command shell. Alternatively, if your Dockerfile
uses an ENTRYPOINT
to run the same command ("sh -c"
), args
will execute in a command shell.
For more information about using the CMD
instruction with GitHub Actions, see Dockerfile support for GitHub Actions.
Example: Defining arguments for the Docker container
runs:
using: 'docker'
image: 'Dockerfile'
args:
- ${{ inputs.greeting }}
- 'foo'
- 'bar'
branding
Optional You can use a color and Feather icon to create a badge to personalize and distinguish your action. Badges are shown next to your action name in GitHub Marketplace.
Example: Configuring branding for an action
branding:
icon: 'award'
color: 'green'
branding.color
The background color of the badge. Can be one of: white
, black
, yellow
, blue
, green
, orange
, red
, purple
, or gray-dark
.
branding.icon
The name of the v4.28.0 Feather icon to use.
Omitted icons
Brand icons, and all the following icons, are omitted.
- coffee
- columns
- divide-circle
- divide-square
- divide
- frown
- hexagon
- key
- meh
- mouse-pointer
- smile
- tool
- x-octagon
Exhaustive list of all currently supported icons
- activity
- airplay
- alert-circle
- alert-octagon
- alert-triangle
- align-center
- align-justify
- align-left
- align-right
- anchor
- aperture
- archive
- arrow-down-circle
- arrow-down-left
- arrow-down-right
- arrow-down
- arrow-left-circle
- arrow-left
- arrow-right-circle
- arrow-right
- arrow-up-circle
- arrow-up-left
- arrow-up-right
- arrow-up
- at-sign
- award
- bar-chart-2
- bar-chart
- battery-charging
- battery
- bell-off
- bell
- bluetooth
- bold
- book-open
- book
- bookmark
- box
- briefcase
- calendar
- camera-off
- camera
- cast
- check-circle
- check-square
- check
- chevron-down
- chevron-left
- chevron-right
- chevron-up
- chevrons-down
- chevrons-left
- chevrons-right
- chevrons-up
- circle
- clipboard
- clock
- cloud-drizzle
- cloud-lightning
- cloud-off
- cloud-rain
- cloud-snow
- cloud
- code
- command
- compass
- copy
- corner-down-left
- corner-down-right
- corner-left-down
- corner-left-up
- corner-right-down
- corner-right-up
- corner-up-left
- corner-up-right
- cpu
- credit-card
- crop
- crosshair
- database
- delete
- disc
- dollar-sign
- download-cloud
- download
- droplet
- edit-2
- edit-3
- edit
- external-link
- eye-off
- eye
- fast-forward
- feather
- file-minus
- file-plus
- file-text
- file
- film
- filter
- flag
- folder-minus
- folder-plus
- folder
- gift
- git-branch
- git-commit
- git-merge
- git-pull-request
- globe
- grid
- hard-drive
- hash
- headphones
- heart
- help-circle
- home
- image
- inbox
- info
- italic
- layers
- layout
- life-buoy
- link-2
- link
- list
- loader
- lock
- log-in
- log-out
- map-pin
- map
- maximize-2
- maximize
- menu
- message-circle
- message-square
- mic-off
- mic
- minimize-2
- minimize
- minus-circle
- minus-square
- minus
- monitor
- moon
- more-horizontal
- more-vertical
- move
- music
- navigation-2
- navigation
- octagon
- package
- paperclip
- pause-circle
- pause
- percent
- phone-call
- phone-forwarded
- phone-incoming
- phone-missed
- phone-off
- phone-outgoing
- phone
- pie-chart
- play-circle
- play
- plus-circle
- plus-square
- plus
- power
- printer
- radio
- refresh-ccw
- refresh-cw
- repeat
- rewind
- rotate-ccw
- rotate-cw
- rss
- save
- scissors
- search
- send
- server
- settings
- share-2
- share
- shield-off
- shield
- shopping-bag
- shopping-cart
- shuffle
- sidebar
- skip-back
- skip-forward
- slash
- sliders
- smartphone
- speaker
- square
- star
- stop-circle
- sun
- sunrise
- sunset
- table
- tablet
- tag
- target
- terminal
- thermometer
- thumbs-down
- thumbs-up
- toggle-left
- toggle-right
- trash-2
- trash
- trending-down
- trending-up
- triangle
- truck
- tv
- type
- umbrella
- underline
- unlock
- upload-cloud
- upload
- user-check
- user-minus
- user-plus
- user-x
- user
- users
- video-off
- video
- voicemail
- volume-1
- volume-2
- volume-x
- volume
- watch
- wifi-off
- wifi
- wind
- x-circle
- x-square
- x
- zap-off
- zap
- zoom-in
- zoom-out