Pipeline decorator expression context

Azure DevOps Services

Pipeline decorators have access to context about the pipeline in which they run. As a pipeline decorator author, you can use this context to make decisions about the decorator's behavior. The information available in context is different for pipelines and for release. Also, decorators run after task names are resolved to task GUIDs. When your decorator wants to reference a task, it should use the GUID rather than the name or keyword.


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Pipeline resources are available on the resources object.


Currently, there's only one key: repositories. repositories is a map from repo ID to information about the repository.

In a designer build, the primary repo alias is __designer_repo. In a YAML pipeline, the primary repo is called self. In a release pipeline, repositories aren't available. Release artifact variables are available.

For example, to print the name of the self repo in a YAML pipeline:

- script: echo ${{ resources.repositories['self'].name }}

Repositories contain these properties:

resources['repositories']['self'] =
	"alias": "self",
	"id": "<repo guid>",
	"type": "Git",
	"version": "<commit hash>",
	"name": "<repo name>",
	"project": "<project guid>",
	"defaultBranch": "<default ref of repo, like 'refs/heads/main'>",
	"ref": "<current pipeline ref, like 'refs/heads/topic'>",
	"versionInfo": {
		"author": "<author of tip commit>",
		"message": "<commit message of tip commit>"
	"checkoutOptions": {}


Job details are available on the job object.

The data looks similar to:

job = 
	"steps": [
			"environment": null,
			"inputs": {
				"script": "echo hi"
			"type": "Task",
			"task": {
				"id": "d9bafed4-0b18-4f58-968d-86655b4d2ce9",
				"name": "CmdLine",
				"version": "2.146.1"
			"condition": null,
			"continueOnError": false,
			"timeoutInMinutes": 0,
			"id": "5c09f0b5-9bc3-401f-8cfb-09c716403f48",
			"name": "CmdLine",
			"displayName": "CmdLine",
			"enabled": true

For instance, to conditionally add a task only if it doesn't already exist:

- ${{ if not(containsValue(job.steps.*.task.id, 'f3ab91e7-bed6-436a-b651-399a66fe6c2a')) }}:
  - script: echo conditionally inserted


Pipeline variables are also available.

For instance, if the pipeline had a variable called myVar, its value would be available to the decorator as variables['myVar'].

For example, to give a decorator an opt-out, we could look for a variable. Pipeline authors who wish to opt out of the decorator can set this variable, and the decorator won't be injected. If the variable isn't present, then the decorator is injected as usual.


- ${{ if ne(variables['skipInjecting'], 'true') }}:
  - script: echo Injected the decorator

Then, in a pipeline in the organization, the author can request the decorator not to inject itself.


  skipInjecting: true
- script: echo This is the only step. No decorator is added.

Task names and GUIDs

Decorators run after tasks have already been turned into GUIDs. Consider the following YAML:

- checkout: self
- bash: echo This is the Bash task
- task: PowerShell@2
    targetType: inline
    script: Write-Host This is the PowerShell task

Each of those steps maps to a task. Each task has a unique GUID. Task names and keywords map to task GUIDs before decorators run. If a decorator wants to check for the existence of another task, it must search by task GUID rather than by name or keyword.

For normal tasks (which you specify with the task keyword), you can look at the task's task.json to determine its GUID. For special keywords like checkout and bash in the previous example, you can use the following GUIDs:

Keyword GUID Task Name
checkout 6D15AF64-176C-496D-B583-FD2AE21D4DF4 n/a, see note below
bash 6C731C3C-3C68-459A-A5C9-BDE6E6595B5B Bash
script D9BAFED4-0B18-4F58-968D-86655B4D2CE9 CmdLine
powershell E213FF0F-5D5C-4791-802D-52EA3E7BE1F1 PowerShell
pwsh E213FF0F-5D5C-4791-802D-52EA3E7BE1F1 PowerShell
publish ECDC45F6-832D-4AD9-B52B-EE49E94659BE PublishPipelineArtifact
download 61F2A582-95AE-4948-B34D-A1B3C4F6A737 DownloadPipelineArtifact

After resolving task names and keywords, the previous YAML becomes:

- task: 6D15AF64-176C-496D-B583-FD2AE21D4DF4@1
    repository: self
- task: 6C731C3C-3C68-459A-A5C9-BDE6E6595B5B@3
    targetType: inline
    script: echo This is the Bash task
- task: E213FF0F-5D5C-4791-802D-52EA3E7BE1F1@2
    targetType: inline
    script: Write-Host This is the PowerShell task


Each of these GUIDs can be found in the task.json for the corresponding in-box task. The only exception is checkout, which is a native capability of the agent. Its GUID is built into the Azure Pipelines service and agent.