Task types & usage

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Azure Pipelines | Azure DevOps Server 2019 | TFS 2018 | TFS 2017 | TFS 2015

Note

In Microsoft Team Foundation Server (TFS) 2018 and previous versions, build and release pipelines are called definitions, runs are called builds, service connections are called service endpoints, stages are called environments, and jobs are called phases.

A task is the building block for defining automation in a pipeline. A task is simply a packaged script or procedure that has been abstracted with a set of inputs.

When you add a task to your pipeline, it may also add a set of demands to the pipeline. The demands define the prerequisites that must be installed on the agent for the task to run. When you run the build or deployment, an agent that meets these demands will be chosen.

When you run a job, all the tasks are run in sequence, one after the other. To run the same set of tasks in parallel on multiple agents, or to run some tasks without using an agent, see jobs.

By default, all tasks run in the same context, whether that's on the host or in a job container. You may optionally use step targets to control context for an individual task.

When you run a job, all the tasks are run in sequence, one after the other, on an agent. To run the same set of tasks in parallel on multiple agents, or to run some tasks without using an agent, see jobs.

Custom tasks

We provide some built-in tasks to enable fundamental build and deployment scenarios. We have also provided guidance for creating your own custom task.

In addition, Visual Studio Marketplace offers a number of extensions; each of which, when installed to your subscription or collection, extends the task catalog with one or more tasks. Furthermore, you can write your own custom extensions to add tasks to Azure Pipelines or TFS.

In YAML pipelines, you refer to tasks by name. If a name matches both an in-box task and a custom task, the in-box task will take precedence. You can use a fully-qualified name for the custom task to avoid this risk:

steps:
- task: myPublisherId.myExtensionId.myContributionId.myTaskName@1

Task versions

Tasks are versioned, and you must specify the major version of the task used in your pipeline. This can help to prevent issues when new versions of a task are released. Tasks are typically backwards compatible, but in some scenarios you may encounter unpredictable errors when a task is automatically updated.

When a new minor version is released (for example, 1.2 to 1.3), your build or release will automatically use the new version. However, if a new major version is released (for example 2.0), your build or release will continue to use the major version you specified until you edit the pipeline and manually change to the new major version. The build or release log will include an alert that a new major version is available.

In YAML, you specify the major version using @ in the task name. For example, to pin to version 2 of the PublishTestResults task:

steps:
- task: PublishTestResults@2

YAML pipelines aren't available in TFS.

Task control options

Each task offers you some Control Options.

Control options are available as keys on the task section.

- task: string  # reference to a task and version, e.g. "VSBuild@1"
  condition: expression     # see below
  continueOnError: boolean  # 'true' if future steps should run even if this step fails; defaults to 'false'
  enabled: boolean          # whether or not to run this step; defaults to 'true'
  timeoutInMinutes: number  # how long to wait before timing out the task
  target: string            # 'host' or the name of a container resource to target

The timeout period begins when the task starts running. It does not include the time the task is queued or is waiting for an agent.

In this YAML, PublishTestResults@2 will run even if the previous step fails because of the succeededOrFailed() condition.

steps:
- task: UsePythonVersion@0
  inputs:
    versionSpec: '3.7'
    architecture: 'x64'
- task: PublishTestResults@2
  inputs:
    testResultsFiles: "**/TEST-*.xml"
  condition: succeededOrFailed()

Note

For the full schema, see YAML schema for task.

Conditions

  • Only when all previous dependencies have succeeded. This is the default if there is not a condition set in the YAML.

  • Even if a previous dependency has failed, unless the run was canceled. Use succeededOrFailed() in the YAML for this condition.

  • Even if a previous dependency has failed, even if the run was canceled. Use always() in the YAML for this condition.

  • Only when a previous dependency has failed. Use failed() in the YAML for this condition.

Step target

Tasks run in an execution context, which is either the agent host or a container. An individual step may override its context by specifying a target. Available options are the word host to target the agent host plus any containers defined in the pipeline. For example:

resources:
  containers:
  - container: pycontainer
    image: python:3.8

steps:
- task: SampleTask@1
  target: host
- task: AnotherTask@1
  target: pycontainer

Here, the SampleTask runs on the host and AnotherTask runs in a container.

YAML pipelines aren't available in TFS.

Build tool installers (Azure Pipelines)

Tool installers enable your build pipeline to install and control your dependencies. Specifically, you can:

  • Install a tool or runtime on the fly (even on Microsoft-hosted agents) just in time for your CI build.

  • Validate your app or library against multiple versions of a dependency such as Node.js.

For example, you can set up your build pipeline to run and validate your app for multiple versions of Node.js.

Example: Test and validate your app on multiple versions of Node.js

Tip

Want a visual walkthrough? See our April 19 news release.

Create an azure-pipelines.yml file in your project's base directory with the following contents.

pool:
  vmImage: 'Ubuntu 16.04'

steps:
# Node install
- task: NodeTool@0
  displayName: Node install
  inputs:
    versionSpec: '6.x' # The version we're installing
# Write the installed version to the command line
- script: which node

Create a new build pipeline and run it. Observe how the build is run. The Node.js Tool Installer downloads the Node.js version if it is not already on the agent. The Command Line script logs the location of the Node.js version on disk.

YAML pipelines aren't available in TFS.

Tool installer tasks

For a list of our tool installer tasks, see Tool installer tasks.

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