Context and expression syntax for workflows¶

You can access context information and evaluate expressions in workflows.

About contexts and expressions¶

You can use expressions to programmatically set variables in workflow files and access contexts. An expression can be any combination of literal values, references to a context, or functions. You can combine literals, context references, and functions using operators.

Expressions are commonly used with the conditional if keyword in a workflow file to determine whether a step should run. When an if conditional is true, the step will run.

You need to use specific syntax to tell the OpenTestFactory orchestrator to evaluate an expression rather than treat it as a string.

${{ <expression> }}

When you use expressions in an if conditional, you may omit the expression syntax (${{ }}) because the orchestrator automatically evaluates the if conditional as an expression. For more information about if conditionals, see “Workflow syntax for OpenTestFactory orchestrator.”

Warning

When creating workflows and provider tasks, you should always consider whether your code might execute untrusted input from possible attackers. Certain contexts should be treated as untrusted input, as an attacker could insert their own malicious content. For more information, see “Understanding the risk of script injections.”

Example expression in an `if` conditional¶

steps:
  - run: dir /s
    if: runner.os == 'windows'  # or: ${{ runner.os == 'windows' }}

Example setting an environment variable¶

variables:
  my_env_var: ${{ <expression> }}

Contexts¶

Contexts are a way to access information about workflow runs, execution environments, jobs, and steps. Contexts use the expression syntax.

${{ <context> }}

Context name	Type	Description
`opentf`	`object`	Information about the workflow run. For more information, see `opentf` context.
`variables`	`object`	Contains environment variables set in a workflow, job, or step. For more information, see `variables` context.
`resources`	`object`	Information about the resources set in a workflow. For more information, see `resources` context.
`job`	`object`	Information about the currently executing job. For more information, see `job` context.
`steps`	`object`	Information about the steps that have been run in this job. For more information, see `steps` context.
`runner`	`object`	Information about the execution environment that is running the current job. For more information, see `runner` context.
`needs`	`object`	Enables access to the outputs of all jobs that are defined as a dependency of the current job. For more information, see `needs` context.
`inputs`	`object`	Contains the inputs of a reusable or manually triggered workflow. For more information, see `inputs` context.

As part of an expression, you may access context information using one of two syntaxes.

Index syntax: opentf['job']
Property dereference syntax: opentf.job

To use property dereference syntax, the property name must:

start with a-Z or _.
be followed by a-Z 0-9 - or _.

Determining when to use contexts¶

The OpenTestFactory orchestrator includes a collection of variables called contexts and a similar collection of variables called default environment variables. These variables are intended for use at different points in the workflow:

Default environment variables: These variables exist only on the runner that is executing your job. For more information, see “Default environment variables.”
Contexts: You can use most contexts at any point in your workflow, including when default environment variables would be unavailable. For example, you can use contexts with expressions to perform initial processing before the job is routed to an execution environment for execution; this allows you to use a context with the conditional if keyword to determine whether a step should run. Once the job is running, you can also retrieve context variables from the execution environment that is executing the job, such as runner.os. For details of where you can use various contexts within a workflow, see “Context availability.”

The following example demonstrates how these different types of environment variables can be used together in a job:

metdata:
  name: CI
jobs:
  prod-check:
    if: ${{ opentf.actor == 'octocat' }}
    runs-on: linux
    steps:
      - run: echo "Deploying to production server on behalf of $OPENTF_ACTOR"

In this example, the if statement checks the opentf.actor context to determine the caller’s name; if the name is octocat, then the subsequent steps are executed. The if check is processed by the OpenTestFactory orchestrator, and the job is only sent to the execution environment if the result is true. Once the job is sent to the execution environment, the step is executed and refers to the $OPENTF_ACTOR environment variable from the execution environment.

Context availability¶

Different contexts are available throughout a workflow run. For example, the secrets context may only be used at certain places within a job.

In addition, some functions may only be used in certain places. For example, the success() function is not available everywhere.

The following table indicates where each context and special function can be used within a workflow. Unless listed below, a function can be used anywhere.

Workflow key	Context	Special functions
`variables`	`opentf`, `secrets`, `inputs`
`jobs.<job_id>.continue-on-error`	`opentf`, `needs`, `inputs`
`jobs.<job_id>.defaults.run`	`opentf`, `needs`, `variables`, `inputs`
`jobs.<job_id>.variables`	`opentf`, `needs`, `secrets`, `inputs`
`jobs.<job_id>.if`	`opentf`, `needs`, `inputs`	`always`, `cancelled`, `success`, `failure`
`jobs.<job_id>.name`	`opentf`, `needs`, `inputs`
`jobs.<job_id>.outputs.<output_id>`	`opentf`, `needs`, `job`, `runner`, `variables`, `secrets`, `steps`, `inputs`
`jobs.<job_id>.runs-on`	`opentf`, `needs`, `inputs`
`jobs.<job_id>.secrets.<secrets_id>`	`opentf`, `needs`, `secrets`, `inputs`
`jobs.<job_id>.steps.continue-on-error`	`opentf`, `needs`, `job`, `runner`, `variables`, `secrets`, `steps`, `inputs`
`jobs.<job_id>.steps.variables`	`opentf`, `needs`, `job`, `runner`, `variables`, `secrets`, `steps`, `inputs`
`jobs.<job_id>.steps.if`	`opentf`, `needs`, `job`, `runner`, `variables`, steps, `inputs`	`always`, `cancelled`, `success`, `failure`
`jobs.<job_id>.steps.name`	`opentf`, `needs`, `job`, `runner`, `variables`, `secrets`, `steps`, `inputs`
`jobs.<job_id>.steps.run`	`opentf`, `needs`, `job`, `runner`, `variables`, `secrets`, `steps`, `inputs`
`jobs.<job_id>.steps.timeout-minutes`	`opentf`, `needs`, `job`, `runner`, `variables`, `secrets`, `steps`, `inputs`
`jobs.<job_id>.steps.with`	`opentf`, `needs`, `job`, `runner`, `variables`, `secrets`, `steps`, `inputs`, `resources`
`jobs.<job_id>.steps.working-directory`	`opentf`, `needs`, `job`, `runner`, `variables`, `secrets`, `steps`, `inputs`
`jobs.<job_id>.timeout-minutes`	`opentf`, `needs`, `inputs`
`jobs.<job_id>.with.<with_id>`	`opentf`, `needs`, `inputs`, `resources`

`opentf` context¶

The opentf context contains information about the workflow run and the event that triggered the run. You can read most of the opentf context data in environment variables. For more information about environment variables, see “Using environment variables.”

Warning

When using the whole opentf context, be mindful that it includes sensitive information such as opentf.token. The orchestrator masks secrets when they are printed to the console, but you should be cautious when exporting or printing the context.

Property name	Type	Description
`opentf`	`object`	The top-level context available during any job or step in a workflow.
`opentf.workflow`	`string`	The name of the workflow. If the workflow file doesn’t specify a name, the value of this property is the full path of the workflow file in the repository.
`opentf.namespace`	`string`	The name of the namespace the workflow belongs to.
`opentf.job`	`string`	The `job_id` of the current job.
`opentf.actor`	`string`	The login of the user that initiated the workflow run.
`opentf.token`	`string`	A token to authenticate on behalf of the orchestrator plugin.
`opentf.step`	`string`	The name of the step currently running. The orchestrator removes special characters or uses the name `run` when the current step runs a script. If you use the same function more than once in the same job, the name will include a suffix with the sequence number. For example, the first script you run will have the name `run1`, and the second script will be named `run2`. Similarly, the second invocation of `actions/checkout` will be `actionscheckout2`.

Example contents of the `opentf` context¶

The following example context is from a workflow run triggered by the push event.

Note

This context is an example only. The content of a context depends on the workflow that you are running. Contexts, objects, and properties will vary significantly under different workflow run conditions.

{
  "token": "***",
  "job": "dump_contexts_to_log",
  "actor": "octocat",
  "workflow": "Context testing",
  "namespace": "default",
  "step": "run12"
}

Example usage of the `opentf` context¶

This example workflow uses the opentf.name context to run a job only if the workflow was triggered by the expected actor.

metadata:
  name: Run CI
jobs:
  normal_ci:
    runs-on: linux
    steps:
      - uses: actions/checkout@v2
        with:
          repository: https://git.example.com/my_repo.git
      - name: Run normal CI
        run: ./run-tests

  post_ci:
    needs: normal_ci
    runs-on: linux
    if: ${{ opentf.actor == 'octocat' }}
    steps:
      - uses: actions/checkout@v2
        with:
          repository: https://git.example.com/my_repo.git
      - name: Run PR CI
        run: ./run-additional-post-ci

`variables` context¶

The variables context contains environment variables that have been set in a workflow, job, or step. For more information about setting environment variables in your workflow, see “Workflow syntax for OpenTestFactory orchestrator.”

The variables context syntax allows you to use the value of an environment variable in your workflow file. You can use the variables context in any key in a step except for the generator, id, and uses keys. For more information on the step syntax, see “Workflow syntax for OpenTestFactory orchestrator.”

If you want to use the value of an environment variable inside an execution environment, use the execution environment operating system’s normal method for reading environment variables.

Property name	Type	Description
`variables`	`object`	This context changes for each step in a job. You can access this context from any step in a job.
`variables.<var name>`	`string`	The value of a specific environment variable.

Example contents of the `variables` context¶

The content of the variables context is a mapping of environment variable names to their values. The context’s contents can change depending on where it is used in the workflow run.

{
  "first_name": "Mona",
  "super_duper_var": "totally_awesome"
}

Example usage of the `variables` context¶

This example workflow shows how the variables context can be configured at the workflow, job, and step levels, as well as using the context in steps.

When more than one environment variable is defined with the same name, the OpenTestFactory orchestrator uses the most specific environment variable. For example, an environment variable defined in a step will override job and workflow variables with the same name, while the step executes. A variable defined for a job will override a workflow variable with the same name, while the job executes.

metadata:
  name: Hi Mascot
variables:
  mascot: Mona
  super_duper_var: totally_awesome

jobs:
  windows_job:
    runs-on: windows
    steps:
      - run: echo Hi ${{ variables.mascot }}  # Hi Mona
      - run: echo Hi ${{ variables.mascot }}  # Hi Octocat
        variables:
          mascot: Octocat
  linux_job:
    runs-on: linux
    variables:
      mascot: Tux
    steps:
      - run: echo 'Hi ${{ variables.mascot }}'  # Hi Tux

`resources` context¶

The resources context contains resources that have been set in a workflow. For more information about setting resources in your workflow, see “Workflow syntax for OpenTestFactory orchestrator.”

The resources context syntax allows you to use the resources in your workflow file.

You can only use the resources context in the value of the with and name keys. For more information on the step syntax, see “Workflow syntax for OpenTestFactory orchestrator.”

Property name	Type	Description
`resources.<resource type>`	`object`	The resource type objects. Possible values are `testmanagers`, `repositories`, or `files`.
`resources.<resource type>.<name>`	`object`	The set of properties for the resource. There is at least a name property, the other are resource type dependent.

Example contents of the `resources` context¶

This example resources context shows two linked files and one defined repository.

{
  "files": {
    "config1": {
      "name": "config1",
      "url": "https://cdn.example.com/abcfoo"
    },
    "config2": {
      "name": "config2",
      "url": "https://cdn.example.com/defbar"
    }
  },
  "repositories": {
    "myrepo": {
      "name": "myrepo",
      "type": "bitbucket",
      "repository": "example/my-example-repo.git",
      "endpoint": "https://bitbucket.org"
    }
  }
}

Example usage of the `resources` context¶

This example workflow takes two configuration files and builds the project twice. The configuration files are provided when triggering the workflow, using for example:

opentf-ctl \
  run workflow bibuild.yaml \
  -f config1=local/conf1.properties \
  -f config2=local/conf2.properties

metadata:
  name: Build twice
resources:
  files:
  - config1
  - config2
  repositories:
  - name: myrepo    
    type: bitbucket
    repository: example/my-example-repo.git
    endpoint: https://bitbucket.org

jobs:
  build:
    - uses: actions/checkout@v2
      with:
        repository: ${{ resources.repositories.myrepo }}
    - uses: actions/put-file@v1
      with:
        file: config1
        path: conf/config.properties
    - name: Build using first configuration
      run: ./build.sh --target target/build-using-first-config
    - uses: actions/put-file@v1
      with:
        file: config2
        path: conf/config.properties
    - name: Build using second configuration
      run: ./build.sh --target target/build-using-second-config

`job` context¶

The job context contains information about the currently running job.

Property name	Type	Description
`job`	`object`	This context changes for each job in a workflow run. You can access this context from any step in a job.
`job.status`	`string`	The current status of the job. Possible values are `success`, `failure`, or `cancelled`.

Example contents of the `job` context¶

This example job context only contains the status property.

{
  "status": "success"
}

`steps` context¶

The steps context contains information about the steps in the current job that have an id specified and have already run.

Property name	Type	Description
`steps`	`object`	This context changes for each step in a job. You can access this context from any step in a job.
`steps.<step id>.outputs`	`object`	The set of outputs defined for the step. For more information, see “Metadata syntax for OpenTestFactory orchestrator plugins.”
`steps.<step id>.outputs.<output name>`	`string`	The value of a specific output.
`steps.<step id>.outcome`	`string`	The result of a completed step before continue-on-error is applied. Possible values are `success`, `failure`, `cancelled`, or `skipped`. When a `continue-on-error` step fails, the outcome is `failure`, but the final conclusion is `success`.
`steps.<step id>.conclusion`	`string`	The result of a completed step after `continue-on-error` is applied. Possible values are `success`, `failure`, `cancelled`, or `skipped`. When a `continue-on-error` step fails, the outcome is `failure`, but the final conclusion is `success`.

Example contents of the steps context¶

This example steps context shows two previous steps that had an id specified. The first step had the id named checkout, and the second generate_number. The generate_number step had an output named random_number.

{
  "checkout": {
    "outputs": {},
    "outcome": "success",
    "conclusion": "success"
  },
  "generate_number": {
    "outputs": {
      "random_number": "1"
    },
    "outcome": "success",
    "conclusion": "success"
  }
}

Example usage of the steps context¶

This example workflow generates a random number as an output in one step, and a later step uses the steps context to read the value of that output.

metadata:
  name: Generate random failure
jobs:
  randomly-failing-job:
    runs-on: linux
    steps:
      - id: checkout
        uses: actions/checkout@v2
        with:
          repository: https://git.example.com/my_repo.git
      - name: Generate 0 or 1
        id: generate_number
        run:  echo "::set-output name=random_number::$(($RANDOM % 2))"
      - name: Pass or fail
        run: |
          if [[ ${{ steps.generate_number.outputs.random_number }} == 0 ]]; then exit 0; else exit 1; fi

`runner` context¶

The runner context contains information about the execution environment that is executing the current job.

Property name	Type	Description
`runner`	`object`	This context changes for each job in a workflow run. This object contains all the properties listed below.
`runner.os`	`string`	The operating system of the runner executing the job. Possible values are `linux`, `windows`, or `macos`.
`runner.temp`	`string`	The path of the temporary directory for the execution environment. This directory is guaranteed to be empty at the start of each job, even on self-hosted execution environments.

Example contents of the `runner` context¶

The following example context is from a Linux-based execution environment.

{
  "os": "linux",
  "temp": "/home/runner/work/_temp"
}

Example usage of the `runner` context¶

This example workflow uses the runner context to set the path to the temporary directory to write logs, and if the workflow fails, it uploads those logs as artifacts.

metadata:
  name: Build
jobs:
  build:
    runs-on: linux
    steps:
      - uses: actions/checkout@v2
        with:
          repository: https://git.example.com/my_repo.git
      - name: Build with logs
        run: |
          mkdir ${{ runner.temp }}/build_logs
          ./build.sh --log-path ${{ runner.temp }}/build_logs
      - name: Upload logs on fail
        if: ${{ failure() }}
        uses: actions/upload-artifact@v3
        with:
          name: Build failure logs
          path: ${{ runner.temp }}/build_logs

`needs` context¶

The needs context contains outputs from all jobs that are defined as a dependency of the current job. For more information on defining job dependencies, see “Workflow syntax for OpenTestFactory orchestrator.”

Property name	Type	Description
`needs.<job id>`	`object`	A single job that the current job depends on.
`needs.<job id>.outputs.<output name>`	`string`	The value of a specific output for a job that the current job depends on.
`needs.<job id>.outputs`	`object`	The set of outputs of a job that the current job depends on.
`needs.<job id>.result`	`string`	The result of a job that the current job depends on. Possible values are `success`, `failure`, or `cancelled`.

Example contents of the `needs` context¶

The following example contents of the needs context shows information for two jobs that the current job depends on.

{
  "build": {
    "result": "success",
    "outputs": {
      "build_id": "ABC123"
    }
  },
  "deploy": {
    "result": "failure",
    "outputs": {}
  }
}

Example usage of the `needs` context¶

This example workflow has three jobs: a build job that does a build, a deploy job that requires the build job, and a debug job that requires both the build and deploy jobs and runs only if there is a failure in the workflow. The deploy job also uses the needs context to access an output from the build job.

metadata:
  name: Build and deploy
jobs:
  build:
    runs-on: linux
    outputs:
      build_id: ${{ steps.build_step.outputs.build_id }}
    steps:
      - uses: actions/checkout@v2
        with:
          repository: https://git.example.com/my_repo.git
      - name: Build
        id: build_step
        run: |
          ./build
          echo "::set-output name=build_id::$BUILD_ID"
  deploy:
    needs: build
    runs-on: linux
    steps:
      - uses: actions/checkout@v2
        with:
          repository: https://git.example.com/my_repo.git
      - run: ./deploy --build ${{ needs.build.outputs.build_id }}
  debug:
    needs: [build, deploy]
    runs-on: linux
    if: ${{ failure() }}
    steps:
      - uses: actions/checkout@v2
        with:
          repository: https://git.example.com/my_repo.git
      - run: ./debug

`inputs` context¶

The inputs context contains input properties passed to a function. For reusable workflows, the input names and types are defined in the workflow_call event configuration of a reusable workflow, and the input values are passed from jobs.<job_id>.with in an external workflow that calls the reusable workflow. For manually triggered workflows, the inputs are defined in the workflow_dispatch event configuration of a workflow.

There are no standard properties in the inputs context, only those which are defined in the workflow file.

Property name	Type	Description
`inputs`	`object`	This context is only available in a function. You can access this context from any step in a function. This object contains the properties listed below.
`inputs.<name>`	`string` or `number` or `boolean`	Each input value passed from an external workflow.

Literals¶

As part of an expression, you can use boolean, null, number, or string data types. Boolean literals are not case-sensitive, so you can use true or True.

Data type	Literal value
`boolean`	`true` or `false`
`null`	`null`
`number`	Any number format supported by JSON.
`string`	You must use single quotes. Escape literal single-quotes with a single quote.

Example¶

variables:
  myNull: ${{ null }}
  myBoolean: ${{ false }}
  myIntegerNumber: ${{ 711 }}
  myFloatNumber: ${{ -9.2 }}
  myHexNumber: ${{ 0xff }}
  myExponentialNumber: ${{ -2.99-e2 }}
  myString: ${{ 'Mona the Octocat' }}
  myEscapedString: ${{ 'It''s open source!' }}

Operators¶

Operator	Description	Usage
`( )`	Logical grouping	`((foo == 4) \|\| (bar == 5)) && (baz == 6)`
`[ ]`	Index	`variables['VAR']`
`.`	Property dereference	`variables.VAR`
`<`	Less than	`12 < 4`
`<=`	Less than or equal	`12 <= 4`
`>`	Greater than	`12 > 4`
`>=`	Greater than or equal	`12 >= 4`
`==`	Equal	`variables.VAR == 'foo'`
`!=`	Not equal	`12 != 4`
`~=`	Match regular expression	`variables.VAR ~= '^abc.*'`
`&&`	And	`true && false`
`\|\|`	Or	`true \|\| false`

The orchestrator performs loose equality comparisons.

If the types do not match, the orchestrator coerces the type to a number. The orchestrator casts data types to a number using these conversions:

Type	Result
Null	`0`
Boolean	`true` returns `1` `false` returns `0`
String	Parsed from any legal JSON number format, otherwise `NaN`. Note: empty string returns `0`.
Array	`NaN`
Object	`NaN`

A comparison of one NaN to another NaN does not result in true. For more information, see the “NaN Mozilla docs.”
The orchestrator ignores the case when comparing strings.
For more information on the regular expression syntax, see “Python re module.”
Objects and arrays are only considered equal when they are the same instance.

Job-status check functions¶

You can use the following status check functions as expressions in if conditionals. If your if expression does not contain any of the status functions it will automatically result in success(). For more information about if conditionals, see “Workflow syntax for OpenTestFactory orchestrator.”

success¶

Returns true when none of the previous steps have failed or been canceled.

Example¶

steps:
  ...
  - name: The job has succeeded
    if: ${{ success() }}

always¶

Always returns true, even when canceled. A job or step will not run when a critical failure prevents the task from running. For example, if getting sources failed.

Example¶

if: ${{ always() }}

cancelled¶

Returns true if the workflow was canceled.

Example¶

if: ${{ cancelled() }}

failure¶

Returns true when any previous step of a job fails.

Example¶

steps:
  ...
  - name: The job has failed
    if: ${{ failure() }}

Context and expression syntax for workflows¶

About contexts and expressions¶

Example expression in an if conditional¶

Example setting an environment variable¶

Contexts¶

Determining when to use contexts¶

Context availability¶

opentf context¶

Example contents of the opentf context¶

Example usage of the opentf context¶

variables context¶

Example contents of the variables context¶

Example usage of the variables context¶

resources context¶

Example contents of the resources context¶

Example usage of the resources context¶

job context¶

Example contents of the job context¶

steps context¶

Example contents of the steps context¶

Example usage of the steps context¶

runner context¶

Example contents of the runner context¶

Example usage of the runner context¶

needs context¶

Example contents of the needs context¶

Example usage of the needs context¶

inputs context¶

Literals¶

Example¶

Operators¶

Job-status check functions¶

success¶

Example¶

always¶

Example¶

cancelled¶

Example¶

failure¶

Example¶

Example expression in an `if` conditional¶

`opentf` context¶

Example contents of the `opentf` context¶

Example usage of the `opentf` context¶

`variables` context¶

Example contents of the `variables` context¶

Example usage of the `variables` context¶

`resources` context¶

Example contents of the `resources` context¶

Example usage of the `resources` context¶

`job` context¶

Example contents of the `job` context¶

`steps` context¶

`runner` context¶

Example contents of the `runner` context¶

Example usage of the `runner` context¶

`needs` context¶

Example contents of the `needs` context¶

Example usage of the `needs` context¶

`inputs` context¶