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Variáveis de ambiente

GitHub define as variáveis do ambiente para cada execução do fluxo de trabalho GitHub Actions. Você também pode definir variáveis de ambiente personalizadas no seu arquivo do fluxo de trabalho.

Sobre as variáveis de ambiente

You can use environment variables to store information that you want to reference in your workflow. You reference environment variables within a workflow step or an action, and the variables are interpolated on the runner machine that runs your workflow. Commands that run in actions or workflow steps can create, read, and modify environment variables.

You can set your own custom environment variables, you can use the default environment variables that GitHub sets automatically, and you can also use any other environment variables that are set in the working environment on the runner. As variáveis de ambiente diferenciam entre maiúsculas e minúsculas.

To set a custom environment variable, you must define it in the workflow file. The scope of a custom environment variable is limited to the element in which it is defined. You can define environment variables that are scoped for:

name: Greeting on variable day

on:
  workflow_dispatch

env:
  DAY_OF_WEEK: Monday

jobs:
  greeting_job:
    runs-on: ubuntu-latest
    env:
      Greeting: Hello
    steps:
      - name: "Say Hello Mona it's Monday"
        run: echo "$Greeting $First_Name. Today is $DAY_OF_WEEK!"
        env:
          First_Name: Mona

The example above shows three custom environment variables being used in an echo command: $DAY_OF_WEEK, $Greeting, and $First_Name. The values for these environment variables are set, and scoped, at the workflow, job, and step level respectively.

Because environment variable interpolation is done after a workflow job is sent to a runner machine, you must use the appropriate syntax for the shell that's used on the runner. In this example, the workflow specifies ubuntu-latest. By default, Linux runners use the bash shell, so you must use the syntax $NAME. If the workflow specified a Windows runner, you would use the syntax for PowerShell, $env:NAME. For more information about shells, see "Workflow syntax for GitHub Actions."

Note: You can list the entire set of environment variables that are available to a workflow step by using run: env in a step and then examining the output for the step.

Using contexts to access environment variable values

In addition to environment variables, GitHub Actions also allows you to set and read values using contexts. Environment variables and contexts are intended for use at different points in the workflow.

Environment variables are always interpolated on the virtual machine runner. However, parts of a workflow are processed by GitHub Actions and are not sent to the runner. You cannot use environment variables in these parts of a workflow file. Instead, you can use contexts. For example, an if conditional, which determines whether a job or step is sent to the runner, is always processed by GitHub Actions. You can use a context in an if conditional statement to access the value of an environment variable.

env:
  DAY_OF_WEEK: Monday

jobs:
  greeting_job:
    runs-on: ubuntu-latest
    env:
      Greeting: Hello
    steps:
      - name: "Say Hello Mona it's Monday"
        if: ${{ env.DAY_OF_WEEK == 'Monday' }}
        run: echo "$Greeting $First_Name. Today is $DAY_OF_WEEK!"
        env:
          First_Name: Mona

In this modification of the first example, we've introduced an if conditional. The workflow step is now only run if DAYS_OF_WEEK is set to "Monday". We access this value from the if conditional statement by using the env context.

Note: Contexts are usually denoted using the dollar sign and curly braces, as ${{ context.property }}. In an if conditional, the ${{ and }} are optional, but if you use them they must enclose the entire comparison statement, as shown above.

You will commonly use either the env or github context to access environment variable values in parts of the workflow that are processed before jobs are sent to runners.

ContextoUse caseExemplo
envReference custom environment variables defined in the workflow.${{ env.MY_VARIABLE }}
githubReference information about the workflow run and the event that triggered the run.${{ github.repository }}

There are many other contexts that you can use for a variety of purposes in your workflows. Para obter mais informações, consulte "Contextos". For details of where you can use specific contexts within a workflow, see "Context availability."

Other types of variables

In most places in a workflow, the only types of variables that you can use are either environment variables, such as $MY_VARIABLE, or the equivalent context property, such as ${{ env.MY_VARIABLE }}. Exceptions are:

  • Inputs for the workflow_call and workflow_dispatch events, which allow you to pass values to a workflow. For more information, see on.workflow_call.inputs and on.workflow_dispatch.inputs.
  • Job outputs, which allow you to pass values between jobs in a workflow. For more information, see jobs.<job_id>.outputs.
  • The variables in a format expression, which allow you to replace parts of a string. For more information, see format.

Convenções de nomenclatura para variáveis de ambiente

When you set a custom environment variable, you cannot use any of the default environment variable names. For a complete list of these, see "Default environment variables" below. Se você tentar substituir o valor de uma dessas variáveis de ambiente padrão, a atribuição será ignorada.

Qualquer variável de ambiente nova que você definir e apontar para um local no sistema de arquivos deve ter um sufixo _PATH. The HOME, GITHUB_ENV, and GITHUB_WORKSPACE default environment variables are exceptions to this convention.

Variáveis padrão de ambiente

The default environment variables that GitHub sets are available to every step in a workflow.

É altamente recomendável que as ações usem as variáveis do ambiente para acessar o sistema do arquivo em vez de usar os caminhos do arquivo com codificação rígida. GitHub define as variáveis de ambiente para ações a serem usadas em todos os ambientes executores.

Variável de ambienteDescrição
CIDefinido sempre como verdadeiro.
GITHUB_ACTIONO nome da ação atualmente em execução ou o id de uma etapa. For example, for an action, __repo-owner_name-of-action-repo.

GitHub removes special characters, and uses the name __run when the current step runs a script without an id. If you use the same script or action more than once in the same job, the name will include a suffix that consists of the sequence number preceded by an underscore. Por exemplo, o primeiro script que você executar terá o nome __run e o segundo script será denominado __run_2. Da mesma forma, a segunda invocação de actions/checkout será actionscheckout2.
GITHUB_ACTION_PATHO caminho onde uma ação está localizada. Esta propriedade só é compatível com ações compostas. Você pode usar este caminho para acessar arquivos localizados no mesmo repositório da ação. For example, /home/runner/work/_actions/repo-owner/name-of-action-repo/v1.
GITHUB_ACTION_REPOSITORYPara uma etpa que executa uma ação, este é o nome do proprietário e do repositório da ação. Por exemplo, actions/checkout.
GITHUB_ACTIONSDefinido sempre como verdadeiro quando GitHub Actions estiver executando o fluxo de trabalho. Você pode usar esta variável para diferenciar quando os testes estão sendo executados localmente ou por GitHub Actions.
GITHUB_ACTORNome da pessoa ou aplicativo que iniciou o fluxo de trabalho. Por exemplo, octocat.
GITHUB_API_URLRetorna a URL da API. For example: https://[hostname]/api/v3.
GITHUB_BASE_REFThe name of the base ref or target branch of the pull request in a workflow run. This is only set when the event that triggers a workflow run is either pull_request or pull_request_target. For example, main.
GITHUB_ENVThe path on the runner to the file that sets environment variables from workflow commands. This file is unique to the current step and changes for each step in a job. For example, /home/runner/work/_temp/_runner_file_commands/set_env_87406d6e-4979-4d42-98e1-3dab1f48b13a. Para obter mais informações, consulte "Comandos do fluxo de trabalho para GitHub Actions".
GITHUB_EVENT_NAMEThe name of the event that triggered the workflow. For example, workflow_dispatch.
GITHUB_EVENT_PATHO caminho para o arquivo no executor que contém a carga completa do webhook do evento. Por exemplo, /github/workflow/event.json.
GITHUB_GRAPHQL_URLRetorna a URL API do GraphQL. For example: https://[hostname]/api/graphql.
GITHUB_HEAD_REFThe head ref or source branch of the pull request in a workflow run. This property is only set when the event that triggers a workflow run is either pull_request or pull_request_target. For example, feature-branch-1.
GITHUB_JOBO job_id do trabalho atual. For example, greeting_job.
GITHUB_PATHThe path on the runner to the file that sets system PATH variables from workflow commands. This file is unique to the current step and changes for each step in a job. For example, /home/runner/work/_temp/_runner_file_commands/add_path_899b9445-ad4a-400c-aa89-249f18632cf5. Para obter mais informações, consulte "Comandos do fluxo de trabalho para GitHub Actions."
GITHUB_REFBranch ou ref tag que acionou a execução do fluxo de trabalho. For branches this is the format refs/heads/<branch_name>, and for tags it is refs/tags/<tag_name>. This variable is only set if a branch or tag is available for the event type. Por exemplo, refs/heads/feature-branch-1.
GITHUB_REPOSITORYThe owner and repository name. Por exemplo, octocat/Hello-World.
RUNNER_NAMEO nome do executor que executa a tarefa. For example, Hosted Agent

Observação:

  • If you need to use a workflow run's URL from within a job, you can combine these environment variables: $GITHUB_SERVER_URL/$GITHUB_REPOSITORY/actions/runs/$GITHUB_RUN_ID
  • Most of the default environment variables have a corresponding, and similarly named, context property. For example, the value of the GITHUB_REF environment variable can be read during workflow processing using the ${{ github.ref }} context property.

Detecting the operating system

You can write a single workflow file that can be used for different operating systems by using the RUNNER_OS default environment variable and the corresponding context property ${{ runner.os }}. For example, the following workflow could be run successfully if you changed the operating system from macos-latest to windows-latest without having to alter the syntax of the environment variables, which differs depending on the shell being used by the runner.

jobs:
  if-Windows-else:
    runs-on: macos-latest
    steps:
      - name: condition 1
        if: runner.os == 'Windows'
        run: echo "The operating system on the runner is $env:RUNNER_OS."
      - name: condition 2
        if: runner.os != 'Windows'
        run: echo "The operating system on the runner is not Windows, it's $RUNNER_OS."

In this example, the two if statements check the os property of the runner context to determine the operating system of the runner. if conditionals are processed by GitHub Actions, and only steps where the check resolves as true are sent to the runner. Here one of the checks will always be true and the other false, so only one of these steps is sent to the runner. Once the job is sent to the runner, the step is executed and the environment variable in the echo command is interpolated using the appropriate syntax ($env:NAME for PowerShell on Windows, and $NAME for bash and sh on Linux and MacOS). In this example, the statement runs-on: macos-latest means that the second step will be run.

Passing values between steps and jobs in a workflow

If you generate a value in one step of a job, you can use the value in subsequent steps of the same job by assigning the value to an existing or new environment variable and then writing this to the GITHUB_ENV environment file. The environment file can be used directly by an action, or from a shell command in the workflow file by using the run keyword. Para obter mais informações, consulte "Comandos do fluxo de trabalho para GitHub Actions".

If you want to pass a value from a step in one job in a workflow to a step in another job in the workflow, you can define the value as a job output. You can then reference this job output from a step in another job. Para obter mais informações, consulte "Sintaxe de fluxo de trabalho para o GitHub Actions".