如果你使用的是V2的actions/checkout，那么你总是可以运行git branch——show-current来获取当前签出的分支的名称。

要将其设置为环境变量，我使用以下语法:

- name: Extract branch name
  shell: bash
  run: echo "::set-env name=BRANCH_NAME::$(echo ${GITHUB_REF#refs/heads/} | sed 's/\//_/g')"
- name: Test
  run: echo "${BRANCH_NAME}"

我发现这个语法在这里:Github动作-启动worflows#如何定义环境变量?# 68

Rmq: sed 's/\//_/g'将用_替换分支名称中的/

我只是在GitHub Actions中使用bash脚本做了一个简单的测试:

#!/bin/bash

echo Reserved for REPO_NAME=${GITHUB_REPOSITORY##*/}
echo GITHUB_REF=${GITHUB_REF}
echo EXTRACT_GITHUB_REF=${GITHUB_REF##*/}
echo EXTRACT_GITHUB_REF_HEADS=$(echo ${GITHUB_REF#refs/heads/})

cd $REPO_NAME
git checkout ${GITHUB_REF##*/}
git checkout $(echo ${GITHUB_REF#refs/heads/})

以下是输出的截图:

因此${GITHUB_REF##*/}和$(echo ${GITHUB_REF#refs/heads/})都是正确的

下面是一个适用于push和pull_request事件的完整工作流

name: whichBranch
on: [pull_request, push]

jobs:
  which_branch:
    runs-on: ubuntu-latest
    steps:
      - name: Extract branch name on push
        if: github.event_name != 'pull_request'
        shell: bash
        run: echo "::set-env name=BRANCH_NAME::$(echo ${GITHUB_REF#refs/heads/})"
        id: extract_branch

      - name: Extract branch name on pull request
        if: github.event_name == 'pull_request'
        run: echo "::set-env name=BRANCH_NAME::$(echo ${GITHUB_HEAD_REF})"

      - name: Print branch name
        run: echo 'The branch name is' $BRANCH_NAME

你可以使用https://github.com/rlespinasse/github-slug-action

# Just add this  => 
- name: Inject slug/short variables
  uses: rlespinasse/github-slug-action@v3.x



# And you get this  => 
- name: Print slug/short variables
  run: |
    echo "Slug variables"
    echo " - ${{ env.GITHUB_REF_SLUG }}"    
    echo " - ${{ env.GITHUB_HEAD_REF_SLUG }}"
    echo " - ${{ env.GITHUB_BASE_REF_SLUG }}"
    echo " - ${{ env.GITHUB_REPOSITORY_SLUG }}"
    # output e.g. : master feat-new-feature v1.0.0 product-1.0.0-rc.2 new-awesome-product
    echo "Slug URL variables"
    echo " - ${{ env.GITHUB_REF_SLUG_URL }}"
    echo " - ${{ env.GITHUB_HEAD_REF_SLUG_URL }}"
    echo " - ${{ env.GITHUB_BASE_REF_SLUG_URL }}"
    echo " - ${{ env.GITHUB_REPOSITORY_SLUG_URL }}"
    # output e.g. : master feat-new-feature v1-0-0 product-1-0-0-rc-2 new-awesome-product
    echo "Short SHA variables"
    echo " - ${{ env.GITHUB_SHA_SHORT }}"
    # output e.g. : ffac537e

我们目前有一个单独的作业，它在所有其他作业之前运行。该步骤根据分支名称决定在什么环境中运行。我们的分支与部署基础设施和代码库的特定环境相关联。每个环境都有自己的秘密(github企业特性)。

输出环境变量可用于所有其他连续作业。您可以在步骤中使用该变量，例如将其设置为NODE_ENV，或者用它标记docker图像。您还可以在该特定变量上设置并发性，以确保同一时间只运行使用相同值的单个作业或工作流。这使得它非常强大。

下面是我上面描述的一个例子:

name: Build pipeline
on:
  push:
    branches:
      - feature/*
      - develop
      - release/*
      - main

jobs:
  environments:
    name: Set environment
    runs-on: ubuntu-latest
    steps:
      - run: echo "Setting $ENVIRONMENT.."
    outputs:
      # Defaults to 'dev' in case of a feature branch
      # You could also use the contains expression if needed
      environment: ${{ github.ref == 'refs/heads/main' && 'prd' || (startsWith(github.ref, 'refs/heads/release/') && 'acc' || github.ref == 'refs/heads/develop' && 'tst' || 'dev') }}

  build:
    name: Docker build
    runs-on: ubuntu-latest
    needs: [environments]
    environment: ${{ needs.environments.outputs.environment }} # Enterprise only
    concurrency: ${{ needs.environments.outputs.environment }}
    env:
      ENVIRONMENT: ${{ needs.environments.outputs.environment }}
    steps:
      - name: Checkout
        uses: actions/checkout@v3
      - name: Build
        run: |
          docker build . \
            -t hello/world:${{ needs.environments.outputs.environment }}

注意:因为提取环境名称不是在bash或powershell中完成的，你被绑定到github动作提供的有限表达式。如果你需要更花哨的东西，你可以用不同的方式来做，这不是唯一的真理。然而，我总是喜欢让事情简单易懂。

替代(快速)选项

如果你不介意使用其他人的github动作，你可以使用市场上的许多动作之一，做一个找到一个替换。这里可以找到一个例子，它看起来像:

on: [push]

jobs:
  replace-job:
    runs-on: ubuntu-latest
    name: 'Find and replace'
    steps:
      - name: Checkout
        uses: actions/checkout@v2
      - name: Remove refs/heads/ from string
        uses: mad9000/actions-find-and-replace-string@1
        id: findandreplace
        with:
          source: ${{ github.ref }}
          find: 'refs/heads/'
          replace: ''
      - name: Branch name
        run: echo "The branch name is ${{ steps.findandreplace.outputs.value }}"