GitHub ActionsでFirebase CLIを利用する際にOpenID Connectを利用して認証するための下準備スクリプト

github-actions-oidc.sh

#!/bin/bash
set -euxo pipefail

while [ $# -gt 0 ]; do
  case "$1" in
  --project-id=*)
    PROJECT_ID="${1#*=}"
    ;;
  --github-user-name=*)
    GITHUB_USER_NAME="${1#*=}"
    ;;
  --github-repo-name=*)
    GITHUB_REPO_NAME="${1#*=}"
    ;;
  --github-repository-owner=*)
    GITHUB_REPOSITORY_OWNER="${1#*=}"
    ;;
  *)
    echo "Usage: $0 --project-id=kingu-42 --github-user-name=KoheiKanagu --github-repo-name=kingu_dev"
    exit 1
    ;;
  esac
  shift
done

SERVICE_ACCOUNT_NAME=github-actions@$PROJECT_ID.iam.gserviceaccount.com # Modify as needed
WORKLOAD_IDENTITY_PROVIDER=github-actions-pool                          # Modify as needed
OIDC_PROVIDER_NAME=github-actions-provider                              # Modify as needed

gcloud config set project "$PROJECT_ID"

gcloud services enable iamcredentials.googleapis.com
gcloud iam service-accounts create github-actions

# Firebaseの基本的な機能は使えるはずだが、別途ロールが必要になる場合がある。
# 参考: https://firebase.google.com/docs/projects/iam/permissions
gcloud projects add-iam-policy-binding "$PROJECT_ID" \
  --member="serviceAccount:$SERVICE_ACCOUNT_NAME" \
  --role="roles/firebase.developAdmin"

# Cloud Functionsに必要
gcloud projects add-iam-policy-binding "$PROJECT_ID" \
  --member="serviceAccount:$SERVICE_ACCOUNT_NAME" \
  --role="roles/cloudfunctions.serviceAgent"

# Firebase Remote Configに必要
gcloud projects add-iam-policy-binding "$PROJECT_ID" \
  --member="serviceAccount:$SERVICE_ACCOUNT_NAME" \
  --role="roles/cloudconfig.admin"

# Firebase Extensionsに必要
# roles/editor は過剰であるがFirebase ExtensionsがBetaだからか、適切なロールが存在しない。
# おそらく firebaseextensions.instances.list があればよいはずだが...
# https://github.com/firebase/firebase-tools/issues/6060#issuecomment-1622913149
gcloud projects add-iam-policy-binding "$PROJECT_ID" \
  --member="serviceAccount:$SERVICE_ACCOUNT_NAME" \
  --role="roles/editor"

# Firebase Extensionsに必要
# 正確には firebase deploy で必要になるようだが、Extensionsのデプロイ以外では必要とされないような？
# https://github.com/firebase/firebase-tools/issues/5777#issuecomment-1531835346
gcloud services enable cloudbilling.googleapis.com

gcloud iam workload-identity-pools create $WORKLOAD_IDENTITY_PROVIDER \
  --location="global"

gcloud iam workload-identity-pools providers create-oidc $OIDC_PROVIDER_NAME \
  --location="global" \
  --workload-identity-pool=$WORKLOAD_IDENTITY_PROVIDER \
  --attribute-mapping="google.subject=assertion.sub,attribute.repository=assertion.repository,attribute.actor=assertion.actor" \
  --attribute-condition="assertion.repository_owner=='$GITHUB_REPOSITORY_OWNER'" \
  --issuer-uri="https://token.actions.githubusercontent.com"

GITHUB_ACTIONS_POOL_PROJECT_ID=$(gcloud iam workload-identity-pools describe $WORKLOAD_IDENTITY_PROVIDER --location="global" --format="value(name)" | awk -F'/' '{print $2}')

gcloud iam service-accounts add-iam-policy-binding "$SERVICE_ACCOUNT_NAME" \
  --role="roles/iam.workloadIdentityUser" \
  --member="principalSet://iam.googleapis.com/projects/$GITHUB_ACTIONS_POOL_PROJECT_ID/locations/global/workloadIdentityPools/github-actions-pool/attribute.repository/$GITHUB_USER_NAME/$GITHUB_REPO_NAME"

cat <<EOF
====================================
jobs:
  deploy:
    runs-on: ubuntu-latest
    permissions:
      id-token: write
      contents: read
    steps:
      - uses: actions/checkout@v4
      - name: Authenticate to Google Cloud
        uses: google-github-actions/auth@v1.1.1
        with:
          workload_identity_provider: 'projects/$GITHUB_ACTIONS_POOL_PROJECT_ID/locations/global/workloadIdentityPools/github-actions-pool/providers/github-actions-provider'
          service_account: '$SERVICE_ACCOUNT_NAME'
====================================

OR

gh variable set WORKLOAD_IDENTITY_PROVIDER --body 'projects/$GITHUB_ACTIONS_POOL_PROJECT_ID/locations/global/workloadIdentityPools/github-actions-pool/providers/github-actions-provider' --repo $GITHUB_USER_NAME/$GITHUB_REPO_NAME
gh variable set SERVICE_ACCOUNT --body '$SERVICE_ACCOUNT_NAME' --repo $GITHUB_USER_NAME/$GITHUB_REPO_NAME
EOF

cat <<'EOF'

====================================
jobs:
  deploy:
    runs-on: ubuntu-latest
    permissions:
      id-token: write
      contents: read
    steps:
      - uses: actions/checkout@v4
      - name: Authenticate to Google Cloud
        uses: google-github-actions/auth@v1.1.1
        with:
          workload_identity_provider: ${{ vars.WORKLOAD_IDENTITY_PROVIDER }}
          service_account: ${{ vars.SERVICE_ACCOUNT }}
====================================
EOF

参考: https://zenn.dev/kou_pg_0131/articles/gh-actions-oidc-gcp