Add support for GCP_SA_KEY as an alternative to FIREBASE_TOKEN (#27)

.gitignore

@@ -1,2 +1,3 @@
 
 .history/
+.idea/

Dockerfile

@@ -16,4 +16,4 @@ COPY LICENSE README.md /
 COPY "entrypoint.sh" "/entrypoint.sh"
 
 ENTRYPOINT ["/entrypoint.sh"]
-CMD ["--help"]
+CMD ["--help"]

README.md

@@ -9,7 +9,12 @@ This Action for [firebase-tools](https://github.com/firebase/firebase-tools) ena
 
 ## Environment variables
 
-* `FIREBASE_TOKEN` - **Required**. The token to use for authentication. This token can be aquired through the `firebase login:ci` command.
+* `FIREBASE_TOKEN` - **Required if GCP_SA_KEY is not set**. The token to use for authentication. This token can be aquired through the `firebase login:ci` command.
+
+* `GCP_SA_KEY` - **Required if FIREBASE_TOKEN is not set**. A base64 encoded private key (json format) for a Service Account with the `Firebase Admin` role in the project, and if your deploying functions you would also need the `Cloud Functions Developer` role. 
+And since the deploy service account is using the App Engine default service account in the deploy process, it also 
+needs the `Service Account User` role.
+If your only doing Hosting `Firebase Hosting Admin` is enough.
 
 * `PROJECT_ID` - **Optional**. To specify a specific project to use for all commands, not required if you specify a project in your `.firebaserc` file.
 
@@ -60,6 +65,13 @@ jobs:
         env:
           FIREBASE_TOKEN: ${{ secrets.FIREBASE_TOKEN }}
 ```
+Alternatively:
+
+```yaml
+        env:
+          GCP_SA_KEY: ${{ secrets.GCP_SA_KEY }}
+```
+
 
 If you have multiple hosting environments you can specify which one in the args line. 
 e.g. `args: deploy --only hosting:[environment name]`

entrypoint.sh

@@ -2,18 +2,25 @@
 
 set -e
 
-if [ -z "$FIREBASE_TOKEN" ]; then
-    echo "FIREBASE_TOKEN is required to run commands with the firebase cli"
-    exit 126
+if [ -z "$FIREBASE_TOKEN" ] && [ -z "$GCP_SA_KEY" ]; then
+  echo "Either FIREBASE_TOKEN or GCP_SA_KEY is required to run commands with the firebase cli"
+  exit 126
+fi
+
+if [ -n "$GCP_SA_KEY" ]; then
+  echo "Storing GCP_SA_KEY in /opt/gcp_key.json"
+  echo "$GCP_SA_KEY" | base64 -d > /opt/gcp_key.json
+  echo "Exporting GOOGLE_APPLICATION_CREDENTIALS=/opt/gcp_key.json"
+  export GOOGLE_APPLICATION_CREDENTIALS=/opt/gcp_key.json
 fi
 
 if [ -n "$PROJECT_PATH" ]; then
-    cd $PROJECT_PATH
+  cd "$PROJECT_PATH"
 fi
 
 if [ -n "$PROJECT_ID" ]; then
     echo "setting firebase project to $PROJECT_ID"
-    firebase use --add $PROJECT_ID
+    firebase use --add "$PROJECT_ID"
 fi
 
 sh -c "firebase $*"