emulators:exec support for Storage emulator (#3337)

Author: samtstern

src/emulator/commandUtils.ts

@@ -331,6 +331,15 @@ async function runScript(script: string, extraEnv: Record<string, string>): Prom
     env[FirestoreEmulator.FIRESTORE_EMULATOR_ENV_ALT] = address;
   }
 
+  const storageInstance = EmulatorRegistry.get(Emulators.STORAGE);
+  if (storageInstance) {
+    const info = storageInstance.getInfo();
+    const address = EmulatorRegistry.getInfoHostString(info);
+
+    env[Constants.FIREBASE_STORAGE_EMULATOR_HOST] = address;
+    env[Constants.CLOUD_STORAGE_EMULATOR_HOST] = `http://${address}`;
+  }
+
   const authInstance = EmulatorRegistry.get(Emulators.AUTH);
   if (authInstance) {
     const info = authInstance.getInfo();

src/emulator/constants.ts

@@ -63,7 +63,8 @@ export class Constants {
   static FIREBASE_STORAGE_EMULATOR_HOST = "FIREBASE_STORAGE_EMULATOR_HOST";
 
   // Environment variable to override SDK/CLI to point at the Firebase Storage emulator
-  // for firebase-admin <= 9.6.0
+  // for firebase-admin <= 9.6.0. Unlike the FIREBASE_STORAGE_EMULATOR_HOST variable
+  // this one must start with 'http://'.
   static CLOUD_STORAGE_EMULATOR_HOST = "STORAGE_EMULATOR_HOST";
 
   // Environment variable to discover the Emulator HUB