feat: add emulator configuration to firebase_init tool

This change enhances the firebase_init MCP tool to allow for the configuration of Firebase emulators. It refactors the emulators setup logic in `src/init/features/emulators.ts` into `askQuestions` and `actuate` functions. The `firebase_init` tool now calls the `actuate` function to programmatically configure emulators, passing settings through the `featureInfo` object. A new `emulators` field has been added to the input schema to support this functionality.

Author: google-labs-jules[bot]

src/init/features/emulators.ts

@@ -9,105 +9,136 @@ import { AdditionalInitFns } from "../../emulator/initEmulators";
 import { Config } from "../../config";
 import { EmulatorsConfig } from "../../firebaseConfig";
 
-interface EmulatorsInitSelections {
-  emulators?: Emulators[];
-  download?: boolean;
+export interface EmulatorsInfo {
+  emulators: Emulators[];
+  download: boolean;
+  config: EmulatorsConfig;
 }
 
-export async function doSetup(setup: Setup, config: Config) {
+export async function emulatorsAskQuestions(setup: Setup, config: Config): Promise<void> {
   const choices = ALL_SERVICE_EMULATORS.map((e) => {
     return {
       value: e,
-      // TODO: latest versions of inquirer have a name vs description.
-      // We should learn more and whether it's worth investing in.
       name: Constants.description(e),
       checked: config?.has(e) || config?.has(`emulators.${e}`),
     };
   });
 
-  const selections: EmulatorsInitSelections = {};
-  selections.emulators = await checkbox<Emulators>({
+  const selectedEmulators = await checkbox<Emulators>({
     message:
       "Which Firebase emulators do you want to set up? " +
       "Press Space to select emulators, then Enter to confirm your choices.",
     choices: choices,
   });
 
-  if (!selections.emulators) {
+  if (!selectedEmulators || !selectedEmulators.length) {
     return;
   }
 
-  setup.config.emulators = setup.config.emulators || {};
-  const emulators: EmulatorsConfig = setup.config.emulators || {};
-  for (const selected of selections.emulators) {
-    if (selected === "extensions") continue;
-    const selectedEmulator = emulators[selected] || {};
+  setup.featureInfo = setup.featureInfo || {};
+  const emulatorsInfo: EmulatorsInfo = {
+    emulators: selectedEmulators,
+    config: {},
+    download: false,
+  };
+  setup.featureInfo.emulators = emulatorsInfo;
+
+  const newConfig = emulatorsInfo.config;
+  const existingConfig = setup.config.emulators || {};
 
-    const currentPort = selectedEmulator.port;
+  for (const selected of selectedEmulators) {
+    if (selected === "extensions") continue;
+    newConfig[selected] = {};
+    const currentPort = existingConfig[selected]?.port;
     if (currentPort) {
       utils.logBullet(`Port for ${selected} already configured: ${clc.cyan(currentPort)}`);
     } else {
-      selectedEmulator.port = await number({
+      newConfig[selected]!.port = await number({
         message: `Which port do you want to use for the ${clc.underline(selected)} emulator?`,
         default: Constants.getDefaultPort(selected),
       });
     }
-    emulators[selected] = selectedEmulator;
 
     const additionalInitFn = AdditionalInitFns[selected];
     if (additionalInitFn) {
       const additionalOptions = await additionalInitFn(config);
       if (additionalOptions) {
-        emulators[selected] = {
-          ...setup.config.emulators[selected],
-          ...additionalOptions,
-        };
+        Object.assign(newConfig[selected]!, additionalOptions);
       }
     }
   }
 
-  if (selections.emulators.length) {
+  if (selectedEmulators.length) {
     const uiDesc = Constants.description(Emulators.UI);
-    if (setup.config.emulators.ui && setup.config.emulators.ui.enabled !== false) {
-      const currentPort = setup.config.emulators.ui.port || "(automatic)";
-      utils.logBullet(`${uiDesc} already enabled with port: ${clc.cyan(currentPort)}`);
-    } else {
-      const ui = setup.config.emulators.ui || {};
-      setup.config.emulators.ui = ui;
+    const existingUiConfig = existingConfig.ui || {};
+    newConfig.ui = {};
 
-      ui.enabled = await confirm({
+    let enableUi: boolean;
+    if (existingUiConfig.enabled !== undefined) {
+      utils.logBullet(`${uiDesc} already ${existingUiConfig.enabled ? "enabled" : "disabled"}.`);
+      enableUi = existingUiConfig.enabled;
+    } else {
+      enableUi = await confirm({
         message: `Would you like to enable the ${uiDesc}?`,
         default: true,
       });
+    }
+    newConfig.ui.enabled = enableUi;
 
-      if (ui.enabled) {
-        ui.port = await number({
+    if (newConfig.ui.enabled) {
+      const currentPort = existingUiConfig.port;
+      if (currentPort) {
+        utils.logBullet(`Port for ${uiDesc} already configured: ${clc.cyan(currentPort)}`);
+      } else {
+        newConfig.ui.port = await number({
           message: `Which port do you want to use for the ${clc.underline(uiDesc)} (leave empty to use any available port)?`,
           required: false,
         });
       }
     }
+  }
 
-    selections.download = await confirm({
+  if (selectedEmulators.length) {
+    emulatorsInfo.download = await confirm({
       message: "Would you like to download the emulators now?",
       default: true,
     });
   }
+}
+
+export async function emulatorsActuate(setup: Setup, config: Config): Promise<void> {
+  const emulatorsInfo = setup.featureInfo?.emulators;
+  if (!emulatorsInfo) {
+    return;
+  }
+
+  setup.config.emulators = setup.config.emulators || {};
+  const emulatorsConfig = setup.config.emulators;
+
+  // Merge the config from the questions into the main config.
+  for (const emulatorName of Object.keys(emulatorsInfo.config)) {
+    const key = emulatorName as keyof EmulatorsConfig;
+    if (key === "ui") {
+      emulatorsConfig.ui = { ...emulatorsConfig.ui, ...emulatorsInfo.config.ui };
+    } else if (emulatorsInfo.config[key]) {
+      emulatorsConfig[key] = { ...emulatorsConfig[key], ...emulatorsInfo.config[key] };
+    }
+  }
 
   // Set the default behavior to be single project mode.
-  if (setup.config.emulators.singleProjectMode === undefined) {
-    setup.config.emulators.singleProjectMode = true;
+  if (emulatorsConfig.singleProjectMode === undefined) {
+    emulatorsConfig.singleProjectMode = true;
   }
 
-  if (selections.download) {
-    for (const selected of selections.emulators) {
+  if (emulatorsInfo.download) {
+    for (const selected of emulatorsInfo.emulators) {
       if (isDownloadableEmulator(selected)) {
         await downloadIfNecessary(selected);
       }
     }
 
-    if (setup?.config?.emulators?.ui?.enabled) {
-      downloadIfNecessary(Emulators.UI);
+    if (emulatorsConfig.ui?.enabled) {
+      await downloadIfNecessary(Emulators.UI);
     }
   }
-}
+}

src/init/index.ts

@@ -38,6 +38,7 @@ export interface SetupInfo {
   dataconnectSdk?: features.DataconnectSdkInfo;
   storage?: features.StorageInfo;
   apptesting?: features.ApptestingInfo;
+  emulators?: features.EmulatorsInfo;
 }
 
 interface Feature {
@@ -84,7 +85,11 @@ const featuresList: Feature[] = [
     askQuestions: features.storageAskQuestions,
     actuate: features.storageActuate,
   },
-  { name: "emulators", doSetup: features.emulators },
+  {
+    name: "emulators",
+    askQuestions: features.emulatorsAskQuestions,
+    actuate: features.emulatorsActuate,
+  },
   { name: "extensions", doSetup: features.extensions },
   { name: "project", doSetup: features.project }, // always runs, sets up .firebaserc
   { name: "remoteconfig", doSetup: features.remoteconfig },

src/mcp/tools/core/init.ts

@@ -5,12 +5,18 @@ import { DEFAULT_RULES } from "../../../init/features/database";
 import { actuate, Setup, SetupInfo } from "../../../init/index";
 import { freeTrialTermsLink } from "../../../dataconnect/freeTrial";
 import { requireGeminiToS } from "../../errors";
+import { Emulators } from "../../../emulator/types";
+
+const emulatorHostPortSchema = z.object({
+  host: z.string().optional().describe("The host to use for the emulator."),
+  port: z.number().optional().describe("The port to use for the emulator."),
+});
 
 export const init = tool(
   {
     name: "init",
     description:
-      "Initializes selected Firebase features in the workspace (Firestore, Data Connect, Realtime Database). All features are optional; provide only the products you wish to set up. " +
+      "Initializes selected Firebase features in the workspace (Firestore, Data Connect, Realtime Database, Emulators). All features are optional; provide only the products you wish to set up. " +
       "You can initialize new features into an existing project directory, but re-initializing an existing feature may overwrite configuration. " +
       "To deploy the initialized features, run the `firebase deploy` command after `firebase_init` tool.",
     inputSchema: z.object({
@@ -121,6 +127,31 @@ export const init = tool(
           .describe(
             "Provide this object to initialize Firebase Storage in this project directory.",
           ),
+        emulators: z
+          .object({
+            auth: emulatorHostPortSchema.optional(),
+            database: emulatorHostPortSchema.optional(),
+            firestore: emulatorHostPortSchema.optional(),
+            functions: emulatorHostPortSchema.optional(),
+            hosting: emulatorHostPortSchema.optional(),
+            storage: emulatorHostPortSchema.optional(),
+            pubsub: emulatorHostPortSchema.optional(),
+            ui: z
+              .object({
+                enabled: z.boolean().optional(),
+                host: z.string().optional(),
+                port: z.union([z.string(), z.number()]).optional(),
+              })
+              .optional(),
+            singleProjectMode: z
+              .boolean()
+              .optional()
+              .describe("If true, do not warn on detection of multiple project IDs."),
+          })
+          .optional()
+          .describe(
+            "Provide this object to configure Firebase emulators in this project directory.",
+          ),
       }),
     }),
     annotations: {
@@ -178,8 +209,32 @@ export const init = tool(
         apps: [],
       };
     }
+    if (features.storage) {
+      featuresList.push("storage");
+      featureInfo.storage = {
+        rulesFilename: features.storage.rules_filename,
+        rules: features.storage.rules,
+        writeRules: true,
+      };
+    }
+    if (features.emulators) {
+      featuresList.push("emulators");
+      const emulatorKeys = Object.keys(features.emulators).filter(
+        (key) =>
+          key !== "ui" &&
+          key !== "singleProjectMode" &&
+          Object.values(Emulators).includes(key as Emulators),
+      ) as Emulators[];
+
+      featureInfo.emulators = {
+        emulators: emulatorKeys,
+        config: features.emulators,
+        download: true, // Non-interactive, so default to downloading.
+      };
+    }
+
     const setup: Setup = {
-      config: config?.src,
+      config: config?.src || {},
       rcfile: rc?.data,
       projectId: projectId,
       features: [...featuresList],
@@ -206,4 +261,4 @@ To get started:
 `,
     );
   },
-);
+);