From 0eea258fc118be22af8cd5adef30973ad744ead8 Mon Sep 17 00:00:00 2001
From: Alex Pascal <apascal07@gmail.com>
Date: Fri, 10 May 2024 12:32:27 -0700
Subject: [PATCH 1/2] Write tools config in `genkit init`.

---
 .../nextjs.genkit-tools.config.js.template    |  6 +++++
 genkit-tools/cli/src/commands/init.ts         | 25 +++++++++++++++++++
 genkit-tools/common/src/runner/runner.ts      | 10 +++++---
 3 files changed, 37 insertions(+), 4 deletions(-)
 create mode 100644 genkit-tools/cli/config/nextjs.genkit-tools.config.js.template

diff --git a/genkit-tools/cli/config/nextjs.genkit-tools.config.js.template b/genkit-tools/cli/config/nextjs.genkit-tools.config.js.template
new file mode 100644
index 0000000000..0b44568054
--- /dev/null
+++ b/genkit-tools/cli/config/nextjs.genkit-tools.config.js.template
@@ -0,0 +1,6 @@
+module.exports = {
+  runner: {
+    mode: 'harness',
+    files: [$GENKIT_HARNESS_FILES],
+  },
+};
diff --git a/genkit-tools/cli/src/commands/init.ts b/genkit-tools/cli/src/commands/init.ts
index eff440b9b2..8175b94234 100644
--- a/genkit-tools/cli/src/commands/init.ts
+++ b/genkit-tools/cli/src/commands/init.ts
@@ -150,6 +150,8 @@ const sampleTemplatePaths: Record<Platform, string> = {
   nextjs: '../../config/nextjs.genkit.ts.template',
 };
 
+const nextjsToolsConfigTemplatePath = '../../config/nextjs.genkit-tools.config.js.template';
+
 /** Supported runtimes for the init command. */
 const supportedRuntimes: Runtime[] = ['node'];
 
@@ -250,6 +252,7 @@ export const init = new Command('init')
       ) {
         generateSampleFile(platform, modelOptions[model].plugin, plugins);
       }
+      generateToolsConfig(platform);
     } catch (error) {
       logger.error(error);
       process.exit(1);
@@ -325,6 +328,28 @@ async function updatePackageJson() {
   fs.writeFileSync(packageJsonPath, JSON.stringify(newPackageJson, null, 2));
 }
 
+/**
+ * Generates an appropriate tools config for the given platform.
+ * @param platform platform
+ */
+function generateToolsConfig(platform: Platform) {
+  if (platform === 'nextjs') {
+    const templatePath = path.join(__dirname, nextjsToolsConfigTemplatePath);
+    let template = fs.readFileSync(templatePath, 'utf8');
+    if (fs.existsSync('src/app')) {
+      template = template.replace('$GENKIT_HARNESS_FILES', `'./src/app/*.ts'`);
+    } else if (fs.existsSync('app')) {
+      template = template.replace('$GENKIT_HARNESS_FILES', `'./app/*.js'`);
+    } else {
+      throw new Error(
+        'Unable to resolve source folder (app or src/app) of you next.js app.'
+      );
+    }
+    const configPath = path.join(process.cwd(), 'genkit-tools.conf.js');
+    fs.writeFileSync(configPath, template, 'utf8');
+  }
+}
+
 /**
  * Generates a sample index.ts file.
  * @param platform Deployment platform.
diff --git a/genkit-tools/common/src/runner/runner.ts b/genkit-tools/common/src/runner/runner.ts
index 57d338cafb..c1ee24be40 100644
--- a/genkit-tools/common/src/runner/runner.ts
+++ b/genkit-tools/common/src/runner/runner.ts
@@ -110,11 +110,13 @@ export class Runner {
     }
     if (this.autoReload) {
       const config = await findToolsConfig();
-      this.buildCommand = config?.builder?.cmd;
-      if (!this.buildCommand && detectRuntime(process.cwd()) === 'node') {
-        this.buildCommand = 'npm run build';
+      if (config?.runner?.mode !== 'harness') {
+        this.buildCommand = config?.builder?.cmd;
+        if (!this.buildCommand && detectRuntime(process.cwd()) === 'node') {
+          this.buildCommand = 'npm run build';
+        }
+        this.build();
       }
-      this.build();
       this.watchForChanges();
     }
     return this.startApp();

From 7fff4f84750e2e64ab75ea74bfacb276ce780afd Mon Sep 17 00:00:00 2001
From: Alex Pascal <apascal07@gmail.com>
Date: Fri, 10 May 2024 12:35:56 -0700
Subject: [PATCH 2/2] Update init.ts

---
 genkit-tools/cli/src/commands/init.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/genkit-tools/cli/src/commands/init.ts b/genkit-tools/cli/src/commands/init.ts
index 8175b94234..6b56568088 100644
--- a/genkit-tools/cli/src/commands/init.ts
+++ b/genkit-tools/cli/src/commands/init.ts
@@ -150,7 +150,8 @@ const sampleTemplatePaths: Record<Platform, string> = {
   nextjs: '../../config/nextjs.genkit.ts.template',
 };
 
-const nextjsToolsConfigTemplatePath = '../../config/nextjs.genkit-tools.config.js.template';
+const nextjsToolsConfigTemplatePath =
+  '../../config/nextjs.genkit-tools.config.js.template';
 
 /** Supported runtimes for the init command. */
 const supportedRuntimes: Runtime[] = ['node'];