Wrap up python emulator support.

package.json

@@ -11,7 +11,9 @@
     "build:publish": "tsc --build tsconfig.publish.json && npm run copyfiles",
     "build:watch": "npm run build && tsc --watch",
     "clean": "rimraf lib dev",
-    "copyfiles": "node -e \"const fs = require('fs'); fs.mkdirSync('./lib', {recursive:true}); fs.copyFileSync('./src/dynamicImport.js', './lib/dynamicImport.js')\"",
+    "copyfiles": "npm run copyDynamicImportModule && npm run copyEmulatorFiles",
+    "copyDynamicImportModule": "node -e \"const fs = require('fs'); fs.mkdirSync('./lib', {recursive:true}); fs.copyFileSync('./src/dynamicImport.js', './lib/dynamicImport.js')\"",
+    "copyEmulatorFiles": "cp ./src/emulator/functionsEmulatorRuntime.py ./lib/emulator/functionsEmulatorRuntime.py",
     "format": "npm run format:ts && npm run format:other",
     "format:other": "npm run lint:other -- --write",
     "format:ts": "npm run lint:ts -- --fix --quiet",

src/emulator/functionsEmulator.ts

@@ -1304,7 +1304,7 @@ export class FunctionsEmulator implements EmulatorInstance {
     backend: EmulatableBackend,
     envs: Record<string, string>
   ): Promise<FunctionsRuntimeInstance> {
-    const args = [path.join(__dirname, "functionsEmulatorRuntime")];
+    const args = [path.join(__dirname, "functionsEmulatorRuntime.py")];
 
     if (this.args.debugPort) {
       this.logger.log(
@@ -1329,6 +1329,7 @@ export class FunctionsEmulator implements EmulatorInstance {
     const childProcess = runWithVirtualEnv([bin, ...args], backend.functionsDir, {
       ...process.env,
       ...envs,
+      HOST: "localhost",
       PORT: port.toString(),
     });
 

src/emulator/functionsEmulatorRuntime.py

@@ -0,0 +1,30 @@
+# Copyright 2023 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""A light wrapper around the Functions Framework for the purpose of emulator support."""
+
+import os
+from functions_framework import create_app
+from functions_framework._http.flask import FlaskApplication
+
+def create_server(host, port):
+    app = create_app()
+    FlaskApplication(app, host, port, False).run()
+
+
+def main():
+    create_server(os.environ["HOST"], os.environ["PORT"])
+
+
+if __name__ == "__main__":
+    main()

src/functions/python.ts

@@ -20,11 +20,14 @@ export function runWithVirtualEnv(
   const command = process.platform === "win32" ? venvActivate : "source";
   const args = [process.platform === "win32" ? "" : venvActivate, "&&", ...commandAndArgs];
   logger.debug(`Running command with virtualenv: command=${command}, args=${JSON.stringify(args)}`);
+  logger.debug(JSON.stringify(envs));
 
   return spawn(command, args, {
     shell: true,
     cwd,
     stdio: [/* stdin= */ "ignore", /* stdout= */ "pipe", /* stderr= */ "inherit"],
-    ...envs,
+    // Linting disabled since internal types expect NODE_ENV which does not apply to Python runtimes.
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-explicit-any
+    env: envs as any,
   });
 }