feat(executors): Implement serve

Closes #3

package.json

@@ -37,6 +37,7 @@
   "dependencies": {
     "@swc/helpers": "~0.3.3",
     "esbuild-azure-functions": "^1.2.0",
+    "rxjs": "^7.5.7",
     "tslib": "^2.3.0"
   }
 }

packages/azure-functions/executors.json

@@ -5,6 +5,11 @@
       "implementation": "./src/executors/build/executor",
       "schema": "./src/executors/build/schema.json",
       "description": "build executor"
+    },
+    "serve": {
+      "implementation": "./src/executors/serve/executor",
+      "schema": "./src/executors/serve/schema.json",
+      "description": "serve executor"
     }
   }
 }

packages/azure-functions/src/executors/serve/executor.ts

@@ -0,0 +1,80 @@
+import { ExecutorContext } from '@nrwl/devkit';
+import { eachValueFrom } from '@nrwl/devkit/src/utils/rxjs-for-await';
+import * as child_process from 'child_process';
+import { build, BuilderConfigType, watch } from 'esbuild-azure-functions';
+import * as path from 'path';
+import { map, Observable } from 'rxjs';
+import { ServeExecutorSchema } from './schema';
+
+export default async function* runExecutor(
+  options: ServeExecutorSchema,
+  ctx: ExecutorContext
+) {
+  let subProcess: child_process.ChildProcess | null = null;
+
+  const exitHandler = () => {
+    subProcess?.kill('SIGINT');
+  };
+
+  process.on('SIGUSR1', exitHandler);
+  process.on('SIGUSR2', exitHandler);
+  process.on('SIGINT', exitHandler);
+  process.on('SIGTERM', exitHandler);
+
+  const nxProject = ctx.workspace.projects[ctx.projectName];
+  const project = path.join(ctx.root, nxProject.root);
+  const outDir = path.join(ctx.root, 'dist', nxProject.root);
+
+  const config: BuilderConfigType = {
+    project,
+    advancedOptions: {
+      enableDirnameShim: true,
+      enableRequireShim: true,
+    },
+    clean: true,
+    logLevel: options.logLevel || 'verbose',
+    esbuildOptions: {
+      outdir: outDir,
+      minify: true,
+      sourcemap: true,
+    },
+  };
+
+  // build once so there are existing artifacts when starting
+  // the Azure Functions CLI
+  await build(config);
+
+  subProcess = spawnFuncProcess(project);
+
+  await watch({
+    ...config,
+    clean: false,
+    onRebuild: async (errors) => {
+      if (!errors) {
+        // Hack needed because func only hot reloads for changes inside the cwd.
+        subProcess?.kill('SIGINT');
+
+        subProcess = spawnFuncProcess(project);
+      }
+    },
+  });
+
+  return yield* eachValueFrom(
+    new Observable((s) => () => s.complete()).pipe(
+      map(() => ({ success: true }))
+    )
+  );
+}
+
+function spawnFuncProcess(cwd: string) {
+  const subProcess = child_process.spawn('func', ['start'], {
+    cwd,
+    stdio: [process.stdin, process.stdout, process.stderr, 'pipe'],
+  });
+
+  subProcess.on('error', (error) => {
+    console.error(error);
+  });
+
+  return subProcess;
+}

packages/azure-functions/src/executors/serve/schema.d.ts

@@ -0,0 +1,5 @@
+import { BuilderLogLevelType } from 'esbuild-azure-functions/build/src/lib/models';
+
+export interface ServeExecutorSchema {
+  logLevel?: BuilderLogLevelType;
+}

packages/azure-functions/src/executors/serve/schema.json

@@ -0,0 +1,16 @@
+{
+  "$schema": "http://json-schema.org/schema",
+  "cli": "nx",
+  "title": "Serve executor",
+  "description": "",
+  "type": "object",
+  "properties": {
+    "logLevel": {
+      "type": "string",
+      "description": "Builder log level",
+      "enum": ["verbose", "info", "warn", "error", "off"],
+      "$default": "verbose"
+    }
+  },
+  "required": []
+}