Merge pull request #20298 from backstage/rugvip/windev

backend-next: fixes for development on Windows

.changeset/itchy-monkeys-reply.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-dev-utils': patch
+---
+
+Fix an issue where early IPC responses would be lost.

.changeset/red-bees-try.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Fixed an issue where the new backend start command would not gracefully shut down the backend process on Windows.

packages/backend-dev-utils/src/ipcClient.ts

@@ -38,6 +38,8 @@ type Response =
 const requestType = '@backstage/cli/channel/request';
 const responseType = '@backstage/cli/channel/response';
 
+const IPC_TIMEOUT_MS = 5000;
+
 /**
  * The client side of an IPC communication channel.
  *
@@ -78,43 +80,43 @@ export class BackstageIpcClient {
         body,
       };
 
-      this.#sendMessage(request, (e: Error) => {
-        if (e) {
-          reject(e);
+      let timeout: NodeJS.Timeout | undefined = undefined;
+
+      const messageHandler = (response: Response) => {
+        if (response?.type !== responseType) {
+          return;
+        }
+        if (response.id !== id) {
           return;
         }
 
-        let timeout: NodeJS.Timeout | undefined = undefined;
+        clearTimeout(timeout);
+        timeout = undefined;
+        process.removeListener('message', messageHandler);
 
-        const messageHandler = (response: Response) => {
-          if (response?.type !== responseType) {
-            return;
-          }
-          if (response.id !== id) {
-            return;
+        if ('error' in response) {
+          const error = new Error(response.error.message);
+          if (response.error.name) {
+            error.name = response.error.name;
           }
+          reject(error);
+        } else {
+          resolve(response.body as TResponseBody);
+        }
+      };
 
-          if ('error' in response) {
-            const error = new Error(response.error.message);
-            if (response.error.name) {
-              error.name = response.error.name;
-            }
-            reject(error);
-          } else {
-            resolve(response.body as TResponseBody);
-          }
+      timeout = setTimeout(() => {
+        reject(new Error(`IPC request '${method}' with ID ${id} timed out`));
+        process.removeListener('message', messageHandler);
+      }, IPC_TIMEOUT_MS);
+      timeout.unref();
 
-          clearTimeout(timeout);
-          process.removeListener('message', messageHandler);
-        };
+      process.addListener('message', messageHandler as () => void);
 
-        timeout = setTimeout(() => {
-          reject(new Error(`IPC request '${method}' with ID ${id} timed out`));
-          process.removeListener('message', messageHandler);
-        }, 5000);
-        timeout.unref();
-
-        process.addListener('message', messageHandler as () => void);
+      this.#sendMessage(request, (e: Error) => {
+        if (e) {
+          reject(e);
+        }
       });
     });
   }

packages/cli/package.json

@@ -78,6 +78,7 @@
     "cross-fetch": "^3.1.5",
     "cross-spawn": "^7.0.3",
     "css-loader": "^6.5.1",
+    "ctrlc-windows": "^2.1.0",
     "diff": "^5.0.0",
     "esbuild": "^0.19.0",
     "esbuild-loader": "^2.18.0",

packages/cli/src/lib/experimental/startBackendExperimental.ts

@@ -18,6 +18,7 @@ import { FSWatcher, watch } from 'chokidar';
 
 import { BackendServeOptions } from '../bundler/types';
 import type { ChildProcess } from 'child_process';
+import { ctrlc } from 'ctrlc-windows';
 import { IpcServer } from './IpcServer';
 import { ServerDataStore } from './ServerDataStore';
 import debounce from 'lodash/debounce';
@@ -57,7 +58,11 @@ export async function startBackendExperimental(options: BackendServeOptions) {
     if (child && !child.killed && child.exitCode === null) {
       // We always wait for the existing process to exit, to make sure we don't get IPC conflicts
       shutdownPromise = new Promise(resolve => child!.once('exit', resolve));
-      child.kill();
+      if (process.platform === 'win32' && child.pid) {
+        ctrlc(child.pid);
+      } else {
+        child.kill();
+      }
       await shutdownPromise;
       shutdownPromise = undefined;
     }

yarn.lock

@@ -3795,6 +3795,7 @@ __metadata:
     cross-fetch: ^3.1.5
     cross-spawn: ^7.0.3
     css-loader: ^6.5.1
+    ctrlc-windows: ^2.1.0
     del: ^7.0.0
     diff: ^5.0.0
     esbuild: ^0.19.0
@@ -23050,6 +23051,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"ctrlc-windows@npm:^2.1.0":
+  version: 2.1.0
+  resolution: "ctrlc-windows@npm:2.1.0"
+  checksum: 0f0582ba9516290d3e90ea7b91710f8b9b110e1ed29b7c84ebd44c16368b2553722b86a17226120ca3ea0ef679ac3596f48104cc113cfb7c3d07260f6c92e38b
+  languageName: node
+  linkType: hard
+
 "d3-array@npm:2 - 3, d3-array@npm:2.10.0 - 3, d3-array@npm:^3.1.6":
   version: 3.2.3
   resolution: "d3-array@npm:3.2.3"