fix(builders): display server console message

Fixes #1355

Author: alan-agius4

modules/builders/src/ssr-dev-server/index.ts

@@ -30,11 +30,18 @@ import {
   catchError,
   startWith,
   mapTo,
+  ignoreElements,
 } from 'rxjs/operators';
-import { getAvailablePort, execAsObservable } from './utils';
+import { getAvailablePort, spawnAsObservable } from './utils';
 import * as browserSync from 'browser-sync';
 import { join } from 'path';
 
+/** Log messages to ignore and not rely to the logger */
+const IGNORED_STDOUT_MESSAGES = [
+  'server listening on',
+  'Angular is running in the development mode. Call enableProdMode() to enable the production mode.'
+];
+
 export type SSRDevServerBuilderOptions = Schema & json.JsonObject;
 
 export function execute(
@@ -77,7 +84,7 @@ export function execute(
           if (!s.success) {
             return of(s);
           }
-          return startNodeServer(s, nodeServerPort).pipe(
+          return startNodeServer(s, nodeServerPort, context.logger).pipe(
             mapTo(s),
             catchError(err => {
               context.logger.error(`A server error has occurred.\n${mapErrorToMessage(err)}`);
@@ -126,16 +133,29 @@ export function execute(
   );
 }
 
-function startNodeServer(serverOutput: BuilderOutput, port: number): Observable<void> {
+function startNodeServer(
+  serverOutput: BuilderOutput,
+  port: number,
+  logger: logging.LoggerApi,
+): Observable<void> {
   const outputPath = serverOutput.outputPath as string;
   const path = join(outputPath, 'main.js');
   const env = { ...process.env, PORT: '' + port };
 
-  return execAsObservable(`node ${path}`, { env })
+  return spawnAsObservable('node', [`"${path}"`], { env, shell: true })
     .pipe(
       // Emit a signal after the process has been started
+      tap(({ stderr, stdout }) => {
+        if (stderr) {
+          logger.error(stderr);
+        }
+
+        if (stdout && !IGNORED_STDOUT_MESSAGES.some(x => stdout.includes(x))) {
+          logger.info(stdout);
+        }
+      }),
+      ignoreElements(),
       startWith(undefined),
-      mapTo(undefined),
     );
 }
 

modules/builders/src/ssr-dev-server/utils.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import { exec, ExecOptions } from 'child_process';
+import { spawn, SpawnOptions } from 'child_process';
 import { Observable } from 'rxjs';
 import * as treeKill from 'tree-kill';
 import { createServer, AddressInfo } from 'net';
@@ -24,18 +24,29 @@ export function getAvailablePort(): Promise<number> {
   });
 }
 
-export function execAsObservable(command: string, options: ExecOptions):
-  Observable<{ stdout: string, stderr: string }> {
+export function spawnAsObservable(
+  command: string,
+  args: string[] = [],
+  options: SpawnOptions = {}
+): Observable<{ stdout?: string, stderr?: string }> {
   return new Observable(obs => {
-    const proc = exec(command, options, (err, stdout, stderr) => {
-      if (err) {
-        obs.error(err);
-        return;
-      }
+    const proc = spawn(command, args, options);
+    if (!proc) {
+      obs.error(new Error(`${command} cannot be spawned.`));
+      return;
+    }
+
+    if (proc.stdout) {
+      proc.stdout.on('data', data => obs.next({ stdout: data.toString() }));
+    }
+
+    if (proc.stderr) {
+      proc.stderr.on('data', data => obs.next({ stderr: data.toString() }));
+    }
 
-      obs.next({ stdout, stderr });
-      obs.complete();
-    });
+    proc
+      .on('error', err => obs.error(err))
+      .on('close', () => obs.complete());
 
     return () => {
       if (!proc.killed) {