fix(bundler): Pass Webpack output to logger in a single record (#1414)

Co-authored-by: James Watkins-Harvey <[email protected]>

package.json

@@ -58,6 +58,7 @@
     "@types/ms": "^0.7.34",
     "@types/node": "^20.10.8",
     "@types/stack-utils": "^2.0.3",
+    "@types/supports-color": "^8.1.3",
     "@typescript-eslint/eslint-plugin": "^6.18.1",
     "@typescript-eslint/parser": "^6.18.1",
     "arg": "^5.0.2",

packages/worker/package.json

@@ -26,10 +26,14 @@
     "rxjs": "^7.8.1",
     "source-map": "^0.7.4",
     "source-map-loader": "^4.0.2",
+    "supports-color": "^8.1.1",
     "swc-loader": "^0.2.3",
     "unionfs": "^4.5.1",
     "webpack": "^5.89.0"
   },
+  "devDependencies": {
+    "@types/supports-color": "^8.1.3"
+  },
   "bugs": {
     "url": "https://github.com/temporalio/sdk-typescript/issues"
   },

packages/worker/src/logger.ts

@@ -1,4 +1,5 @@
 import { formatWithOptions } from 'node:util';
+import * as supportsColor from 'supports-color';
 import { getTimeOfDay } from '@temporalio/core-bridge';
 import { LogLevel, LogMetadata, Logger } from '@temporalio/common';
 
@@ -13,11 +14,23 @@ export interface LogEntry {
   meta?: LogMetadata;
 }
 
+/**
+ * @internal
+ */
+interface LoggerWithColorSupport extends Logger {
+  [loggerHasColorsSymbol]?: boolean;
+}
+
 export const LogTimestamp = Symbol.for('log_timestamp');
 
 const severities: LogLevel[] = ['TRACE', 'DEBUG', 'INFO', 'WARN', 'ERROR'];
 
-const format = formatWithOptions.bind(undefined, { colors: true });
+/**
+ * @internal
+ */
+const loggerHasColorsSymbol = Symbol.for('logger_has_colors');
+const stderrHasColors = !!supportsColor.stderr;
+const format = formatWithOptions.bind(undefined, { colors: stderrHasColors });
 
 /**
  * Log messages to `stderr` using basic formatting
@@ -53,6 +66,8 @@ export class DefaultLogger implements Logger {
     protected readonly logFunction = defaultLogFunction
   ) {
     this.severity = severities.indexOf(this.level);
+    (this as LoggerWithColorSupport)[loggerHasColorsSymbol] =
+      (logFunction === defaultLogFunction && stderrHasColors) ?? false;
   }
 
   log(level: LogLevel, message: string, meta?: LogMetadata): void {
@@ -88,6 +103,13 @@ export class DefaultLogger implements Logger {
   }
 }
 
+/**
+ * @internal
+ */
+export function hasColorSupport(logger: Logger): boolean {
+  return (logger as LoggerWithColorSupport)[loggerHasColorsSymbol] ?? false;
+}
+
 export function withMetadata(logger: Logger, meta: LogMetadata | (() => LogMetadata)): Logger {
   return new LoggerWithMetadata(logger, meta);
 }
@@ -105,6 +127,7 @@ class LoggerWithMetadata implements Logger {
       this.parentLogger = parent;
       this.metaChain = [meta];
     }
+    (this as LoggerWithColorSupport)[loggerHasColorsSymbol] = hasColorSupport(parent);
   }
 
   log(level: LogLevel, message: string, meta?: LogMetadata): void {

packages/worker/src/workflow/bundler.ts

@@ -5,7 +5,7 @@ import util from 'node:util';
 import * as unionfs from 'unionfs';
 import * as memfs from 'memfs';
 import { Configuration, webpack } from 'webpack';
-import { DefaultLogger, Logger } from '../logger';
+import { DefaultLogger, Logger, hasColorSupport } from '../logger';
 import { toMB } from '../utils';
 
 export const defaultWorkflowInterceptorModules = [require.resolve('../workflow-log-interceptor')];
@@ -262,10 +262,12 @@ exports.importInterceptors = function importInterceptors() {
             const hasError = stats.hasErrors();
             // To debug webpack build:
             // const lines = stats.toString({ preset: 'verbose' }).split('\n');
-            const lines = stats.toString({ chunks: false, colors: true, errorDetails: true }).split('\n');
-            for (const line of lines) {
-              this.logger[hasError ? 'error' : 'info'](line);
-            }
+            const webpackOutput = stats.toString({
+              chunks: false,
+              colors: hasColorSupport(this.logger),
+              errorDetails: true,
+            });
+            this.logger[hasError ? 'error' : 'info'](webpackOutput);
             if (hasError) {
               reject(
                 new Error(