Build Tooling: Define build concurrency explicitly

Author: aduth

.travis.yml

@@ -25,7 +25,9 @@ branches:
 before_install:
   - nvm install
 
-env: PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=true
+env:
+  - PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=true
+  - HARDWARE_CONCURRENCY=2
 
 jobs:
   include:

bin/packages/build.js

@@ -44,7 +44,15 @@ if ( ! files.length ) {
 	};
 }
 
-const worker = workerFarm( require.resolve( './build-worker' ) );
+const options = {};
+if ( process.env.HARDWARE_CONCURRENCY ) {
+	// WorkerFarm is configured to use the number of CPUs available as the
+	// default value. This can be overwritten for finite control or for use in
+	// uncooperative continuous integration.
+	options.maxConcurrentWorkers = Number( process.env.HARDWARE_CONCURRENCY );
+}
+
+const worker = workerFarm( options, require.resolve( './build-worker' ) );
 
 let complete = 0;