diff --git a/lib/stackdriver.js b/lib/stackdriver.js
index cb74f28..b1eb766 100644
--- a/lib/stackdriver.js
+++ b/lib/stackdriver.js
@@ -81,6 +81,21 @@ function StackdriverBackend(startupTime, config, emitter) {
 	if (this.sourceFromPrefix) {
 		util.log('Source will be inferred from each metric prefix, separated by "' + this.sourcePrefixSeparator + '", all points sent to Stackdriver for that metric will be associated with that instance');
 	} else if (this.source) {
+		var sys = require('sys');
+	 	var exec = require('child_process').exec;
+	 	
+	 	if (this.source == 'detect-aws') {
+	 		// Amazon EC2 instance - connect to local metadata service to grab instance ID
+		 	var child = exec('wget -q -O - http://169.254.169.254/latest/meta-data/instance-id', function(error, stdout, stdin) {
+		 		this.source = stdout;
+		  	});
+	 	} else if (this.source == 'detect-gce') {
+	 		// Google Compute Engine instance - connect to local metadata service to grab instance ID
+	 		var child = exec('wget -q -O - http://metadata/computeMetadata/v1/instance/id --header "X-Google-Metadata-Request: true"', function(error, stdout, stdin) {
+		 		this.source = stdout;
+		  	});	
+	 	}
+		
 		util.log('Source param set to ' + this.source + ', all points sent to Stackdriver will be associated with that instance');
 	}