Merge pull request #62 from librato/chore/tagging-improvements

Support global tag of host from config/hostname

lib/librato.js

@@ -24,7 +24,7 @@ url_parse = require('url').parse,
 var tunnelAgent = null;
 
 var debug, logAll;
-var api, email, token, period, sourceName, sourceRegex, includeMetrics, excludeMetrics;
+var api, email, token, period, sourceName, hostName, sourceRegex, includeMetrics, excludeMetrics;
 
 // How long to wait before retrying a failed post, in seconds
 var retryDelaySecs = 5;
@@ -295,12 +295,20 @@ var flush_stats = function librato_flush(ts, metrics)
     measureName = parse_and_set_tags(measureName, measure);
 
     // Use first capturing group as source name
-    if (!writeToLegacy && sourceRegex && (match = measureName.match(sourceRegex)) && match[1]) {
+    if (sourceRegex && (match = measureName.match(sourceRegex)) && match[1]) {
       measure.source = sanitize_name(match[1]);
       // Remove entire matching string from the measure name & add global prefix.
       measure.name = sanitize_name(measureName.slice(0, match.index) + measureName.slice(match.index + match[0].length));
+
+      // Create a measurement-level tag named source
+      measure.tags.source = measure.source;
     } else {
       measure.name = sanitize_name(measureName);
+
+      // Use the global config sourceName as a source tag, if it exists.
+      if (sourceName !== null) {
+        measure.tags.source = sourceName;
+      }
     }
 
     if (brokenMetrics[measure.name]) {
@@ -538,6 +546,7 @@ exports.init = function librato_init(startup_time, config, events, logger)
     email = config.librato.email;
     token = config.librato.token;
     sourceName = config.librato.source;
+    hostName = config.librato.host;
     sourceRegex = config.librato.sourceRegex;
     snapTime = config.librato.snapTime;
     includeMetrics = config.librato.includeMetrics;
@@ -576,10 +585,10 @@ exports.init = function librato_init(startup_time, config, events, logger)
       skipInternalMetrics = config.librato.skipInternalMetrics;
     }
 
-    if (sourceName == null) {
+    if (hostName == null) {
       var os = require('os');
 
-      sourceName = os.hostname();
+      hostName = os.hostname();
     }
 
     if (config.librato.proxy && config.librato.proxy.uri) {
@@ -626,8 +635,8 @@ exports.init = function librato_init(startup_time, config, events, logger)
       writeToLegacy = config.librato.writeToLegacy;
     }
 
-    // Set host as a global tag
-    tags['host'] = sourceName;
+    // Set host as a global tag. Defaults to os.hostname()
+    tags.host = hostName;
   }
 
   if (!email || !token) {