Add support for User-Agent additions (#19)

Follow libhoney-go's lead here and add a special configuration option that lets the user put additional info in the User-Agent string.

For the go sdk we use this to tag integrations, and the same will hold true here.

Also, it's about time we flipped out of beta so people can start getting updates via semver as opposed to explicitly updating to a new beta.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "libhoney",
-  "version": "1.0.0-beta.10",
+  "version": "1.0.0",
   "description": "Javascript library for sending data to Honeycomb",
   "bugs": "https://github.com/honeycombio/libhoney-js/issues",
   "repository": {

src/libhoney.js

@@ -37,7 +37,10 @@ const defaults = Object.freeze({
   maxResponseQueueSize: 1000,
 
   // if this is set to true, all sending is disabled.  useful for disabling libhoney when testing
-  disabled: false
+  disabled: false,
+
+  // If this is non-empty, append it to the end of the User-Agent header.
+  userAgentAddition: ""
 });
 
 /**

src/transmission.js

@@ -11,7 +11,7 @@
 import superagent from 'superagent';
 import urljoin from 'urljoin';
 
-const userAgent = "libhoney-js/LIBHONEY_JS_VERSION";
+const USER_AGENT = "libhoney-js/LIBHONEY_JS_VERSION";
 
 const _global = (typeof window !== "undefined" ? window :
                  typeof global !== "undefined" ? global : undefined);
@@ -151,6 +151,8 @@ export class Transmission {
       this._pendingWorkCapacity = options.pendingWorkCapacity;
     }
 
+    this._userAgentAddition = options.userAgentAddition || "";
+
     // Included for testing; to stub out randomness and verify that an event
     // was dropped.
     this._randomFn = Math.random;
@@ -201,7 +203,7 @@ export class Transmission {
 
     let batchAgg = new BatchEndpointAggregator(batch);
 
-    let finishBatch = () => {
+    const finishBatch = () => {
       this._batchCount--;
 
       let queueLength = this._eventQueue.length;
@@ -232,6 +234,12 @@ export class Transmission {
           return;
         }
 
+        let userAgent = USER_AGENT;
+        let trimmedAddition = this._userAgentAddition.trim();
+        if (trimmedAddition) {
+          userAgent = `${USER_AGENT} ${trimmedAddition}`;
+        }
+
         var start = Date.now();
         req
           .set('X-Hny-Team', batch.writeKey)

test/transmission_test.js

@@ -427,4 +427,48 @@ describe('transmission', function() {
       }));
     }
   });
+
+  it('should allow user-agent additions', function(done) {
+    var responseCount = 0;
+    var responseExpected = 2;
+
+    var UAs = [
+      { dataset: "test-transmission1", addition: "", probe: (ua) => ua.indexOf("libhoney") === 0 && ua.indexOf("addition") === -1 },
+      { dataset: "test-transmission2", addition: "user-agent addition", probe: (ua) => ua.indexOf("libhoney") === 0 && ua.indexOf("addition") !== -1 },
+    ];
+
+    // set up our endpoints
+    UAs.forEach(ua =>
+      mock.post(`http://localhost:9999/1/batch/${ua.dataset}`, function(req) {
+        if (!ua.probe(req.headers["user-agent"])) {
+          done(new Error("unexpected user-agent addition"));
+        }
+        return {};
+      })
+    );
+
+    // now send our events through separate transmissions with different UA additions
+    UAs.forEach(ua => {
+      var transmission = new Transmission({
+        batchSizeTrigger: 1, // so we'll send individual events
+        responseCallback (queue) {
+          let responses = queue.splice(0, queue.length);
+          responseCount += responses.length;
+          if (responseCount === responseExpected) {
+            done();
+          }
+        },
+        userAgentAddition: ua.addition
+      });
+
+      transmission.sendPresampledEvent(new ValidatedEvent({
+        apiHost: "http://localhost:9999",
+        writeKey: "123456789",
+        dataset: ua.dataset,
+        sampleRate: 1,
+        timestamp: new Date(),
+        postData: JSON.stringify({ a: 1, b: 2 })
+      }));
+    });
+  });
 });