Change span ID to use random bytes

src/span-data.ts

@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import * as crypto from 'crypto';
 import * as util from 'util';
 
 import {Constants} from './constants';
@@ -43,21 +42,12 @@ interface StackFrame {
   column_number?: number;
 }
 
-// Use 6 bytes of randomness only as JS numbers are doubles not 64-bit ints.
-const SPAN_ID_RANDOM_BYTES = 6;
-
-// Use the faster crypto.randomFillSync when available (Node 7+) falling back to
-// using crypto.randomBytes.
-const spanIdBuffer = Buffer.alloc(SPAN_ID_RANDOM_BYTES);
-const randomFillSync = crypto.randomFillSync;
-const randomBytes = crypto.randomBytes;
-const spanRandomBuffer = randomFillSync ?
-    () => randomFillSync(spanIdBuffer) :
-    () => randomBytes(SPAN_ID_RANDOM_BYTES);
+// This evaluates to a large whole number such that any fractional number
+// between 0 and 1 multiplied by it will always give a whole number.
+const SPAN_ID_MAX = (1 << 30) * (1 << 30);
 
 function randomSpanId() {
-  // tslint:disable-next-line:ban Needed to parse hexadecimal.
-  return parseInt(spanRandomBuffer().toString('hex'), 16).toString();
+  return String(Math.random() * SPAN_ID_MAX);
 }
 
 export class SpanData implements SpanDataInterface {

test/test-span-data.ts

@@ -71,7 +71,7 @@ describe('SpanData', function() {
         assert.ok(typeof spanId === 'string');
         assert.ok(spanId.match(/\d+/));
         assert.ok(Number(spanId) > 0);
-        assert.equal(Number(spanId).toString(), spanId);
+        assert.strictEqual(Number(spanId).toString(), spanId);
       }
     });
   });

test/test-trace-header-context.ts

@@ -118,19 +118,19 @@ describe('test-trace-header-context', function() {
       var receivedSpanId = receivedSpanIdAndOptions[0];
       var receivedTraceOptions = receivedSpanIdAndOptions[1];
       // Trace ID and trace options should be the same in sender and receiver.
-      assert.equal(receivedTraceId, sentTraceId);
-      assert.equal(receivedTraceOptions, sentTraceOptions);
+      assert.strictEqual(receivedTraceId, sentTraceId);
+      assert.strictEqual(receivedTraceOptions, sentTraceOptions);
       // Span ID should be different as receiver generates a new span ID.
-      assert.notEqual(receivedSpanId, sentSpanId);
+      assert.notStrictEqual(receivedSpanId, sentSpanId);
 
       res.send(common.serverRes);
       var traces = common.getTraces();
-      assert.equal(traces.length, 2);
-      assert.equal(traces[0].spans.length, 2);
-      assert.equal(traces[1].spans.length, 1);
-      assert.equal(traces[0].spans[0].name, '/');
-      assert.equal(traces[0].spans[1].name, 'localhost');
-      assert.equal(traces[1].spans[0].name, '/self');
+      assert.strictEqual(traces.length, 2);
+      assert.strictEqual(traces[0].spans.length, 2);
+      assert.strictEqual(traces[1].spans.length, 1);
+      assert.strictEqual(traces[0].spans[0].name, '/');
+      assert.strictEqual(traces[0].spans[1].name, 'localhost');
+      assert.strictEqual(traces[1].spans[0].name, '/self');
       common.cleanTraces();
       server.close();
       done();