Add insertId on log entries (#2021)

package.json

@@ -56,6 +56,7 @@
     "@google-cloud/common-grpc": "^0.2.1",
     "arrify": "^1.0.0",
     "async": "^2.1.4",
+    "eventid": "^0.1.0",
     "extend": "^3.0.0",
     "google-gax": "^0.12.2",
     "google-proto-files": "^0.10.0",

src/entry.js

@@ -21,10 +21,13 @@
 'use strict';
 
 var commonGrpc = require('@google-cloud/common-grpc');
+var EventId = require('eventid');
 var extend = require('extend');
 var is = require('is');
 var isCircular = require('is-circular');
 
+var eventId = new EventId();
+
 /**
  * Create an entry object to define new data to insert into a log.
  *
@@ -87,6 +90,17 @@ function Entry(metadata, data) {
     timestamp: new Date()
   }, metadata);
 
+  // JavaScript date has a very coarse granularity (millisecond), which makes
+  // it quite likely that multiple log entries would have the same timestamp.
+  // The Logging API doesn't guarantee to preserve insertion order for entries
+  // with the same timestamp. The service does use `insertId` as a secondary
+  // ordering for entries with the same timestamp. `insertId` needs to be
+  // globally unique (within the project) however.
+  //
+  // We use a globally unique monotonically increasing EventId as the
+  // insertId.
+  this.metadata.insertId = this.metadata.insertId || eventId.new();
+
   this.data = data;
 }
 

system-test/logging.js

@@ -351,8 +351,8 @@ describe('Logging', function() {
       var entry1 = log.entry('1');
 
       setTimeout(function() {
-        var entry3 = log.entry('3');
-        var entry2 = log.entry({ timestamp: entry3.metadata.timestamp }, '2');
+        var entry2 = log.entry('2');
+        var entry3 = log.entry({ timestamp: entry2.metadata.timestamp }, '3');
 
         // Re-arrange to confirm the timestamp is sent and honored.
         log.write([entry2, entry3, entry1], options, function(err) {
@@ -369,6 +369,22 @@ describe('Logging', function() {
       }, 1000);
     });
 
+    it('should preserve order for sequential write calls', function(done) {
+      var messages =  ['1', '2', '3', '4', '5'];
+
+      messages.forEach(function(message) {
+        log.write(log.entry(message));
+      });
+
+      setTimeout(function() {
+        log.getEntries({ pageSize: messages.length }, function(err, entries) {
+          assert.ifError(err);
+          assert.deepEqual(entries.reverse().map(prop('data')), messages);
+          done();
+        });
+      }, WRITE_CONSISTENCY_DELAY_MS);
+    });
+
     it('should write an entry with primitive values', function(done) {
       var logEntry = log.entry({
         when: new Date(),

test/entry.js

@@ -24,6 +24,13 @@ var util = require('@google-cloud/common').util;
 
 function FakeGrpcService() {}
 
+var fakeEventIdNewOverride;
+
+function FakeEventId() {}
+FakeEventId.prototype.new = function() {
+  return (fakeEventIdNewOverride || util.noop).apply(null, arguments);
+};
+
 describe('Entry', function() {
   var Entry;
   var entry;
@@ -35,11 +42,13 @@ describe('Entry', function() {
     Entry = proxyquire('../src/entry.js', {
       '@google-cloud/common-grpc': {
         Service: FakeGrpcService
-      }
+      },
+      'eventid': FakeEventId
     });
   });
 
   beforeEach(function() {
+    fakeEventIdNewOverride = null;
     extend(FakeGrpcService, GrpcService);
     entry = new Entry(METADATA, DATA);
   });
@@ -67,6 +76,34 @@ describe('Entry', function() {
       assert.strictEqual(entry.metadata.timestamp, timestamp);
     });
 
+    it('should assign insertId to metadata', function() {
+      var eventId = 'event-id';
+
+      fakeEventIdNewOverride = function() {
+        return eventId;
+      };
+
+      var entry = new Entry();
+
+      assert.strictEqual(entry.metadata.insertId, eventId);
+    });
+
+    it('should not assign insertId if one is already set', function() {
+      var eventId = 'event-id';
+
+      fakeEventIdNewOverride = function() {
+        return eventId;
+      };
+
+      var userDefinedInsertId = 'user-defined-insert-id';
+
+      var entry = new Entry({
+        insertId: userDefinedInsertId
+      });
+
+      assert.strictEqual(entry.metadata.insertId, userDefinedInsertId);
+    });
+
     it('should localize data', function() {
       assert.strictEqual(entry.data, DATA);
     });