Flush data after both writes and fix a test

lib/storage.js

@@ -34,6 +34,17 @@ storage.ensureFileDoesntExist = function (file, callback) {
 };
 
 
+/**
+ *  Flush data in OS buffer to storage if corresponding option is set
+ */
+storage.flushToStorage = function (filename, callback) {
+  fs.open(filename, 'r', function (err, fd) {
+    if (err) { return callback(err); }
+    fs.fsync(fd, function (err) { return callback(err); });
+  });
+};
+
+
 /**
  * Fully write or rewrite the datafile, immune to crashes during the write operation (data will not be lost)
  * @param {String} filename
@@ -52,7 +63,10 @@ storage.crashSafeWriteFile = function (filename, data, cb) {
   , function (cb) {
       storage.exists(filename, function (exists) {
         if (exists) {
-          storage.rename(filename, oldFilename, function (err) { return cb(err); });
+          storage.rename(filename, oldFilename, function (err) {
+            if (err) { return cb(err); }
+            storage.flushToStorage(oldFilename, cb);   // Ensure filename doesn't exist due to rename atomicity
+          });
         } else {
           return cb();
         }
@@ -64,8 +78,9 @@ storage.crashSafeWriteFile = function (filename, data, cb) {
   , function (cb) {
       storage.rename(tempFilename, filename, function (err) { return cb(err); });
     }
+  , async.apply(storage.flushToStorage, filename)
   , async.apply(storage.ensureFileDoesntExist, oldFilename)
-  ], function (err) { if (err) { return callback(err); } else { return callback(null); } })
+  ], function (err) { return callback(err); })
 };
 
 

test/db.test.js

@@ -285,7 +285,7 @@ describe('Database', function () {
           insertedDoc.createdAt.should.equal(insertedDoc.updatedAt);
           assert.isDefined(insertedDoc._id);
           Object.keys(insertedDoc).length.should.equal(4);
-          assert.isBelow(Math.abs(insertedDoc.createdAt.getTime() - beginning), 15);   // No more than 15ms should have elapsed
+          assert.isBelow(Math.abs(insertedDoc.createdAt.getTime() - beginning), 30);   // No more than 30ms should have elapsed (worst case, if there is a flush)
 
           // Modifying results of insert doesn't change the cache
           insertedDoc.bloup = "another";
@@ -332,7 +332,7 @@ describe('Database', function () {
       d.insert(newDoc, function (err, insertedDoc) {
         Object.keys(insertedDoc).length.should.equal(4);
         insertedDoc.createdAt.getTime().should.equal(234);   // Not modified
-        assert.isBelow(insertedDoc.updatedAt.getTime() - beginning, 15);   // Created
+        assert.isBelow(insertedDoc.updatedAt.getTime() - beginning, 30);   // Created
 
         d.find({}, function (err, docs) {
           assert.deepEqual(insertedDoc, docs[0]);
@@ -354,7 +354,7 @@ describe('Database', function () {
       d.insert(newDoc, function (err, insertedDoc) {
         Object.keys(insertedDoc).length.should.equal(4);
         insertedDoc.updatedAt.getTime().should.equal(234);   // Not modified
-        assert.isBelow(insertedDoc.createdAt.getTime() - beginning, 15);   // Created
+        assert.isBelow(insertedDoc.createdAt.getTime() - beginning, 30);   // Created
 
         d.find({}, function (err, docs) {
           assert.deepEqual(insertedDoc, docs[0]);
@@ -961,8 +961,8 @@ describe('Database', function () {
       var beginning = Date.now();
       d = new Datastore({ filename: testDb, autoload: true, timestampData: true });
       d.insert({ hello: 'world' }, function (err, insertedDoc) {
-        assert.isBelow(insertedDoc.updatedAt.getTime() - beginning, 15);
+        assert.isBelow(insertedDoc.updatedAt.getTime() - beginning, 30);
-        assert.isBelow(insertedDoc.createdAt.getTime() - beginning, 15);
+        assert.isBelow(insertedDoc.createdAt.getTime() - beginning, 30);
         Object.keys(insertedDoc).length.should.equal(4);
 
         // Wait 100ms before performing the update
@@ -976,7 +976,7 @@ describe('Database', function () {
               docs[0].createdAt.should.equal(insertedDoc.createdAt);
               docs[0].hello.should.equal('mars');
               assert.isAbove(docs[0].updatedAt.getTime() - beginning, 99);   // updatedAt modified
-              assert.isBelow(docs[0].updatedAt.getTime() - step1, 15);   // updatedAt modified
+              assert.isBelow(docs[0].updatedAt.getTime() - step1, 30);   // updatedAt modified
 
               done();
             });
@@ -1815,19 +1815,19 @@ describe('Database', function () {
           ;
 
         d.getAllData().length.should.equal(0);
-
+        d.ensureIndex({ fieldName: 'z' }, function () {
-        d.ensureIndex({ fieldName: 'z' });
+          d.ensureIndex({ fieldName: 'a' }, function () {
-        d.ensureIndex({ fieldName: 'a' });
             d.indexes.a.tree.getNumberOfKeys().should.equal(0);
             d.indexes.z.tree.getNumberOfKeys().should.equal(0);
 
             fs.writeFile(testDb, rawData, 'utf8', function () {
-          d.loadDatabase(function () {
+              d.loadDatabase(function (err) {
                 var doc1 = _.find(d.getAllData(), function (doc) { return doc.z === "1"; })
                   , doc2 = _.find(d.getAllData(), function (doc) { return doc.z === "2"; })
                   , doc3 = _.find(d.getAllData(), function (doc) { return doc.z === "3"; })
                   ;
 
+                assert.isNull(err);
                 d.getAllData().length.should.equal(3);
 
                 d.indexes.z.tree.getNumberOfKeys().should.equal(3);
@@ -1845,6 +1845,9 @@ describe('Database', function () {
             });
           });
 
+        });
+      });
+
       it('If a unique constraint is not respected, database loading will not work and no data will be inserted', function (done) {
         var now = new Date()
           , rawData = model.serialize({ _id: "aaa", z: "1", a: 2, ages: [1, 5, 12] }) + '\n' +