Lock now considers the creation time and compares against a ttl so

a lock is not keep forever in case of failure.

Pending: lazy removal of expired locks.

lib/cartodb/template_maps.js

@@ -44,6 +44,8 @@ function TemplateMaps(redis_pool, signed_maps, opts) {
 
   // User template locks (HASH:tpl_id->ctime)
   this.key_usr_tpl_lck = dot.template("map_tpl|{{=it.owner}}|locks");
+
+  this.lock_ttl = this.opts['lock_ttl'] || 5000;
 }
 
 var o = TemplateMaps.prototype;
@@ -93,24 +95,24 @@ o._redisCmd = function(redisFunc, redisArgs, callback) {
 
 // @param callback function(err, obtained)
 o._obtainTemplateLock = function(owner, tpl_id, callback) {
-  var that = this;
+    var that = this,
-  var gotLock = false;
+        lockKey = this.key_usr_tpl_lck({owner:owner});
     Step (
         function obtainLock() {
-      var ctime = Date.now();
+            that._redisCmd('HGET', [lockKey, tpl_id], this);
-      that._redisCmd('HSETNX', [that.key_usr_tpl_lck({owner:owner}), tpl_id, ctime], this);
         },
-    function checkLock(err, locked) {
+        function checkLock(err, lockTime) {
-      if ( err ) throw err;
+            if (err) { throw err; }
-      if ( ! locked ) {
+
-        // Already locked
+            var _newLockTime = Date.now();
-        // TODO: unlock if expired ?
+            if (!lockTime || ((_newLockTime - lockTime) > that.lock_ttl)) {
+                that._redisCmd('HSET', [lockKey, tpl_id, _newLockTime], this);
+            } else {
                 throw new Error("Template '" + tpl_id + "' of user '" + owner + "' is locked");
             }
-      return gotLock = true;
         },
-    function finish(err) {
+        function finish(err, hsetValue) {
-      callback(err, gotLock);
+            callback(err, !!hsetValue);
         }
     );
 };

test/unit/cartodb/template_maps.test.js

@@ -13,6 +13,14 @@ suite('template_maps', function() {
   var redis_pool = RedisPool(global.environment.redis);
   var signed_maps = new SignedMaps(redis_pool);
 
+    var validTemplate = {
+        version:'0.0.1',
+        name: 'first',
+        auth: {},
+        layergroup: {}
+    };
+    var owner = 'me';
+    
   test('does not accept template with unsupported version', function(done) {
     var tmap = new TemplateMaps(redis_pool, signed_maps);
     assert.ok(tmap);
@@ -503,4 +511,88 @@ suite('template_maps', function() {
     );
   });
 
+    var redisCmdFunc = TemplateMaps.prototype._redisCmd;
+
+    function runWithRedisStubbed(stubbedCommands, func) {
+        TemplateMaps.prototype._redisCmd = function(redisFunc, redisArgs, callback) {
+            redisFunc = redisFunc.toLowerCase();
+            if (stubbedCommands.hasOwnProperty(redisFunc)) {
+                callback(null, stubbedCommands[redisFunc]);
+            } else {
+                throw 'Unknown command';
+            }
+        };
+
+        func();
+
+        TemplateMaps.prototype._redisCmd = redisCmdFunc;
+    }
+
+    test('_obtainTemplateLock with no previous value, happy case', function(done) {
+        runWithRedisStubbed({hget: null, hset: 1}, function() {
+            var templateMaps = new TemplateMaps(redis_pool, signed_maps);
+
+            templateMaps._obtainTemplateLock(owner, validTemplate.name, function(err, gotLock) {
+                assert.ok(!err);
+                assert.ok(gotLock);
+                done();
+            });
+        });
+    });
+
+    test('_obtainTemplateLock no lock for non expired ttl, simulates obtaining two locks at same time', function(done) {
+        runWithRedisStubbed({hget: Date.now()}, function() {
+            var templateMaps = new TemplateMaps(redis_pool, signed_maps);
+
+            templateMaps._obtainTemplateLock(owner, validTemplate.name, function(err, gotLock) {
+                assert.ok(!!err);
+                assert.equal(gotLock, false);
+                done();
+            });
+        });
+    });
+
+
+    test('_obtainTemplateLock no lock for non expired ttl, last millisecond of valid ttl', function(done) {
+        var nowValue = Date.now(),
+            nowFunc = Date.now;
+        Date.now = function() {
+            return nowValue;
+        };
+        var lockTtl = 1000;
+        runWithRedisStubbed({hget: Date.now() - lockTtl, hset: true}, function() {
+            var templateMaps = new TemplateMaps(redis_pool, signed_maps, {lock_ttl: lockTtl});
+
+            templateMaps._obtainTemplateLock(owner, validTemplate.name, function(err, gotLock) {
+                assert.ok(!!err);
+                assert.equal(gotLock, false);
+
+                Date.now = nowFunc;
+
+                done();
+            });
+        });
+    });
+
+    test('_obtainTemplateLock gets lock for expired ttl, first millisecond of invalid ttl', function(done) {
+        var nowValue = Date.now(),
+            nowFunc = Date.now;
+        Date.now = function() {
+            return nowValue;
+        };
+        var lockTtl = 1000;
+        runWithRedisStubbed({hget: Date.now() - lockTtl - 1, hset: true}, function() {
+            var templateMaps = new TemplateMaps(redis_pool, signed_maps, {lock_ttl: lockTtl});
+
+            templateMaps._obtainTemplateLock(owner, validTemplate.name, function(err, gotLock) {
+                assert.ok(!err);
+                assert.ok(gotLock);
+
+                Date.now = nowFunc;
+
+                done();
+            });
+        });
+    });
+
 });