tarn - npm Package Compare versions

Comparing version 0.1.0 to 0.1.1

index.js

 var Promise = require('bluebird');
+var RECURSION_LIMIT = 100;
 
@@ -26,16 +27,16 @@ function Tarn(opt) {
 
-  if (!checkOptionalTime(opt.acquireTimeoutMs)) {
-    throw new Error('Tarn: invalid opt.acquireTimeoutMs ' + JSON.stringify(opt.acquireTimeoutMs));
+  if (!checkOptionalTime(opt.acquireTimeoutMillis)) {
+    throw new Error('Tarn: invalid opt.acquireTimeoutMillis ' + JSON.stringify(opt.acquireTimeoutMillis));
   }
 
-  if (!checkOptionalTime(opt.createTimeoutMs)) {
-    throw new Error('Tarn: invalid opt.createTimeoutMs ' + JSON.stringify(opt.createTimeoutMs));
+  if (!checkOptionalTime(opt.createTimeoutMillis)) {
+    throw new Error('Tarn: invalid opt.createTimeoutMillis ' + JSON.stringify(opt.createTimeoutMillis));
   }
 
-  if (!checkOptionalTime(opt.idleTimeoutMs)) {
-    throw new Error('Tarn: invalid opt.idleTimeoutMs ' + JSON.stringify(opt.idleTimeoutMs));
+  if (!checkOptionalTime(opt.idleTimeoutMillis)) {
+    throw new Error('Tarn: invalid opt.idleTimeoutMillis ' + JSON.stringify(opt.idleTimeoutMillis));
   }
 
-  if (!checkOptionalTime(opt.reapIntervalMs)) {
-    throw new Error('Tarn: invalid opt.reapIntervalMs ' + JSON.stringify(opt.reapIntervalMs));
+  if (!checkOptionalTime(opt.reapIntervalMillis)) {
+    throw new Error('Tarn: invalid opt.reapIntervalMillis ' + JSON.stringify(opt.reapIntervalMillis));
   }
@@ -45,8 +46,9 @@
   this.destroyer = opt.destroy;
+  this.validate = typeof opt.validate === 'function' ? opt.validate : function () { return true; };
   this.log = opt.log || function () {};
 
-  this.acquireTimeoutMs = opt.acquireTimeoutMs || 30000;
-  this.createTimeoutMs = opt.createTimeoutMs || 30000;
-  this.idleTimeoutMs = opt.idleTimeoutMs || 30000;
-  this.reapIntervalMs = opt.reapIntervalMs || 1000;
+  this.acquireTimeoutMillis = opt.acquireTimeoutMillis || 30000;
+  this.createTimeoutMillis = opt.createTimeoutMillis || 30000;
+  this.idleTimeoutMillis = opt.idleTimeoutMillis || 30000;
+  this.reapIntervalMillis = opt.reapIntervalMillis || 1000;
 
@@ -65,3 +67,3 @@ this.min = opt.min;
     self.check();
-  }, this.reapIntervalMs);
+  }, this.reapIntervalMillis);
 }
@@ -88,3 +90,3 @@
 
-  var pendingAcquire = new PendingOperation(this.acquireTimeoutMs);
+  var pendingAcquire = new PendingOperation(this.acquireTimeoutMillis);
   this.pendingAcquires.push(pendingAcquire);
@@ -97,3 +99,3 @@
 
-  this._tryAcquireNext();
+  this._tryAcquireNext(0);
   return pendingAcquire;
@@ -109,3 +111,3 @@ };
       this.free.push(new FreeResource(used.resource));
-      this._tryAcquireNext();
+      this._tryAcquireNext(0);
       return true;
@@ -128,3 +130,3 @@ }
 
-    if (duration(timestamp, free.timestamp) > this.idleTimeoutMs && numDestroyed < maxDestroy) {
+    if (duration(timestamp, free.timestamp) > this.idleTimeoutMillis && numDestroyed < maxDestroy) {
       numDestroyed++;
@@ -144,4 +146,6 @@ this._destroy(free.resource);
 
-Tarn.prototype._tryAcquireNext = function () {
-  if (this.used.length >= this.max || this.pendingAcquires.length === 0) {
+Tarn.prototype._tryAcquireNext = function (recursion) {
+  recursion = (recursion || 0) + 1;
+
+  if (this.used.length >= this.max || this.pendingAcquires.length === 0 || recursion > RECURSION_LIMIT) {
     // Nothing to do.
@@ -152,3 +156,3 @@ return;
   if (this.free.length > 0) {
-    this._acquireNext();
+    this._acquireNext(recursion);
   } else if (this.used.length + this.pendingCreates.length < this.max && this.pendingCreates.length < this.pendingAcquires.length) {
@@ -158,5 +162,5 @@ var self = this;
     this._create().promise.then(function () {
-      self._tryAcquireNext();
+      self._tryAcquireNext(recursion);
     }).catch(function (err) {
-      self.log('Tarn: resource creator threw an exception', err.stack);
+      self.log('Tarn: resource creator threw an exception ' + err.stack, 'warn');
     });
@@ -166,13 +170,29 @@ }
 
-Tarn.prototype._acquireNext = function () {
+Tarn.prototype._acquireNext = function (recursion) {
   while (this.free.length > 0 && this.pendingAcquires.length > 0) {
-    var pendingAcquire = this.pendingAcquires.shift();
+    var pendingAcquire = this.pendingAcquires[0];
+    var free = this.free[0];
 
-    if (!pendingAcquire.isRejected()) {
-      var free = this.free.shift();
+    if (pendingAcquire.isRejected()) {
+      this.pendingAcquires.shift();
+      continue;
+    }
 
-      this.used.push(new UsedResource(free.resource));
-      pendingAcquire._resolve(free.resource);
+    if (!this.validate(free.resource)) {
+      this.free.shift();
+      this._destroy(free.resource);
+      continue;
     }
+
+    this.pendingAcquires.shift();
+    this.free.shift();
+
+    this.used.push(new UsedResource(free.resource));
+    pendingAcquire._resolve(free.resource);
   }
+
+  // If we destroyed invalid resources, we may need to create new ones.
+  if (this.pendingAcquires.length > this.pendingCreates.length) {
+    this._tryAcquireNext(recursion);
+  }
 };
@@ -183,27 +203,21 @@
 
-  var pendingCreate = new PendingOperation(this.createTimeoutMs);
+  var pendingCreate = new PendingOperation(this.createTimeoutMillis);
   this.pendingCreates.push(pendingCreate);
 
-  // nextTick is needed to make sure the creation happens asynchronously.
-  try {
-    self.creator(function (err, resource) {
-      remove(self.pendingCreates, pendingCreate);
+  callbackOrPromise(self.creator, []).then(function (resource) {
+    remove(self.pendingCreates, pendingCreate);
 
-      if (err) {
-        pendingCreate._reject(err);
-      } else {
-        if (pendingCreate.isRejected()) {
-          // This happens if the pending operation times out or is aborted. In any case,
-          // we need to destroy the resource since no-one will ever use it.
-          this._destroy(resource);
-        } else {
-          self.free.push(new FreeResource(resource));
-          pendingCreate._resolve(resource);
-        }
-      }
-    });
-  } catch (err) {
+    if (pendingCreate.isRejected()) {
+      // This happens if the pending operation times out or is aborted. In any case,
+      // we need to destroy the resource since no-one will ever use it.
+      this._destroy(resource);
+    } else {
+      self.free.push(new FreeResource(resource));
+      pendingCreate._resolve(resource);
+    }
+  }).catch(function (err) {
     remove(self.pendingCreates, pendingCreate);
+
     pendingCreate._reject(err);
-  }
+  });
 
@@ -217,3 +231,3 @@ return pendingCreate;
   } catch (err) {
-    this.log('Tarn: resource destroyer threw an exception', err.stack);
+    this.log('Tarn: resource destroyer threw an exception ' + err.stack, 'warn');
   }
@@ -283,4 +297,24 @@ };
 
+function callbackOrPromise(func, args) {
+  return new Promise(function (resolve, reject) {
+    args.push(function (err, resource) {
+      if (err) {
+        reject(err);
+      } else {
+        resolve(resource);
+      }
+    });
+
+    Promise.try(function () {
+      return func.apply(undefined, args);
+    }).then(function (res) {
+      if (res) {
+        resolve(res);
+      }
+    }).catch(reject);
+  });
+}
+
 module.exports = {
   Tarn: Tarn
 };

package.json

 {
   "name": "tarn",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "description": "Simple and robust resource pool for node.js",
@@ -8,3 +8,4 @@ "main": "index.js",
   "scripts": {
-    "test": "mocha --slow 10 --timeout 5000 --reporter spec tests.js"
+    "test": "mocha --slow 10 --timeout 5000 --reporter spec tests.js",
+    "test-bail": "mocha --slow 10 --timeout 5000 --reporter spec --bail tests.js"
   },
@@ -11,0 +12,0 @@ "author": {

README.md

 [![Build Status](https://travis-ci.org/Vincit/tarn.js.svg?branch=master)](https://travis-ci.org/Vincit/tarn.js)
 
-## Why yet another pool for node?
+## Why yet another resource pool?
 
-Tarn is focused in robustness and ability to recover from errors. Tarn has timeouts for all operations
+Tarn is focused on robustness and ability to recover from errors. Tarn has timeouts for all operations
 that can fail or timeout so that you should never end up with pool full of crap. Tarn has a comprehensive
@@ -24,3 +24,5 @@ test suite and we are committed to adding tests and fixing all bugs that are found.
 
-  // function that creates a resource
+  // function that creates a resource. You can either pass the resource
+  // to the callback or return a promise that resolves the resource
+  // (but not both).
   create: (cb) => {
@@ -30,3 +32,11 @@ cb(null, new SomeResource());
   
-  // function that destroys a resource
+  // validates a connection before it is used. Return true or false
+  // from it. If false is returned, the resource is destroyed and a
+  // another one is acquired.
+  validate: (resource) {
+    return true;
+  },
+  
+  // function that destroys a resource. This is always synchronous
+  // as nothing waits for the return value.
   destroy: (someResource) => {
@@ -44,13 +54,13 @@ someResource.cleanup();
   // if a resource cannot be acquired
-  acquireTimeoutMs: 30000,
+  acquireTimeoutMillis: 30000,
   
   // create operations are cancelled after this many milliseconds
   // if a resource cannot be acquired
-  createTimeoutMs: 30000,
+  createTimeoutMillis: 30000,
   
   // free resouces are destroyed after this many milliseconds
-  idleTimeoutMs: 30000,
+  idleTimeoutMillis: 30000,
   
   // how often to check for idle resources to destroy
-  reapIntervalMs: 1000
+  reapIntervalMillis: 1000
 });
@@ -57,0 +67,0 @@

New alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Fixed alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

11727

increased by14.66%

Lines of code

240

increased by12.68%

Number of lines in readme file

83

increased by13.7%

No dependency changes