Extended pool to handle multiple keys

The connection pool now handles connections to multiple URI, this work
is a precursor to handling multiple connections in the driver.

Author: pontusmelke

src/v1/driver.js

@@ -69,7 +69,7 @@ class Driver {
     let conn = connect(this._url, this._config);
     conn.initialize(this._userAgent, this._token, streamObserver);
     conn._id = sessionId;
-    conn._release = () => release(conn);
+    conn._release = () => release(this._url, conn);
 
     this._openSessions[sessionId] = conn;
     return conn;
@@ -108,7 +108,7 @@ class Driver {
    * @return {Session} new session.
    */
   session() {
-    let conn = this._pool.acquire();
+    let conn = this._pool.acquire(this._url);
     return new Session( conn, (cb) => {
       // This gets called on Session#close(), and is where we return
       // the pooled 'connection' instance.

src/v1/internal/connector.js

@@ -162,13 +162,15 @@ class Connection {
    * @constructor
    * @param channel - channel with a 'write' function and a 'onmessage'
    *                  callback property
+   * @param url - url to connect to
    */
-  constructor (channel) {
+  constructor (channel, url) {
     /**
      * An ordered queue of observers, each exchange response (zero or more
      * RECORD messages followed by a SUCCESS message) we recieve will be routed
      * to the next pending observer.
      */
+    this.url = url;
     this._pendingObservers = [];
     this._currentObserver = undefined;
     this._ch = channel;
@@ -441,7 +443,7 @@ function connect( url, config = {}) {
     trust : config.trust || (hasFeature("trust_on_first_use") ? "TRUST_ON_FIRST_USE" : "TRUST_CUSTOM_CA_SIGNED_CERTIFICATES"),
     trustedCertificates : config.trustedCertificates || [],
     knownHosts : config.knownHosts
-  }));
+  }), url);
 }
 
 export default {

src/v1/internal/pool.js

@@ -35,14 +35,15 @@ class Pool {
     this._destroy = destroy;
     this._validate = validate;
     this._maxIdle = maxIdle;
-    this._pool = [];
+    this._pools = {};
     this._release = this._release.bind(this);
   }
 
-  acquire() {
+  acquire(key) {
     let resource;
-    while( this._pool.length ) {
-      resource = this._pool.pop();
+    let pool = this._pools[key] || [];
+    while( pool.length ) {
+      resource = pool.pop();
 
       if( this._validate(resource) ) {
         return resource;
@@ -52,11 +53,16 @@ class Pool {
     return this._create(this._release);
   }
 
-  _release(resource) {
-    if( this._pool.length >= this._maxIdle || !this._validate(resource) ) {
+  _release(key, resource) {
+    let pool = this._pools[key];
+    if (!pool) {
+      pool = [];
+      this._pools[key] = pool;
+    }
+    if( pool.length >= this._maxIdle || !this._validate(resource) ) {
       this._destroy(resource);
     } else {
-      this._pool.push(resource);
+      pool.push(resource);
     }
   }
 }

test/internal/pool.test.js

@@ -23,11 +23,12 @@ describe('Pool', function() {
   it('allocates if pool is empty', function() {
     // Given
     var counter = 0;
+    var key = "bolt://localhost:7687";
     var pool = new Pool( function (release) { return new Resource(counter++, release) } );
 
     // When
-    var r0 = pool.acquire();
-    var r1 = pool.acquire();
+    var r0 = pool.acquire(key);
+    var r1 = pool.acquire(key);
 
     // Then
     expect( r0.id ).toBe( 0 );
@@ -37,22 +38,45 @@ describe('Pool', function() {
   it('pools if resources are returned', function() {
     // Given a pool that allocates
     var counter = 0;
+    var key = "bolt://localhost:7687";
     var pool = new Pool( function (release) { return new Resource(counter++, release) } );
 
     // When
-    var r0 = pool.acquire();
-    r0.close();
-    var r1 = pool.acquire();
+    var r0 = pool.acquire(key);
+    r0.close(key);
+    var r1 = pool.acquire(key);
 
     // Then
     expect( r0.id ).toBe( 0 );
     expect( r1.id ).toBe( 0 );
   });
 
+  it('handles multiple keys', function() {
+    // Given a pool that allocates
+    var counter = 0;
+    var key1 = "bolt://localhost:7687";
+    var key2 = "bolt://localhost:7688";
+    var pool = new Pool( function (release) { return new Resource(counter++, release) } );
+
+    // When
+    var r0 = pool.acquire(key1);
+    var r1 = pool.acquire(key2);
+    r0.close(key1);
+    var r2 = pool.acquire(key1);
+    var r3 = pool.acquire(key2);
+
+    // Then
+    expect( r0.id ).toBe( 0 );
+    expect( r1.id ).toBe( 1 );
+    expect( r2.id ).toBe( 0 );
+    expect( r3.id ).toBe( 2 );
+  });
+
   it('frees if pool reaches max size', function() {
     // Given a pool that tracks destroyed resources
     var counter = 0,
         destroyed = [];
+    var key = "bolt://localhost:7687";
     var pool = new Pool(
       function (release) { return new Resource(counter++, release) },
       function (resource) { destroyed.push(resource); },
@@ -61,12 +85,12 @@ describe('Pool', function() {
     );
 
     // When
-    var r0 = pool.acquire();
-    var r1 = pool.acquire();
-    var r2 = pool.acquire();
-    r0.close();
-    r1.close();
-    r2.close();
+    var r0 = pool.acquire(key);
+    var r1 = pool.acquire(key);
+    var r2 = pool.acquire(key);
+    r0.close(key);
+    r1.close(key);
+    r2.close(key);
 
     // Then
     expect( destroyed.length ).toBe( 1 );
@@ -77,6 +101,7 @@ describe('Pool', function() {
     // Given a pool that allocates
     var counter = 0,
       destroyed = [];
+    var key = "bolt://localhost:7687";
     var pool = new Pool(
       function (release) { return new Resource(counter++, release) },
       function (resource) { destroyed.push(resource); },
@@ -85,10 +110,10 @@ describe('Pool', function() {
     );
 
     // When
-    var r0 = pool.acquire();
-    var r1 = pool.acquire();
-    r0.close();
-    r1.close();
+    var r0 = pool.acquire(key);
+    var r1 = pool.acquire(key);
+    r0.close(key);
+    r1.close(key);
 
     // Then
     expect( destroyed.length ).toBe( 2 );
@@ -97,8 +122,8 @@ describe('Pool', function() {
   });
 });
 
-function Resource( id, release ) {
+function Resource( id, release) {
   var self = this;
   this.id = id;
-  this.close = function() { release(self); };
+  this.close = function(key) { release(key, self); };
 }