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jakewinsjakewins
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Add basic session pooling
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‎src/v1/internal/pool.js‎

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/**
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* Copyright (c) 2002-2016 "Neo Technology,"
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* Network Engine for Objects in Lund AB [http://neotechnology.com]
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*
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* This file is part of Neo4j.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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class Pool {
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/**
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* @param create an allocation function that creates a new resource. It's given
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* a single argument, a function that will return the resource to
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* the pool if invoked, which is meant to be called on .dispose
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* or .close or whatever mechanism the resource uses to finalize.
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* @param destroy called with the resource when it is evicted from this pool
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* @param validate called at various times (like when an instance is acquired and
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* when it is returned). If this returns false, the resource will
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* be evicted
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* @param maxIdle the max number of resources that are allowed idle in the pool at
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* any time. If this threshold is exceeded, resources will be evicted.
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*/
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constructor(create, destroy=(()=>true), validate=(()=>true), maxIdle=50) {
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this._create = create;
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this._destroy = destroy;
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this._validate = validate;
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this._maxIdle = maxIdle;
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this._pool = [];
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this._release = this._release.bind(this);
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}
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acquire() {
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if( this._pool.length > 0 ) {
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return this._pool.pop();
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} else {
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return this._create( this._release );
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}
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}
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_release(resource) {
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if( this._pool.length >= this._maxIdle || !this._validate(resource) ) {
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this._destroy(resource);
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} else {
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this._pool.push(resource);
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}
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}
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}
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export default {
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Pool
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}

‎src/v1/session.js‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -68,7 +68,7 @@ class Session {
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* Begin a new transaction in this session. A session can have at most one transaction running at a time, if you
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* want to run multiple concurrent transactions, you should use multiple concurrent sessions.
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*
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* While a transaction is open the session cannot be used to run statements.
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* While a transaction is open the session cannot be used to run statements outside the transaction.
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*
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* @returns {Transaction} - New Transaction
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*/
@@ -82,8 +82,8 @@ class Session {
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}
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/**
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* Close connection
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* @param {function()} cb - Function to be called on connection close
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* Close this session
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* @param {function()} cb - Function to be called after the session has been closed
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* @return
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*/
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close(cb) {

‎test/internal/connector.test.js‎

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@@ -21,7 +21,7 @@ var connect = require("../../lib/v1/internal/connector.js").connect;
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describe('connector', function() {
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fit('should read/write basic messages', function(done) {
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it('should read/write basic messages', function(done) {
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// Given
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var conn = connect("bolt://localhost")
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‎test/internal/pool.test.js‎

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/**
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* Copyright (c) 2002-2016 "Neo Technology,"
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* Network Engine for Objects in Lund AB [http://neotechnology.com]
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*
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* This file is part of Neo4j.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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var Pool = require('../../lib/v1/internal/pool').Pool;
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fdescribe('Pool', function() {
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it('allocates if pool is empty', function() {
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// Given
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var counter = 0;
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var pool = new Pool( function (release) { return new Resource(counter++, release) } );
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// When
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var r0 = pool.acquire();
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var r1 = pool.acquire();
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// Then
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expect( r0.id ).toBe( 0 );
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expect( r1.id ).toBe( 1 );
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});
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it('pools if resources are returned', function() {
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// Given a pool that allocates
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var counter = 0;
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var pool = new Pool( function (release) { return new Resource(counter++, release) } );
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// When
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var r0 = pool.acquire();
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r0.close();
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var r1 = pool.acquire();
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// Then
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expect( r0.id ).toBe( 0 );
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expect( r1.id ).toBe( 0 );
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});
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it('frees if pool reaches max size', function() {
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// Given a pool that tracks destroyed resources
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var counter = 0,
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destroyed = [];
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var pool = new Pool(
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function (release) { return new Resource(counter++, release) },
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function (resource) { destroyed.push(resource); },
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function (resource) { return true; },
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2 // maxIdle
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);
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// When
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var r0 = pool.acquire();
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var r1 = pool.acquire();
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var r2 = pool.acquire();
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r0.close();
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r1.close();
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r2.close();
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// Then
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expect( destroyed.length ).toBe( 1 );
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expect( destroyed[0].id ).toBe( r2.id );
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});
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it('frees if validate returns false', function() {
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// Given a pool that allocates
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var counter = 0,
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destroyed = [];
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var pool = new Pool(
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function (release) { return new Resource(counter++, release) },
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function (resource) { destroyed.push(resource); },
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function (resource) { return false; },
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1000 // maxIdle
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);
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// When
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var r0 = pool.acquire();
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var r1 = pool.acquire();
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r0.close();
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r1.close();
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// Then
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expect( destroyed.length ).toBe( 2 );
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expect( destroyed[0].id ).toBe( r0.id );
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expect( destroyed[1].id ).toBe( r1.id );
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});
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});
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function Resource( id, release ) {
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var self = this;
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this.id = id;
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this.close = function() { release(self); };
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}

‎test/v1/session.test.js‎

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@@ -194,7 +194,7 @@ describe('session', function() {
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.then(function(result) {
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var sum = result.summary;
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expect(sum.notifications.length).toBeGreaterThan(0);
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expect(sum.notifications[0].code).toBe("Neo.ClientNotification.Statement.CartesianProduct");
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expect(sum.notifications[0].code).toBe("Neo.ClientNotification.Statement.CartesianProductWarning");
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expect(sum.notifications[0].title).toBe("This query builds a cartesian product between disconnected patterns.");
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expect(sum.notifications[0].position.column).toBeGreaterThan(0);
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done();

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