transaction

Transaction support for in memory objects (Beta)

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Transaction support for in memory objects. For robustness and performance both

Lock/Commit/Rollback in memory objects just like access data in traditional database

var T = require('transaction');
var Q = require('q');

var obj = {simple : 1, compound : {key : 1}};

// Make object transactionable
T.transactionable(obj);

// You can also specify which keys to include or exclude
// Object attributes which cannot be deepcopyed must be excluded
// (like reference to outer resources or circular reference)
// T.transactionable(obj, {includeKeys : 'key1 key2'});
// T.transactionable(obj, {excludeKeys : 'key1 key2'});

// Execute code in a new 'database connection'
// The 'connection/lock/commit/rollback' terminologies are similar to traditional database
T.execute(function(){
    return Q.fcall(function(){
        // lock obj for write
        // lock from other execute content will block
        // and read from other execute content will always see old value until commit
        // You can also lock multiple objects by T.lock([obj1, obj2]);
        return T.lock(obj); 
    })
    .then(function(){ 
        obj.simple = 2; // Set 'simple' value

        // obj.compound.key = 2; // Oops! Don't do this!
        var compound = obj.compound; // Retrieve 'compound' value
        compound.key = 2;
        obj.compound = compound; // Set 'compound' value

        T.commit(); // All locks will be released after commit or rollback

        console.log(obj.simple); // Read only access
        // obj.simple = 3; // Oops! Should lock first
    })
    .then(function(){
        return T.lock(obj);
    })
    .then(function(){
        obj.simple = 3;
        throw new Error('Exception here!');	
    })
    .then(function(){
        T.commit(); // This will not execute
    }, function(err){
        T.rollback(); // Should rolled back
    })
    .then(function(){
        console.log(obj.simple); // output: 2
    });
});

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.