@y2nk4/Thrift Pool

This repo is modified based on another repo, check License declaration for more.

Features

• Promise Supported :zap:

• Connection Pool based on node-pool :beer:

Introduction

WARNING: This Version has not been verified in a production scene yet, please do more testing before use it on a production scene

Issues and PR are welcome!

A module that wraps thrift interfaces in connection pooling logic to make them more resilient.

The node thrift code exposes a service and types file. The node thrift client also exposes interfaces to create connections to the thrift server. There is no way to use the node thrift library to do connection pooling or to create new connections if existing connections fail.

This library takes in a thrift service and wraps the methods with connection pooling logic (based on node-pool).

Installation

npm install @y2nk4/node-thrift-pool

Usage

var thrift = require('thrift'),
    Service = require('./gen-nodejs/Service'),
    Types = require('./gen-nodejs/types'),
    thriftPool = require('@y2nk4/node-thrift-pool');

var thrift_client = thriftPool(thrift, Service, {host: "localhost", port: 9090});

/*
 * thrift_client is now an initialized thrift client that uses connection pooling behind the scenes
 */

// Regular callback
thrift_client.method(function(err, returned_data){
    console.log(err, returned_data)
});

// Using Promise
let returned_data = await thrift_client.method()

Promisify

The Thrift has already implemented the Promise, if you don't pass a callback function for the last parameter, the library will assume that you are expecting a Promise, then of course, returns a Promise.

Supported pooling options

Options to use when creating pool, defaults match those used by node-pool.

• host - Required - The host of the thrift server to connect to
• port - Required - The port of the thrift server to connect to
• log - Default: false - true/false or function
• max_connections - Default: 1 - Max number of connections to keep open at any given time
• min_connections - Default: 0 - Min number of connections to keep open at any given time
• idle_timeout - Default: 30000 - Time (ms) to wait until closing idle connections
• ttl - Default: undefined - Time (+/-50%) (ms) past which to destroy the connection. For more explanation, see below
• ssl - Default: false - Whether to use SSL/TLS

ttl

When using load balancers such as Amazon's ELB service, a common deploy strategy is to deploy new instances with new versions of your code, attach them to the load balancer, and detach the old ones. This doesn't work very well with persistent connections, however. New connections go to the new servers, but any open connections to the old servers remain and are eventually closed by the server when the servers turn off. This causes any in-flight requests on those connections to error with Error: Thrift-pool: Connection closed.

The ttl option treats any connection older than ttl (+/-50%) as invalid, so if something tries to acquite it, they'll get a more recent connection instead. If you set this time lower than the connection drain timeout of your load balancer, you can guarantee that all connections to the old servers are closed before the servers are stopped.

We use some amount of randomness (+/- 50%) of this time to ensure that all of your connections are not marked invalid simultaneously.

As an example, we have our connection drain timeout set to five minutes, so when you're removing instances from the ELB, any connections older than five minutes are just cut off. Based on that, we set our ttl to two minutes, and guarantee that all connections will be destroyed sometime after one to three minutes.

Thrift options - optional

All thrift options are supported and can be passed in as an object in addition to the pooling options.

var thrift_options = {
    timeout: 250
};
var thrift_client = thriftPool(thrift, Service, {host: "localhost", port: 9090}, thrift_options);

Note: If the timeout option is passed in the thrift_options object, a timeout listener will be added to the connection.

• If the timeout event is emitted on a connection while it is in the pool, the connection will be invalidated and treated the same way as if an error or close event had been emitted.
• If the timeout event is emitted after the connection is acquired a timeout error will be returned: new Error "Connection timeout".

Development

After making any changes, please add or run any required tests. Tests are located in the test directory, and can be run via npm:

npm test

• The debug package is used to simplify debugging. To turn on logging: export DEBUG=thrift-pool
• Source hosted at GitHub
• Report issues, questions, feature requests on GitHub Issues

Pull requests are welcome! Please ensure your patches are well tested. Please create separate branches for separate features/patches.

License declaration

This version of code edited Based On node-thrift-pool, Source hosted at GitHub

Edited Source host at GitHub

Edited For Fixing an issue

Now it will not throw the Error if it occurs Errors while encoding the params or calling the remote function. Instead, it will callback the error by using the cb function This can prevent the issue that the try/catch cannot catch the error in an asynchronous function

And I don't have much experience with CoffeeScript, so I decided to deprecate the CoffeeScript, and using the pure JavaScript instead.

But the original code is still available on the /deprecated folder.