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https://github.com/byteclubfr/node-reqrep
Request/Reply pattern using Redis as backend
https://github.com/byteclubfr/node-reqrep
Last synced: 1 day ago
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Request/Reply pattern using Redis as backend
- Host: GitHub
- URL: https://github.com/byteclubfr/node-reqrep
- Owner: byteclubfr
- License: isc
- Created: 2015-02-19T23:24:20.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2015-02-20T01:21:56.000Z (over 9 years ago)
- Last Synced: 2024-04-24T12:26:15.662Z (7 months ago)
- Language: JavaScript
- Size: 141 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://travis-ci.org/lmtm/node-reqrep)
[](https://david-dm.org/lmtm/node-reqrep)
[](https://david-dm.org/lmtm/node-reqrep#info=devDependencies)
Request/Reply
=============
Implement the Request/Reply pattern using Redis as backend. This pattern is typically used to handle pool of workers which we expect a result from.
If you don't care about the result from the worker, then take a look at [pushpull](https://github.com/lmtm/node-pushpull).
Installation
------------
```sh
npm install --save reqrep
```
You may want to install `hiredis` to, whenever possible:
```sh
npm install --save-optional hiredis
```
Usage
-----
Look at (and run) [`sample.js`](./sample.js) for a working example.
```js
// Workers
function onJob (data, cb) {
// Received job's data
console.log("Received job", this._internalId);
// Send result:
cb(null, 42);
}
var worker1 = new Reply(options);
worker1._internalId = "worker1";
var worker2 = new Reply(options);
worker2._internalId = "worker2";
// Schedulers
var sender = new Request(options);
for (var i = 0; i < 20; i++) {
sender.send({"someData": i}, function (err, reply) {
// …
});
}
```
Request API
-----------
* **`new Request(options)`**: constructor, see *Options* below
* **`send(data, onReply, onPushed)`**: send a new job, you can provide two optional callbacks:
* `onReply(err, reply)` is called whenever a worker has replied
* `onPushed(err, data)` is called as soon as the job has been properly pushed
* **`error` event**: emitter when an error occurs (seriously)
* **`end()`**: close the underlying clients
Reply API
---------
* **`new Request(options)`**: constructor, see *Options* below
* **`error` event**: emitter when an error occurs (seriously)
* **`end()`**: close the underlying clients
You will note there is no "job" or "data" event. When a job is received, `options.onJob` is called with following arguments:
* Job's data
* A callback you're supposed to called once result is available: `callback(err, result)`
* The job internal ID (for debugging or logging purpose)
Options
-------
`Request` and `Reply` take any valid option from [pushpull](https://github.com/lmtm/node-pushpull).
* **`queue`** is **not** the real Redis key name, but only a prefix
* Note: generated keys are `{queue}replies:*` and `{queue}requests`
* **`onJob`** (mandatory) is called when a job is received by a `Reply` instance
* Format: `onJob(data, callback(err, result), id)`
TODO
----
* Current implementation is suboptimal, a new connection to Redis is open each time a job is sent. This has to be fixed before real production usage.