Splitter

(c) 2011 TomTom International BV (c) 2017 Eric Bowman

Introduction

Splitter is a transparent reverse proxy which splits incoming HTTP requests into two backend requests, one of which goes to a "reference server", and the other of which goes to a "shadow server". The response from the reference server is sent back as the response to the original request, while the response from the shadow server is discarded. Optionally, the incoming request and both responses may be logged to a MongoDB server.

Splitter is written in Scala, and uses the JBoss Netty library.

Building

Splitter may be built using sbt:

./sbt

> update
> test

Configuration

Configuration is done using a configuration file, similar to those used by the now-defunct "Configgy" library.

port = 8080
reference = "localhost:9090"
shadow = "localhost:9191"

enableShadowing = true

referenceHostname = "reference.test.tomtom.com"
shadowHostname = "shadow.tomtom.com"

# "none" | "mongodb"
capture = "none"

audit {
   level = "info"
   console = true
   truncate = true
   file = "default"
}

pool {
    maxOpenConnections = 70
    maxWaitMs = 5000
    maxIdleConnections = 8
    msBetweenEvictionRuns = 10000
    numTestsPerEvictionRuns = 3
    maxIdleTimeMs = 60000
    connectTimeoutMillis = 30000
    receiveTimeoutMillis = 120000
    keepAlive = true
}

mongo {
    host = "localhost"
    port = 27017
    db = "splitter"
}

Running Splitter

To run splitter within sbt, you can do:

> run [path to config file]

There are 3 runnable apps; sbt will ask you which one you want to run; you should run:

tomtom.splitter.layer7.Proxy

If you have built a self-contained jar (using 'sbt assembly'), you can run it like:

java -jar splitter-assembly-0.14-SNAPSHOT.jar [path to config file]

Future Directions

This tool is still pretty raw, but already useful. It might be nice to support other means besides MongoDB for logging requests.

Also note that it assumes a few ports are free for running the tests; it would be nice to make this configurable or dynamic.

Credits

The idea for this came from https://github.com/neotyk who made an earlier version (but on which this version is only based conceptually).

Thanks to TomTom for letting me release this as ASL.

Enjoy!

Eric Bowman ebowman@boboco.ie