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Request splitting reverse proxy
Scala Shell
branch: master

Stop catching Throwable, just Exception

When OOM happens, the server has to be killed from the outside.
I thought this might help, but it has no effect. But anyhow I don't
think there is too much point catching Throwable, and it's considered
bad practice anyhow
latest commit 37af03134c
Eric Bowman authored
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project Ported to latest scala & libraries. Added scoverage support.
src Stop catching Throwable, just Exception
.gitignore Initial github commit
LICENSE Ported to latest scala & libraries. Added scoverage support.
build.sbt Convert to scala-logging
echo.config Bug fix around default values of subconfig.
ofbiz.config RequestMapper now config-file driven.
sbt Port to sbt 0.10.1
sbt-launch.jar Upgrade to sbt 0.11.2. Remove growler.
transparent.config Initial github commit
turbo.config RequestMapper now config-file driven.


(c) 2011 TomTom International BV


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.


Splitter may be built using sbt:


> update
> test


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 = ""
shadowHostname = ""

# "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:


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.


The idea for this came from who made an earlier version (but on which this version is only based conceptually).

Thanks to TomTom for letting me release this as ASL.


Eric Bowman

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