#Shadow Proxy
##Introduction
Shadow is a HTTP debugging proxy that sits in front of an existing service and a service with new code changes. It copies and directs incoming requests to both downstream services and compares the responses from those services.
Shadowing deployments allows users to assert expected behaviors on the new codebase and detect unexpected behavioral changes before pushing new code into production.
Shadow comes with a UI that allows users to monitor the stream of requests live.
- Java 1.6+
- SBT 0.12.1+
- Clone the repository:
git clone https://github.com/twilio/shadow.git - Build the JAR:
sbt assembly
This generates an assembled Jar with all dependencies in /target/shadow-assembly-<VERSION>.jar
No escalated privledges needed unless you are using privileged ports. Just copy the Jar built in the previous step on to your existing server.
Make a copy of the example configuration application.conf.example and change the settings to fit your environment.
akka {
loglevel = INFO
}
shadow {
version = "0.1-SNAPSHOT"
# host and port to listen to incoming requests
proxy-host = localhost
proxy-port = 8000
# host and port for the ui
ui-host = localhost
ui-port = 8081
# host and port of the service we are transitioning from
# shadow returns responses from this host
trueServer {
host = "httpbin.org"
port = 80
}
# host and port of the service we are transitioning to
shadowServer {
host = "httpbin.org"
port = 80
}
}
spray.can.server {
server-header = shadow-server/${shadow.version}
# max request timeout
request-timeout = 15s
stats-support = true
}
spray.can.client {
user-agent-header = shadow/${shadow.version}
}
Running java -jar -Dconfig.file=application.conf shadow-assembly-<VERSION>.jar will start the server in the foreground.
We recommend using a supervisor such as jsvc or runit to manage running shadow
Be default, the UI can be accessed at http:https://localhost:8081
Tests are found under src/main/test/scala/
To run them, use: sbt test
