SparkJava Instrumentation Agent

Quickly add data-tracking metrics to SparkJava responses without modifying any code

SJIA is a Java Agent that allows for instantaneous metric monitoring without adding any code in your project. Responses are modified with headers that indicate metrics such as round trip time. SJIA also includes an optional built-in monitoring application that allows you to see live updates of the performance of your SparkJava routes.

Usage

Download a release package of SJIA, unzip/untar and execute your application with the javaagent jvm flag set to point to the SJIA jar executable.

Response Headers Only

java -javagent:sjia.jar -jar application.jar

Open Monitoring Application

java -javagent:sjia.jar=monitor -jar application.jar

The monitoring application will open a web server on port 45000. The latest statistics can be retrieved by issuing a GET command to http://localhost:45000/stats. Doing so will retrieve a JSON object structured like:

{
 "*": {
  "max": 51.0,
  "min": 50.0,
  "avg": 50.2
 },
  "/metrix": {
  "max": 51.0,
  "min": 50.0,
  "avg": 50.2
 }
}

Visiting the address http://localhost:45000 in a web browser will open the the metric monitoring utility.

Response Headers

Metrics in the form of HTTP Response Headers are added to every route.

Header	Description
X-metric-time-min	Minimum Response Time
X-metric-time-max	Maximum Response Time
X-metric-time-avg	Mean Response Time
X-metric-time	Response Time
X-metric-body-min	Minimum Response Body Size
X-metric-body-max	Maximum Response Body Size
X-metric-body-mvg	Mean Response Body Size
X-metric-body	Response Body Size (bytes)

Example

Download the release file, unzip the sjia.jar and example.jar. Execute the following command:

java -javagent:sjia.jar=monitor -jar example.jar

The example webapp is accessible via http://localhost:4567, and the SJIA monitoring application is accessible via http://localhost:45000.

Building

git clone https://github.com/argonotix/sjia.git
cd sjia
chmod +x ./gradlew
./gradlew build shadowJar
cp ./agent/build/libs/agent-0.1-all.jar ./sjia.jar

License

Distributed under the MIT license.