rxjava-agent

Project provides java agent to debug rxjava subscription. Goal of it agent is to avoid rxjava operators using unbounded subscription with Long#MAX_VALUE - they use ERROR/DROP/BUFFER overflow strategies to manage backpressure and in effect application can fail or loose data. However, there is a group of applications which should run Subscription#request with manageable value after data is processed to keep memory under control and to not lose data.

Agent will add instrumentation to method request in any class implementing org.reactivestreams.Subscription - if it is executed with argument bigger than 10_000 then warning is logged. It is achieved with ByteBuddy instrumentation.

Threshold can be changed using Java property, eg -Drxjava.agent.subscription.request-logging-threshold=500

By default, warning includes stacktrace to identify which rxjava operator executed Subscription#request method. Stacktrace can be switched to normal warning with using a property -Drxjava.agent.subscription.log-stacktrace=false

Build

Use gradle to build agent JAR and run tests. Agent jar uses -all suffix and contains code running instrumentation and ByteBuddy code in ShadowJar. Agent jar will be placed in build/libs/rxjava-agent-1.0-SNAPSHOT-all.jar.

./gradlew build

Use agent directly

Use -javaagent argument to enable this Java agent on your application or tests. For example:

java -javaagent:../rxjava-agent/build/libs/rxjava-agent-1.0-SNAPSHOT-all.jar ...

# OR
java -Drxjava.agent.subscription.request-logging-threshold=500 \
  -javaagent:../rxjava-agent/build/libs/rxjava-agent-1.0-SNAPSHOT-all.jar ...

Use agent in Gradle tests

Publish the agent to mavenLocal repository

./gradlew publishToMavenLocal

Update Gradle config for project which will use the rxjava-agent to attach it when running tests

repositories {
  // ...
  mavenLocal()
}

val rxjavaAgent = configurations.create("rxjavaAgent")

dependencies {
    // ...
    rxjavaAgent("pl.kodstark:rxjava-agent:1.0.0-SNAPSHOT:all") { isTransitive = false }
}

tasks.withType<Test> {
    // ...
    jvmArgs = listOf(
        "-javaagent:${rxjavaAgent.asPath}"
    )
}