Chaos Dukey

This is a Java agent to inject chaos delays and/or failures into specific Java classes and methods.

Download the JAR file

Download the latest JAR file chaos-dukey-<VERSION>-all.jar from https://github.com/komamitsu/chaos-dukey/releases.

Usage

Set -javaagent Java option to the downloaded JAR file with the parameters.

Parameters

Parameter	Description	Default value
delay.typeNamePattern	[For delay injection] Type name pattern to filter classes and interfaces. Supports Java's regex format.	No targeted classes or interfaces
delay.methodNamePattern	[For delay injection] Method name pattern to filter methods. Supports Java's regex format.	No targeted methods
delay.waitMode	[For delay injection] RANDOM: waits for random duration between 1 ms and maxDelayMillis. FIXED: waits for maxDelayMillis.	RANDOM
delay.ppm	[For delay injection] Parts per million (ppm) chance that a delay injection occurs. Cannot be specified with percentage.	20000 ppm (2%)
delay.percentage	[For delay injection] Percentage chance that a delay injection occurs. Cannot be specified with ppm.	2% (20000 ppm)
delay.maxDelayMillis	[For delay injection] Maximum delay in millis.	500 ms
failure.typeNamePattern	[For failure injection] Type name pattern to filter classes and interfaces. Supports Java's regex format.	No targeted classes or interfaces
failure.methodNamePattern	[For failure injection] Method name pattern to filter methods. Supports Java's regex format.	No targeted methods
failure.exception	[For failure injection] Exception thrown from the target methods.	java.lang.RuntimeException
failure.ppm	[For failure injection] Parts per million (ppm) chance that a delay injection occurs. Cannot be specified with percentage.	20000 ppm (2%)
failure.percentage	[For failure injection] Percentage chance that a delay injection occurs. Cannot be specified with ppm.	2% (20000 ppm)
debug	Specifies whether to output debug information to STDERR.	false
configFile	The path to properties file that contains the parameters above. Other parameters will be ignored if this parameter is specified.	----

Example

Without a config file

java -javaagent:/path/to/chaos-dukey-x.x.x-all.jar=delay.typeNamePattern=^org\.komamitsu\.transaction\.(?:LockManager|OCCManager)$,delay.methodNamePattern=^(?:lock.*|cas.*)$,delay.waitMode=RANDOM,delay.percentage=1,delay.maxDelayMillis=1500,failure.typeNamePattern=^org\.komamitsu\.repository\..*Repository$,failure.methodNamePattern=^(?:get.*|save.*|delete.*)$,failure.ppm=1000,failure.exceptionClassName=java.io.IOException ...

With a config file

• /path/to/chaos-dukey.properties

delay.typeNamePattern=^org\.komamitsu\.transaction\.(?:LockManager|OCCManager)$
delay.methodNamePattern=^(?:lock.*|compareAndSwap)$
delay.waitMode=RANDOM
delay.percentage=1
delay.maxDelayMillis=1500
failure.typeNamePattern=^org\.komamitsu\.repository\..*Repository$
failure.methodNamePattern=^(?:get.*|save.*|delete.*)$
failure.ppm=1000
failure.exceptionClassName=java.io.IOException

java -javaagent:/path/to/chaos-dukey-x.x.x-all.jar=configFile=/path/to/chaos-dukey.properties ...

Note

This is only for testing purpose, and don't use it in production since it would affect the performance.

Development

Pre-commit hook

This project uses pre-commit to automate code format and so on as much as possible. If you're interested in the development of this project, please install pre-commit and the git hook script as follows.

$ ls -a .pre-commit-config.yaml
.pre-commit-config.yaml
$ pre-commit install

The code formatter is automatically executed when committing files. A commit will fail and be formatted by the formatter when any invalid code format is detected. Try to commit the change again.