groovy-memory-limiter

Limits memory allocation in a Groovy script by regularly checking allocated memory. It also offers stats on script memory use.

Checking memory

The limiter will regularly check for the amount of memory allocated by the script's executing thread. If it is exceeded, a callback will be executed to a method expecting a MemoryQuotaCheck instance, which can be queried to find out more about the infringement or used to reconfigure the limit.

If you are not interrupting the script in response to the quota infringement, you may want to disable further reporting via MemoryQuotaCheck.setEnabled().

Also, for added flexibility, the script's binding can also be retrieved via MemoryQuotaCheck.getScriptBinding().

From Java

The following code will call the QuotaInfringementHandler#handle method at the beginning of the Groovy method().

public class MemoryLimit {
    public static void main() {}
        Map<String, Object> map = new HashMap<>();
        map.put("limit", 1024 * 1024 * 2); // 1KB
        map.put("handlerClass", QuotaInfringementHandler.class);
        map.put("handlerMethod", "handle");
        CompilerConfiguration compilerConfiguration = new CompilerConfiguration();
        compilerConfiguration.addCompilationCustomizers(new ASTTransformationCustomizer(map, CheckMemoryQuota.class));
        GroovyShell groovyShell = new GroovyShell(compilerConfiguration);
        //noinspection GroovyUnusedAssignment
        groovyShell.evaluate(
            "def garbage = new byte[1024 * 1024 * 3]\n"
                + "def method() { /* do nothing */ }\n"
                + "method() \n"
                + "return 5"
        );
    }
}

From Groovy

Just annotate your script with @CheckMemoryQuota(limit=bytes, handlerClass=Handler.class, handlerMethod="methodName").

Recovering stats after execution

Average and peak memory consumption can be recovered from the MemoryQuotaCheck instance after the script finishes execution. Just recover it from the Script object like this.

Script script = groovyShell.parse(yourGroovy);

script.run();
MemoryQuotaCheck memoryQuotaCheck =
    (MemoryQuotaCheck) script.getProperty(MemoryQuotaCheck.CHECKER_FIELD);

Caveats

This uses com.sun.management.ThreadMXBean to watch memory allocation of a thread and thus it will only run on JVM providing such class (ie. Oracle's JVM).

The quota only applies to the thread that first launches the Groovy script. This will not work on multi-threaded code.

Checks are inserted at the beginning of every loop iteration, closure and method call. If the memory limit is infringed during a library call or on a long row of assignments, the limiter will not be notified until one of those ocurrs.

Credit

This project is a fork of groovy-memory-limiter by Denis Kirpichenkov (d0k1).