seratch / taskun

A simple crond thread on the JVM

taskun - A simple cron daemon thread on the JVM

What's this

"taskun" is an implementation of UNIX "crond" on the JVM, and it also has some extended notations.

How to install

Maven

<dependencies>
  <dependency>
    <groupId>com.github.seratch.taskun</groupId>
    <artifactId>taskun-scheduler</artifactId>
    <version>[1.5,)</version>
  </dependency>
  <dependency>
    <groupId>com.github.seratch.taskun</groupId>
    <artifactId>taskun-servlet-extension</artifactId>
    <version>[1.5,)</version>
  </dependency>
  
  <!-- OPTIONAL EXTENSIONS -->
  <dependency>
    <groupId>com.github.seratch.taskun</groupId>
    <artifactId>taskun-log4j-extension</artifactId>
    <version>[1.5,)</version>
  </dependency>
  <dependency>
    <groupId>com.github.seratch.taskun</groupId>
    <artifactId>taskun-guice-extension</artifactId>
    <version>[1.5,)</version>
  </dependency>
  <dependency>
    <groupId>com.github.seratch.taskun</groupId>
    <artifactId>taskun-spring-extension</artifactId>
    <version>[1.5,)</version>
  </dependency>
  <dependency>
    <groupId>com.github.seratch.taskun</groupId>
    <artifactId>taskun-s2-extension</artifactId>
    <version>[1.5,)</version>
  </dependency>
</dependencies>

Snippet1: Running taskun

src/main/java/snippet/EchoWorker.java

package snippet;
public class EchoWorker implements Runnable {
  public void run() {
    System.out.println("Hello, World!");
  }
}

src/main/resources/crontab.txt

*/1 * * * * snippet.EchoWorker

src/main/java/snippet/SampleMain.java

package snippet;
public static void main(String[] args) throws Exception {
  Taskun taskun = TaskunFactory.getInstance();
  taskun.initialize(new TaskunConfig());
  taskun.start();
  Thread.sleep(20000L);
}

Snippet2: Running snippet servlet

git clone [email protected]:seratch/taskun.git
cd taskun/taskun-servlet-extension
mvn jetty:run

# And you will see "Hello, World!" endlessly in the console.

[INFO] Started Jetty Server
[INFO] Starting scanner at interval of 3 seconds.
2011/04/02 0:00:53 com.github.seratch.taskun.taskun.crond.CronDaemon initialize
INFO: ----- Taskun scheduler initialized -----
2011/04/02 0:00:53 com.github.seratch.taskun.taskun.crond.CronDaemon initialize
INFO: Working at seratch-imac(seratch-imac)
2011/04/02 0:00:53 com.github.seratch.taskun.taskun.crond.CronDaemon initialize
INFO: Interval invocation : 3sec,com.github.seratch.taskun.servlet.snippet.EchoWorker,1
2011/04/02 0:00:53 com.github.seratch.taskun.taskun.crond.CronDaemon initialize
INFO: Crontab invocation : */1 * * * * com.github.seratch.taskun.servlet.snippet.EchoWorker*3
2011/04/02 0:00:53 com.github.seratch.taskun.taskun.crond.CronDaemon initialize
INFO: ----------------------------------------
2011/04/02 0:00:53 com.github.seratch.taskun.servlet.snippet.SnippetTaskunServlet init
INFO: Taskun scheduler has started!
[NamedServers:]
Hello, World! (Thread:20,Sat Apr 02 00:00:58 JST 2011)
Hello, World! (Thread:21,Sat Apr 02 00:01:00 JST 2011)
Hello, World! (Thread:20,Sat Apr 02 00:01:00 JST 2011)
...

Snippet3: Running taskun in your webapp

src/main/webapp/WEB-INF/web.xml

<servlet>
  <servlet-name>taskunServlet</servlet-name>
  <servlet-class>com.github.seratch.taskun.servlet.impl.SimpleTaskunServlet</servlet-class>
  <load-on-startup>3</load-on-startup>
</servlet>

src/main/resources/crontab.txt

*/1 * * * * com.github.seratch.taskun.servlet.snippet.EchoWorker*3
interval:3sec initial:5sec com.github.seratch.taskun.servlet.snippet.EchoWorker

src/main/resources/taskun.properties

enableInvokingTaskun=true
enableLoggingForEachCrondInvocation=true
namedServer1=.*server1
namedServer2=server2*.example.com
namedServer3=

Deploy and run

Snippet4: Injecting taskun, config and worker instances

NOTICE: taskun-guice-extension, taskun-spring-extension or taskun-s2-extension is required.

• taskun-guice-extension
• taskun-spring-extension
• taskun-s2-extension

Snippet5: Using extended notations

Invoking seconds intervals

"initial" is waiting time for the first invoking since taskun taskun started.

interval:3sec initial:5sec snippet.EchoWorker

Invoking several threads at once.

Following will invoke 3 threads to do same command(=EchoWorker) at once:

*/1 * * * * snippet.EchoWorker*3

Snippet6: Using log4j for taskun logging

NOTICE: taskun-log4j-extension is required.

• taskun-log4j-extension

It is reuirqed to set LogImplClass to config.

package snippet;
 
import com.github.seratch.taskun.logging.TaskunLogLog4jImpl;
 
public static void main(String[] args) throws Exception {
  Taskun taskun = TaskunFactory.getInstance();
  TaskunConfig config = new TaskunConfig();
  config.setLogImplClass(TaskunLogLog4jImpl.class); 
  taskun.initialize(config);
  taskun.start();
  Thread.sleep(20000L);
}

taskun's Issues

Scheduler for interval executions stops when worker throwed Exception

src/
└── main
    ├── resources
    │   └── crontab.txt
    └── scala
        └── Hello.scala

• src/main/scala/Hello.scala

class Hello extends Runnable {
  override def run() {
    println("Hello! (" + new java.util.Date + ")")
    throw new RuntimeException
  }
}

• src/main/resources/crontab.txt

*/1 * * * * Hello
interval:3sec initial:5sec Hello

• main

import com.github.seratch.taskun.scheduler._
val taskun = TaskunFactory.getInstance()
taskun.initialize(new config.TaskunConfig)
taskun.start()

Crontab parser bug

OK:

The following settings work as expected.

0,10,20,30,40,50 9,10,11,12 * * * example.Worker

NG:

In this case, "9,10,11,12" is ignored.

*/10 9,10,11,12 * * * example.Worker

It seems to be a crontab parser's bug and should be fixed.

TaskunLogLog4jImpl use commons-logging instead of log4j

I think TaskunLogLog4jImpl don't use log4j.
This class means TaskunLogCommonsLoggingImpl.