Demo Javatron

A java tron for the demo platform.

Javatron is compatible with the demo-deployer.

It can be deployed with a similar configuration, and can participate in a tron chain with other trons like itself or other languages. The simulator can also be used to drive traffic to Javatron.

Requirement

When hosting on a physical host or VM, javatron requires at least 700MB of memory. When deployed with the deployer, a memmon watchdog process ensures the process is recycled if the memory consumption exceed this threshold.

Behaviors

Javatron supports the below behaviors. For more information, see the Behavior Documentation

• Throw
• Compute
• Memory Allocation
• Invalid Query

Running with Docker

You can run Javatron with the provided Dockerfile at the root. After ensuring your docker application is started on your machine, run the below commmand while in the root of the repository

Building the docker image

docker build -t javatron .

Running Javatron on the default port of 8081

docker run -it -p 8081:8081 javatron

Running the unit tests (handled with maven)

docker run -it --entrypoint mvn javatron test

Deploy with demo-deployer

This java application can be deployed with the demo-deployer using the /deploy scripts in this repository. Here is an example of the deploy config that can be used to deploy a javatron service on an AWS/EC2 instance:

{
  "services": [
    {
      "id": "java1",
      "source_repository": "https://github.com/newrelic/demo-javatron.git",
      "deploy_script_path": "deploy/linux/roles",
      "port": 5001,
      "destinations": ["host"],
      "params": {
        "delay_start_ms": 5000
      }
    }
  ],

  "resources": [
    {
      "id": "host",
      "provider": "aws",
      "type": "ec2",
      "size": "t2.micro"
    }
  ]
}

The deploy scripts are using Tomcat, and due to its installation resides in the /opt location of the host. Therefore, only 1 instance of Javatron can be deployed per host. There is currently no validations nor assertions that ensure this incorrect configuration is used.

Tomcat is configured with a max heap memory size of 700MB. A memory watchdog process memmon is implemented to recycle the process once that threshold (polling once per min).

User Acceptance Tests

The user_acceptance_tests folder contains automated tests which run on github and are triggered by PR events. For more information, see User Acceptance Tests.

Params

• delay_start_ms can be used to delay the time the service starts by this amount in milliseconds. During that interval, any incoming http request will error.
• database_user is used when connecting to a database. It defines the user to connect as.
• database_password is used when connecting to a database. It defines the password to use when connecting as the user denoted in the database_user field.
• database_host is used when connecting to a database. Its value should be the IP address of the database.
• database_port is used when connecting to a database. Its value should be the port that the database is listening on.

Newrelic instrumentation

Javatron can be instrumented with newrelic. To do so you can reference the instrumentation role using the deployer configuration below. Note, you'll also need to install the ansible galaxy plugin locally before running the deployer, using the command: ansible-galaxy install newrelic.newrelic_java_agent

{

  "instrumentations": {
    "services":[
      {
        "id": "nr_agent_java",
        "service_ids": ["java1"],
        "provider": "newrelic",
        "source_repository": "https://github.com/newrelic/demo-newrelic-instrumentation.git",
        "deploy_script_path": "deploy/java/linux/tomcat/roles"
      }
    ]
  }

}

Log support

Logging is supported through the use of log4j using a log4j2.xml file in the /webapp/WEB-INF folder. To enable logs-in-context you can use the deployer configuration below.

{

  "instrumentations": {
    "services":[
      {
        "id": "nr_logging_in_context",
        "service_ids": ["java1"],
        "provider": "newrelic",
        "source_repository": "https://github.com/newrelic/demo-newrelic-instrumentation.git",
        "deploy_script_path": "deploy/logging_in_context/roles"
      }
    ]
  }

}

Cron jobs support

Cron jobs can be registered upon deployment using the demo-deployer Files configuration for the service. Here is an example for restarting a java1 service every hour, at the 0 minute.

{
  "services": [
    {
      "id": "java1",
      "display_name": "Java1",
      "source_repository": "https://github.com/newrelic/demo-javatron.git",
      "deploy_script_path": "deploy/linux/roles",
      "port": 5001,
      "destinations": ["host"],
      "files": [
        {
          "destination_filepath": "javatron/cronjob.json",
          "content": [
              {
                  "frequency": "0 * * * *",
                  "job": "/usr/bin/supervisorctl restart java1",
                  "root": true
              }
          ]
        }
      ]
    }
  ]
}

Contributing

We encourage your contributions to improve demo-javatron! Keep in mind when you submit your pull request, you'll need to sign the CLA via the click-through using CLA-Assistant. You only have to sign the CLA one time per project.

If you have any questions, or to execute our corporate CLA, required if your contribution is on behalf of a company, please drop us an email at opensource@newrelic.com.

A note about vulnerabilities

As noted in our security policy, New Relic is committed to the privacy and security of our customers and their data. We believe that providing coordinated disclosure by security researchers and engaging with the security community are important means to achieve our security goals.

If you believe you have found a security vulnerability in this project or any of New Relic's products or websites, we welcome and greatly appreciate you reporting it to New Relic through HackerOne.

License

demo-javatron is licensed under the Apache 2.0 License.