Demo Nodetron

A nodeJS tron for the demo platform.

Nodetron 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 Nodetron.

Behaviors

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

• Throw
• Compute
• Memory Allocation
• Invalid Query

Requirement

When hosting on a physical host or VM (not serverless/lambda), nodetron requires at least 800MB of memory. When deployed with the deployer, a memmon watchdog process ensures the process is recycled if the memory consumption exceed this threshold.

Configuration

The Nodetron configuration is located in a json configuration file, typically stored under the /config folder. It is similar the the other tron config structure. Here is an example showing 2 app dependencies:

{
  "id": "nodetron2",
  "port": 3002,
  "dependencies": [
    {
      "id":"app2",
      "urls":["http://localhost:5002"]
    },
    {
      "id":"app3",
      "urls":["http://localhost:5003"]
    }
  ],
  "database": {
    "name": "",
    "host": "",
    "port": "",
    "user": "",
    "password": ""
  }
}

API endpoints and purposes

Endpoint	Purpose
/api/inventory	Fetch a JSON list of inventory items
/api/inventory/{item_id}	Fetch a single JSON inventory item by its id
/api/validateMessage?message=	Returns true for validation of message
/api/database/health	Returns HTTP-200 if database is connected, HTTP-500 otherwise
/api/behaviors	Fetch a JSON list of available behaviors

Demo-Deployer

Nodetron can be also be deployed with the demo-deployer, and supports Logging and Logging in Context. Nodetron can also be instrumented with browser, using the same nodejs agent definition. Here is a deployer config example:

{
  "services": [
    {
      "id": "node1",
      "destinations": ["host1"],
      "display_name": "Nodetron",
      "source_repository": "https://github.com/newrelic/demo-nodetron.git",
      "deploy_script_path": "/deploy/linux/roles",
      "port": 3002,
      "params": {
        "delay_start_ms": 5000,
        "database_user": "testuser",
        "database_password": "<password here>",
        "database_host": "127.0.0.1",
        "database_port": 5000
      }
    }
  ],
  "resources": [
    {
      "id": "host1",
      "provider": "aws",
      "type": "ec2",
      "size": "t2.micro"
    }
  ],
  "instrumentations": {
    "services":[
      {
        "id": "nr_node_agent",
        "service_ids": ["node1"],
        "provider": "newrelic",
        "source_repository": "https://github.com/newrelic/demo-newrelic-instrumentation.git",
        "deploy_script_path": "deploy/node/linux/roles",
        "version": "6.4.1"
      }
    ]
  }
}

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.

Docker support

Nodetron can be run in docker. A dockerfile is available at the root, you can use the commands below to build the image, run the test and run nodetron itself with the default config example

docker build -t nodetron .
docker run -it --entrypoint npm nodetron test
docker run -it -p 3001:3001 nodetron

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 node1 service every hour, at the 0 minute.

{
  "services": [
    {
      "id": "node1",
      "display_name": "Node1",
      "source_repository": "https://github.com/newrelic/demo-nodetron.git",
      "deploy_script_path": "deploy/linux/roles",
      "port": 5001,
      "destinations": ["host"],
      "files": [
        {
          "destination_filepath": "engine/cronjob.json",
          "content": [
              {
                  "frequency": "0 * * * *",
                  "job": "/usr/bin/supervisorctl restart node1",
                  "root": true
              }
          ]
        }
      ]
    }
  ]
}

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

Contributing

We encourage your contributions to improve demo-nodetron! 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.

License

demo-nodetron is licensed under the Apache 2.0 License. demo-nodetron also uses source code from third-party libraries. You can find full details on which libraries are used and the terms under which they are licensed in the third-party notices document.