thomsonreuters/cta-healthcheck

cta-healthcheck

HealthCheck Modules for Compass Test Automation, One of Libraries in CTA-OSS Framework

General Overview

Guidelines

We aim to give you brief guidelines here.

1. Usage
2. Configuration
3. Dependencies
4. Properties
5. Update HealthCheck Status
6. Query

1. Usage

'use strict';

const HealthCheck = require('cta-healthcheck');

const instance = new HealthCheck(dependencies, configuration);
const status = {
  ...
};
instance.update(status);

The constructor requires dependencies and configuration.

The HealthCheck provides update() method to update the status of service.

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2. Configuration

Because the HealthCheck is a tool, the configuration is vital.

'use strict';

const configuration = {
  name: 'healthcheck',
  module: 'cta-healthcheck',
  dependencies: {
    express: 'express',
  },
  properties: {
    file: './healths.json',
    queue: 'cta.healths',
    topic: 'cta.healths',
    url: 'http://domain.com:3000/healthcheck',
  },
};

The configuration has these following fields:

• name - defines a name of the HealthCheck tool which can be any name
• module - must be 'cta-healthcheck'
• dependencies - defines dependencies, see on dependencies section
• properties - defines properties, see on properties section

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3. Dependencies

Here are examples.

'use strict';

const dependencies = {
  express: 'sample.express',
  messaging: 'sample.messaging',
  request: 'sample.request',
};

...

const tools = [{
  name: 'sample.express',
  module: 'cta-expresswrapper',
  properties: {
    port: 8080,
  },
}, {
  name: 'sample.messaging',
  module: 'cta-messaging',
  properties: {
    provider: 'rabbitmq',
    parameters: {
      url: 'amqp://localhost?heartbeat=60',
      ack: 'auto',
    },
  },
}, {
  name: 'sample.request',
  module: 'cta-tool-request',
  properties: {}
}];

The HealthCheck requires express as dependencies.

• express (required) - defines a name of the express tool

• messaging (optional) - defines a name of the messaging tool

• request (optional) - defines a name of the request tool

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4. Properties

'use strict';

const properties = {
  file: './healths.json',
  queue: 'cta.healths',
  topic: 'cta.healths',
  url: 'http://domain.com:3000/healthcheck',
};

• file - defines full path to a file where to store healths for resiliency

• queue - defines messaging queue name where to produce HealthCheck updates

• topic - defines messaging topic name where to publish HealthCheck updates

• url - defines api url of a server (basically the healthcheck data service) where to post HealthCheck updates

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5. Update HealthCheck Status

This shows how update() method has been using:

...
const instance = new HealthCheck(dependencies, configuration);
const status = {
  ...
};
instance.update(status);

HealthCheck Status

The Status has the structure as following:

const status = {
  name: string;
  service: string;
  status: string;
  reason: string;
};

• name - defines the name of application
• service - defines the name of service
• status - defines the current status of service: green, yellow, and red
  • green - the service is in proper status
  • yellow - the service is in critical status, but it can still be used properly
  • red - the service is in not-working status, but it cannot be used properly
• reason - defines the reason of status

Usage inside Brick

const Brick = require('cta-brick');

class SampleBrick extends Brick {
  constructor(cementHelper, config) {
    super(cementHelper, config);  // calling Brick's constructor
    
    // HealthCheck is available as dependencies.
    // By calling update(), the HealthCheck sends a status.
    this.cementHelper.dependencies.healthcheck.update({
      name: 'SampleApplication',
      service: 'SampleService',
      status: 'green',
    });
  }
}

module.exports = SampleBrick;

The Brick has HealthCheck as its dependencies. By calling Brick's constructor, the HealthCheck is available as SampleBrick's dependencies. Calling update() sends a status.

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6. Query

The HealthCheck provides a query via Express.

There four ways to query:

• No Mode Query

• Full Mode Query

• Current Mode Query

• Previous Mode Query

No Mode Query

REST Query - GET :: /healthcheck

// with no mode provided
{
  'status': 'green'
}

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Full Mode Query

REST Query - GET :: /healthcheck?mode=full

// with 'full' mode provided
{
  status: 'green',
  statuses: {
    SampleApplication: {
      status: 'green',
      current: {
        services: {
          alpha: {
            date: '2017-12-25T18:00:00.000Z',
            status: 'green'
          },
          beta: {
            date: '2017-12-24T11:00:00.000Z',
            status: 'green'
          }
        }
      },
      previous: {
        services: {
          alpha: {
            date: '2017-12-24T12:00:00.000Z',
            status: 'red'
          }
        }
      }
    }
  }
}

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Current Mode Query

REST Query - GET :: /healthcheck?mode=current

// with 'current' mode provided
{
  status: 'green',
  statuses: {
    SampleApplication: {
      status: 'green',
      current: {
        services: {
          alpha: {
            date: '2017-12-25T18:00:00.000Z',
            status: 'green'
          },
          beta: {
            date: '2017-12-24T11:00:00.000Z',
            status: 'green'
          }
        }
      }
    }
  }
}

back

Previous Mode Query

REST Query - GET :: /healthcheck?mode=previous

// with 'previous' mode provided
{
  status: 'green',
  statuses: {
    SampleApplication: {
      status: 'green',
      previous: {
        services: {
          alpha: {
            date: '2017-12-24T12:00:00.000Z',
            status: 'red'
          }
        }
      }
    }
  }
}

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To Do

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Considerations

Should we change specific, close-to-'ExpressJS' dependencies.express to a common name, dependencies.[restapp]?

const config = {
  ...
  dependencies: {
    express: 'my-express',  =>  restapp: 'my-express',
  },
  ...
};

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