@fresh8/copacetic/README.hbs

# Copacetic
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A package to help your service check the health of its dependencies.


## Requirements
Node v6.4.0 and above

## Installation
```
npm install @fresh8/copacetic --save
```

#### Quick Start - Javascript
```javascript
const Copacetic = require('@fresh8/copacetic')
const level = require('@fresh8/copacetic').dependencyLevel

const copacetic = Copacetic()

// Register a dependency
copacetic.registerDependency({
  name: 'My-Dependency',
  url: 'https://my-Dependency.io',
  // Defaults to SOFT
  level: level.HARD
})


// Check its health
copacetic
  .check({
    name: 'My-Dependency',
    retries: 2
  })
  .on('healthy', (Dependency) => {
    /**
     * { name: 'My-Dependency',
     *   healthy: true/false,
     *   lastChecked: Date,
     *   level: 'SOFT'
     * }
     */
  })
  .on('unhealthy', (Dependency) => {
    // Handle degraded state...
  })

// in promise mode
copacetic.eventEmitterMode = false

copacetic
  .check({ name: 'my-web-service' })
  .then((res) => {
    console.log(`${res.name} is healthy!`)
  })
  .catch((err) => {
    console.log(err)
  })
```

#### Quick Start - Typescript
```typescript
import * as Copacetic from '@fresh8/copacetic'

const copacetic = Copacetic('my-service')

const myDependencyOverHttp : Copacetic.DependencyOptions = {
  name: 'my-web-service',
  url: 'http://example.com'
}

copacetic.registerDependency(myDependencyOverHttp)

instance
  .check({ name: 'my-web-service' })
  .on('healthy', (res: Copacetic.Health) => {
    // do something with your healthy dependency :)
  })
  .on('unhealthy', (res: Copacetic.Health) => {
    // handle degraded state
  })

// in promise mode
copacetic.eventEmitterMode = false

async function waitForWebService () {
  try {
    const res = await instance
      .check<Copacetic.Health>({ name: 'my-web-service' })

    console.log(`${res.name} is healthy!`)
  } catch (err) {
    console.log(err)
  }
}
```

#### Quick Start - cluster mode
```js

const Copacetic = require('@fresh8/copacetic')
const level = require('@fresh8/copacetic').dependencyLevel

const copacetic = Copacetic("A name", false)

Copacetic.cluster.attach(copacetic)

if (process.worker) {
    //register your usual dependencies like databases


    //use the line below to have the worker ask the master process a full health report
    copacetic.checkCluster() //`checkCluster` is only defined if the process is a worker and if you called `attach()`
        .then(console.log)
} else {
    copacetic.checkAll()
        .then(() => {
            console.log(copacetic.healthReport) //Contains health information as reported by the workers
        })
}
```

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