Mutable Meta client for node

Service Discovery and Config manager

This package is a wrapper to the background service Mutable Meta. Mutable Meta is responsible for service discovery and service configuration.

API

const Meta = require('@mutable/meta')

All methods are asynchronous, and take a node-style error-first callback as last argument. If no callback is supplied, a promise is returned instead.

Service Discovery

Meta.services() -> Array

Returns all the currently known service names.

Example:

  Meta.services()
    .then((_services) => {
      // returns an object {}
    })

Meta.service(service: String) -> Service

Returns a particular service.

Example:

  Meta.service("email")
    .then((service) => {
      request.post(`http://${service}/api/v1/demo/email`,
        {json:req.body},
        (error, response, body) => {
          if(error){
            console.error('can not reach email service')
            return res.send(500,{error:error,result:'can not reach email service'})
          }
          res.send({result:"email sent"})
        })
    })

or

  Meta.service("email", (config) => {

    // returns a object
    // {"hostname":"127.0.0.1", "port":3001, toString(): "127.0.0.1:3001" }
    // in a string it prints concat host and port

    request.post(`http://${service}/api/v1/demo/email`,
    {json:req.body},
    (error, response, body) => {
      if(error){
        console.error('can not reach email service')
        return res.send(500,{error:error,result:'can not reach email service'})
      }

      res.send({result:"email sent"})
    })
  })

Config

Meta.config() -> JSON

Fetches the JSON configuration for the current service.

Example:

  Meta.config()
    .then((_config) => {
      // returns an object {}
    })

For non-mutable deployments set USE_SECRETS=true environment variable to set secrets in the config. Use CONFIG environment variable to store configs when using secrets. Use SECRET_ prefix to set secrets as object in the config.

Example:

	USE_SECRETS=true CONFIG={"key":"value"} SECRET_SENDGRID_KEY='your_key' SECRET_REDIS='{"db":00}' node app.js

Resulting in this config object:

{
	"key": "value",
	sendgrid_key: "your_key",
	redis: {
		"db": 00
	}
}

SECRET_ prefix gets removed when setting the key in the config object.

DNS

For non-mutable deployments set DNS environment variable to true and use DNS_POSTFIX variable to modify the service url

Example:

DNS=true DNS_POSTFIX='.default.csv.cluster.local' node app.js

Result target: http://your-web-service.default.scv.cluster.local/

Resources

• Service Discovery and Config
• Mutable.io Docs