Hello Service (microservice chaining)

This example illustrates microservice chaining / proxying where one microservice uses another microservice as part of its implementation.

This package defined two services:

• PublicHelloService: which defines a simple /hello endpoint that delegates to our PrivateHelloService
• PrivateHelloService: which defines a simple /hello endpoint that returns { msg: "Hello world!" }

Flow

Client                       PublicHelloService                 PrivateHelloService
  |                          
  |        GET /hello            
  | ---------------------------> /hello
                                    |           GET /hello
                                    | -----------------------------> /hello
                                                                       |
                                        200: { msg: "Hello world!" }   |
                                    <----------------------------------|
                                    |
      200: { msg: "Hello world!" }  |
  |<--------------------------------|

Installing the service

We encourage you to clone the git repository so you can play around with the code.

$ git clone -b carbon-0.7 git@github.com:carbon-io-examples/example__hello-world-service-chaining.git
$ cd example__hello-world-service-chaining
$ npm install

Running the services

Start the private service:

$ node lib/PrivateHelloService

Start the public service (order does not matter):

$ node lib/PublicHelloService

For cmdline help:

$ node lib/PublicHelloService -h

or

$ node lib/PrivateHelloService -h

Accessing the service

To access the /hello endpoint on the public service:

$ curl localhost:8888/hello
{ msg: "Hello world!" }

Running the unit tests

This example comes with a simple unit test written in Carbon.io's test framework called TestTube. It is located in the test directory.

$ node test/HelloServiceTest

or

$ npm test

Generating API documentation (aglio flavor)

To generate documentation using aglio, install it as a devDependency:

$ npm install -D --no-optional aglio

Using --no-optional speeds up aglio's install time significantly. Then generate the docs using these commands:

$ node lib/PrivateHelloService gen-static-docs --flavor aglio --out docs/private-api.html

$ node lib/PublicHelloService gen-static-docs --flavor aglio --out docs/public-api.html

View current documentation

• Private service
• Public service