Demo API Gateway

This is a Demo API gateway implemented using go kit. You will need golang installed. The apigateway code lives in the apigateway sub-directory and there are two example services:

• A Python web service
• A gRPC server

Install gb

The complete documentation for gb can be found here, but here are the two steps involved:

$ go get github.com/constabulary/gb/...
$ go get github.com/constabulary/gb/cmd/gb-vendor

Your $GOPATH/bin must be in your $PATH as well.

Consul

We will use consul for service discovery. To install it, follow the official docs here and then start the agent in dev mode:

$consul agent -dev
.. 
...

Start the web application

Our Python web application relies on flask and consulate, so you will need those installed before you can run it and register itself with consul. Using a virtual environment is recommended:

$ virtualenv python-web-app
$ . ./python-web-app/bin/activate
$ cd webap-1
$ pip install requirements.txt
$ python app.py

Start the gRPC service

$ cd grpc-app-1/server
$ gb build
$ ./bin/server

Start the API gateway

$ cd apigateway
$ gb build
$ ./bin/apigatway
ts=2016-11-15T06:44:51Z caller=subscriber.go:48 service=projects tags=[] instances=1
ts=2016-11-15T06:44:51Z caller=subscriber.go:48 service=verification tags=[] instances=1
ts=2016-11-15T06:44:51Z caller=main.go:256 transport=HTTP addr=:8000

Make requests

API Gateway Features

Auth header missing:

$ http POST 127.0.0.1:8000/projects/ title=MyProejct Auth-Header-V:121
HTTP/1.1 400 Bad Request
Content-Length: 31
Content-Type: text/plain; charset=utf-8
Date: Tue, 15 Nov 2016 02:50:19 GMT
X-Content-Type-Options: nosniff

Decode: Auth-Header-V1 missing

Rate limiting example response:

$ http POST 127.0.0.1:8000/projects/ title=MyProejct Auth-Header-V1:121
HTTP/1.1 503 Service Unavailable
Content-Length: 24
Content-Type: text/plain; charset=utf-8
Date: Tue, 15 Nov 2016 02:49:39 GMT
X-Content-Type-Options: nosniff

Do: rate limit exceeded

Project creation

$ http POST 127.0.0.1:8000/projects/ Auth-Header-V1:3121 title=foobar11121
HTTP/1.1 200 OK
Content-Length: 39
Content-Type: application/json; charset=utf-8
Date: Sat, 26 Nov 2016 05:48:14 GMT

{
    "id": 123,
    "url": "Project-foobar11121"
}

Verification service:

$ http GET 127.0.0.1:8000/verify/ id:=1233 token=vasds Auth-Header-V1:121
HTTP/1.1 200 OK
Content-Length: 40
Content-Type: application/json; charset=utf-8
Date: Tue, 15 Nov 2016 02:47:21 GMT

{
    "Err": null,
    "Message": "Verified: 1233"
}

Resources

• https://peter.bourgon.org/applied-go-kit
• https://gokit.io