Web Client Integration

The MDK provide integration points for common HTTP client frameworks. The number of supported frameworks will grow over time.

Hooking up the MDK will do the following:

1. Timeouts will be extracted from the MDK session and used to set the request timeout.
2. The given MDK session will be transmitted to the destination server via a X-MDK-CONTEXT HTTP header.

The session may contain sensitive information, so this functionality should only be used within servers under your own control.

JavaScript

Request

To use MDK with the Request library you can npm install datawire_mdk_request. In particular, forMDKSession creates an object that looks like a request object but has timeout and MDK session header support:

var mdk = require('datawire_mdk').mdk;
var process = require('process');
var mdk_request = require('datawire_mdk_request');

mdk = mdk.start();
process.on('exit', function () {
    mdk.stop();
});

var mdkSession = mdk.session();
mdkSession.setTimeout(1.0);

var requestMDK = mdk_request.forMDKSession(mdkSession);
requestMDK("http://example.com", function (error, response, body) {
    console.log(body);
});
// You can also do requestMDK.get(...), etc..

Python

Requests

To use MDK with the Requests library you can use the mdk.requests.requests_session API, which creates a requests.Session object. For example, if you’re using the MDK Flask integration:

from flask import g, Flask

from mdk.flask import mdk_setup
from mdk.requests import requests_session

app = Flask(__name__)

@app.route("/")
def proxy():
    # Lookup backend server using MDK Discovery.
    node = g.mdk_session.resolve("backend_service", "1.0")

    # Use requests to do a HTTP GET that includes the MDK
    # session context and a timeout derived from the session
    # timeout:
    req_ssn = requests_session(g.mdk_session)
    return req_ssn.get(node.address).text

if __name__ == '__main__':
    mdk_setup(app, timeout=10.0)
    app.run()

Ruby

Faraday

To use MDK with the Faraday library you can gem install faraday_mdk and then:

require 'faraday'
require 'mdk'
require 'faraday_mdk'

mdk = ::Quark::Mdk.start
session = mdk.session
session.setTimeout(1.0)
conn = Faraday.new(:url => ARGV[0]) do |faraday|
  # Add middleware for the MDK session:
  faraday.request :mdk_session, session
  faraday.adapter  Faraday.default_adapter
end

response = conn.get
puts(response.body)
mdk.stop