helloRPC

Hello RPC Example

This example demonstrates how Quark can implement cross-language RPC.

Hello Service Contract

The Hello service contract is expressed in hello.q. The service contract includes the service interface (hello.Hello) along with the value classes (hello.Request and hello.Response) used to interact with the service. The hello.q file also defines the names of the client and server stubs (hello.HelloClient, and hello.HelloServer).

Writing a client

The example provides two clients written to use the service (pyclient.py, HelloRPCClient.java). Both these clients follow the same basic pattern. A client instance can be constructed by passing in to the client constructor the runtime integration and the URL of the server.

Writing a server

The server code files (pyserver.py, jsserver.js, HelloRPCServer.java) also follow the same basic pattern. A server instance can be constructed by passing in to the server constructor the runtime integration and the implementation of the contract interface. Then the integration can serve the service on the given URL.

Running this example

The clients expect to find the service on http://127.0.0.1:8910/hello and each server runs there. Thus you may run a single server at a time, as well as any number of clients.

To get started, download the example by cloning its git repository as follows:

    git clone https://github.com/datawire/quark.git

All of the directions below assume you are starting from repoBase/examples/helloRPC where repoBase is the location where you cloned the repository above.

Python

Compile and install the Service Contract in hello.q:

    quark install hello.q --python

Run the Python server with

    python pyserver.py

Run the Python client with

    python pyclient.py

Java

Compile and install the Service Contract in hello.q:

    quark install hello.q --java

Compile the Java server and client with

    mvn compile

Run the Java server with

    mvn exec:java -Dexec.mainClass=helloRPC.HelloRPCServer

Run the Java client with

    mvn exec:java -Dexec.mainClass=helloRPC.HelloRPCClient

JavaScript using Node

Compile and install the Service Contract in hello.q:

    quark install hello.q --javascript

Run the Javascript server with

    node jsserver.js

Run the Javascript client with

    node jsclient.js

JavaScript from the browser

To use Quark from the browser, you compile to JavaScript as above, but then bundle up the JavaScript to allow the browser to use require() to load them. We presently use browserify for this step.

The easy way

You can run make browser and the included Makefile will

• create a local node_modules directory for you, to avoid cluttering up anything else on your system,
• install browserify, to bundle up the modules we need for the browser,
• install uglifyjs, to minify the bundled-up JavaScript,
• compile Quark to JavaScript, and finally
• bundle the JavaScript up for the browser.

Note that compiling to JavaScript will install to the local node_modules when you do this.

By hand

To do all the above by hand:

    mkdir node_modules
    npm install browserify uglifyjs
    quark install --javascript hello.q
    node_modules/.bin/browserify -d -o bhello.js -x ws -r quark -r quark/quark_node_runtime -r hello
    node_modules/.bin/uglifyjs --mangle --compress -o bhello-min.js bhello.js

Note that you can skip creating a local node_modules directory if you don't mind installing browserify, uglifyjs, and hello into your existing npm environment, but that you'll have change the path to browserify and uglifyjs above if you do.

Note also that if you do create a local node_modules directory then Quark will install hello into it.

Finally, note that you can skip running uglifyjs if you edit the appropriate <script> tag in hello.html.

Once built

However you build things, once you're ready to go you'll need to first start any of the RPC servers. The easiest way is just to run the JavaScript server, since we've just built that!

    node jsserver.js

Finally, open hello.html in your Web browser.

Ruby (a non-pollutive method, does not install gems in system ruby install)

Compile and install the Service Contract in hello.q:

    quark compile hello.q --ruby
    bundle install

Run the Ruby server with

    bundle exec ruby rbserver.rb

Run the Ruby client with

    bundle exec ruby rbclient.rb