sergshabal/currency-exchange

End to end currency exchange implementation

currency-exchange

End to end currency exchange implementation

The following components make up the currency exchange infrastructure

                                                           +------------------+        +-----------+
                                   +--------------+        | ce-operation-hub +--+---->| ce-engine |
                                   | ce-front-end +--+---->|------------------|  |     |-----------|
                               +-->|--------------|  |     | Receives, logs   |  |  +--+ Order     |
                               |   |   REST API   |<----+  | and distributes  |  |  |  | matching  |
                               |   +--------------+  |  |  | operations       |  |  |  +-----------+
                               |                     |  |  +------------------+  |  |
                               |                     |  |                        |  |
                +-----------+  |   +--------------+  |  |                        |  |  +-----------+
+----------+    |  haproxy  |  |   | ce-front-end +--+  |                        +--|->| ce-engine |
| Internet |<-->|-----------|<-+-->|--------------|  |  |                        |  |  |-----------|
+----------+    | Load      |  |   |   REST API   |<----+                        |  +--+ Order     |
                | Balancer  |  |   +--------------+  |  |                        |  |  | matching  |
                +-----------+  |                     |  |    +--------------+    |  |  +-----------+
                               |                     |  |    | ce-delta-hub |    |  |
                               |   +--------------+  |  |    |--------------|    |  |
                               |   | ce-front-end +--+  |    | Receives     |    |  |  +-----------+
                               +-->|--------------|     |    | market state |    +--|->| ce-engine |
                                   |   REST API   |<----+----+ deltas and   |       |  |-----------|
                                   +--------------+          | distributes  |<------+--+ Order     |
                                                             | them         |          | matching  |
                                                             +--------------+          +-----------+

• Each ce-engine instance is redundant and will receive all the operations that are submitted to the ce-operation-hub
• Each ce-front-end instance will receive every delta so that it has the complete market state and can respond to queries without bothering downstream components
• The ce-delta-hub instance collects the deltas produced by all the ce-engine instances but only forwards one of each to the ce-front-end instances

Contributing

Note that this project is an end to end development environment for the various currency exchange components. As such those components are included here as git submodules. Clone using the --recursive option.

$ git clone --recursive https://github.com/pghalliday/currency-exchange.git

If you don't then after cloning you will need to initialise the submodules and the submodules of the submodules.

$ git submodule update --init --recursive

You should then use vagrant (see below) to instantiate VMs for each component and work in them.

NB. Remember to commit the submodules you are working in first before commiting the changes to the currency-exchange project.

For specifics with regard to working in each submodule see their respective README.md

Prerequisites

• VirtualBox - https://www.virtualbox.org/wiki/Downloads
• Vagrant - http://downloads.vagrantup.com/

Additionally the following vagrant plugins should be installed

$ vagrant plugin install vagrant-omnibus
$ vagrant plugin install vagrant-berkshelf

Using the test-runners

The distributed test runner

This should be the default method of running end to end tests as it is the most like the target deployment environment. This runner creates a VM for each server instance and as such requires quite a lot of memory

• Start all the VMs (this will definitely take a very long time the first time it is run)

$ cd currency-exchange
$ cd test-runners/distributed
$ vagrant up

• connect to the test-runner instance

$ vagrant ssh test-runner

• Run the tests

vagrant@test-runner:~$ cd /vagrant
vagrant@test-runner:/vagrant$ npm test

• To work in the components

$ vagrant ssh [component-name]
vagrant@[component-name]:~$ cd /[component-name]
vagrant@[component-name]:/[component-name]$ npm test

• Note that after making changes it will be necessary to restart the component instances before running end to end tests

vagrant@[component-name]:/[component-name]$ npm restart

• When working in the ce-front-end or ce-engine source it is necessary to restart all the instances before running end to end tests. As the tests are always run when the VMs are reloaded this can be achieved by restarting all the VMs

$ vagrant reload

The standalone test runner

This is a less memory intensive test runner as it uses only 1 VM. It is also used by Travis which currently does not support multiple VMs

• Start the VM

$ cd currency-exchange
$ cd test-runners/standalone
$ vagrant up

• connect to the test-runner instance

$ vagrant ssh

• Run the tests

vagrant@test-runner:~$ cd /vagrant
vagrant@test-runner:/vagrant$ npm test

• To work in the components

vagrant@test-runner:~$ cd /[component-name]
vagrant@test-runner:/[component-name]$ npm test

• After changes it will be necessary to restart the server instances before re-running the end to end tests

vagrant@test-runner:~$ cd /vagrant
vagrant@test-runner:/vagrant$ npm restart
vagrant@test-runner:/vagrant$ npm test

License

Copyright © 2013 Peter Halliday
Licensed under the MIT license.