by Thomas

we decided NOT to use hazelcast - so you have to ignore it when reading the description below

• java application with the play framework and a rest api
  • makes creating a rest api easy
  • everyone knows java
  • integrated webserver (no tomcat or war deployments)
  • can be easily packaged into a *.deb package
• uses hazelcast as an in-memory grid
  • hazelcast allows us to create a shared memory between the directory and all chain nodes
  • it has automatic node discovery for EC2
    • upon startup each chain node simply adds it own public key to the data grid
  • it supports failover scenarios
  • it scales well
  • we can easily exchange the public keys and find out which nodes are available
  • java usage is trivial: you get a simple Map<S, T> object to exchange data between clients (other collection classes are also available)
• provision new VMs via the amazon API
  • after a machine has been created, we need to install the chain node software (see below)
  • I would suggest using ansible (http://www.ansible.com/home) for this
    • works over ssh
    • you can write bash scripts
• rest resources
  • get-chain
  • get-available-nodes

• also a java application with play and rest
  • also use hazelcast
  • use bouncycastle to generate keys and put them into hazelcast
  • logging can also be done via hazelcast (=> centralized logging)
• rest resources
  • post-request (request is the name of the resource; return a future with the answer)

• java with play and rest
  • access directory rest-resources
  • use bouncycastle for encryption
  • web UI to visualize the result - probably provide a jsonapi (http://jsonapi.org/) for this and write a small SPA in javascript

• since it's so trivial and doesn't do anything with encryption (which is where I would avoid using a different library in our solution - i.e. all application that encrypt something should do so with the same library) we can use anything we want
• either also use java with play or a nodejs server (it's like ~20 LOC in node)

• everyone knows java
• easy deployments
• well supported in IDEs (especially intellij IDEA - which is free for students)
• integrated boilerplates
• check out a short introduction
• if you change java code, you just need to reload the browser to see the changes
• IMHO easier to grasp than spring or JSF/Java EE applications
  • less state in the application server
• integrated app-server and support for NIO
• easy to learn templating langauge (@manuel you can also use groovy templating ^^)