OpenRiskNet registry

This repository contains the source code for the OpenRiskNet Registry component. The Registry is a web app that runs inside an OpenRiskNet Virtual Research Environment (=OpenShift/Kubernetes cluster) and auto-discovers REST style APIs that provide an OpenAPI definition with OpenRiskNet service annotations.

Architecture

The Registry is implemented with the F# programming language using the SAFE project scaffold that enables use of F# on both the client (transpiled to Javascript) as well as on the backend on .NET Core in a linux docker container.

The frontend connects to the backend and regularly polls the list of available services. The backend is implemented using a couple of agents that send each other messages for processing events and the usual ASP.NET core/Kestrel based HTTP server to answer requests by clients.

The agents use the F# MailboxProcessor class for implementation and provide a simplified IAgent interface that describes a read-only state and a way to post typed messages to the agent.

The Kubernetes agent uses the Kubernetes API to listen for Kubernetes services in any namespace. When it finds one, it checks if one of the OpenRiskNet Kubernetes/OpenShift annotations are present with the URL of the OpenAPI document to index and if so the post a message to the OpenApiProcessingAgent.

The OpenAPI processing agent receives requests to index (or remove) annotated OpenAPI documents to the service index. It then performs the following steps:

1. download the OpenAPI json or yaml
2. parse the OpenAPI document
3. dereferences OpenAPI references so every definition is inlined (e.g. shared response definitions)
4. rename the OpenAPI top level x-orn-@context to @context to turn the document into a valid Json-LD document
5. parses the result as a Json-LD document into an in-memory triple store

Because this chain can take a few seconds, the OpenAPI processing agent is instantiated a couple of times (currently 19 agents at a time) for a balanced amount of concurrency that are wrapped by a load balancing agent.

The OpenAPI services agent is only concerned with keeping a list of active services and their state.

The FeedbackAgent is used to collect messages in a thread safe way.

Build instructions

The easiest way to build the registry is to run a docker build on the Dockerfile.

If you want to build and run the registry locally you need the following installed:

• dotnet core sdk version 2.1 or higher
• the paket package manager
• the fake build tool
• node version >= 8 (and ideally yarn but npm should also work) Once you have the prerequisites, just run fake build -t run to run an interactive development server with hot reloading of the client and server or fake build to build and package everything.

Notes

OpenRiskNet is a 3 year project funded by the European Commission within Horizon2020 EINFRA-22-2016 Programme (Grant Agreement 731075; start date 1 December 2016).