Typhon 🐲

Typhon is a wrapper around Go's net/http library that we use at Monzo to build RPC servers and clients in our microservices platform.

It provides a number of conveniences and tries to promote safety wherever possible. Here's a short list of interesting features in Typhon:

• No need to close body.Close() in clients
  Forgetting to body.Close() in a client when the body has been dealt with is a common source of resource leaks in Go programs in our experience. Typhon ensures that – unless you're doing something really weird with the body – it will be closed automatically.

• Middleware "filters"
  Filters are decorators around Services; in Typhon servers and clients share common functionality by composing it functionally.

• Body encoding and decoding
  Marshalling and unmarshalling request bodies to structs is such a common operation that our Request and Response objects support them directly. If the operations fail, the errors are propagated automatically since that's nearly always what a server will want.

• Propagation of cancellation
  When a server has done handling a request, the request's context is automatically cancelled, and these cancellations are propagated through the distributed call stack. This lets downstream servers conserve work producing responses that are no longer needed.

• Error propagation
  Responses have an inbuilt Error attribute, and serialisation/deserialisation of these errors into HTTP errors is taken care of automatically. We recommend using this in conjunction with monzo/terrors.

• Full HTTP/1.1 and HTTP/2.0 support
  Applications implemented using Typhon can communicate over HTTP/1.1 or HTTP/2.0. Typhon has support for full duplex communication under HTTP/2.0, and h2c (HTTP/2.0 over TCP, ie. without TLS) is also supported if required.