The HTTP Module for WeGO

The WeGO http module. This module is an “extension” for the base framework of WeGO. It exposes the HTTP transport. The module has methods to both expose a service via HTTP and to consume a HTTP service by providing a HTTP proxy.

Exposing a service via HTTP

The http transport registers itelf under WeGO framework. It gets called when every Service registers its operations under WeGO. The URL configured for the operation is exposed to the outside world via HTTP. This is called by the WeGO framework only when it is in “server mode” i.e. when a service exists and is configured in the ServiceDescriptor. For client side registrations, the service is registered but no transport is exposed. The registration is only responsible for determining “proxy calls”

The HTTP module currently supports JSON as the default encoding mechanism. Other encoders will be added in the future.

The transport uses go-kit and MUX to expose the HTTP transport. The MUX is enhanced with middleware that works well with New Relic so that the HTTP request/response statistics are automatically captured. The HTTP transport uses the entry point to actually invoke the service. The entry point is generic and can be used across protocols.

The entry point is discussed in the middlewares section

Consuming an HTTP service

A client-side registration is sufficient to access a service using a HTTP Proxy. In this case, the server will not register a handler. Instead, the client obtains the service descriptor to know about how to access the service. In addition, it looks for a property called service name + “host_port”. If it does not find this property, it defaults to localhost: + wego.port to access the service.

The proxy delegates to a proxy_end point which is discussed in the Middlewares section.