rest

HTTPmux

The REST Plugin is a infrastructure Plugin which allows app plugins to handle HTTP requests (see the diagram below) in this sequence:

1. httpmux starts the HTTP server in its own goroutine
2. Plugins register their handlers with REST Plugin. To service HTTP requests, a plugin must first implement a handler function and register it at a given URL path using the RegisterHTTPHandler method. REST Plugin uses an HTTP request multiplexer from the gorilla/mux package to register the HTTP handlers by the specified URL path.
3. HTTP server routes HTTP requests to their respective registered handlers using the gorilla/mux multiplexer.

Configuration

• the server's port can be defined using commandline flag http-port or via the environment variable HTTP_PORT.

Example

The following example demonstrates the usage of the REST Plugin plugin API:

// httpExampleHandler returns a very simple HTTP request handler.
func httpExampleHandler(formatter *render.Render) http.HandlerFunc {

    // An example HTTP request handler which prints out attributes of 
    // a trivial Go structure in JSON format.
    return func(w http.ResponseWriter, req *http.Request) {
        formatter.JSON(w, http.StatusOK, struct{ Example string }{"This is an example"})
    }
}

// Register our HTTP request handler as a GET method serving at 
// the URL path "/example".
httpmux.RegisterHTTPHandler("/example", httpExampleHandler, "GET")

Once the handler is registered with REST Plugin and the agent is running, you can use curl to verify that it is operating properly:

$ curl -X GET http://localhost:9191/example
{
  "Example": "This is an example"
}