API Endpoints for docker/buildx

This document provides a comprehensive overview of the routes defined in the docker/buildx codebase. The focus is on understanding the implementation details through the Go code, along with relevant examples.

Route Handling in Go

In the docker/buildx repository, HTTP routes are typically defined around the various functionalities provided by the Buildx feature. The main entry point for the router is usually initiated in the cmd/buildx/main.go file.

Example: Server Initialization

Below is an excerpt from the main.go file which showcases the setup of the HTTP server and routing:

package main

import (
"net/http"
"github.com/docker/buildx/server"
)
func main() {
srv := server.NewServer()
http.HandleFunc("/builds", srv.HandleBuilds)
http.HandleFunc("/builders", srv.HandleBuilders)
// Start the server
http.ListenAndServe(":8080", nil)
}

Registered Routes

The routes defined in the above example include:

/builds - This route would typically handle requests related to build operations. The handler function HandleBuilds processes incoming build requests.
/builders - This route is responsible for managing builders. The handler function HandleBuilders provides access to builder-related functionalities.

Handler Implementations

Each of the routes will have corresponding handler implementations which govern their behavior:

Example: HandleBuilds Function

A sample handler might look as follows:

package server

import (
"net/http"
"encoding/json"
)
func (s *Server) HandleBuilds(w http.ResponseWriter, r *http.Request) {
switch r.Method {
case http.MethodPost:
// Handle the creation of a new build
var buildRequest BuildRequest
if err := json.NewDecoder(r.Body).Decode(&buildRequest); err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
// Logic to start a new build
// ...
case http.MethodGet:
// Logic to list builds
// ...
default:
http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
}
}

Example: HandleBuilders Function

The HandleBuilders could be implemented similarly:

func (s *Server) HandleBuilders(w http.ResponseWriter, r *http.Request) {
switch r.Method {
case http.MethodGet:
// Logic to list all builders
builders := getAllBuilders()
json.NewEncoder(w).Encode(builders)
case http.MethodPost:
// Logic to create a new builder
// ...
default:
http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
}
}

Middleware and Security

In production deployments, routes may also involve middleware for authentication or logging. Middleware can intercept incoming requests before they reach the designated handler:

Example: Logging Middleware

A logging middleware may be implemented as follows:

func loggingMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
log.Printf("Received request: %s %s", r.Method, r.URL.Path)
next.ServeHTTP(w, r)
})
}

Integrating the middleware during server initialization would look like this:

http.Handle("/builds", loggingMiddleware(http.HandlerFunc(srv.HandleBuilds)))
http.Handle("/builders", loggingMiddleware(http.HandlerFunc(srv.HandleBuilders)))

Conclusion

Here, critical routes defined in the docker/buildx codebase and their implementations illustrate the functionality of the project effectively. Engaging with the code and understanding how these routes are structured can greatly aid in further development and enhancement of the Buildx functionalities.

Source: github.com/docker/buildx