dotcloud/docker

package server // import "github.com/docker/docker/api/server"

import (
    "context"
    "net/http"

    "github.com/containerd/log"
    "github.com/docker/docker/api/server/httpstatus"
    "github.com/docker/docker/api/server/httputils"
    "github.com/docker/docker/api/server/middleware"
    "github.com/docker/docker/api/server/router"
    "github.com/docker/docker/api/server/router/debug"
    "github.com/docker/docker/api/types"
    "github.com/docker/docker/dockerversion"
    "github.com/gorilla/mux"
    "go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
)

// versionMatcher defines a variable matcher to be parsed by the router
// when a request is about to be served.
const versionMatcher = "/v{version:[0-9.]+}"

// Server contains instance details for the server
type Server struct {
    middlewares []middleware.Middleware
}

// UseMiddleware appends a new middleware to the request chain.
// This needs to be called before the API routes are configured.
func (s *Server) UseMiddleware(m middleware.Middleware) {
    s.middlewares = append(s.middlewares, m)
}

func (s *Server) makeHTTPHandler(handler httputils.APIFunc, operation string) http.HandlerFunc {
    return otelhttp.NewHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // Define the context that we'll pass around to share info
        // like the docker-request-id.
        //
        // The 'context' will be used for global data that should
        // apply to all requests. Data that is specific to the
        // immediate function being called should still be passed
        // as 'args' on the function call.

        // use intermediate variable to prevent "should not use basic type
        // string as key in context.WithValue" golint errors
        ctx := context.WithValue(r.Context(), dockerversion.UAStringKey{}, r.Header.Get("User-Agent"))

        r = r.WithContext(ctx)
        handlerFunc := s.handlerWithGlobalMiddlewares(handler)

        vars := mux.Vars(r)
        if vars == nil {
            vars = make(map[string]string)
        }

        if err := handlerFunc(ctx, w, r, vars); err != nil {
            statusCode := httpstatus.FromError(err)
            if statusCode >= 500 {
                log.G(ctx).Errorf("Handler for %s %s returned error: %v", r.Method, r.URL.Path, err)
            }
            _ = httputils.WriteJSON(w, statusCode, &types.ErrorResponse{
                Message: err.Error(),
            })
        }
    }), operation).ServeHTTP
}

// CreateMux returns a new mux with all the routers registered.
func (s *Server) CreateMux(routers ...router.Router) *mux.Router {
    m := mux.NewRouter()

    log.G(context.TODO()).Debug("Registering routers")
    for _, apiRouter := range routers {
        for _, r := range apiRouter.Routes() {
            f := s.makeHTTPHandler(r.Handler(), r.Method()+" "+r.Path())

            log.G(context.TODO()).Debugf("Registering %s, %s", r.Method(), r.Path())
            m.Path(versionMatcher + r.Path()).Methods(r.Method()).Handler(f)
            m.Path(r.Path()).Methods(r.Method()).Handler(f)
        }
    }

    debugRouter := debug.NewRouter()
    for _, r := range debugRouter.Routes() {
        f := s.makeHTTPHandler(r.Handler(), r.Method()+" "+r.Path())
        m.Path("/debug" + r.Path()).Handler(f)
    }

    notFoundHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        _ = httputils.WriteJSON(w, http.StatusNotFound, &types.ErrorResponse{
            Message: "page not found",
        })
    })

    m.HandleFunc(versionMatcher+"/{path:.*}", notFoundHandler)
    m.NotFoundHandler = notFoundHandler
    m.MethodNotAllowedHandler = notFoundHandler

    return m
}