106 lines
2.1 KiB
Go
106 lines
2.1 KiB
Go
// Package http is a http reverse proxy handler
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package http
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import (
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"errors"
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"fmt"
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"math/rand"
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"net/http"
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"net/http/httputil"
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"net/url"
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"github.com/unistack-org/micro/v3/api"
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"github.com/unistack-org/micro/v3/api/handler"
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"github.com/unistack-org/micro/v3/register"
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)
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const (
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Handler = "http"
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)
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type httpHandler struct {
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options handler.Options
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// set with different initializer
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s *api.Service
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}
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func (h *httpHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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service, err := h.getService(r)
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if err != nil {
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w.WriteHeader(500)
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return
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}
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if len(service) == 0 {
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w.WriteHeader(404)
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return
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}
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rp, err := url.Parse(service)
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if err != nil {
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w.WriteHeader(500)
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return
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}
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httputil.NewSingleHostReverseProxy(rp).ServeHTTP(w, r)
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}
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// getService returns the service for this request from the selector
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func (h *httpHandler) getService(r *http.Request) (string, error) {
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var service *api.Service
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if h.s != nil {
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// we were given the service
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service = h.s
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} else if h.options.Router != nil {
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// try get service from router
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s, err := h.options.Router.Route(r)
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if err != nil {
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return "", err
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}
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service = s
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} else {
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// we have no way of routing the request
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return "", errors.New("no route found")
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}
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if len(service.Services) == 0 {
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return "", errors.New("no route found")
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}
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// get the nodes for this service
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nodes := make([]*register.Node, 0, len(service.Services))
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for _, srv := range service.Services {
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nodes = append(nodes, srv.Nodes...)
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}
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// select a random node
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node := nodes[rand.Int()%len(nodes)]
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return fmt.Sprintf("http://%s", node.Address), nil
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}
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func (h *httpHandler) String() string {
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return "http"
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}
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// NewHandler returns a http proxy handler
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func NewHandler(opts ...handler.Option) handler.Handler {
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options := handler.NewOptions(opts...)
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return &httpHandler{
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options: options,
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}
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}
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// WithService creates a handler with a service
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func WithService(s *api.Service, opts ...handler.Option) handler.Handler {
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options := handler.NewOptions(opts...)
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return &httpHandler{
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options: options,
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s: s,
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}
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}
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