Created
July 20, 2020 15:14
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HTTP <> GRPC Cortex Distributors
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package main | |
import ( | |
"fmt" | |
"log" | |
"net/http" | |
"github.com/gorilla/mux" | |
"github.com/weaveworks/common/httpgrpc" | |
"github.com/weaveworks/common/httpgrpc/server" | |
"google.golang.org/grpc" | |
) | |
const grpcServiceConfig = `{"loadBalancingPolicy":"round_robin"}` | |
type grpcProxy struct { | |
client httpgrpc.HTTPClient | |
} | |
func main() { | |
// if this DNS entry returns a list of IPs the above grpcServiceConfig will make grpc attempt to load balance over them | |
distributorHostPort := "localhost:9001" | |
listenHostPort := "192.168.1.126:8000" | |
// grpc client (sends to distributor) | |
dialOptions := []grpc.DialOption{ | |
grpc.WithDefaultServiceConfig(grpcServiceConfig), | |
grpc.WithInsecure(), | |
} | |
conn, err := grpc.Dial(distributorHostPort, dialOptions...) | |
if err != nil { | |
panic(err) | |
} | |
proxy := &grpcProxy{ | |
client: httpgrpc.NewHTTPClient(conn), | |
} | |
// http server (receives from pushes from client) | |
// Note: the handler has been added to two common paths. Use whatever makes sense for your config | |
r := mux.NewRouter() | |
r.HandleFunc("/api/v1/push", proxy.ServeHTTP) | |
r.HandleFunc("/api/prom/push", proxy.ServeHTTP) | |
http.Handle("/", r) | |
handler := http.Handler(r) | |
srv := &http.Server{ | |
Handler: handler, | |
Addr: listenHostPort, | |
} | |
fmt.Println("listening...") | |
log.Fatal(srv.ListenAndServe()) | |
} | |
// ServeHTTP implements http.Handler | |
func (g *grpcProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) { | |
req, err := server.HTTPRequest(r) | |
if err != nil { | |
fmt.Println(err) | |
return | |
} | |
resp, err := g.client.Handle(r.Context(), req) | |
if err != nil { | |
// Some errors will actually contain a valid resp, just need to unpack it | |
var ok bool | |
resp, ok = httpgrpc.HTTPResponseFromError(err) | |
if !ok { | |
fmt.Println(err) | |
return | |
} | |
} | |
if err := server.WriteResponse(w, resp); err != nil { | |
http.Error(w, err.Error(), http.StatusInternalServerError) | |
return | |
} | |
} |
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