User guide gRPC

docs/user-guide/grpc.md

@@ -0,0 +1,148 @@
+# gRPC example
+
+This section explains how to use Traefik as reverse proxy for gRPC application with self-signed certificates.
+
+!!! warning
+    As gRPC needs HTTP2, we need valid HTTPS certificates on both gRPC Server and Træfik.
+
+<p align="center">
+<img src="/img/grpc.svg" alt="gRPC architecture" title="gRPC architecture" />
+</p>
+
+## gRPC Server certificate
+
+In order to secure the gRPC server, we generate a self-signed certificate for backend url:
+
+```bash
+openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout ./backend.key -out ./backend.crt
+```
+
+That will prompt for information, the important answer is:
+
+```
+Common Name (e.g. server FQDN or YOUR name) []: backend.local
+```
+
+## gRPC Client certificate
+
+Generate your self-signed certificate for frontend url:
+
+```bash
+openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout ./frontend.key -out ./frontend.crt
+```
+
+with
+
+```
+Common Name (e.g. server FQDN or YOUR name) []: frontend.local
+```
+
+## Træfik configuration
+
+At last, we configure our Træfik instance to use both self-signed certificates.
+
+```toml
+defaultEntryPoints = ["https"]
+
+# For secure connection on backend.local
+RootCAs = [ "./backend.cert" ]
+
+[entryPoints]
+  [entryPoints.https]
+  address = ":4443"
+    [entryPoints.https.tls]
+     # For secure connection on frontend.local
+     [[entryPoints.https.tls.certificates]]
+     certFile = "./frontend.cert"
+     keyFile  = "./frontend.key"
+
+
+[web]
+  address = ":8080"
+
+[file]
+
+[backends]
+  [backends.backend1]
+    [backends.backend1.servers.server1]
+    # Access on backend with HTTPS
+    url = "https://backend.local:8080"
+
+
+[frontends]
+  [frontends.frontend1]
+  backend = "backend1"
+    [frontends.frontend1.routes.test_1]
+    rule = "Host:frontend.local"
+```
+
+## Conclusion
+
+We don't need specific configuration to use gRPC in Træfik, we just need to be careful that all the exchanges (between client and Træfik, and between Træfik and backend) are valid HTTPS communications (without `InsecureSkipVerify` enabled) because gRPC use HTTP2.
+
+## A gRPC example in go
+
+We will use the gRPC greeter example in [grpc-go](https://github.com/grpc/grpc-go/tree/master/examples/helloworld)
+
+!!! warning
+    In order to use this gRPC example, we need to modify it to use HTTPS
+
+So we modify the "gRPC server example" to use our own self-signed certificate:
+
+```go
+// ...
+
+// Read cert and key file
+BackendCert := ioutil.ReadFile("./backend.cert")
+BackendKey := ioutil.ReadFile("./backend.key")
+
+// Generate Certificate struct
+cert, err := tls.X509KeyPair(BackendCert, BackendKey)
+if err != nil {
+  return err
+}
+
+// Create credentials
+creds := credentials.NewServerTLSFromCert(&cert)
+
+// Use Credentials in gRPC server options
+serverOption := grpc.Creds(creds)
+var s *grpc.Server = grpc.NewServer(serverOption)
+defer s.Stop()
+
+helloworld.RegisterGreeterServer(s, &myserver{})
+err := s.Serve(lis)
+
+// ...
+```
+
+Next we will modify gRPC Client to use our Træfik self-signed certificate:
+
+```go
+// ...
+
+// Read cert file
+FrontendCert := ioutil.ReadFile("./frontend.cert")
+
+// Create CertPool
+roots := x509.NewCertPool()
+roots.AppendCertsFromPEM(FrontendCert)
+
+// Create credentials
+credsClient := credentials.NewClientTLSFromCert(roots, "")
+
+// Dial with specific Transport (with credentials)
+conn, err := grpc.Dial("https://frontend:4443", grpc.WithTransportCredentials(credsClient))
+if err != nil {
+  return err
+}
+
+defer conn.Close()
+client := helloworld.NewGreeterClient(conn)
+
+name := "World"
+r, err := client.SayHello(context.Background(), &helloworld.HelloRequest{Name: name})
+
+// ...
+```
+

mkdocs.yml

@@ -93,4 +93,5 @@ pages:
     - 'Marathon': 'user-guide/marathon.md'
     - 'Key-value Store Configuration': 'user-guide/kv-config.md'
     - 'Clustering/HA': 'user-guide/cluster.md'
+    - 'gRPC Example': 'user-guide/grpc.md'
   - Benchmarks: benchmarks.md