Add network proxying (#1556)

* Add network proxying

* go fmt

client/grpc/grpc.go

@@ -6,7 +6,6 @@ import (
 	"crypto/tls"
 	"fmt"
 	"net"
-	"os"
 	"strings"
 	"sync/atomic"
 	"time"
@@ -20,6 +19,7 @@ import (
 	"github.com/micro/go-micro/v2/metadata"
 	"github.com/micro/go-micro/v2/registry"
 	"github.com/micro/go-micro/v2/util/config"
+	pnet "github.com/micro/go-micro/v2/util/net"
 
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
@@ -74,27 +74,13 @@ func (g *grpcClient) secure(addr string) grpc.DialOption {
 }
 
 func (g *grpcClient) next(request client.Request, opts client.CallOptions) (selector.Next, error) {
-	service := request.Service()
-
-	// get proxy
-	if prx := os.Getenv("MICRO_PROXY"); len(prx) > 0 {
-		// default name
-		if prx == "service" {
-			prx = "go.micro.proxy"
-		}
-		service = prx
-	}
-
-	// get proxy address
-	if prx := os.Getenv("MICRO_PROXY_ADDRESS"); len(prx) > 0 {
-		opts.Address = []string{prx}
-	}
+	service, address, _ := pnet.Proxy(request.Service(), opts.Address)
 
 	// return remote address
-	if len(opts.Address) > 0 {
+	if len(address) > 0 {
 		return func() (*registry.Node, error) {
 			return &registry.Node{
-				Address: opts.Address[0],
+				Address: address[0],
 			}, nil
 		}, nil
 	}

client/rpc_client.go

@@ -3,7 +3,6 @@ package client
 import (
 	"context"
 	"fmt"
-	"os"
 	"sync/atomic"
 	"time"
 
@@ -17,6 +16,7 @@ import (
 	"github.com/micro/go-micro/v2/registry"
 	"github.com/micro/go-micro/v2/transport"
 	"github.com/micro/go-micro/v2/util/buf"
+	"github.com/micro/go-micro/v2/util/net"
 	"github.com/micro/go-micro/v2/util/pool"
 )
 
@@ -322,46 +322,18 @@ func (r *rpcClient) Options() Options {
 	return r.opts
 }
 
-// hasProxy checks if we have proxy set in the environment
-func (r *rpcClient) hasProxy() bool {
-	// get proxy
-	if prx := os.Getenv("MICRO_PROXY"); len(prx) > 0 {
-		return true
-	}
-
-	// get proxy address
-	if prx := os.Getenv("MICRO_PROXY_ADDRESS"); len(prx) > 0 {
-		return true
-	}
-
-	return false
-}
-
 // next returns an iterator for the next nodes to call
 func (r *rpcClient) next(request Request, opts CallOptions) (selector.Next, error) {
-	service := request.Service()
-
-	// get proxy
-	if prx := os.Getenv("MICRO_PROXY"); len(prx) > 0 {
-		// default name
-		if prx == "service" {
-			prx = "go.micro.proxy"
-		}
-		service = prx
-	}
-
-	// get proxy address
-	if prx := os.Getenv("MICRO_PROXY_ADDRESS"); len(prx) > 0 {
-		opts.Address = []string{prx}
-	}
+	// try get the proxy
+	service, address, _ := net.Proxy(request.Service(), opts.Address)
 
 	// return remote address
-	if len(opts.Address) > 0 {
-		nodes := make([]*registry.Node, len(opts.Address))
+	if len(address) > 0 {
+		nodes := make([]*registry.Node, len(address))
 
-		for i, address := range opts.Address {
+		for i, addr := range address {
 			nodes[i] = &registry.Node{
-				Address: address,
+				Address: addr,
 				// Set the protocol
 				Metadata: map[string]string{
 					"protocol": "mucp",
@@ -461,7 +433,7 @@ func (r *rpcClient) Call(ctx context.Context, request Request, response interfac
 	retries := callOpts.Retries
 
 	// disable retries when using a proxy
-	if r.hasProxy() {
+	if _, _, ok := net.Proxy(request.Service(), callOpts.Address); ok {
 		retries = 0
 	}
 
@@ -552,7 +524,7 @@ func (r *rpcClient) Stream(ctx context.Context, request Request, opts ...CallOpt
 	retries := callOpts.Retries
 
 	// disable retries when using a proxy
-	if r.hasProxy() {
+	if _, _, ok := net.Proxy(request.Service(), callOpts.Address); ok {
 		retries = 0
 	}
 

util/net/net.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"os"
 	"strconv"
 	"strings"
 )
@@ -77,3 +78,40 @@ func Listen(addr string, fn func(string) (net.Listener, error)) (net.Listener, e
 	// why are we here?
 	return nil, fmt.Errorf("unable to bind to %s", addr)
 }
+
+// Proxy returns the proxy and the address if it exits
+func Proxy(service string, address []string) (string, []string, bool) {
+	var hasProxy bool
+
+	// get proxy
+	if prx := os.Getenv("MICRO_PROXY"); len(prx) > 0 {
+		// default name
+		if prx == "service" {
+			prx = "go.micro.proxy"
+		}
+		service = prx
+		hasProxy = true
+	}
+
+	// get proxy address
+	if prx := os.Getenv("MICRO_PROXY_ADDRESS"); len(prx) > 0 {
+		address = []string{prx}
+		hasProxy = true
+	}
+
+	if prx := os.Getenv("MICRO_NETWORK"); len(prx) > 0 {
+		// default name
+		if prx == "service" {
+			prx = "go.micro.network"
+		}
+		service = prx
+		hasProxy = true
+	}
+
+	if prx := os.Getenv("MICRO_NEWORK_ADDRESS"); len(prx) > 0 {
+		address = []string{prx}
+		hasProxy = true
+	}
+
+	return service, address, hasProxy
+}