client: add proxy option (#1885)

* client: add proxy option

* client: add WithProxy CallOption

* use address option

* ProxyAddress => Proxy

util/net/net.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"os"
 	"strconv"
 	"strings"
 )
@@ -78,43 +77,3 @@ 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. we parse out address if present
-	if prx := os.Getenv("MICRO_PROXY"); len(prx) > 0 {
-		// default name
-		if prx == "service" {
-			prx = "go.micro.proxy"
-			address = nil
-		}
-
-		// check if its an address
-		if v := strings.Split(prx, ":"); len(v) > 1 {
-			address = []string{prx}
-		}
-
-		service = prx
-		hasProxy = true
-
-		return service, address, hasProxy
-	}
-
-	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_NETWORK_ADDRESS"); len(prx) > 0 {
-		address = []string{prx}
-		hasProxy = true
-	}
-
-	return service, address, hasProxy
-}