support links in the proxy

proxy/grpc/grpc.go

@@ -10,6 +10,7 @@ import (
 	"github.com/micro/go-micro/client/grpc"
 	"github.com/micro/go-micro/codec"
 	"github.com/micro/go-micro/config/options"
+	"github.com/micro/go-micro/errors"
 	"github.com/micro/go-micro/proxy"
 	"github.com/micro/go-micro/server"
 )
@@ -61,6 +62,10 @@ func readLoop(r server.Request, s client.Stream) error {
 	}
 }
 
+func (p *Proxy) SendRequest(ctx context.Context, req client.Request, rsp client.Response) error {
+	return errors.InternalServerError("go.micro.proxy.grpc", "SendRequest is unsupported")
+}
+
 // ServeRequest honours the server.Proxy interface
 func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server.Response) error {
 	// set default client

proxy/http/http.go

@@ -10,6 +10,7 @@ import (
 	"net/url"
 	"path"
 
+	"github.com/micro/go-micro/client"
 	"github.com/micro/go-micro/config/options"
 	"github.com/micro/go-micro/errors"
 	"github.com/micro/go-micro/proxy"
@@ -44,6 +45,10 @@ func getEndpoint(hdr map[string]string) string {
 	return ""
 }
 
+func (p *Proxy) SendRequest(ctx context.Context, req client.Request, rsp client.Response) error {
+	return errors.InternalServerError("go.micro.proxy.http", "SendRequest is unsupported")
+}
+
 // ServeRequest honours the server.Router interface
 func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server.Response) error {
 	if p.Endpoint == "" {

proxy/mucp/mucp.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"sort"
 	"strings"
 	"sync"
 
@@ -12,6 +13,7 @@ import (
 	"github.com/micro/go-micro/codec"
 	"github.com/micro/go-micro/codec/bytes"
 	"github.com/micro/go-micro/config/options"
+	"github.com/micro/go-micro/errors"
 	"github.com/micro/go-micro/proxy"
 	"github.com/micro/go-micro/router"
 	"github.com/micro/go-micro/server"
@@ -26,9 +28,12 @@ type Proxy struct {
 	// Endpoint specifies the fixed service endpoint to call.
 	Endpoint string
 
-	// The client to use for outbound requests
+	// The client to use for outbound requests in the local network
 	Client client.Client
 
+	// Links are used for outbound requests not in the local network
+	Links map[string]client.Client
+
 	// The router for routes
 	Router router.Router
 
@@ -76,7 +81,7 @@ func readLoop(r server.Request, s client.Stream) error {
 }
 
 // toNodes returns a list of node addresses from given routes
-func toNodes(routes map[uint64]router.Route) []string {
+func toNodes(routes []router.Route) []string {
 	var nodes []string
 	for _, node := range routes {
 		address := node.Address
@@ -88,15 +93,33 @@ func toNodes(routes map[uint64]router.Route) []string {
 	return nodes
 }
 
-func (p *Proxy) getRoute(service string) ([]string, error) {
+func (p *Proxy) getLink(r router.Route) (client.Client, error) {
+	if r.Link == "local" || len(p.Links) == 0 {
+		return p.Client, nil
+	}
+	l, ok := p.Links[r.Link]
+	if !ok {
+		return nil, errors.InternalServerError("go.micro.proxy", "route not found")
+	}
+	return l, nil
+}
+
+func (p *Proxy) getRoute(service string) ([]router.Route, error) {
+	toSlice := func(r map[uint64]router.Route) []router.Route {
+		var routes []router.Route
+		for _, v := range r {
+			routes = append(routes, v)
+		}
+		return routes
+	}
+
 	// lookup the route cache first
 	p.Lock()
 	routes, ok := p.Routes[service]
 	if ok {
 		p.Unlock()
-		return toNodes(routes), nil
+		return toSlice(routes), nil
 	}
-	p.Routes[service] = make(map[uint64]router.Route)
 	p.Unlock()
 
 	// lookup the routes in the router
@@ -113,12 +136,16 @@ func (p *Proxy) getRoute(service string) ([]string, error) {
 	// update the proxy cache
 	p.Lock()
 	for _, route := range results {
+		// create if does not exist
+		if _, ok := p.Routes[service]; !ok {
+			p.Routes[service] = make(map[uint64]router.Route)
+		}
 		p.Routes[service][route.Hash()] = route
 	}
 	routes = p.Routes[service]
 	p.Unlock()
 
-	return toNodes(routes), nil
+	return toSlice(routes), nil
 }
 
 // manageRouteCache applies action on a given route to Proxy route cache
@@ -171,12 +198,27 @@ func (p *Proxy) watchRoutes() {
 	}
 }
 
+func (p *Proxy) SendRequest(ctx context.Context, req client.Request, rsp client.Response) error {
+	return errors.InternalServerError("go.micro.proxy", "SendRequest is unsupported")
+}
+
 // ServeRequest honours the server.Router interface
 func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server.Response) error {
-	// service name
+	// determine if its local routing
-	service := req.Service()
+	var local bool
-	endpoint := req.Endpoint()
+	// address to call
 	var addresses []string
+	// routes
+	var routes []router.Route
+	// service name to call
+	service := req.Service()
+	// endpoint to call
+	endpoint := req.Endpoint()
+
+	// are we network routing or local routing
+	if len(p.Links) == 0 {
+		local = true
+	}
 
 	// call a specific backend endpoint either by name or address
 	if len(p.Endpoint) > 0 {
@@ -190,7 +232,7 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 				return err
 			}
 			// set the address
-			addresses = addr
+			routes = addr
 			// set the name
 			service = p.Endpoint
 		}
@@ -201,16 +243,69 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 		if err != nil {
 			return err
 		}
-		addresses = addr
+		routes = addr
 	}
 
+	// if the address is already set just serve it
+	// TODO: figure it out if we should know to pick a link
+	if len(addresses) > 0 {
+		// serve the normal way
+		return p.serveRequest(ctx, p.Client, service, endpoint, req, rsp, client.WithAddress(addresses...))
+	}
+
+	// sort the routes in order of metric
+	sort.Slice(routes, func(i, j int) bool { return routes[i].Metric < routes[j].Metric })
+
+	// there's no links e.g we're local routing then just serve it with addresses
+	if local {
 		var opts []client.CallOption
 
-	// set address if available
+		// set address if available via routes or specific endpoint
-	if len(addresses) > 0 {
+		if len(routes) > 0 {
+			addresses := toNodes(routes)
 			opts = append(opts, client.WithAddress(addresses...))
 		}
 
+		// serve the normal way
+		return p.serveRequest(ctx, p.Client, service, endpoint, req, rsp, opts...)
+	}
+
+	var gerr error
+
+	// we're routing globally with multiple links
+	// so we need to pick a link per route
+	for _, route := range routes {
+		// pick the link or error out
+		link, err := p.getLink(route)
+		if err != nil {
+			// ok let's try again
+			gerr = err
+			continue
+		}
+
+		// set the address to call
+		addresses := toNodes([]router.Route{route})
+
+		// do the request with the link
+		gerr = p.serveRequest(ctx, link, service, endpoint, req, rsp, client.WithAddress(addresses...))
+		// return on no error since we succeeded
+		if gerr == nil {
+			return nil
+		}
+
+		// return where the context deadline was exceeded
+		if gerr == context.Canceled || gerr == context.DeadlineExceeded {
+			return err
+		}
+
+		// otherwise attempt to do it all over again
+	}
+
+	// if we got here something went really badly wrong
+	return gerr
+}
+
+func (p *Proxy) serveRequest(ctx context.Context, link client.Client, service, endpoint string, req server.Request, rsp server.Response, opts ...client.CallOption) error {
 	// read initial request
 	body, err := req.Read()
 	if err != nil {
@@ -218,14 +313,14 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 	}
 
 	// create new request with raw bytes body
-	creq := p.Client.NewRequest(service, endpoint, &bytes.Frame{body}, client.WithContentType(req.ContentType()))
+	creq := link.NewRequest(service, endpoint, &bytes.Frame{body}, client.WithContentType(req.ContentType()))
 
 	// not a stream so make a client.Call request
 	if !req.Stream() {
 		crsp := new(bytes.Frame)
 
 		// make a call to the backend
-		if err := p.Client.Call(ctx, creq, crsp, opts...); err != nil {
+		if err := link.Call(ctx, creq, crsp, opts...); err != nil {
 			return err
 		}
 
@@ -238,7 +333,7 @@ func (p *Proxy) ServeRequest(ctx context.Context, req server.Request, rsp server
 	}
 
 	// create new stream
-	stream, err := p.Client.Stream(ctx, creq, opts...)
+	stream, err := link.Stream(ctx, creq, opts...)
 	if err != nil {
 		return err
 	}
@@ -300,6 +395,7 @@ func NewSingleHostProxy(endpoint string) *Proxy {
 // NewProxy returns a new proxy which will route based on mucp headers
 func NewProxy(opts ...options.Option) proxy.Proxy {
 	p := new(Proxy)
+	p.Links = map[string]client.Client{}
 	p.Options = options.NewOptions(opts...)
 	p.Options.Init(options.WithString("mucp"))
 
@@ -320,6 +416,12 @@ func NewProxy(opts ...options.Option) proxy.Proxy {
 		p.Client = client.DefaultClient
 	}
 
+	// get client
+	links, ok := p.Options.Values().Get("proxy.links")
+	if ok {
+		p.Links = links.(map[string]client.Client)
+	}
+
 	// get router
 	r, ok := p.Options.Values().Get("proxy.router")
 	if ok {

proxy/proxy.go

@@ -13,6 +13,8 @@ import (
 // Proxy can be used as a proxy server for go-micro services
 type Proxy interface {
 	options.Options
+	// SendRequest honours the client.Router interface
+	SendRequest(context.Context, client.Request, client.Response) error
 	// ServeRequest honours the server.Router interface
 	ServeRequest(context.Context, server.Request, server.Response) error
 }
@@ -35,3 +37,20 @@ func WithClient(c client.Client) options.Option {
 func WithRouter(r router.Router) options.Option {
 	return options.WithValue("proxy.router", r)
 }
+
+// WithLink sets a link for outbound requests
+func WithLink(name string, c client.Client) options.Option {
+	return func(o *options.Values) error {
+		var links map[string]client.Client
+		v, ok := o.Get("proxy.links")
+		if ok {
+			links = v.(map[string]client.Client)
+		} else {
+			links = map[string]client.Client{}
+		}
+		links[name] = c
+		// save the links
+		o.Set("proxy.links", links)
+		return nil
+	}
+}