Make resolver Build() take a target struct (#1567)

resolver/dns/dns_resolver.go

@@ -65,8 +65,8 @@ type dnsBuilder struct {
 }
 
 // Build creates and starts a DNS resolver that watches the name resolution of the target.
-func (b *dnsBuilder) Build(target string, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
-	host, port, err := parseTarget(target)
+func (b *dnsBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
+	host, port, err := parseTarget(target.Endpoint)
 	if err != nil {
 		return nil, err
 	}

resolver/dns/dns_resolver_test.go

@@ -681,7 +681,7 @@ func testDNSResolver(t *testing.T) {
 	for _, a := range tests {
 		b := NewBuilder()
 		cc := &testClientConn{target: a.target}
-		r, err := b.Build(a.target, cc, resolver.BuildOption{})
+		r, err := b.Build(resolver.Target{Endpoint: a.target}, cc, resolver.BuildOption{})
 		if err != nil {
 			t.Fatalf("%v\n", err)
 		}
@@ -753,7 +753,7 @@ func testDNSResolveNow(t *testing.T) {
 	for _, a := range tests {
 		b := NewBuilder()
 		cc := &testClientConn{target: a.target}
-		r, err := b.Build(a.target, cc, resolver.BuildOption{})
+		r, err := b.Build(resolver.Target{Endpoint: a.target}, cc, resolver.BuildOption{})
 		if err != nil {
 			t.Fatalf("%v\n", err)
 		}
@@ -830,7 +830,7 @@ func testIPResolver(t *testing.T) {
 	for _, v := range tests {
 		b := NewBuilder()
 		cc := &testClientConn{target: v.target}
-		r, err := b.Build(v.target, cc, resolver.BuildOption{})
+		r, err := b.Build(resolver.Target{Endpoint: v.target}, cc, resolver.BuildOption{})
 		if err != nil {
 			t.Fatalf("%v\n", err)
 		}
@@ -887,7 +887,7 @@ func TestResolveFunc(t *testing.T) {
 	b := NewBuilder()
 	for _, v := range tests {
 		cc := &testClientConn{target: v.addr}
-		r, err := b.Build(v.addr, cc, resolver.BuildOption{})
+		r, err := b.Build(resolver.Target{Endpoint: v.addr}, cc, resolver.BuildOption{})
 		if err == nil {
 			r.Close()
 		}

resolver/manual/manual.go

@@ -39,13 +39,11 @@ type Resolver struct {
 	scheme string
 
 	// Fields actually belong to the resolver.
-	target string
-	cc     resolver.ClientConn
+	cc resolver.ClientConn
 }
 
 // Build returns itself for Resolver, because it's both a builder and a resolver.
-func (r *Resolver) Build(target string, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
-	r.target = target
+func (r *Resolver) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
 	r.cc = cc
 	return r, nil
 }

resolver/passthrough/passthrough.go

@@ -21,17 +21,13 @@
 // test only.
 package passthrough
 
-import (
-	"strings"
-
-	"google.golang.org/grpc/resolver"
-)
+import "google.golang.org/grpc/resolver"
 
 const scheme = "passthrough"
 
 type passthroughBuilder struct{}
 
-func (*passthroughBuilder) Build(target string, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
+func (*passthroughBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
 	r := &passthroughResolver{
 		target: target,
 		cc:     cc,
@@ -45,13 +41,12 @@ func (*passthroughBuilder) Scheme() string {
 }
 
 type passthroughResolver struct {
-	target string
+	target resolver.Target
 	cc     resolver.ClientConn
 }
 
 func (r *passthroughResolver) start() {
-	addr := strings.TrimPrefix(r.target, scheme+":///")
-	r.cc.NewAddress([]resolver.Address{{Addr: addr}})
+	r.cc.NewAddress([]resolver.Address{{Addr: r.target.Endpoint}})
 }
 
 func (*passthroughResolver) ResolveNow(o resolver.ResolveNowOption) {}

resolver/resolver.go

@@ -102,13 +102,21 @@ type ClientConn interface {
 	NewServiceConfig(serviceConfig string)
 }
 
+// Target represents a target for gRPC, as specified in:
+// https://github.com/grpc/grpc/blob/master/doc/naming.md.
+type Target struct {
+	Scheme    string
+	Authority string
+	Endpoint  string
+}
+
 // Builder creates a resolver that will be used to watch name resolution updates.
 type Builder interface {
 	// Build creates a new resolver for the given target.
 	//
 	// gRPC dial calls Build synchronously, and fails if the returned error is
 	// not nil.
-	Build(target string, cc ClientConn, opts BuildOption) (Resolver, error)
+	Build(target Target, cc ClientConn, opts BuildOption) (Resolver, error)
 	// Scheme returns the scheme supported by this resolver.
 	// Scheme is defined at https://github.com/grpc/grpc/blob/master/doc/naming.md.
 	Scheme() string