From 4ff959ef50a6e2e2872de9a4fd85aff2d3a4a366 Mon Sep 17 00:00:00 2001
From: Ben Toogood <ben@micro.mu>
Date: Thu, 9 Apr 2020 11:03:33 +0100
Subject: [PATCH] Dynamic Namespace

---
 api/handler/http/http_test.go |  2 +-
 api/resolver/options.go       | 15 +++++++++++++--
 api/resolver/path/path.go     |  4 +++-
 api/resolver/resolver.go      |  9 ++++++++-
 api/resolver/vpath/vpath.go   | 10 ++++++----
 5 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/api/handler/http/http_test.go b/api/handler/http/http_test.go
index 6844a45a..f0ccd1ff 100644
--- a/api/handler/http/http_test.go
+++ b/api/handler/http/http_test.go
@@ -58,7 +58,7 @@ func testHttp(t *testing.T, path, service, ns string) {
 		router.WithHandler("http"),
 		router.WithRegistry(r),
 		router.WithResolver(vpath.NewResolver(
-			resolver.WithNamespace(ns),
+			resolver.WithNamespace(resolver.StaticNamespace(ns)),
 		)),
 	)
 
diff --git a/api/resolver/options.go b/api/resolver/options.go
index ce4b2e49..eb9ce875 100644
--- a/api/resolver/options.go
+++ b/api/resolver/options.go
@@ -1,11 +1,22 @@
 package resolver
 
+import (
+	"net/http"
+
+	"github.com/micro/go-micro/v2/auth"
+)
+
 // NewOptions returns new initialised options
 func NewOptions(opts ...Option) Options {
 	var options Options
 	for _, o := range opts {
 		o(&options)
 	}
+
+	if options.Namespace == nil {
+		options.Namespace = StaticNamespace(auth.DefaultNamespace)
+	}
+
 	return options
 }
 
@@ -16,8 +27,8 @@ func WithHandler(h string) Option {
 	}
 }
 
-// WithNamespace sets the namespace being used
-func WithNamespace(n string) Option {
+// WithNamespace sets the function which determines the namespace for a request
+func WithNamespace(n func(*http.Request) string) Option {
 	return func(o *Options) {
 		o.Namespace = n
 	}
diff --git a/api/resolver/path/path.go b/api/resolver/path/path.go
index 88bec8a7..84a92656 100644
--- a/api/resolver/path/path.go
+++ b/api/resolver/path/path.go
@@ -18,8 +18,10 @@ func (r *Resolver) Resolve(req *http.Request) (*resolver.Endpoint, error) {
 	}
 
 	parts := strings.Split(req.URL.Path[1:], "/")
+	ns := r.opts.Namespace(req)
+
 	return &resolver.Endpoint{
-		Name:   r.opts.Namespace + "." + parts[0],
+		Name:   ns + "." + parts[0],
 		Host:   req.Host,
 		Method: req.Method,
 		Path:   req.URL.Path,
diff --git a/api/resolver/resolver.go b/api/resolver/resolver.go
index 12854b19..81e8194d 100644
--- a/api/resolver/resolver.go
+++ b/api/resolver/resolver.go
@@ -31,7 +31,14 @@ type Endpoint struct {
 
 type Options struct {
 	Handler   string
-	Namespace string
+	Namespace func(*http.Request) string
 }
 
 type Option func(o *Options)
+
+// StaticNamespace returns the same namespace for each request
+func StaticNamespace(ns string) func(*http.Request) string {
+	return func(*http.Request) string {
+		return ns
+	}
+}
diff --git a/api/resolver/vpath/vpath.go b/api/resolver/vpath/vpath.go
index f1e49399..cf407ded 100644
--- a/api/resolver/vpath/vpath.go
+++ b/api/resolver/vpath/vpath.go
@@ -33,7 +33,7 @@ func (r *Resolver) Resolve(req *http.Request) (*resolver.Endpoint, error) {
 	parts := strings.Split(req.URL.Path[1:], "/")
 	if len(parts) == 1 {
 		return &resolver.Endpoint{
-			Name:   addNamespace(r.opts.Namespace, parts...),
+			Name:   r.withNamespace(req, parts...),
 			Host:   req.Host,
 			Method: req.Method,
 			Path:   req.URL.Path,
@@ -43,7 +43,7 @@ func (r *Resolver) Resolve(req *http.Request) (*resolver.Endpoint, error) {
 	// /v1/foo
 	if re.MatchString(parts[0]) {
 		return &resolver.Endpoint{
-			Name:   addNamespace(r.opts.Namespace, parts[0:2]...),
+			Name:   r.withNamespace(req, parts[0:2]...),
 			Host:   req.Host,
 			Method: req.Method,
 			Path:   req.URL.Path,
@@ -51,7 +51,7 @@ func (r *Resolver) Resolve(req *http.Request) (*resolver.Endpoint, error) {
 	}
 
 	return &resolver.Endpoint{
-		Name:   addNamespace(r.opts.Namespace, parts[0]),
+		Name:   r.withNamespace(req, parts[0]),
 		Host:   req.Host,
 		Method: req.Method,
 		Path:   req.URL.Path,
@@ -62,9 +62,11 @@ func (r *Resolver) String() string {
 	return "path"
 }
 
-func addNamespace(ns string, parts ...string) string {
+func (r *Resolver) withNamespace(req *http.Request, parts ...string) string {
+	ns := r.opts.Namespace(req)
 	if len(ns) == 0 {
 		return strings.Join(parts, ".")
 	}
+
 	return strings.Join(append([]string{ns}, parts...), ".")
 }