http: support standby redirects

http/handler.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"net/url"
 	"strings"
 
 	"github.com/hashicorp/vault/logical"
@@ -62,8 +63,12 @@ func parseRequest(r *http.Request, out interface{}) error {
 
 // request is a helper to perform a request and properly exit in the
 // case of an error.
-func request(core *vault.Core, w http.ResponseWriter, r *logical.Request) (*logical.Response, bool) {
+func request(core *vault.Core, w http.ResponseWriter, reqURL *url.URL, r *logical.Request) (*logical.Response, bool) {
 	resp, err := core.HandleRequest(r)
+	if err == vault.ErrStandby {
+		respondStandby(core, w, reqURL)
+		return resp, false
+	}
 	if respondCommon(w, resp) {
 		return resp, false
 	}
@@ -75,6 +80,49 @@ func request(core *vault.Core, w http.ResponseWriter, r *logical.Request) (*logi
 	return resp, true
 }
 
+// respondStandby is used to trigger a redirect in the case that this Vault is currently a hot standby
+func respondStandby(core *vault.Core, w http.ResponseWriter, reqURL *url.URL) {
+	// Request the leader address
+	_, advertise, err := core.Leader()
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, err)
+		return
+	}
+
+	// If there is no leader, generate a 503 error
+	if advertise == "" {
+		err = fmt.Errorf("no active Vault instance found")
+		respondError(w, http.StatusServiceUnavailable, err)
+		return
+	}
+
+	// Parse the advertise location
+	advertiseURL, err := url.Parse(advertise)
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, err)
+		return
+	}
+
+	// Generate a redirect URL
+	redirectURL := url.URL{
+		Scheme:   advertiseURL.Scheme,
+		Host:     advertiseURL.Host,
+		Path:     reqURL.Path,
+		RawQuery: reqURL.RawQuery,
+	}
+
+	// Ensure there is a scheme, default to https
+	if redirectURL.Scheme == "" {
+		redirectURL.Scheme = "https"
+	}
+
+	// If we have an address, redirect! We use a 307 code
+	// because we don't actually know if its permanent and
+	// the request method should be preserved.
+	w.Header().Set("Location", redirectURL.String())
+	w.WriteHeader(307)
+}
+
 // requestAuth adds the token to the logical.Request if it exists.
 func requestAuth(r *http.Request, req *logical.Request) *logical.Request {
 	// Attach the cookie value as the token if we have it

http/logical.go

@@ -56,7 +56,7 @@ func handleLogical(core *vault.Core) http.Handler {
 		// Make the internal request. We attach the connection info
 		// as well in case this is an authentication request that requires
 		// it. Vault core handles stripping this if we need to.
-		resp, ok := request(core, w, requestAuth(r, &logical.Request{
+		resp, ok := request(core, w, r.URL, requestAuth(r, &logical.Request{
 			Operation: op,
 			Path:      path,
 			Data:      req,

http/logical_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/hashicorp/vault/physical"
 	"github.com/hashicorp/vault/vault"
 )
 
@@ -66,3 +67,73 @@ func TestLogical_noExist(t *testing.T) {
 	}
 	testResponseStatus(t, resp, 404)
 }
+
+func TestLogical_StandbyRedirect(t *testing.T) {
+	ln1, addr1 := TestListener(t)
+	defer ln1.Close()
+	ln2, addr2 := TestListener(t)
+	defer ln2.Close()
+
+	// Create an HA Vault
+	inm := physical.NewInmemHA()
+	conf := &vault.CoreConfig{Physical: inm, AdvertiseAddr: addr1}
+	core1, err := vault.NewCore(conf)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	key, root := vault.TestCoreInit(t, core1)
+	if _, err := core1.Unseal(vault.TestKeyCopy(key)); err != nil {
+		t.Fatalf("unseal err: %s", err)
+	}
+
+	// Create a second HA Vault
+	conf2 := &vault.CoreConfig{Physical: inm, AdvertiseAddr: addr2}
+	core2, err := vault.NewCore(conf2)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if _, err := core2.Unseal(vault.TestKeyCopy(key)); err != nil {
+		t.Fatalf("unseal err: %s", err)
+	}
+
+	TestServerWithListener(t, ln1, addr1, core1)
+	TestServerWithListener(t, ln2, addr2, core2)
+	TestServerAuth(t, addr1, root)
+
+	// WRITE to STANDBY
+	resp := testHttpPut(t, addr2+"/v1/secret/foo", map[string]interface{}{
+		"data": "bar",
+	})
+	testResponseStatus(t, resp, 307)
+
+	//// READ to standby
+	resp, err = http.Get(addr2 + "/v1/auth/token/lookup-self")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	var actual map[string]interface{}
+	expected := map[string]interface{}{
+		"renewable":      false,
+		"lease_duration": float64(0),
+		"data": map[string]interface{}{
+			"meta":         nil,
+			"num_uses":     float64(0),
+			"path":         "auth/token/root",
+			"policies":     []interface{}{"root"},
+			"display_name": "root",
+			"id":           root,
+		},
+		"auth": nil,
+	}
+	testResponseStatus(t, resp, 200)
+	testResponseBody(t, resp, &actual)
+	delete(actual, "lease_id")
+	if !reflect.DeepEqual(actual, expected) {
+		t.Fatalf("bad: %#v %#v", actual, expected)
+	}
+
+	//// DELETE to standby
+	resp = testHttpDelete(t, addr2+"/v1/secret/foo")
+	testResponseStatus(t, resp, 307)
+}

http/sys_lease.go

@@ -37,7 +37,7 @@ func handleSysRenew(core *vault.Core) http.Handler {
 			}
 		}
 
-		resp, ok := request(core, w, requestAuth(r, &logical.Request{
+		resp, ok := request(core, w, r.URL, requestAuth(r, &logical.Request{
 			Operation: logical.WriteOperation,
 			Path:      "sys/renew/" + path,
 			Data: map[string]interface{}{

http/sys_policy.go

@@ -15,7 +15,7 @@ func handleSysListPolicies(core *vault.Core) http.Handler {
 			return
 		}
 
-		resp, ok := request(core, w, requestAuth(r, &logical.Request{
+		resp, ok := request(core, w, r.URL, requestAuth(r, &logical.Request{
 			Operation: logical.ReadOperation,
 			Path:      "sys/policy",
 		}))
@@ -64,7 +64,7 @@ func handleSysDeletePolicy(core *vault.Core, w http.ResponseWriter, r *http.Requ
 		return
 	}
 
-	_, ok := request(core, w, requestAuth(r, &logical.Request{
+	_, ok := request(core, w, r.URL, requestAuth(r, &logical.Request{
 		Operation: logical.DeleteOperation,
 		Path:      "sys/policy/" + path,
 	}))
@@ -88,7 +88,7 @@ func handleSysReadPolicy(core *vault.Core, w http.ResponseWriter, r *http.Reques
 		return
 	}
 
-	resp, ok := request(core, w, requestAuth(r, &logical.Request{
+	resp, ok := request(core, w, r.URL, requestAuth(r, &logical.Request{
 		Operation: logical.ReadOperation,
 		Path:      "sys/policy/" + path,
 	}))
@@ -119,7 +119,7 @@ func handleSysWritePolicy(core *vault.Core, w http.ResponseWriter, r *http.Reque
 		return
 	}
 
-	_, ok := request(core, w, requestAuth(r, &logical.Request{
+	_, ok := request(core, w, r.URL, requestAuth(r, &logical.Request{
 		Operation: logical.WriteOperation,
 		Path:      "sys/policy/" + path,
 		Data: map[string]interface{}{