Leader redirection almost complete

cmd/rqlited/main.go

@@ -33,6 +33,7 @@ var raftAddr string
 var joinAddr string
 var dsn string
 var inMem bool
+var disRedirect bool
 var cpuprofile string
 
 const desc = `rqlite is a distributed system that provides a replicated SQLite database.`
@@ -43,6 +44,7 @@ func init() {
 	flag.StringVar(&joinAddr, "join", "", "host:port of leader to join")
 	flag.StringVar(&dsn, "dsn", "", `SQLite DSN parameters. E.g. "cache=shared&mode=memory"`)
 	flag.BoolVar(&inMem, "mem", false, "Use an in-memory database")
+	flag.BoolVar(&disRedirect, "noredir", false, "Disable leader-redirect")
 	flag.StringVar(&cpuprofile, "cpuprofile", "", "Write CPU profile to file")
 	flag.Usage = func() {
 		fmt.Fprintf(os.Stderr, "\n%s\n\n", desc)
@@ -101,6 +103,7 @@ func main() {
 
 	// Create the HTTP query server.
 	s := httpd.New(httpAddr, store)
+	s.DisableRedirect = disRedirect
 	if err := s.Start(); err != nil {
 		log.Fatalf("failed to start HTTP server: %s", err.Error())
 

http/service.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	sql "github.com/otoolep/rqlite/db"
+	"github.com/otoolep/rqlite/store"
 )
 
 // Store is the interface the Raft-driven database must implement.
@@ -62,6 +63,8 @@ type Service struct {
 	store Store // The Raft-backed database store.
 
 	lastBackup time.Time // Time of last successful backup.
+
+	DisableRedirect bool // Disable leader-redirection.
 }
 
 // New returns an uninitialized HTTP service.
@@ -248,8 +251,11 @@ func (s *Service) handleExecute(w http.ResponseWriter, r *http.Request) {
 
 	results, err := s.store.Execute(queries, isTx)
 	if err != nil {
+		if err == store.ErrNotLeader && !s.DisableRedirect {
+			http.Redirect(w, r, s.store.Leader(), http.StatusTemporaryRedirect)
+			return
+		}
 		resp.Error = err.Error()
-
 	} else {
 		resp.Results = results
 	}
@@ -309,8 +315,11 @@ func (s *Service) handleQuery(w http.ResponseWriter, r *http.Request) {
 
 	results, err := s.store.Query(queries, isTx, !noLeader, verify)
 	if err != nil {
+		if err == store.ErrNotLeader && !s.DisableRedirect {
+			http.Redirect(w, r, s.store.Leader(), http.StatusTemporaryRedirect)
+			return
+		}
 		resp.Error = err.Error()
-
 	} else {
 		resp.Results = results
 	}

store/store.go

@@ -6,6 +6,7 @@ package store
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -224,7 +225,7 @@ func (s *Store) Stats() (map[string]interface{}, error) {
 // Execute executes queries that return no rows, but do modify the database.
 func (s *Store) Execute(queries []string, tx bool) ([]*sql.Result, error) {
 	if s.raft.State() != raft.Leader {
-		return nil, fmt.Errorf("not leader")
+		return nil, ErrNotLeader
 	}
 
 	c := &command{
@@ -276,7 +277,7 @@ func (s *Store) Query(queries []string, tx, leader, verify bool) ([]*sql.Rows, e
 	defer s.mu.RUnlock()
 
 	if leader && s.raft.State() != raft.Leader {
-		return nil, fmt.Errorf("not leader")
+		return nil, ErrNotLeader
 	}
 
 	if verify {