update

Makefile

@@ -9,7 +9,7 @@ LABS=" lab1 lab2a lab2b lab2c lab2d lab3a lab3b lab4a lab4b "
 	@echo "Preparing $@-handin.tar.gz"
 	@if echo $(LABS) | grep -q " $@ " ; then \
 		echo "Tarring up your submission..." ; \
-		tar cvzf $@-handin.tar.gz \
+		COPYFILE_DISABLE=1 tar cvzf $@-handin.tar.gz \
 			"--exclude=src/main/pg-*.txt" \
 			"--exclude=src/main/diskvd" \
 			"--exclude=src/mapreduce/824-mrinput-*.txt" \

src/shardctrler/config.go

@@ -301,9 +301,11 @@ func (cfg *config) Leader() (bool, int) {
 	defer cfg.mu.Unlock()
 
 	for i := 0; i < cfg.n; i++ {
-		_, is_leader := cfg.servers[i].rf.GetState()
+		if cfg.servers[i] != nil {
-		if is_leader {
+			_, is_leader := cfg.servers[i].rf.GetState()
-			return true, i
+			if is_leader {
+				return true, i
+			}
 		}
 	}
 	return false, 0

src/shardctrler/server.go

@@ -59,7 +59,7 @@ func (sc *ShardCtrler) Raft() *raft.Raft {
 
 //
 // servers[] contains the ports of the set of
-// servers that will cooperate via Paxos to
+// servers that will cooperate via Raft to
 // form the fault-tolerant shardctrler service.
 // me is the index of the current server in servers[].
 //

src/shardctrler/test_test.go

@@ -1,12 +1,13 @@
 package shardctrler
 
 import (
+	"fmt"
 	"sync"
 	"testing"
+	"time"
 )
 
 // import "time"
-import "fmt"
 
 func check(t *testing.T, groups []int, ck *Clerk) {
 	c := ck.Query(-1)
@@ -377,4 +378,26 @@ func TestMulti(t *testing.T) {
 	}
 
 	fmt.Printf("  ... Passed\n")
+
+	fmt.Printf("Test: Check Same config on servers ...\n")
+
+	isLeader, leader := cfg.Leader()
+	if !isLeader {
+		t.Fatalf("Leader not found")
+	}
+	c := ck.Query(-1) // Config leader claims
+
+	cfg.ShutdownServer(leader)
+
+	attempts := 0
+	for isLeader, leader = cfg.Leader(); isLeader; time.Sleep(1 * time.Second) {
+		if attempts++; attempts >= 3 {
+			t.Fatalf("Leader not found")
+		}
+	}
+
+	c1 = ck.Query(-1)
+	check_same_config(t, c, c1)
+
+	fmt.Printf("  ... Passed\n")
 }

src/shardkv/common.go

@@ -2,7 +2,7 @@ package shardkv
 
 //
 // Sharded key/value server.
-// Lots of replica groups, each running op-at-a-time paxos.
+// Lots of replica groups, each running Raft.
 // Shardctrler decides which group serves each shard.
 // Shardctrler may change shard assignment from time to time.
 //

src/shardkv/test_test.go

@@ -453,6 +453,74 @@ func TestConcurrent2(t *testing.T) {
 	fmt.Printf("  ... Passed\n")
 }
 
+func TestConcurrent3(t *testing.T) {
+	fmt.Printf("Test: concurrent configuration change and restart...\n")
+
+	cfg := make_config(t, 3, false, 300)
+	defer cfg.cleanup()
+
+	ck := cfg.makeClient()
+
+	cfg.join(0)
+
+	n := 10
+	ka := make([]string, n)
+	va := make([]string, n)
+	for i := 0; i < n; i++ {
+		ka[i] = strconv.Itoa(i)
+		va[i] = randstring(1)
+		ck.Put(ka[i], va[i])
+	}
+
+	var done int32
+	ch := make(chan bool)
+
+	ff := func(i int, ck1 *Clerk) {
+		defer func() { ch <- true }()
+		for atomic.LoadInt32(&done) == 0 {
+			x := randstring(1)
+			ck1.Append(ka[i], x)
+			va[i] += x
+		}
+	}
+
+	for i := 0; i < n; i++ {
+		ck1 := cfg.makeClient()
+		go ff(i, ck1)
+	}
+
+	t0 := time.Now()
+	for time.Since(t0) < 12*time.Second {
+		cfg.join(2)
+		cfg.join(1)
+		time.Sleep(time.Duration(rand.Int()%900) * time.Millisecond)
+		cfg.ShutdownGroup(0)
+		cfg.ShutdownGroup(1)
+		cfg.ShutdownGroup(2)
+		cfg.StartGroup(0)
+		cfg.StartGroup(1)
+		cfg.StartGroup(2)
+
+		time.Sleep(time.Duration(rand.Int()%900) * time.Millisecond)
+		cfg.leave(1)
+		cfg.leave(2)
+		time.Sleep(time.Duration(rand.Int()%900) * time.Millisecond)
+	}
+
+	time.Sleep(2 * time.Second)
+
+	atomic.StoreInt32(&done, 1)
+	for i := 0; i < n; i++ {
+		<-ch
+	}
+
+	for i := 0; i < n; i++ {
+		check(t, ck, ka[i], va[i])
+	}
+
+	fmt.Printf("  ... Passed\n")
+}
+
 func TestUnreliable1(t *testing.T) {
 	fmt.Printf("Test: unreliable 1...\n")
 
@@ -748,74 +816,6 @@ func TestChallenge1Delete(t *testing.T) {
 	fmt.Printf("  ... Passed\n")
 }
 
-func TestChallenge1Concurrent(t *testing.T) {
-	fmt.Printf("Test: concurrent configuration change and restart (challenge 1)...\n")
-
-	cfg := make_config(t, 3, false, 300)
-	defer cfg.cleanup()
-
-	ck := cfg.makeClient()
-
-	cfg.join(0)
-
-	n := 10
-	ka := make([]string, n)
-	va := make([]string, n)
-	for i := 0; i < n; i++ {
-		ka[i] = strconv.Itoa(i)
-		va[i] = randstring(1)
-		ck.Put(ka[i], va[i])
-	}
-
-	var done int32
-	ch := make(chan bool)
-
-	ff := func(i int, ck1 *Clerk) {
-		defer func() { ch <- true }()
-		for atomic.LoadInt32(&done) == 0 {
-			x := randstring(1)
-			ck1.Append(ka[i], x)
-			va[i] += x
-		}
-	}
-
-	for i := 0; i < n; i++ {
-		ck1 := cfg.makeClient()
-		go ff(i, ck1)
-	}
-
-	t0 := time.Now()
-	for time.Since(t0) < 12*time.Second {
-		cfg.join(2)
-		cfg.join(1)
-		time.Sleep(time.Duration(rand.Int()%900) * time.Millisecond)
-		cfg.ShutdownGroup(0)
-		cfg.ShutdownGroup(1)
-		cfg.ShutdownGroup(2)
-		cfg.StartGroup(0)
-		cfg.StartGroup(1)
-		cfg.StartGroup(2)
-
-		time.Sleep(time.Duration(rand.Int()%900) * time.Millisecond)
-		cfg.leave(1)
-		cfg.leave(2)
-		time.Sleep(time.Duration(rand.Int()%900) * time.Millisecond)
-	}
-
-	time.Sleep(2 * time.Second)
-
-	atomic.StoreInt32(&done, 1)
-	for i := 0; i < n; i++ {
-		<-ch
-	}
-
-	for i := 0; i < n; i++ {
-		check(t, ck, ka[i], va[i])
-	}
-
-	fmt.Printf("  ... Passed\n")
-}
-
 //
 // optional test to see whether servers can handle
 // shards that are not affected by a config change