rename all remaining packages to internal/ (#12418)

This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`

internal/dsync/dsync_test.go

@@ -0,0 +1,430 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package dsync
+
+import (
+	"context"
+	"fmt"
+	golog "log"
+	"math/rand"
+	"net"
+	"net/http"
+	"net/rpc"
+	"os"
+	"strconv"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+)
+
+const numberOfNodes = 5
+
+var ds *Dsync
+var rpcPaths []string // list of rpc paths where lock server is serving.
+
+var nodes = make([]string, numberOfNodes) // list of node IP addrs or hostname with ports.
+var lockServers []*lockServer
+
+func startRPCServers() {
+	for i := range nodes {
+		server := rpc.NewServer()
+		ls := &lockServer{
+			mutex:   sync.Mutex{},
+			lockMap: make(map[string]int64),
+		}
+		server.RegisterName("Dsync", ls)
+		// For some reason the registration paths need to be different (even for different server objs)
+		server.HandleHTTP(rpcPaths[i], fmt.Sprintf("%s-debug", rpcPaths[i]))
+		l, e := net.Listen("tcp", ":"+strconv.Itoa(i+12345))
+		if e != nil {
+			golog.Fatal("listen error:", e)
+		}
+		go http.Serve(l, nil)
+
+		lockServers = append(lockServers, ls)
+	}
+
+	// Let servers start
+	time.Sleep(10 * time.Millisecond)
+}
+
+// TestMain initializes the testing framework
+func TestMain(m *testing.M) {
+	const rpcPath = "/dsync"
+
+	rand.Seed(time.Now().UTC().UnixNano())
+
+	for i := range nodes {
+		nodes[i] = fmt.Sprintf("127.0.0.1:%d", i+12345)
+	}
+	for i := range nodes {
+		rpcPaths = append(rpcPaths, rpcPath+"-"+strconv.Itoa(i))
+	}
+
+	// Initialize net/rpc clients for dsync.
+	var clnts []NetLocker
+	for i := 0; i < len(nodes); i++ {
+		clnts = append(clnts, newClient(nodes[i], rpcPaths[i]))
+	}
+
+	ds = &Dsync{
+		GetLockers: func() ([]NetLocker, string) { return clnts, uuid.New().String() },
+	}
+
+	startRPCServers()
+
+	os.Exit(m.Run())
+}
+
+func TestSimpleLock(t *testing.T) {
+
+	dm := NewDRWMutex(ds, "test")
+
+	dm.Lock(id, source)
+
+	// fmt.Println("Lock acquired, waiting...")
+	time.Sleep(2500 * time.Millisecond)
+
+	dm.Unlock()
+}
+
+func TestSimpleLockUnlockMultipleTimes(t *testing.T) {
+
+	dm := NewDRWMutex(ds, "test")
+
+	dm.Lock(id, source)
+	time.Sleep(time.Duration(10+(rand.Float32()*50)) * time.Millisecond)
+	dm.Unlock()
+
+	dm.Lock(id, source)
+	time.Sleep(time.Duration(10+(rand.Float32()*50)) * time.Millisecond)
+	dm.Unlock()
+
+	dm.Lock(id, source)
+	time.Sleep(time.Duration(10+(rand.Float32()*50)) * time.Millisecond)
+	dm.Unlock()
+
+	dm.Lock(id, source)
+	time.Sleep(time.Duration(10+(rand.Float32()*50)) * time.Millisecond)
+	dm.Unlock()
+
+	dm.Lock(id, source)
+	time.Sleep(time.Duration(10+(rand.Float32()*50)) * time.Millisecond)
+	dm.Unlock()
+}
+
+// Test two locks for same resource, one succeeds, one fails (after timeout)
+func TestTwoSimultaneousLocksForSameResource(t *testing.T) {
+
+	dm1st := NewDRWMutex(ds, "aap")
+	dm2nd := NewDRWMutex(ds, "aap")
+
+	dm1st.Lock(id, source)
+
+	// Release lock after 10 seconds
+	go func() {
+		time.Sleep(10 * time.Second)
+		// fmt.Println("Unlocking dm1")
+
+		dm1st.Unlock()
+	}()
+
+	dm2nd.Lock(id, source)
+
+	// fmt.Printf("2nd lock obtained after 1st lock is released\n")
+	time.Sleep(2500 * time.Millisecond)
+
+	dm2nd.Unlock()
+}
+
+// Test three locks for same resource, one succeeds, one fails (after timeout)
+func TestThreeSimultaneousLocksForSameResource(t *testing.T) {
+
+	dm1st := NewDRWMutex(ds, "aap")
+	dm2nd := NewDRWMutex(ds, "aap")
+	dm3rd := NewDRWMutex(ds, "aap")
+
+	dm1st.Lock(id, source)
+
+	// Release lock after 10 seconds
+	go func() {
+		time.Sleep(10 * time.Second)
+		// fmt.Println("Unlocking dm1")
+
+		dm1st.Unlock()
+	}()
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	go func() {
+		defer wg.Done()
+
+		dm2nd.Lock(id, source)
+
+		// Release lock after 10 seconds
+		go func() {
+			time.Sleep(2500 * time.Millisecond)
+			// fmt.Println("Unlocking dm2")
+
+			dm2nd.Unlock()
+		}()
+
+		dm3rd.Lock(id, source)
+
+		// fmt.Printf("3rd lock obtained after 1st & 2nd locks are released\n")
+		time.Sleep(2500 * time.Millisecond)
+
+		dm3rd.Unlock()
+	}()
+
+	go func() {
+		defer wg.Done()
+
+		dm3rd.Lock(id, source)
+
+		// Release lock after 10 seconds
+		go func() {
+			time.Sleep(2500 * time.Millisecond)
+			// fmt.Println("Unlocking dm3")
+
+			dm3rd.Unlock()
+		}()
+
+		dm2nd.Lock(id, source)
+
+		// fmt.Printf("2nd lock obtained after 1st & 3rd locks are released\n")
+		time.Sleep(2500 * time.Millisecond)
+
+		dm2nd.Unlock()
+	}()
+
+	wg.Wait()
+}
+
+// Test two locks for different resources, both succeed
+func TestTwoSimultaneousLocksForDifferentResources(t *testing.T) {
+
+	dm1 := NewDRWMutex(ds, "aap")
+	dm2 := NewDRWMutex(ds, "noot")
+
+	dm1.Lock(id, source)
+	dm2.Lock(id, source)
+
+	// fmt.Println("Both locks acquired, waiting...")
+	time.Sleep(2500 * time.Millisecond)
+
+	dm1.Unlock()
+	dm2.Unlock()
+
+	time.Sleep(10 * time.Millisecond)
+}
+
+// Test refreshing lock
+func TestFailedRefreshLock(t *testing.T) {
+	// Simulate Refresh RPC response to return no locking found
+	for i := range lockServers {
+		lockServers[i].setRefreshReply(false)
+		defer lockServers[i].setRefreshReply(true)
+	}
+
+	dm := NewDRWMutex(ds, "aap")
+	wg := sync.WaitGroup{}
+	wg.Add(1)
+
+	ctx, cl := context.WithCancel(context.Background())
+	cancel := func() {
+		cl()
+		wg.Done()
+	}
+
+	if !dm.GetLock(ctx, cancel, id, source, Options{Timeout: 5 * time.Minute}) {
+		t.Fatal("GetLock() should be successful")
+	}
+
+	// Wait until context is canceled
+	wg.Wait()
+	if ctx.Err() == nil {
+		t.Fatal("Unexpected error", ctx.Err())
+	}
+
+	// Should be safe operation in all cases
+	dm.Unlock()
+}
+
+// Test Unlock should not timeout
+func TestUnlockShouldNotTimeout(t *testing.T) {
+	dm := NewDRWMutex(ds, "aap")
+
+	if !dm.GetLock(context.Background(), nil, id, source, Options{Timeout: 5 * time.Minute}) {
+		t.Fatal("GetLock() should be successful")
+	}
+
+	// Add delay to lock server responses to ensure that lock does not timeout
+	for i := range lockServers {
+		lockServers[i].setResponseDelay(2 * drwMutexUnlockCallTimeout)
+		defer lockServers[i].setResponseDelay(0)
+	}
+
+	unlockReturned := make(chan struct{}, 1)
+	go func() {
+		dm.Unlock()
+		unlockReturned <- struct{}{}
+	}()
+
+	timer := time.NewTimer(2 * drwMutexUnlockCallTimeout)
+	defer timer.Stop()
+
+	select {
+	case <-unlockReturned:
+		t.Fatal("Unlock timed out, which should not happen")
+	case <-timer.C:
+	}
+}
+
+// Borrowed from mutex_test.go
+func HammerMutex(m *DRWMutex, loops int, cdone chan bool) {
+	for i := 0; i < loops; i++ {
+		m.Lock(id, source)
+		m.Unlock()
+	}
+	cdone <- true
+}
+
+// Borrowed from mutex_test.go
+func TestMutex(t *testing.T) {
+	loops := 200
+	if testing.Short() {
+		loops = 5
+	}
+	c := make(chan bool)
+	m := NewDRWMutex(ds, "test")
+	for i := 0; i < 10; i++ {
+		go HammerMutex(m, loops, c)
+	}
+	for i := 0; i < 10; i++ {
+		<-c
+	}
+}
+
+func BenchmarkMutexUncontended(b *testing.B) {
+	type PaddedMutex struct {
+		*DRWMutex
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		var mu = PaddedMutex{NewDRWMutex(ds, "")}
+		for pb.Next() {
+			mu.Lock(id, source)
+			mu.Unlock()
+		}
+	})
+}
+
+func benchmarkMutex(b *testing.B, slack, work bool) {
+	mu := NewDRWMutex(ds, "")
+	if slack {
+		b.SetParallelism(10)
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		foo := 0
+		for pb.Next() {
+			mu.Lock(id, source)
+			mu.Unlock()
+			if work {
+				for i := 0; i < 100; i++ {
+					foo *= 2
+					foo /= 2
+				}
+			}
+		}
+		_ = foo
+	})
+}
+
+func BenchmarkMutex(b *testing.B) {
+	benchmarkMutex(b, false, false)
+}
+
+func BenchmarkMutexSlack(b *testing.B) {
+	benchmarkMutex(b, true, false)
+}
+
+func BenchmarkMutexWork(b *testing.B) {
+	benchmarkMutex(b, false, true)
+}
+
+func BenchmarkMutexWorkSlack(b *testing.B) {
+	benchmarkMutex(b, true, true)
+}
+
+func BenchmarkMutexNoSpin(b *testing.B) {
+	// This benchmark models a situation where spinning in the mutex should be
+	// non-profitable and allows to confirm that spinning does not do harm.
+	// To achieve this we create excess of goroutines most of which do local work.
+	// These goroutines yield during local work, so that switching from
+	// a blocked goroutine to other goroutines is profitable.
+	// As a matter of fact, this benchmark still triggers some spinning in the mutex.
+	m := NewDRWMutex(ds, "")
+	var acc0, acc1 uint64
+	b.SetParallelism(4)
+	b.RunParallel(func(pb *testing.PB) {
+		c := make(chan bool)
+		var data [4 << 10]uint64
+		for i := 0; pb.Next(); i++ {
+			if i%4 == 0 {
+				m.Lock(id, source)
+				acc0 -= 100
+				acc1 += 100
+				m.Unlock()
+			} else {
+				for i := 0; i < len(data); i += 4 {
+					data[i]++
+				}
+				// Elaborate way to say runtime.Gosched
+				// that does not put the goroutine onto global runq.
+				go func() {
+					c <- true
+				}()
+				<-c
+			}
+		}
+	})
+}
+
+func BenchmarkMutexSpin(b *testing.B) {
+	// This benchmark models a situation where spinning in the mutex should be
+	// profitable. To achieve this we create a goroutine per-proc.
+	// These goroutines access considerable amount of local data so that
+	// unnecessary rescheduling is penalized by cache misses.
+	m := NewDRWMutex(ds, "")
+	var acc0, acc1 uint64
+	b.RunParallel(func(pb *testing.PB) {
+		var data [16 << 10]uint64
+		for i := 0; pb.Next(); i++ {
+			m.Lock(id, source)
+			acc0 -= 100
+			acc1 += 100
+			m.Unlock()
+			for i := 0; i < len(data); i += 4 {
+				data[i]++
+			}
+		}
+	})
+}