pools: unify constructor to NewResourcePool

Signed-off-by: Sugu Sougoumarane <ssougou@gmail.com>

go/pools/resource_pool.go

@@ -78,15 +78,12 @@ type resourceWrapper struct {
 // maxCap specifies the extent to which the pool can be resized
 // in the future through the SetCapacity function.
 // You cannot resize the pool beyond maxCap.
-// If a resource is unused beyond idleTimeout, it's discarded.
+// If a resource is unused beyond idleTimeout, it's replaced
+// with a new one.
 // An idleTimeout of 0 means that there is no timeout.
-func NewResourcePool(factory Factory, capacity, maxCap int, idleTimeout time.Duration) *ResourcePool {
-	return NewPrefilledResourcePool(factory, capacity, maxCap, idleTimeout, 0)
-}
-
-// NewPrefilledResourcePool creates a pre-filled resource pool.
-// prefillParallelism specifies how many resources can be opened in parallel.
-func NewPrefilledResourcePool(factory Factory, capacity, maxCap int, idleTimeout time.Duration, prefillParallelism int) *ResourcePool {
+// A non-zero value of prefillParallism causes the pool to be pre-filled.
+// The value specifies how many resources can be opened in parallel.
+func NewResourcePool(factory Factory, capacity, maxCap int, idleTimeout time.Duration, prefillParallelism int) *ResourcePool {
 	if capacity <= 0 || maxCap <= 0 || capacity > maxCap {
 		panic(errors.New("invalid/out of range capacity"))
 	}
@@ -229,7 +226,7 @@ func (rp *ResourcePool) get(ctx context.Context) (resource Resource, err error)
 // Put will return a resource to the pool. For every successful Get,
 // a corresponding Put is required. If you no longer need a resource,
 // you will need to call Put(nil) instead of returning the closed resource.
-// The will cause a new resource to be created in its place.
+// This will cause a new resource to be created in its place.
 func (rp *ResourcePool) Put(resource Resource) {
 	var wrapper resourceWrapper
 	if resource != nil {

go/pools/resource_pool_test.go

@@ -57,7 +57,7 @@ func TestOpen(t *testing.T) {
 	ctx := context.Background()
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(PoolFactory, 6, 6, time.Second)
+	p := NewResourcePool(PoolFactory, 6, 6, time.Second, 0)
 	p.SetCapacity(5)
 	var resources [10]Resource
 
@@ -197,12 +197,12 @@ func TestOpen(t *testing.T) {
 func TestPrefill(t *testing.T) {
 	lastID.Set(0)
 	count.Set(0)
-	p := NewPrefilledResourcePool(PoolFactory, 5, 5, time.Second, 1)
+	p := NewResourcePool(PoolFactory, 5, 5, time.Second, 1)
 	defer p.Close()
 	if p.Active() != 5 {
 		t.Errorf("p.Active(): %d, want 5", p.Active())
 	}
-	p = NewPrefilledResourcePool(FailFactory, 5, 5, time.Second, 1)
+	p = NewResourcePool(FailFactory, 5, 5, time.Second, 1)
 	defer p.Close()
 	if p.Active() != 0 {
 		t.Errorf("p.Active(): %d, want 0", p.Active())
@@ -213,7 +213,7 @@ func TestShrinking(t *testing.T) {
 	ctx := context.Background()
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(PoolFactory, 5, 5, time.Second)
+	p := NewResourcePool(PoolFactory, 5, 5, time.Second, 0)
 	var resources [10]Resource
 	// Leave one empty slot in the pool
 	for i := 0; i < 4; i++ {
@@ -352,7 +352,7 @@ func TestClosing(t *testing.T) {
 	ctx := context.Background()
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(PoolFactory, 5, 5, time.Second)
+	p := NewResourcePool(PoolFactory, 5, 5, time.Second, 0)
 	var resources [10]Resource
 	for i := 0; i < 5; i++ {
 		r, err := p.Get(ctx)
@@ -406,7 +406,7 @@ func TestIdleTimeout(t *testing.T) {
 	ctx := context.Background()
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(PoolFactory, 1, 1, 10*time.Millisecond)
+	p := NewResourcePool(PoolFactory, 1, 1, 10*time.Millisecond, 0)
 	defer p.Close()
 
 	r, err := p.Get(ctx)
@@ -517,7 +517,7 @@ func TestIdleTimeoutCreateFail(t *testing.T) {
 	ctx := context.Background()
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(PoolFactory, 1, 1, 10*time.Millisecond)
+	p := NewResourcePool(PoolFactory, 1, 1, 10*time.Millisecond, 0)
 	defer p.Close()
 	r, err := p.Get(ctx)
 	if err != nil {
@@ -538,7 +538,7 @@ func TestCreateFail(t *testing.T) {
 	ctx := context.Background()
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(FailFactory, 5, 5, time.Second)
+	p := NewResourcePool(FailFactory, 5, 5, time.Second, 0)
 	defer p.Close()
 	if _, err := p.Get(ctx); err.Error() != "Failed" {
 		t.Errorf("Expecting Failed, received %v", err)
@@ -554,7 +554,7 @@ func TestCreateFailOnPut(t *testing.T) {
 	ctx := context.Background()
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(PoolFactory, 5, 5, time.Second)
+	p := NewResourcePool(PoolFactory, 5, 5, time.Second, 0)
 	defer p.Close()
 	_, err := p.Get(ctx)
 	if err != nil {
@@ -571,7 +571,7 @@ func TestSlowCreateFail(t *testing.T) {
 	ctx := context.Background()
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(SlowFailFactory, 2, 2, time.Second)
+	p := NewResourcePool(SlowFailFactory, 2, 2, time.Second, 0)
 	defer p.Close()
 	ch := make(chan bool)
 	// The third Get should not wait indefinitely
@@ -593,7 +593,7 @@ func TestTimeout(t *testing.T) {
 	ctx := context.Background()
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(PoolFactory, 1, 1, time.Second)
+	p := NewResourcePool(PoolFactory, 1, 1, time.Second, 0)
 	defer p.Close()
 	r, err := p.Get(ctx)
 	if err != nil {
@@ -612,7 +612,7 @@ func TestTimeout(t *testing.T) {
 func TestExpired(t *testing.T) {
 	lastID.Set(0)
 	count.Set(0)
-	p := NewResourcePool(PoolFactory, 1, 1, time.Second)
+	p := NewResourcePool(PoolFactory, 1, 1, time.Second, 0)
 	defer p.Close()
 	ctx, cancel := context.WithDeadline(context.Background(), time.Now().Add(-1*time.Second))
 	r, err := p.Get(ctx)

go/vt/dbconnpool/connection_pool.go

@@ -145,7 +145,7 @@ func (cp *ConnectionPool) Open(info *mysql.ConnParams, mysqlStats *stats.Timings
 	defer cp.mu.Unlock()
 	cp.info = info
 	cp.mysqlStats = mysqlStats
-	cp.connections = pools.NewResourcePool(cp.connect, cp.capacity, cp.capacity, cp.idleTimeout)
+	cp.connections = pools.NewResourcePool(cp.connect, cp.capacity, cp.capacity, cp.idleTimeout, 0)
 	// Check if we need to resolve a hostname (The Host is not just an IP  address).
 	if cp.resolutionFrequency > 0 && net.ParseIP(info.Host) == nil {
 		cp.hostIsNotIP = true
@@ -156,7 +156,7 @@ func (cp *ConnectionPool) Open(info *mysql.ConnParams, mysqlStats *stats.Timings
 			defer cp.wg.Done()
 			for {
 				select {
-				case _ = <-cp.ticker.C:
+				case <-cp.ticker.C:
 					cp.refreshdns()
 				case <-cp.stop:
 					return

go/vt/vttablet/tabletserver/connpool/pool.go

@@ -113,7 +113,7 @@ func (cp *Pool) Open(appParams, dbaParams, appDebugParams *mysql.ConnParams) {
 	f := func() (pools.Resource, error) {
 		return NewDBConn(cp, appParams)
 	}
-	cp.connections = pools.NewPrefilledResourcePool(f, cp.capacity, cp.capacity, cp.idleTimeout, cp.prefillParallelism)
+	cp.connections = pools.NewResourcePool(f, cp.capacity, cp.capacity, cp.idleTimeout, cp.prefillParallelism)
 	cp.appDebugParams = appDebugParams
 
 	cp.dbaPool.Open(dbaParams, tabletenv.MySQLStats)