utils/broadcastwriter -> pkg/broadcastwriter

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)

broadcastwriter/broadcastwriter_test.go

@@ -0,0 +1,144 @@
+package broadcastwriter
+
+import (
+	"bytes"
+	"errors"
+
+	"testing"
+)
+
+type dummyWriter struct {
+	buffer      bytes.Buffer
+	failOnWrite bool
+}
+
+func (dw *dummyWriter) Write(p []byte) (n int, err error) {
+	if dw.failOnWrite {
+		return 0, errors.New("Fake fail")
+	}
+	return dw.buffer.Write(p)
+}
+
+func (dw *dummyWriter) String() string {
+	return dw.buffer.String()
+}
+
+func (dw *dummyWriter) Close() error {
+	return nil
+}
+
+func TestBroadcastWriter(t *testing.T) {
+	writer := New()
+
+	// Test 1: Both bufferA and bufferB should contain "foo"
+	bufferA := &dummyWriter{}
+	writer.AddWriter(bufferA, "")
+	bufferB := &dummyWriter{}
+	writer.AddWriter(bufferB, "")
+	writer.Write([]byte("foo"))
+
+	if bufferA.String() != "foo" {
+		t.Errorf("Buffer contains %v", bufferA.String())
+	}
+
+	if bufferB.String() != "foo" {
+		t.Errorf("Buffer contains %v", bufferB.String())
+	}
+
+	// Test2: bufferA and bufferB should contain "foobar",
+	// while bufferC should only contain "bar"
+	bufferC := &dummyWriter{}
+	writer.AddWriter(bufferC, "")
+	writer.Write([]byte("bar"))
+
+	if bufferA.String() != "foobar" {
+		t.Errorf("Buffer contains %v", bufferA.String())
+	}
+
+	if bufferB.String() != "foobar" {
+		t.Errorf("Buffer contains %v", bufferB.String())
+	}
+
+	if bufferC.String() != "bar" {
+		t.Errorf("Buffer contains %v", bufferC.String())
+	}
+
+	// Test3: Test eviction on failure
+	bufferA.failOnWrite = true
+	writer.Write([]byte("fail"))
+	if bufferA.String() != "foobar" {
+		t.Errorf("Buffer contains %v", bufferA.String())
+	}
+	if bufferC.String() != "barfail" {
+		t.Errorf("Buffer contains %v", bufferC.String())
+	}
+	// Even though we reset the flag, no more writes should go in there
+	bufferA.failOnWrite = false
+	writer.Write([]byte("test"))
+	if bufferA.String() != "foobar" {
+		t.Errorf("Buffer contains %v", bufferA.String())
+	}
+	if bufferC.String() != "barfailtest" {
+		t.Errorf("Buffer contains %v", bufferC.String())
+	}
+
+	writer.Clean()
+}
+
+type devNullCloser int
+
+func (d devNullCloser) Close() error {
+	return nil
+}
+
+func (d devNullCloser) Write(buf []byte) (int, error) {
+	return len(buf), nil
+}
+
+// This test checks for races. It is only useful when run with the race detector.
+func TestRaceBroadcastWriter(t *testing.T) {
+	writer := New()
+	c := make(chan bool)
+	go func() {
+		writer.AddWriter(devNullCloser(0), "")
+		c <- true
+	}()
+	writer.Write([]byte("hello"))
+	<-c
+}
+
+func BenchmarkBroadcastWriter(b *testing.B) {
+	writer := New()
+	setUpWriter := func() {
+		for i := 0; i < 100; i++ {
+			writer.AddWriter(devNullCloser(0), "stdout")
+			writer.AddWriter(devNullCloser(0), "stderr")
+			writer.AddWriter(devNullCloser(0), "")
+		}
+	}
+	testLine := "Line that thinks that it is log line from docker"
+	var buf bytes.Buffer
+	for i := 0; i < 100; i++ {
+		buf.Write([]byte(testLine + "\n"))
+	}
+	// line without eol
+	buf.Write([]byte(testLine))
+	testText := buf.Bytes()
+	b.SetBytes(int64(5 * len(testText)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		setUpWriter()
+		b.StartTimer()
+
+		for j := 0; j < 5; j++ {
+			if _, err := writer.Write(testText); err != nil {
+				b.Fatal(err)
+			}
+		}
+
+		b.StopTimer()
+		writer.Clean()
+		b.StartTimer()
+	}
+}