Make tests for syslog_batch more reliable

This change introduces to reduce the default batch size for testing.
This will make it less cpu intensive to perform the testcases in
short timeframes.

It also replaces most sleeps with Consistently and Eventually.
It makes the timings more forgiving.

This should make it reliable on weak hardware.

src/pkg/egress/syslog/https_batch.go

@@ -11,8 +11,7 @@ import (
 	"code.cloudfoundry.org/loggregator-agent-release/src/pkg/egress"
 )
 
-const BATCHSIZE = 256 * 1024
-
+var DefaultBatchSize = 256 * 1024
 var DefaultSendInterval = 1 * time.Second
 
 type HTTPSBatchWriter struct {
@@ -41,7 +40,7 @@ func NewHTTPSBatchWriter(
 			egressMetric:    egressMetric,
 			syslogConverter: c,
 		},
-		batchSize:    BATCHSIZE,
+		batchSize:    DefaultBatchSize,
 		sendInterval: DefaultSendInterval,
 		egrMsgCount:  0,
 		msgs:         make(chan []byte),

src/pkg/egress/syslog/https_batch_test.go

@@ -17,10 +17,17 @@ import (
 	. "github.com/onsi/gomega"
 )
 
-var string_to_1024_chars = "saljdflajsdssdfsdfljkfkajafjajlköflkjöjaklgljksdjlakljkflkjweljklkwjejlkfekljwlkjefjklwjklsdajkljklwerlkaskldgjksakjekjwrjkljasdjkgfkljwejklrkjlklasdkjlsadjlfjlkadfljkajklsdfjklslkdfjkllkjasdjkflsdlakfjklasldfkjlasdjfkjlsadlfjklaljsafjlslkjawjklerkjljklasjkdfjklwerjljalsdjkflwerjlkwejlkarjklalkklfsdjlfhkjsdfkhsewhkjjasdjfkhwkejrkjahjefkhkasdjhfkashfkjwehfkksadfjaskfkhjdshjfhewkjhasdfjdajskfjwehkfajkankaskjdfasdjhfkkjhjjkasdfjhkjahksdf"
+var string_to_256_chars string
 
 func init() {
-	syslog.DefaultSendInterval = 100 * time.Millisecond // Modify behavior for tests
+	// Modify behavior for tests
+	syslog.DefaultSendInterval = 100 * time.Millisecond
+	syslog.DefaultBatchSize = 5000
+
+	//With the rest of the syslog, this results in a syslogenvelope of the size 400
+	for i := 0; i < 256; i++ {
+		string_to_256_chars += "a"
+	}
 }
 
 var _ = Describe("HTTPS_batch", func() {
@@ -34,10 +41,10 @@ var _ = Describe("HTTPS_batch", func() {
 		b      *syslog.URLBinding
 		writer egress.WriteCloser
 	)
-	string_to_1024_chars += string_to_1024_chars
 
 	BeforeEach(func() {
 		drain = newBatchMockDrain(200)
+		drain.Reset()
 		b = buildURLBinding(
 			drain.URL,
 			"test-app-id",
@@ -57,7 +64,7 @@ var _ = Describe("HTTPS_batch", func() {
 		Expect(writer.Write(env1)).To(Succeed())
 		env2 := buildLogEnvelope("APP", "2", "message 2", loggregator_v2.Log_OUT)
 		Expect(writer.Write(env2)).To(Succeed())
-		time.Sleep(1050 * time.Millisecond)
+		time.Sleep(150 * time.Millisecond)
 
 		Expect(drain.getMessagesSize()).Should(Equal(2))
 		expected := &rfc5424.Message{
@@ -87,24 +94,25 @@ var _ = Describe("HTTPS_batch", func() {
 	})
 
 	It("test batch dispatching with all logs in a given timeframe", func() {
-		env1 := buildLogEnvelope("APP", "1", "string to get log to 1024 characters:"+string_to_1024_chars, loggregator_v2.Log_OUT)
+		env1 := buildLogEnvelope("APP", "1", "string to get log to 400 characters:"+string_to_256_chars, loggregator_v2.Log_OUT)
 		for i := 0; i < 10; i++ {
 			Expect(writer.Write(env1)).To(Succeed())
-			time.Sleep(5 * time.Millisecond)
 		}
-		Expect(drain.getMessagesSize()).Should(Equal(0))
-		time.Sleep(100 * time.Millisecond)
-		Expect(drain.getMessagesSize()).Should(Equal(10))
+		Expect(drain.getMessagesSize()).To(Equal(0))
+		Eventually(drain.getMessagesSize, 180*time.Millisecond).Should(Equal(10))
 	})
 
 	It("test dispatching for batches before timewindow is finished", func() {
-		env1 := buildLogEnvelope("APP", "1", "string to get log to 1024 characters:"+string_to_1024_chars, loggregator_v2.Log_OUT)
-		for i := 0; i < 300; i++ {
+		// One envelope has the size of 400byte
+		env1 := buildLogEnvelope("APP", "1", "string to get log to 400 characters:"+string_to_256_chars, loggregator_v2.Log_OUT)
+
+		for i := 0; i < 20; i++ {
 			Expect(writer.Write(env1)).To(Succeed())
 		}
-		Expect(drain.getMessagesSize()).Should(Equal(256))
-		time.Sleep(101 * time.Millisecond)
-		Expect(drain.getMessagesSize()).Should(Equal(300))
+		// DefaultBatchSize = 5000byte, 12 * 400byte = 4800byte, 13 * 400byte = 5200byte
+		// -> The batch will trigger after 13 messages, and this is not a direct hit to prevent inconsistencies.
+		Expect(drain.getMessagesSize()).Should(Equal(13))
+		Eventually(drain.getMessagesSize, 120*time.Millisecond).Should(Equal(20))
 	})
 
 	It("test for hanging after some ticks", func() {
@@ -113,10 +121,9 @@ var _ = Describe("HTTPS_batch", func() {
 		env1 := buildLogEnvelope("APP", "1", "only a short test message", loggregator_v2.Log_OUT)
 		for i := 0; i < 5; i++ {
 			Expect(writer.Write(env1)).To(Succeed())
-			time.Sleep(300 * time.Millisecond)
+			time.Sleep(220 * time.Millisecond) // this sleeps at least 2 ticks, to trigger once without events
 		}
-		time.Sleep(101 * time.Millisecond)
-		Expect(drain.getMessagesSize()).Should(Equal(5))
+		Eventually(drain.getMessagesSize, 120*time.Millisecond).Should(Equal(5))
 	})
 })
 
@@ -128,8 +135,6 @@ func newBatchMockDrain(status int) *SpyDrain {
 		Expect(err).ToNot(HaveOccurred())
 		defer r.Body.Close()
 
-		println(body)
-
 		message := &rfc5424.Message{}
 
 		messages := bytes.SplitAfter(body, []byte("\n"))

src/pkg/egress/syslog/https_test.go

@@ -251,6 +251,11 @@ type SpyDrain struct {
 	headers  []http.Header
 }
 
+func (d *SpyDrain) Reset() {
+	d.messages = nil
+	d.headers = nil
+}
+
 func (d *SpyDrain) appendMessage(message *rfc5424.Message) {
 	d.mu.Lock()
 	defer d.mu.Unlock()