From f16bef3495ec8e7b50eb620377ac6867fcceb3f2 Mon Sep 17 00:00:00 2001
From: Phillip Whelan <phil@calyptia.com>
Date: Wed, 4 Oct 2023 17:09:03 -0300
Subject: [PATCH] test: add latency test.

Signed-off-by: Phillip Whelan <phil@calyptia.com>
---
 cshared.go        | 14 +++++++
 cshared_test.go   | 98 +++++++++++++++++++++++++++++++++++++++++++++++
 output/decoder.go | 11 ++++++
 3 files changed, 123 insertions(+)

diff --git a/cshared.go b/cshared.go
index d465677..ee6aba5 100644
--- a/cshared.go
+++ b/cshared.go
@@ -139,6 +139,20 @@ func flbPluginReset() {
 	close(theChannel)
 }
 
+func testFLBPluginInputCallback() ([]byte, error) {
+	data := unsafe.Pointer(nil)
+	var csize C.size_t
+
+	FLBPluginInputCallback(&data, &csize)
+
+	if data == nil {
+		return []byte{}, nil
+	}
+
+	defer C.free(data)
+	return C.GoBytes(data, C.int(csize)), nil
+}
+
 // FLBPluginInputCallback this method gets invoked by the fluent-bit
 // runtime, once the plugin has been initialized, the plugin
 // implementation is responsible for handling the incoming data and the
diff --git a/cshared_test.go b/cshared_test.go
index 947a86b..74c4354 100644
--- a/cshared_test.go
+++ b/cshared_test.go
@@ -8,6 +8,8 @@ import (
 	"testing"
 	"time"
 	"unsafe"
+
+	"github.com/calyptia/plugin/output"
 )
 
 type testPluginInputCallbackCtrlC struct{}
@@ -173,6 +175,100 @@ func TestInputCallbackInfinite(t *testing.T) {
 	}
 }
 
+type testPluginInputCallbackLatency struct{}
+
+func (t testPluginInputCallbackLatency) Init(ctx context.Context, fbit *Fluentbit) error {
+	return nil
+}
+
+func (t testPluginInputCallbackLatency) Collect(ctx context.Context, ch chan<- Message) error {
+	tick := time.NewTimer(time.Second * 1)
+	for {
+		select {
+		case <-tick.C:
+			for i := 0; i < 128; i++ {
+				ch <- Message{
+					Time: time.Now(),
+					Record: map[string]string{
+						"Foo": "BAR",
+					},
+				}
+			}
+			tick.Reset(time.Second * 1)
+		case <-ctx.Done():
+			return nil
+		}
+	}
+}
+
+// TestInputCallbackInfiniteLatency is a test of the latency between
+// messages.
+func TestInputCallbackLatency(t *testing.T) {
+	defer flbPluginReset()
+
+	theInput = testPluginInputCallbackLatency{}
+	cdone := make(chan bool)
+	cmsg := make(chan []byte)
+
+	go func() {
+		t := time.NewTicker(collectInterval)
+		for {
+			select {
+			case <-cdone:
+				return
+			case <-t.C:
+				buf, _ := testFLBPluginInputCallback()
+				if len(buf) > 0 {
+					cmsg <- buf
+				}
+			}
+		}
+	}()
+
+	timeout := time.NewTimer(5 * time.Second)
+	msgs := 0
+
+	for {
+		select {
+		case buf := <-cmsg:
+			dec := output.NewByteDecoder(buf)
+			if dec == nil {
+				t.Fatal("dec is nil")
+			}
+
+			for {
+				ret, timestamp, _ := output.GetRecord(dec)
+				if ret == -1 {
+					break
+				}
+				if ret < 0 {
+					t.Fatalf("ret is negative: %d", ret)
+				}
+
+				msgs++
+
+				ts, ok := timestamp.(output.FLBTime)
+				if !ok {
+					t.Fatal()
+				}
+
+				if time.Since(ts.Time) > time.Millisecond*5 {
+					t.Errorf("latency too high: %fms",
+						float64(time.Since(ts.Time)/time.Millisecond))
+				}
+			}
+		case <-timeout.C:
+			timeout.Stop()
+			runCancel()
+
+			if msgs < 128 {
+				t.Fatalf("too few messages: %d", msgs)
+			}
+			return
+		}
+	}
+}
+
 type testInputCallbackInfiniteConcurrent struct{}
 
 var concurrentWait sync.WaitGroup
@@ -182,6 +278,8 @@ func (t testInputCallbackInfiniteConcurrent) Init(ctx context.Context, fbit *Flu
 }
 
 func (t testInputCallbackInfiniteConcurrent) Collect(ctx context.Context, ch chan<- Message) error {
+	defer flbPluginReset()
+
 	for i := 0; i < 64; i++ {
 		go func(ch chan<- Message, id int) {
 			ch <- Message{
diff --git a/output/decoder.go b/output/decoder.go
index d1b438f..aa9e508 100644
--- a/output/decoder.go
+++ b/output/decoder.go
@@ -69,6 +69,17 @@ func NewDecoder(data unsafe.Pointer, length int) *FLBDecoder {
 	return dec
 }
 
+func NewByteDecoder(b []byte) *FLBDecoder {
+	dec := new(FLBDecoder)
+	dec.handle = new(codec.MsgpackHandle)
+	// TODO: handle error.
+	_ = dec.handle.SetBytesExt(reflect.TypeOf(FLBTime{}), 0, &FLBTime{})
+
+	dec.mpdec = codec.NewDecoderBytes(b, dec.handle)
+
+	return dec
+}
+
 func GetRecord(dec *FLBDecoder) (ret int, ts interface{}, rec map[interface{}]interface{}) {
 	var check error
 	var m interface{}