Add large buffer debug logs under protocol_debug_print (#833)

Signed-off-by: Mattia Meleleo <[email protected]>

Author: mmat11

internal/test/integration/docker-compose-elasticsearch.yml

@@ -55,6 +55,7 @@ services:
       OTEL_EBPF_METRICS_FEATURES: "application"
       OTEL_EBPF_BPF_BUFFER_SIZE_HTTP: 1024
       OTEL_EBPF_HTTP_ELASTICSEARCH_ENABLED: true
+      OTEL_EBPF_PROTOCOL_DEBUG_PRINT: true
     depends_on:
       testserver:
         condition: service_started

internal/test/integration/docker-compose-python-aws.yml

@@ -52,6 +52,7 @@ services:
       OTEL_EBPF_METRICS_FEATURES: "application"
       OTEL_EBPF_BPF_BUFFER_SIZE_HTTP: 2048
       OTEL_EBPF_HTTP_AWS_ENABLED: true
+      OTEL_EBPF_PROTOCOL_DEBUG_PRINT: true
     depends_on:
       testserver:
         condition: service_started

pkg/ebpf/common/common.go

@@ -128,6 +128,7 @@ type MisclassifiedEvent struct {
 }
 
 type EBPFParseContext struct {
+	protocolDebug              bool
 	h2c                        *lru.Cache[uint64, h2Connection]
 	redisDBCache               *simplelru.LRU[BpfConnectionInfoT, int]
 	largeBuffers               *expirable.LRU[largeBufferKey, *largeBuffer]
@@ -156,6 +157,7 @@ func ptlog() *slog.Logger { return slog.With("component", "ebpf.ProcessTracer")
 func NewEBPFParseContext(cfg *config.EBPFTracer, spansChan *msg.Queue[[]request.Span], filter ServiceFilter) *EBPFParseContext {
 	var (
 		err                        error
+		protocolDebug              bool
 		redisDBCache               *simplelru.LRU[BpfConnectionInfoT, int]
 		mysqlPreparedStatements    *simplelru.LRU[mysqlPreparedStatementsKey, string]
 		postgresPreparedStatements *simplelru.LRU[postgresPreparedStatementsKey, string]
@@ -170,6 +172,8 @@ func NewEBPFParseContext(cfg *config.EBPFTracer, spansChan *msg.Queue[[]request.
 	largeBuffers := expirable.NewLRU[largeBufferKey, *largeBuffer](1024, nil, 5*time.Minute)
 
 	if cfg != nil {
+		protocolDebug = cfg.ProtocolDebug
+
 		if cfg.RedisDBCache.Enabled {
 			redisDBCache, err = simplelru.NewLRU[BpfConnectionInfoT, int](cfg.RedisDBCache.MaxSize, nil)
 			if err != nil {
@@ -206,6 +210,7 @@ func NewEBPFParseContext(cfg *config.EBPFTracer, spansChan *msg.Queue[[]request.
 	}
 
 	return &EBPFParseContext{
+		protocolDebug:              protocolDebug,
 		h2c:                        h2c,
 		redisDBCache:               redisDBCache,
 		largeBuffers:               largeBuffers,

pkg/ebpf/common/tcp_large_buffer.go

@@ -42,6 +42,10 @@ func appendTCPLargeBuffer(parseCtx *EBPFParseContext, record *ringbuf.Record) (r
 		connInfo:   event.ConnInfo,
 	}
 
+	if parseCtx.protocolDebug {
+		fmt.Printf(">>> LargeBufferAppend: (packet=%d direction=%d action=%d)\n%s\n", event.PacketType, event.Direction, event.Action, string(record.RawSample[hdrSize:hdrSize+event.Len]))
+	}
+
 	switch event.Action {
 	case largeBufferActionInit:
 		newBuffer := make([]byte, event.Len)
@@ -70,9 +74,17 @@ func extractTCPLargeBuffer(parseCtx *EBPFParseContext, traceID [16]uint8, packet
 		connInfo:   connInfo,
 	}
 
+	//nolint:gocritic
 	if lb, ok := parseCtx.largeBuffers.Get(key); ok {
+		if parseCtx.protocolDebug {
+			fmt.Printf("<<< LargeBufferExtract: (packet=%d direction=%d)\n%s\n", key.packetType, key.direction, string(lb.buf))
+		}
 		parseCtx.largeBuffers.Remove(key)
 		return lb.buf, true
+	} else {
+		if parseCtx.protocolDebug {
+			fmt.Println("<<< LargeBufferExtract: not found!")
+		}
 	}
 
 	return nil, false