internal/connshark: Add utility to log activity over a net.Conn

internal/connshark/connshark.go

@@ -0,0 +1,56 @@
+package connshark
+
+import "os"
+import "io"
+import "fmt"
+import "net"
+import "log"
+import "sync"
+import "math/rand"
+import tu "git.tebibyte.media/sashakoshka/hopp/internal/testutil"
+
+type insert struct {
+	net.Conn
+	output io.WriteCloser
+	lock sync.Mutex
+}
+
+func LogDebugFile(underlying net.Conn) net.Conn {
+	file, err := os.Create(fmt.Sprintf("connshark-%08X.log", rand.Uint32()))
+	if err != nil {
+		log.Println("XXX COULD NOT OPEN DEBUG FILE! reason: ", err)
+		return underlying
+	}
+	return Log(underlying, file)
+}
+
+func Log(underlying net.Conn, output io.WriteCloser) net.Conn {
+	return &insert {
+		Conn:   underlying,
+		output: output,
+	}
+}
+
+func (this *insert) Read(buffer []byte) (n int, err error) {
+	if n > 0 {
+		this.lock.Lock()
+		defer this.lock.Unlock()
+		fmt.Fprintf(this.output, "TX: %s\n", tu.HexBytes(buffer[:n]))
+	}
+	return n, err
+}
+
+func (this *insert) Write(buffer []byte) (n int, err error) {
+	n, err = this.Conn.Write(buffer)
+	if n > 0 {
+		this.lock.Lock()
+		defer this.lock.Unlock()
+		fmt.Fprintf(this.output, "RX: %s\n", tu.HexBytes(buffer[:n]))
+	}
+	return n, err
+}
+
+func (this *insert) Close() error {
+	this.output.Close()
+	return this.Conn.Close()
+}