export qlog files if the QLOGDIR env is set in interop client and server

interop/utils/logging.go

@@ -1,8 +1,11 @@
 package utils
 
 import (
+	"fmt"
 	"io"
+	"log"
 	"os"
+	"strings"
 )
 
 // GetSSLKeyLog creates a file for the TLS key log
@@ -17,3 +20,24 @@ func GetSSLKeyLog() (io.WriteCloser, error) {
 	}
 	return f, nil
 }
+
+// GetQLOGWriter creates the QLOGDIR and returns the GetLogWriter callback
+func GetQLOGWriter() (func(connID []byte) io.WriteCloser, error) {
+	qlogDir := os.Getenv("QLOGDIR")
+	if len(qlogDir) == 0 {
+		return nil, nil
+	}
+	if _, err := os.Stat(qlogDir); os.IsNotExist(err) {
+		if err := os.MkdirAll(qlogDir, 0666); err != nil {
+			return nil, fmt.Errorf("failed to create qlog dir %s: %s", qlogDir, err.Error())
+		}
+	}
+	return func(connID []byte) io.WriteCloser {
+		path := fmt.Sprintf("%s/%x.qlog", strings.TrimRight(qlogDir, "/"), connID)
+		f, err := os.Create(path)
+		if err != nil {
+			log.Fatalf("Failed to create qlog file %s: %s", path, err.Error())
+		}
+		return f
+	}, nil
+}