github.com/apernet/quic-go@v0.43.1-0.20240515053213-5e9e635fd9f0/qlog/qlog_dir.go (about)

     1  package qlog
     2  
     3  import (
     4  	"bufio"
     5  	"context"
     6  	"fmt"
     7  	"log"
     8  	"os"
     9  	"strings"
    10  
    11  	"github.com/apernet/quic-go/internal/utils"
    12  	"github.com/apernet/quic-go/logging"
    13  )
    14  
    15  // DefaultTracer creates a qlog file in the qlog directory specified by the QLOGDIR environment variable.
    16  // File names are <odcid>_<perspective>.qlog.
    17  // Returns nil if QLOGDIR is not set.
    18  func DefaultTracer(_ context.Context, p logging.Perspective, connID logging.ConnectionID) *logging.ConnectionTracer {
    19  	var label string
    20  	switch p {
    21  	case logging.PerspectiveClient:
    22  		label = "client"
    23  	case logging.PerspectiveServer:
    24  		label = "server"
    25  	}
    26  	return qlogDirTracer(p, connID, label)
    27  }
    28  
    29  // qlogDirTracer creates a qlog file in the qlog directory specified by the QLOGDIR environment variable.
    30  // File names are <odcid>_<label>.qlog.
    31  // Returns nil if QLOGDIR is not set.
    32  func qlogDirTracer(p logging.Perspective, connID logging.ConnectionID, label string) *logging.ConnectionTracer {
    33  	qlogDir := os.Getenv("QLOGDIR")
    34  	if qlogDir == "" {
    35  		return nil
    36  	}
    37  	if _, err := os.Stat(qlogDir); os.IsNotExist(err) {
    38  		if err := os.MkdirAll(qlogDir, 0o755); err != nil {
    39  			log.Fatalf("failed to create qlog dir %s: %v", qlogDir, err)
    40  		}
    41  	}
    42  	path := fmt.Sprintf("%s/%s_%s.qlog", strings.TrimRight(qlogDir, "/"), connID, label)
    43  	f, err := os.Create(path)
    44  	if err != nil {
    45  		log.Printf("Failed to create qlog file %s: %s", path, err.Error())
    46  		return nil
    47  	}
    48  	return NewConnectionTracer(utils.NewBufferedWriteCloser(bufio.NewWriter(f), f), p, connID)
    49  }