json logging and ironing kinks

cmd/slackdump/internal/cfg/cfg.go

@@ -22,6 +22,7 @@ const (
 var (
 	TraceFile      string
 	LogFile        string
+	JsonHandler    bool
 	Verbose        bool
 	AccessibleMode = (os.Getenv("ACCESSIBLE") != "" && os.Getenv("ACCESSIBLE") != "0")
 
@@ -103,6 +104,7 @@ const (
 func SetBaseFlags(fs *flag.FlagSet, mask FlagMask) {
 	fs.StringVar(&TraceFile, "trace", os.Getenv("TRACE_FILE"), "trace `filename`")
 	fs.StringVar(&LogFile, "log", os.Getenv("LOG_FILE"), "log `file`, if not specified, messages are printed to STDERR")
+	fs.BoolVar(&JsonHandler, "log-json", osenv.Value("JSON_LOG", false), "log in JSON format")
 	fs.BoolVar(&Verbose, "v", osenv.Value("DEBUG", false), "verbose messages")
 
 	if mask&OmitAuthFlags == 0 {

cmd/slackdump/main.go

@@ -175,7 +175,7 @@ func invoke(cmd *base.Command, args []string) error {
 	defer task.End()
 
 	// initialise default logging.
-	if lg, err := initLog(cfg.LogFile, cfg.Verbose); err != nil {
+	if lg, err := initLog(cfg.LogFile, cfg.JsonHandler, cfg.Verbose); err != nil {
 		return err
 	} else {
 		lg.With("command", cmd.Name())
@@ -247,30 +247,36 @@ func initTrace(filename string) error {
 // an error, if any. The stop function must be called in the deferred call, it
 // will close the log file, if it is open. If the error is returned the stop
 // function is nil.
-func initLog(filename string, verbose bool) (*slog.Logger, error) {
+func initLog(filename string, jsonHandler bool, verbose bool) (*slog.Logger, error) {
 	if verbose {
 		slog.SetLogLoggerLevel(slog.LevelDebug)
 	}
-
-	if filename == "" {
-		return slog.Default(), nil
+	var opts = &slog.HandlerOptions{
+		Level: iftrue(verbose, slog.LevelDebug, slog.LevelInfo),
 	}
-
-	slog.Debug("log messages will be written to file", "filename", filename)
-	lf, err := os.OpenFile(filename, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0666)
-	if err != nil {
-		return slog.Default(), fmt.Errorf("failed to create the log file: %w", err)
+	if jsonHandler {
+		slog.SetDefault(slog.New(slog.NewJSONHandler(os.Stderr, opts)))
 	}
-	sl := slog.New(slog.NewTextHandler(lf, &slog.HandlerOptions{
-		Level: iftrue(verbose, slog.LevelDebug, slog.LevelInfo),
-	}))
-	slog.SetDefault(sl)
+	if filename != "" {
+		slog.Debug("log messages will be written to file", "filename", filename)
+		lf, err := os.OpenFile(filename, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0666)
+		if err != nil {
+			return slog.Default(), fmt.Errorf("failed to create the log file: %w", err)
+		}
 
-	base.AtExit(func() {
-		if err := lf.Close(); err != nil {
-			dlog.Printf("failed to close the log file: %s", err)
+		var h slog.Handler = slog.NewTextHandler(lf, opts)
+		if jsonHandler {
+			h = slog.NewJSONHandler(lf, opts)
 		}
-	})
+
+		sl := slog.New(h)
+		slog.SetDefault(sl)
+		base.AtExit(func() {
+			if err := lf.Close(); err != nil {
+				dlog.Printf("failed to close the log file: %s", err)
+			}
+		})
+	}
 
 	return slog.Default(), nil
 }

internal/structures/url_parse.go

@@ -4,6 +4,7 @@ package structures
 
 import (
 	"fmt"
+	"log/slog"
 	"net/url"
 	"regexp"
 	"strings"
@@ -32,6 +33,13 @@ func (u SlackLink) IsThread() bool {
 	return u.ThreadTS != ""
 }
 
+func (u SlackLink) LogValue() slog.Value {
+	if u.ThreadTS == "" {
+		return slog.GroupValue(slog.Group("channel", slog.String("id", u.Channel)))
+	}
+	return slog.GroupValue(slog.Group("thread", slog.String("channel_id", u.Channel), slog.String("thread_ts", u.ThreadTS)))
+}
+
 func (u SlackLink) IsValid() bool {
 	return u.Channel != "" || (u.Channel != "" && u.ThreadTS != "")
 }

stream/conversation.go

@@ -225,8 +225,8 @@ func (cs *Stream) thread(ctx context.Context, sl *structures.SlackLink, callback
 		return fmt.Errorf("not a thread: %s", sl)
 	}
 
-	lg := slog.With("slack_link", sl.String())
-	lg.DebugContext(ctx, "- getting", sl)
+	lg := slog.With("slack_link", sl)
+	lg.DebugContext(ctx, "- getting")
 
 	var cursor string
 	for {