app/vlogscli: allow toggling wrapping long lines with \wrap_long_lines command

app/vlogscli/less_wrapper.go

@@ -17,7 +17,7 @@ func isTerminal() bool {
 	return isatty.IsTerminal(os.Stdout.Fd()) && isatty.IsTerminal(os.Stderr.Fd())
 }
 
-func readWithLess(r io.Reader) error {
+func readWithLess(r io.Reader, wrapLongLines bool) error {
 	if !isTerminal() {
 		// Just write everything to stdout if no terminal is available.
 		_, err := io.Copy(os.Stdout, r)
@@ -48,7 +48,11 @@ func readWithLess(r io.Reader) error {
 	if err != nil {
 		return fmt.Errorf("cannot find 'less' command: %w", err)
 	}
-	p, err := os.StartProcess(path, []string{"less", "-F", "-X"}, &os.ProcAttr{
+	opts := []string{"less", "-F", "-X"}
+	if !wrapLongLines {
+		opts = append(opts, "-S")
+	}
+	p, err := os.StartProcess(path, opts, &os.ProcAttr{
 		Env:   append(os.Environ(), "LESSCHARSET=utf-8"),
 		Files: []*os.File{pr, os.Stdout, os.Stderr},
 	})

app/vlogscli/main.go

@@ -91,6 +91,7 @@ func runReadlineLoop(rl *readline.Instance, incompleteLine *string) {
 	}
 
 	outputMode := outputModeJSONMultiline
+	wrapLongLines := false
 	s := ""
 	for {
 		line, err := rl.ReadLine()
@@ -99,7 +100,7 @@ func runReadlineLoop(rl *readline.Instance, incompleteLine *string) {
 			case io.EOF:
 				if s != "" {
 					// This is non-interactive query execution.
-					executeQuery(context.Background(), rl, s, outputMode)
+					executeQuery(context.Background(), rl, s, outputMode, wrapLongLines)
 				}
 				return
 			case readline.ErrInterrupt:
@@ -163,6 +164,18 @@ func runReadlineLoop(rl *readline.Instance, incompleteLine *string) {
 			s = ""
 			continue
 		}
+		if s == `\wrap_long_lines` {
+			if wrapLongLines {
+				wrapLongLines = false
+				fmt.Fprintf(rl, "wrapping of long lines is disabled\n")
+			} else {
+				wrapLongLines = true
+				fmt.Fprintf(rl, "wrapping of long lines is enabled\n")
+			}
+			historyLines = pushToHistory(rl, historyLines, s)
+			s = ""
+			continue
+		}
 		if line != "" && !strings.HasSuffix(line, ";") {
 			// Assume the query is incomplete and allow the user finishing the query on the next line
 			s += "\n"
@@ -172,7 +185,7 @@ func runReadlineLoop(rl *readline.Instance, incompleteLine *string) {
 
 		// Execute the query
 		ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
-		executeQuery(ctx, rl, s, outputMode)
+		executeQuery(ctx, rl, s, outputMode, wrapLongLines)
 		cancel()
 
 		historyLines = pushToHistory(rl, historyLines, s)
@@ -259,13 +272,14 @@ func printCommandsHelp(w io.Writer) {
 \m - multiline json output mode
 \c - compact output
 \logfmt - logfmt output mode
+\wrap_long_lines - toggles wrapping long lines
 \tail <query> - live tail <query> results
 
 See https://docs.victoriametrics.com/victorialogs/querying/vlogscli/ for more details
 `)
 }
 
-func executeQuery(ctx context.Context, output io.Writer, qStr string, outputMode outputMode) {
+func executeQuery(ctx context.Context, output io.Writer, qStr string, outputMode outputMode, wrapLongLines bool) {
 	if strings.HasPrefix(qStr, `\tail `) {
 		tailQuery(ctx, output, qStr, outputMode)
 		return
@@ -279,7 +293,7 @@ func executeQuery(ctx context.Context, output io.Writer, qStr string, outputMode
 		_ = respBody.Close()
 	}()
 
-	if err := readWithLess(respBody); err != nil {
+	if err := readWithLess(respBody, wrapLongLines); err != nil {
 		fmt.Fprintf(output, "error when reading query response: %s\n", err)
 		return
 	}

docs/VictoriaLogs/CHANGELOG.md

@@ -18,6 +18,7 @@ according to [these docs](https://docs.victoriametrics.com/victorialogs/quicksta
 * FEATURE: [`join` pipe](https://docs.victoriametrics.com/victorialogs/logsql/#join-pipe): add an ability to add prefix to all the log field names from the joined query, by using `| join by (<by_fields>) (<query>) prefix "some_prefix"` syntax.
 * FEATURE: [`_time` filter](https://docs.victoriametrics.com/victorialogs/logsql/#time-filter): allow specifying offset without time range. For example, `_time:offset 1d` matches all the logs until `now-1d` in the [`_time` field](https://docs.victoriametrics.com/victorialogs/keyconcepts/#time-field). This is useful when building graphs for time ranges with some offset in the past.
 * FEATURE: [`/select/logsql/tail` HTTP endpoint](): support for `offset` query arg, which can be used for delayed emission of matching logs during live tailing. Thanks to @Fusl for the initial idea and implementation in [this pull request](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/7428).
+* FEATURE: [vlogscli](https://docs.victoriametrics.com/victorialogs/querying/vlogscli/): allow enabling and disabling wrapping of long lines, which do not fit screen width, with `\wrap_long_lines` command.
 
 * BUGFIX: [HTTP querying APIs](https://docs.victoriametrics.com/victorialogs/querying/#http-api): properly take into account the `end` query arg when calculating time range for [`_time:duration` filter](https://docs.victoriametrics.com/victorialogs/logsql/#time-filter). Previously the `_time:duration` filter was treated as `_time:[now-duration, now)`, while it should be treated as `_time:[end-duration, end)`.