LogViewer

Append-only, auto-scrolling log display with level filtering, substring search, pause/resume, and goroutine-safe Append. Implements Component and Themed.

Construction

lv := blit.NewLogViewer()

LogLine

type LogLine struct {
    Level     blit.LogLevel // LogDebug, LogInfo, LogWarn, LogError
    Timestamp time.Time
    Message   string
    Source    string // Optional — shown in accent color between chip and message
}

Log Levels

Constant	Chip	Color
LogDebug	DBG	Muted
LogInfo	INF	Accent
LogWarn	WRN	Flash
LogError	ERR	Negative

Appending Lines

Append is safe to call from any goroutine:

lv.Append(blit.LogLine{
    Level:     blit.LogInfo,
    Timestamp: time.Now(),
    Source:    "api",
    Message:   "request completed in 42ms",
})

Via Bubble Tea Command

To append from within a Bubble Tea command pipeline:

func fetchData() tea.Cmd {
    return blit.LogAppendCmd(blit.LogLine{
        Level:   blit.LogInfo,
        Message: "data fetched",
    })
}

The LogAppendMsg message type is handled automatically by LogViewer.Update.

Auto-Scroll

The LogViewer auto-scrolls to the bottom as new lines arrive. Scrolling up pauses auto-scroll; pressing end or p resumes it. The status bar shows ▶ LIVE or ⏸ PAUSED.

Level Filtering

Press l to cycle the minimum log level:

debug+ → info+ → warn+ → error → (back to debug+)

Only lines at or above the selected level are shown.

Substring Search

Press / to enter filter mode. The text input is shown at the bottom. The filter matches against both Message and Source. Press Enter or Esc to exit filter mode.

The status bar displays the active filter query alongside the line count (filtered/total lines).

State Methods

lv.Append(line blit.LogLine) // Add a line (goroutine-safe)
lv.Clear()                     // Remove all lines (goroutine-safe)
lv.Lines() []blit.LogLine    // Snapshot of all stored lines (goroutine-safe)

Keybindings

Key	Action
up / k	Scroll up (pauses auto-scroll)
down / j	Scroll down
pgup	Half-page up
pgdown	Half-page down
end	Jump to latest (resumes auto-scroll)
p	Toggle pause / resume
c	Clear all lines
/	Open substring filter input
l	Cycle minimum log level

Example: Background Appender

lv := blit.NewLogViewer()

app := blit.NewApp(
    blit.WithComponent("logs", lv),
)

go func() {
    for line := range logStream {
        lv.Append(blit.LogLine{
            Level:     blit.LogInfo,
            Timestamp: time.Now(),
            Message:   line,
        })
    }
}()

app.Run()