Files
ctrld/cmd/cli/commands_log.go
T
Codescribe 33a5480072 Add log tail command for live log streaming
This commit adds a new `ctrld log tail` subcommand that streams
runtime debug logs to the terminal in real-time, similar to `tail -f`.

Changes:
- log_writer.go: Add Subscribe/tailLastLines for fan-out to tail clients
- control_server.go: Add /log/tail endpoint with streaming response
  - Internal logging: subscribes to logWriter for live data
  - File-based logging: polls log file for new data (200ms interval)
  - Sends last N lines as initial context on connect
- commands.go: Add `log tail` cobra subcommand with --lines/-n flag
- control_client.go: Add postStream() with no timeout for long-lived connections

Usage:
  sudo ctrld log tail          # shows last 10 lines then follows
  sudo ctrld log tail -n 50    # shows last 50 lines then follows
  Ctrl+C to stop
2026-03-23 16:41:54 +07:00

264 lines
6.5 KiB
Go

package cli
import (
"context"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"os"
"os/signal"
"path/filepath"
"syscall"
"github.com/docker/go-units"
"github.com/kardianos/service"
"github.com/spf13/cobra"
)
// LogCommand handles log-related operations
type LogCommand struct {
controlClient *controlClient
}
// NewLogCommand creates a new log command handler
func NewLogCommand() (*LogCommand, error) {
dir, err := socketDir()
if err != nil {
return nil, fmt.Errorf("failed to find ctrld home dir: %w", err)
}
cc := newControlClient(filepath.Join(dir, ctrldControlUnixSock))
return &LogCommand{
controlClient: cc,
}, nil
}
// warnRuntimeLoggingNotEnabled logs a warning about runtime logging not being enabled
func (lc *LogCommand) warnRuntimeLoggingNotEnabled() {
mainLog.Load().Warn().Msg("Runtime debug logging is not enabled")
mainLog.Load().Warn().Msg(`ctrld may be running without "--cd" flag or logging is already enabled`)
}
// SendLogs sends runtime debug logs to ControlD
func (lc *LogCommand) SendLogs(cmd *cobra.Command, args []string) error {
sc := NewServiceCommand()
s, _, err := sc.initializeServiceManager()
if err != nil {
return err
}
status, err := s.Status()
if errors.Is(err, service.ErrNotInstalled) {
mainLog.Load().Warn().Msg("Service not installed")
return nil
}
if status == service.StatusStopped {
mainLog.Load().Warn().Msg("Service is not running")
return nil
}
resp, err := lc.controlClient.post(sendLogsPath, nil)
if err != nil {
return fmt.Errorf("failed to send logs: %w", err)
}
defer resp.Body.Close()
switch resp.StatusCode {
case http.StatusServiceUnavailable:
mainLog.Load().Warn().Msg("Runtime logs could only be sent once per minute")
return nil
case http.StatusMovedPermanently:
lc.warnRuntimeLoggingNotEnabled()
return nil
}
var logs logSentResponse
if err := json.NewDecoder(resp.Body).Decode(&logs); err != nil {
return fmt.Errorf("failed to decode sent logs result: %w", err)
}
if logs.Error != "" {
return fmt.Errorf("failed to send logs: %s", logs.Error)
}
mainLog.Load().Notice().Msgf("Sent %s of runtime logs", units.BytesSize(float64(logs.Size)))
return nil
}
// ViewLogs views current runtime debug logs
func (lc *LogCommand) ViewLogs(cmd *cobra.Command, args []string) error {
sc := NewServiceCommand()
s, _, err := sc.initializeServiceManager()
if err != nil {
return err
}
status, err := s.Status()
if errors.Is(err, service.ErrNotInstalled) {
mainLog.Load().Warn().Msg("Service not installed")
return nil
}
if status == service.StatusStopped {
mainLog.Load().Warn().Msg("Service is not running")
return nil
}
resp, err := lc.controlClient.post(viewLogsPath, nil)
if err != nil {
return fmt.Errorf("failed to get logs: %w", err)
}
defer resp.Body.Close()
switch resp.StatusCode {
case http.StatusMovedPermanently:
lc.warnRuntimeLoggingNotEnabled()
return nil
case http.StatusBadRequest:
mainLog.Load().Warn().Msg("Runtime debug logs are not available")
buf, err := io.ReadAll(resp.Body)
if err != nil {
mainLog.Load().Fatal().Err(err).Msg("Failed to read response body")
}
mainLog.Load().Warn().Msgf("ctrld process response:\n\n%s\n", string(buf))
return nil
case http.StatusOK:
}
var logs logViewResponse
if err := json.NewDecoder(resp.Body).Decode(&logs); err != nil {
return fmt.Errorf("failed to decode view logs result: %w", err)
}
fmt.Print(logs.Data)
return nil
}
// TailLogs streams live runtime debug logs to the terminal
func (lc *LogCommand) TailLogs(cmd *cobra.Command, args []string) error {
sc := NewServiceCommand()
s, _, err := sc.initializeServiceManager()
if err != nil {
return err
}
status, err := s.Status()
if errors.Is(err, service.ErrNotInstalled) {
mainLog.Load().Warn().Msg("Service not installed")
return nil
}
if status == service.StatusStopped {
mainLog.Load().Warn().Msg("Service is not running")
return nil
}
tailLines, _ := cmd.Flags().GetInt("lines")
tailPath := fmt.Sprintf("%s?lines=%d", tailLogsPath, tailLines)
resp, err := lc.controlClient.postStream(tailPath, nil)
if err != nil {
return fmt.Errorf("failed to connect for log tailing: %w", err)
}
defer resp.Body.Close()
switch resp.StatusCode {
case http.StatusMovedPermanently:
lc.warnRuntimeLoggingNotEnabled()
return nil
case http.StatusOK:
default:
return fmt.Errorf("unexpected response status: %d", resp.StatusCode)
}
// Set up signal handling for clean shutdown.
ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
defer stop()
done := make(chan struct{})
go func() {
defer close(done)
// Stream output to stdout.
buf := make([]byte, 4096)
for {
n, readErr := resp.Body.Read(buf)
if n > 0 {
os.Stdout.Write(buf[:n])
}
if readErr != nil {
if readErr != io.EOF {
mainLog.Load().Error().Err(readErr).Msg("Error reading log stream")
}
return
}
}
}()
select {
case <-ctx.Done():
if errors.Is(ctx.Err(), context.Canceled) {
msg := fmt.Sprintf("\nexiting: %s\n", context.Cause(ctx).Error())
os.Stdout.WriteString(msg)
}
case <-done:
}
return nil
}
// InitLogCmd creates the log command with proper logic
func InitLogCmd(rootCmd *cobra.Command) *cobra.Command {
lc, err := NewLogCommand()
if err != nil {
panic(fmt.Sprintf("failed to create log command: %v", err))
}
logSendCmd := &cobra.Command{
Use: "send",
Short: "Send runtime debug logs to ControlD",
Args: cobra.NoArgs,
PreRun: func(cmd *cobra.Command, args []string) {
checkHasElevatedPrivilege()
},
RunE: lc.SendLogs,
}
logViewCmd := &cobra.Command{
Use: "view",
Short: "View current runtime debug logs",
Args: cobra.NoArgs,
PreRun: func(cmd *cobra.Command, args []string) {
checkHasElevatedPrivilege()
},
RunE: lc.ViewLogs,
}
logTailCmd := &cobra.Command{
Use: "tail",
Short: "Tail live runtime debug logs",
Long: "Stream live runtime debug logs to the terminal, similar to tail -f. Press Ctrl+C to stop.",
Args: cobra.NoArgs,
PreRun: func(cmd *cobra.Command, args []string) {
checkHasElevatedPrivilege()
},
RunE: lc.TailLogs,
}
logTailCmd.Flags().IntP("lines", "n", 10, "Number of historical lines to show on connect")
logCmd := &cobra.Command{
Use: "log",
Short: "Manage runtime debug logs",
Args: cobra.OnlyValidArgs,
ValidArgs: []string{
logSendCmd.Use,
logViewCmd.Use,
logTailCmd.Use,
},
}
logCmd.AddCommand(logSendCmd)
logCmd.AddCommand(logViewCmd)
logCmd.AddCommand(logTailCmd)
rootCmd.AddCommand(logCmd)
return logCmd
}