cloudflared-mirror/cmd/cloudflared/tail/cmd.go

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2023-04-05 17:20:53 +00:00
package tail
import (
"encoding/json"
"fmt"
"net/http"
"net/url"
"os"
"os/signal"
"syscall"
"time"
"github.com/mattn/go-colorable"
"github.com/rs/zerolog"
"github.com/urfave/cli/v2"
"nhooyr.io/websocket"
"github.com/cloudflare/cloudflared/logger"
"github.com/cloudflare/cloudflared/management"
)
var (
version string
)
func Init(v string) {
version = v
}
func Command() *cli.Command {
return &cli.Command{
Name: "tail",
Action: Run,
Usage: "Stream logs from a remote cloudflared",
Flags: []cli.Flag{
&cli.StringFlag{
Name: "connector-id",
Usage: "Access a specific cloudflared instance by connector id (for when a tunnel has multiple cloudflared's)",
Value: "",
EnvVars: []string{"TUNNEL_MANAGEMENT_CONNECTOR"},
},
&cli.StringFlag{
Name: "token",
Usage: "Access token for a specific tunnel",
Value: "",
EnvVars: []string{"TUNNEL_MANAGEMENT_TOKEN"},
},
&cli.StringFlag{
Name: "management-hostname",
Usage: "Management hostname to signify incoming management requests",
EnvVars: []string{"TUNNEL_MANAGEMENT_HOSTNAME"},
Hidden: true,
Value: "management.argotunnel.com",
},
&cli.StringFlag{
Name: "trace",
Usage: "Set a cf-trace-id for the request",
Hidden: true,
Value: "",
},
&cli.StringFlag{
Name: logger.LogLevelFlag,
Value: "info",
Usage: "Application logging level {debug, info, warn, error, fatal}. ",
EnvVars: []string{"TUNNEL_LOGLEVEL"},
},
},
}
}
// Middleware validation error struct for returning to the eyeball
type managementError struct {
Code int `json:"code,omitempty"`
Message string `json:"message,omitempty"`
}
// Middleware validation error HTTP response JSON for returning to the eyeball
type managementErrorResponse struct {
Success bool `json:"success,omitempty"`
Errors []managementError `json:"errors,omitempty"`
}
func handleValidationError(resp *http.Response, log *zerolog.Logger) {
if resp.StatusCode == 530 {
log.Error().Msgf("no cloudflared connector available or reachable via management request (a recent version of cloudflared is required to use streaming logs)")
}
var managementErr managementErrorResponse
err := json.NewDecoder(resp.Body).Decode(&managementErr)
if err != nil {
log.Error().Msgf("unable to start management log streaming session: http response code returned %d", resp.StatusCode)
return
}
if managementErr.Success || len(managementErr.Errors) == 0 {
log.Error().Msgf("management tunnel validation returned success with invalid HTTP response code to convert to a WebSocket request")
return
}
for _, e := range managementErr.Errors {
log.Error().Msgf("management request failed validation: (%d) %s", e.Code, e.Message)
}
}
// logger will be created to emit only against the os.Stderr as to not obstruct with normal output from
// management requests
func createLogger(c *cli.Context) *zerolog.Logger {
level, levelErr := zerolog.ParseLevel(c.String(logger.LogLevelFlag))
if levelErr != nil {
level = zerolog.InfoLevel
}
log := zerolog.New(zerolog.ConsoleWriter{
Out: colorable.NewColorable(os.Stderr),
TimeFormat: time.RFC3339,
}).With().Timestamp().Logger().Level(level)
return &log
}
// Run implements a foreground runner
func Run(c *cli.Context) error {
log := createLogger(c)
signals := make(chan os.Signal, 10)
signal.Notify(signals, syscall.SIGTERM, syscall.SIGINT)
defer signal.Stop(signals)
managementHostname := c.String("management-hostname")
token := c.String("token")
u := url.URL{Scheme: "wss", Host: managementHostname, Path: "/logs", RawQuery: "access_token=" + token}
header := make(http.Header)
header.Add("User-Agent", "cloudflared/"+version)
trace := c.String("trace")
if trace != "" {
header["cf-trace-id"] = []string{trace}
}
ctx := c.Context
conn, resp, err := websocket.Dial(ctx, u.String(), &websocket.DialOptions{
HTTPHeader: header,
})
if err != nil {
if resp != nil && resp.StatusCode != http.StatusSwitchingProtocols {
handleValidationError(resp, log)
return nil
}
log.Error().Err(err).Msgf("unable to start management log streaming session")
return nil
}
defer conn.Close(websocket.StatusInternalError, "management connection was closed abruptly")
// Once connection is established, send start_streaming event to begin receiving logs
err = management.WriteEvent(conn, ctx, &management.EventStartStreaming{
ClientEvent: management.ClientEvent{Type: management.StartStreaming},
})
if err != nil {
log.Error().Err(err).Msg("unable to request logs from management tunnel")
return nil
}
readerDone := make(chan struct{})
go func() {
defer close(readerDone)
for {
select {
case <-ctx.Done():
return
default:
event, err := management.ReadServerEvent(conn, ctx)
if err != nil {
if closeErr := management.AsClosed(err); closeErr != nil {
// If the client (or the server) already closed the connection, don't continue to
// attempt to read from the client.
if closeErr.Code == websocket.StatusNormalClosure {
return
}
// Only log abnormal closures
log.Error().Msgf("received remote closure: (%d) %s", closeErr.Code, closeErr.Reason)
return
}
log.Err(err).Msg("unable to read event from server")
return
}
switch event.Type {
case management.Logs:
logs, ok := management.IntoServerEvent(event, management.Logs)
if !ok {
log.Error().Msgf("invalid logs event")
continue
}
// Output all the logs received to stdout
for _, l := range logs.Logs {
fields, err := json.Marshal(l.Fields)
if err != nil {
fields = []byte("unable to parse fields")
log.Debug().Msgf("unable to parse fields from event %+v", l)
}
fmt.Printf("%s %s %s %s %s\n", l.Time, l.Level, l.Event, l.Message, fields)
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}
case management.UnknownServerEventType:
fallthrough
default:
log.Debug().Msgf("unexpected log event type: %s", event.Type)
}
}
}
}()
for {
select {
case <-ctx.Done():
return nil
case <-readerDone:
return nil
case <-signals:
log.Debug().Msg("closing management connection")
// Cleanly close the connection by sending a close message and then
// waiting (with timeout) for the server to close the connection.
conn.Close(websocket.StatusNormalClosure, "")
select {
case <-readerDone:
case <-time.After(time.Second):
}
return nil
}
}
}