ipn/ipnlocal: add logging and locking to c2n /update (#9290)

Log some progress info to make updates more debuggable. Also, track
whether an active update is already started and return an error if
a concurrent update is attempted.

Some planned future PRs:
* add JSON output to `tailscale update`
* use JSON output from `tailscale update` to provide a more detailed
  status of in-progress update (stage, download progress, etc)

Updates #6907

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
pull/9313/head
Andrew Lytvynov 1 year ago committed by GitHub
parent 1eadb2b608
commit 1073b56e18
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23

@ -128,8 +128,8 @@ func NewUpdater(args Arguments) (*Updater, error) {
return nil, err
}
}
if args.PkgsAddr == "" {
args.PkgsAddr = "https://pkgs.tailscale.com"
if up.Arguments.PkgsAddr == "" {
up.Arguments.PkgsAddr = "https://pkgs.tailscale.com"
}
return &up, nil
}

@ -4,6 +4,7 @@
package ipnlocal
import (
"bytes"
"encoding/json"
"errors"
"fmt"
@ -14,6 +15,7 @@ import (
"path/filepath"
"runtime"
"strconv"
"strings"
"time"
"tailscale.com/clientupdate"
@ -38,7 +40,15 @@ func (b *LocalBackend) handleC2N(w http.ResponseWriter, r *http.Request) {
body, _ := io.ReadAll(r.Body)
w.Write(body)
case "/update":
b.handleC2NUpdate(w, r)
switch r.Method {
case http.MethodGet:
b.handleC2NUpdateGet(w, r)
case http.MethodPost:
b.handleC2NUpdatePost(w, r)
default:
http.Error(w, "bad method", http.StatusMethodNotAllowed)
return
}
case "/logtail/flush":
if r.Method != "POST" {
http.Error(w, "bad method", http.StatusMethodNotAllowed)
@ -111,37 +121,27 @@ func (b *LocalBackend) handleC2N(w http.ResponseWriter, r *http.Request) {
}
}
func (b *LocalBackend) handleC2NUpdate(w http.ResponseWriter, r *http.Request) {
// TODO(bradfitz): add some sort of semaphore that prevents two concurrent
// updates, or if one happened in the past 5 minutes, or something.
func (b *LocalBackend) handleC2NUpdateGet(w http.ResponseWriter, r *http.Request) {
b.logf("c2n: GET /update received")
// GET returns the current status, and POST actually begins an update.
if r.Method != "GET" && r.Method != "POST" {
http.Error(w, "bad method", http.StatusMethodNotAllowed)
return
}
res := b.newC2NUpdateResponse()
res.Started = b.c2nUpdateStarted()
// If NewUpdater does not return an error, we can update the installation.
// Exception: When version.IsMacSysExt returns true, we don't support that
// yet. TODO(cpalmer, #6995): Implement it.
//
// Note that we create the Updater solely to check for errors; we do not
// invoke it here. For this purpose, it is ok to pass it a zero Arguments.
prefs := b.Prefs().AutoUpdate()
_, err := clientupdate.NewUpdater(clientupdate.Arguments{})
res := tailcfg.C2NUpdateResponse{
Enabled: envknob.AllowsRemoteUpdate() || prefs.Apply,
Supported: err == nil && !version.IsMacSysExt(),
}
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(res)
}
func (b *LocalBackend) handleC2NUpdatePost(w http.ResponseWriter, r *http.Request) {
b.logf("c2n: POST /update received")
res := b.newC2NUpdateResponse()
defer func() {
if res.Err != "" {
b.logf("c2n: POST /update failed: %s", res.Err)
}
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(res)
}()
if r.Method == "GET" {
return
}
if !res.Enabled {
res.Err = "not enabled"
return
@ -151,6 +151,18 @@ func (b *LocalBackend) handleC2NUpdate(w http.ResponseWriter, r *http.Request) {
return
}
// Check if update was already started, and mark as started.
if !b.trySetC2NUpdateStarted() {
res.Err = "update already started"
return
}
defer func() {
// Clear the started flag if something failed.
if res.Err != "" {
b.setC2NUpdateStarted(false)
}
}()
cmdTS, err := findCmdTailscale()
if err != nil {
res.Err = fmt.Sprintf("failed to find cmd/tailscale binary: %v", err)
@ -172,22 +184,64 @@ func (b *LocalBackend) handleC2NUpdate(w http.ResponseWriter, r *http.Request) {
res.Err = "cmd/tailscale version mismatch"
return
}
cmd := exec.Command(cmdTS, "update", "--yes")
buf := new(bytes.Buffer)
cmd.Stdout = buf
cmd.Stderr = buf
b.logf("c2n: running %q", strings.Join(cmd.Args, " "))
if err := cmd.Start(); err != nil {
res.Err = fmt.Sprintf("failed to start cmd/tailscale update: %v", err)
return
}
res.Started = true
// TODO(bradfitz,andrew): There might be a race condition here on Windows:
// * We start the update process.
// * tailscale.exe copies itself and kicks off the update process
// * msiexec stops this process during the update before the selfCopy exits(?)
// * This doesn't return because the process is dead.
// Run update asynchronously and respond that it started.
go func() {
if err := cmd.Wait(); err != nil {
b.logf("c2n: update command failed: %v, output: %s", err, buf)
} else {
b.logf("c2n: update complete")
}
b.setC2NUpdateStarted(false)
}()
}
func (b *LocalBackend) newC2NUpdateResponse() tailcfg.C2NUpdateResponse {
// If NewUpdater does not return an error, we can update the installation.
// Exception: When version.IsMacSysExt returns true, we don't support that
// yet. TODO(cpalmer, #6995): Implement it.
//
// This seems fairly unlikely, but worth checking.
defer cmd.Wait()
return
// Note that we create the Updater solely to check for errors; we do not
// invoke it here. For this purpose, it is ok to pass it a zero Arguments.
prefs := b.Prefs().AutoUpdate()
_, err := clientupdate.NewUpdater(clientupdate.Arguments{})
return tailcfg.C2NUpdateResponse{
Enabled: envknob.AllowsRemoteUpdate() || prefs.Apply,
Supported: err == nil && !version.IsMacSysExt(),
}
}
func (b *LocalBackend) c2nUpdateStarted() bool {
b.mu.Lock()
defer b.mu.Unlock()
return b.c2nUpdateStatus.started
}
func (b *LocalBackend) setC2NUpdateStarted(v bool) {
b.mu.Lock()
defer b.mu.Unlock()
b.c2nUpdateStatus.started = v
}
func (b *LocalBackend) trySetC2NUpdateStarted() bool {
b.mu.Lock()
defer b.mu.Unlock()
if b.c2nUpdateStatus.started {
return false
}
b.c2nUpdateStatus.started = true
return true
}
// findCmdTailscale looks for the cmd/tailscale that corresponds to the

@ -240,6 +240,8 @@ type LocalBackend struct {
directFileRoot string
directFileDoFinalRename bool // false on macOS, true on several NAS platforms
componentLogUntil map[string]componentLogState
// c2nUpdateStatus is the status of c2n-triggered client update.
c2nUpdateStatus updateStatus
// ServeConfig fields. (also guarded by mu)
lastServeConfJSON mem.RO // last JSON that was parsed into serveConfig
@ -268,6 +270,10 @@ type LocalBackend struct {
clock tstime.Clock
}
type updateStatus struct {
started bool
}
// clientGen is a func that creates a control plane client.
// It's the type used by LocalBackend.SetControlClientGetterForTesting.
type clientGen func(controlclient.Options) (controlclient.Client, error)

@ -39,7 +39,7 @@ type C2NSSHUsernamesResponse struct {
// its Tailscale installation.
type C2NUpdateResponse struct {
// Err is the error message, if any.
Err string
Err string `json:",omitempty"`
// Enabled indicates whether the user has opted in to updates triggered from
// control.

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