gopls/internal/server/prompt.go - tools - Git at Google

 // Copyright 2023 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package server

 import (
 	"context"
 	"fmt"
 	"math/rand"
 	"os"
 	"path/filepath"
 	"strconv"
 	"testing"
 	"time"

 	"golang.org/x/telemetry"
 	"golang.org/x/telemetry/counter"
 	"golang.org/x/tools/gopls/internal/protocol"
 	"golang.org/x/tools/internal/event"
 )

 // promptTimeout is the amount of time we wait for an ongoing prompt before
 // prompting again. This gives the user time to reply. However, at some point
 // we must assume that the client is not displaying the prompt, the user is
 // ignoring it, or the prompt has been disrupted in some way (e.g. by a gopls
 // crash).
 const promptTimeout = 24 * time.Hour

 // gracePeriod is the amount of time we wait before sufficient telemetry data
 // is accumulated in the local directory, so users can have time to review
 // what kind of information will be collected and uploaded when prompting starts.
 const gracePeriod = 7 * 24 * time.Hour

 // samplesPerMille is the prompt probability.
 // Token is an integer between [1, 1000] and is assigned when maybePromptForTelemetry
 // is called first time. Only the user with a token ∈ [1, samplesPerMille]
 // will be considered for prompting.
 const samplesPerMille = 10 // 1% sample rate

 // The following constants are used for testing telemetry integration.
 const (
 	TelemetryPromptWorkTitle    = "Checking telemetry prompt"     // progress notification title, for awaiting in tests
 	GoplsConfigDirEnvvar        = "GOPLS_CONFIG_DIR"              // overridden for testing
 	FakeTelemetryModefileEnvvar = "GOPLS_FAKE_TELEMETRY_MODEFILE" // overridden for testing
 	FakeSamplesPerMille         = "GOPLS_FAKE_SAMPLES_PER_MILLE"  // overridden for testing
 	TelemetryYes                = "Yes, I'd like to help."
 	TelemetryNo                 = "No, thanks."
 )

 // The following environment variables may be set by the client.
 // Exported for testing telemetry integration.
 const (
 	GoTelemetryGoplsClientStartTimeEnvvar = "GOTELEMETRY_GOPLS_CLIENT_START_TIME" // telemetry start time recored in client
 	GoTelemetryGoplsClientTokenEnvvar     = "GOTELEMETRY_GOPLS_CLIENT_TOKEN"      // sampling token
 )

 // getenv returns the effective environment variable value for the provided
 // key, looking up the key in the session environment before falling back on
 // the process environment.
 func (s *server) getenv(key string) string {
 	if v, ok := s.Options().Env[key]; ok {
 		return v
 	}
 	return os.Getenv(key)
 }

 // telemetryMode returns the current effective telemetry mode.
 // By default this is x/telemetry.Mode(), but it may be overridden for tests.
 func (s *server) telemetryMode() string {
 	if fake := s.getenv(FakeTelemetryModefileEnvvar); fake != "" {
 		if data, err := os.ReadFile(fake); err == nil {
 			return string(data)
 		}
 		return "local"
 	}
 	return telemetry.Mode()
 }

 // setTelemetryMode sets the current telemetry mode.
 // By default this calls x/telemetry.SetMode, but it may be overridden for
 // tests.
 func (s *server) setTelemetryMode(mode string) error {
 	if fake := s.getenv(FakeTelemetryModefileEnvvar); fake != "" {
 		return os.WriteFile(fake, []byte(mode), 0666)
 	}
 	return telemetry.SetMode(mode)
 }

 // maybePromptForTelemetry checks for the right conditions, and then prompts
 // the user to ask if they want to enable Go telemetry uploading. If the user
 // responds 'Yes', the telemetry mode is set to "on".
 //
 // The actual conditions for prompting are defensive, erring on the side of not
 // prompting.
 // If enabled is false, this will not prompt the user in any condition,
 // but will send work progress reports to help testing.
 func (s *server) maybePromptForTelemetry(ctx context.Context, enabled bool) {
 	if s.Options().VerboseWorkDoneProgress {
 		work := s.progress.Start(ctx, TelemetryPromptWorkTitle, "Checking if gopls should prompt about telemetry...", nil, nil)
 		defer work.End(ctx, "Done.")
 	}

 	errorf := func(format string, args ...any) {
 		err := fmt.Errorf(format, args...)
 		event.Error(ctx, "telemetry prompt failed", err)
 	}

 	// Only prompt if we can read/write the prompt config file.
 	configDir := s.getenv(GoplsConfigDirEnvvar) // set for testing
 	if configDir == "" && testing.Testing() {
 		// Unless tests set GoplsConfigDirEnvvar, the prompt is a no op.
 		// We don't want tests to interact with os.UserConfigDir().
 		return
 	}
 	if configDir == "" {
 		userDir, err := os.UserConfigDir()
 		if err != nil {
 			errorf("unable to determine user config dir: %v", err)
 			return
 		}
 		configDir = filepath.Join(userDir, "gopls")
 	}

 	// Read the current prompt file.

 	var (
 		promptDir  = filepath.Join(configDir, "prompt")    // prompt configuration directory
 		promptFile = filepath.Join(promptDir, "telemetry") // telemetry prompt file
 	)

 	// prompt states, stored in the prompt file
 	const (
 		pUnknown  = ""        // first time
 		pNotReady = "-"       // user is not asked yet (either not sampled or not past the grace period)
 		pYes      = "yes"     // user said yes
 		pNo       = "no"      // user said no
 		pPending  = "pending" // current prompt is still pending
 		pFailed   = "failed"  // prompt was asked but failed
 	)
 	validStates := map[string]bool{
 		pNotReady: true,
 		pYes:      true,
 		pNo:       true,
 		pPending:  true,
 		pFailed:   true,
 	}

 	// Parse the current prompt file.
 	var (
 		state    = pUnknown
 		attempts = 0 // number of times we've asked already

 		// the followings are recorded after gopls v0.17+.
 		token        = 0   // valid token is [1, 1000]
 		creationTime int64 // unix time sec
 	)
 	if content, err := os.ReadFile(promptFile); err == nil {
 		if n, _ := fmt.Sscanf(string(content), "%s %d %d %d", &state, &attempts, &creationTime, &token); (n == 2 || n == 4) && validStates[state] {
 			// successfully parsed!
 			//  ~ v0.16: must have only two fields, state and attempts.
 			//  v0.17 ~: must have all four fields.
 		} else {
 			state, attempts, creationTime, token = pUnknown, 0, 0, 0
 			// TODO(hyangah): why do we want to present this as an error to user?
 			errorf("malformed prompt result %q", string(content))
 		}
 	} else if !os.IsNotExist(err) {
 		errorf("reading prompt file: %v", err)
 		// Something went wrong. Since we don't know how many times we've asked the
 		// prompt, err on the side of not asking.
 		//
 		// But record this in telemetry, in case some users enable telemetry by
 		// other means.
 		counter.New("gopls/telemetryprompt/corrupted").Inc()
 		return
 	}

 	counter.New(fmt.Sprintf("gopls/telemetryprompt/attempts:%d", attempts)).Inc()

 	// Check terminal conditions.

 	if state == pYes {
 		// Prompt has been accepted.
 		//
 		// We record this counter for every gopls session, rather than when the
 		// prompt actually accepted below, because if we only recorded it in the
 		// counter file at the time telemetry is enabled, we'd never upload it,
 		// because we exclude any counter files that overlap with a time period
 		// that has telemetry uploading is disabled.
 		counter.New("gopls/telemetryprompt/accepted").Inc()
 		return
 	}
 	if state == pNo {
 		// Prompt has been declined. In most cases, this means we'll never see the
 		// counter below, but it's possible that the user may enable telemetry by
 		// other means later on. If we see a significant number of users that have
 		// accepted telemetry but declined the prompt, it may be an indication that
 		// the prompt is not working well.
 		counter.New("gopls/telemetryprompt/declined").Inc()
 		return
 	}
 	if attempts >= 5 { // pPending or pFailed
 		// We've tried asking enough; give up. Record that the prompt expired, in
 		// case the user decides to enable telemetry by other means later on.
 		// (see also the pNo case).
 		counter.New("gopls/telemetryprompt/expired").Inc()
 		return
 	}

 	// We only check enabled after (1) the work progress is started, and (2) the
 	// prompt file has been read. (1) is for testing purposes, and (2) is so that
 	// we record the "gopls/telemetryprompt/accepted" counter for every session.
 	if !enabled {
 		return // prompt is disabled
 	}

 	if s.telemetryMode() == "on" || s.telemetryMode() == "off" {
 		// Telemetry is already on or explicitly off -- nothing to ask about.
 		return
 	}

 	// Transition: pUnknown -> pNotReady
 	if state == pUnknown {
 		// First time; we need to make the prompt dir.
 		if err := os.MkdirAll(promptDir, 0777); err != nil {
 			errorf("creating prompt dir: %v", err)
 			return
 		}
 		state = pNotReady
 	}

 	// Correct missing values.
 	if creationTime == 0 {
 		creationTime = time.Now().Unix()
 		if v := s.getenv(GoTelemetryGoplsClientStartTimeEnvvar); v != "" {
 			if sec, err := strconv.ParseInt(v, 10, 64); err == nil && sec > 0 {
 				creationTime = sec
 			}
 		}
 	}
 	if token == 0 {
 		token = rand.Intn(1000) + 1
 		if v := s.getenv(GoTelemetryGoplsClientTokenEnvvar); v != "" {
 			if tok, err := strconv.Atoi(v); err == nil && 1 <= tok && tok <= 1000 {
 				token = tok
 			}
 		}
 	}

 	// Transition: pNotReady -> pPending if sampled
 	if state == pNotReady {
 		threshold := samplesPerMille
 		if v := s.getenv(FakeSamplesPerMille); v != "" {
 			if t, err := strconv.Atoi(v); err == nil {
 				threshold = t
 			}
 		}
 		if token <= threshold && time.Now().Unix()-creationTime > gracePeriod.Milliseconds()/1000 {
 			state = pPending
 		}
 	}

 	// Acquire the lock and write the updated state to the prompt file before actually
 	// prompting.
 	//
 	// This ensures that the prompt file is writeable, and that we increment the
 	// attempt counter before we prompt, so that we don't end up in a failure
 	// mode where we keep prompting and then failing to record the response.

 	release, ok, err := acquireLockFile(promptFile)
 	if err != nil {
 		errorf("acquiring prompt: %v", err)
 		return
 	}
 	if !ok {
 		// Another process is making decision.
 		return
 	}
 	defer release()

 	if state != pNotReady { // pPending or pFailed
 		attempts++
 	}

 	pendingContent := []byte(fmt.Sprintf("%s %d %d %d", state, attempts, creationTime, token))
 	if err := os.WriteFile(promptFile, pendingContent, 0666); err != nil {
 		errorf("writing pending state: %v", err)
 		return
 	}

 	if state == pNotReady {
 		return
 	}

 	var prompt = `Go telemetry helps us improve Go by periodically sending anonymous metrics and crash reports to the Go team. Learn more at https://go.dev/doc/telemetry.

 Would you like to enable Go telemetry?
 `
 	if s.Options().LinkifyShowMessage {
 		prompt = `Go telemetry helps us improve Go by periodically sending anonymous metrics and crash reports to the Go team. Learn more at [go.dev/doc/telemetry](https://go.dev/doc/telemetry).

 Would you like to enable Go telemetry?
 `
 	}
 	// TODO(rfindley): investigate a "tell me more" action in combination with ShowDocument.
 	params := &protocol.ShowMessageRequestParams{
 		Type:    protocol.Info,
 		Message: prompt,
 		Actions: []protocol.MessageActionItem{
 			{Title: TelemetryYes},
 			{Title: TelemetryNo},
 		},
 	}

 	item, err := s.client.ShowMessageRequest(ctx, params)
 	if err != nil {
 		errorf("ShowMessageRequest failed: %v", err)
 		// Defensive: ensure item == nil for the logic below.
 		item = nil
 	}

 	message := func(typ protocol.MessageType, msg string) {
 		if !showMessage(ctx, s.client, typ, msg) {
 			// Make sure we record that "telemetry prompt failed".
 			errorf("showMessage failed: %v", err)
 		}
 	}

 	result := pFailed
 	if item == nil {
 		// e.g. dialog was dismissed
 		errorf("no response")
 	} else {
 		// Response matches MessageActionItem.Title.
 		switch item.Title {
 		case TelemetryYes:
 			result = pYes
 			if err := s.setTelemetryMode("on"); err == nil {
 				message(protocol.Info, telemetryOnMessage(s.Options().LinkifyShowMessage))
 			} else {
 				errorf("enabling telemetry failed: %v", err)
 				msg := fmt.Sprintf("Failed to enable Go telemetry: %v\nTo enable telemetry manually, please run `go run golang.org/x/telemetry/cmd/gotelemetry@latest on`", err)
 				message(protocol.Error, msg)
 			}

 		case TelemetryNo:
 			result = pNo
 		default:
 			errorf("unrecognized response %q", item.Title)
 			message(protocol.Error, fmt.Sprintf("Unrecognized response %q", item.Title))
 		}
 	}
 	resultContent := []byte(fmt.Sprintf("%s %d %d %d", result, attempts, creationTime, token))
 	if err := os.WriteFile(promptFile, resultContent, 0666); err != nil {
 		errorf("error writing result state to prompt file: %v", err)
 	}
 }

 func telemetryOnMessage(linkify bool) string {
 	format := `Thank you. Telemetry uploading is now enabled.

 To disable telemetry uploading, run %s.
 `
 	var runCmd = "`go run golang.org/x/telemetry/cmd/gotelemetry@latest local`"
 	if linkify {
 		runCmd = "[gotelemetry local](https://golang.org/x/telemetry/cmd/gotelemetry)"
 	}
 	return fmt.Sprintf(format, runCmd)
 }

 // acquireLockFile attempts to "acquire a lock" for writing to path.
 //
 // This is achieved by creating an exclusive lock file at <path>.lock. Lock
 // files expire after a period, at which point acquireLockFile will remove and
 // recreate the lock file.
 //
 // acquireLockFile fails if path is in a directory that doesn't exist.
 func acquireLockFile(path string) (func(), bool, error) {
 	lockpath := path + ".lock"
 	fi, err := os.Stat(lockpath)
 	if err == nil {
 		if time.Since(fi.ModTime()) > promptTimeout {
 			_ = os.Remove(lockpath) // ignore error
 		} else {
 			return nil, false, nil
 		}
 	} else if !os.IsNotExist(err) {
 		return nil, false, fmt.Errorf("statting lockfile: %v", err)
 	}

 	f, err := os.OpenFile(lockpath, os.O_CREATE|os.O_EXCL, 0666)
 	if err != nil {
 		if os.IsExist(err) {
 			return nil, false, nil
 		}
 		return nil, false, fmt.Errorf("creating lockfile: %v", err)
 	}
 	fi, err = f.Stat()
 	if err != nil {
 		return nil, false, err
 	}
 	release := func() {
 		_ = f.Close() // ignore error
 		fi2, err := os.Stat(lockpath)
 		if err == nil && os.SameFile(fi, fi2) {
 			// Only clean up the lockfile if it's the same file we created.
 			// Otherwise, our lock has expired and something else has the lock.
 			//
 			// There's a race here, in that the file could have changed since the
 			// stat above; but given that we've already waited 24h this is extremely
 			// unlikely, and acceptable.
 			_ = os.Remove(lockpath)
 		}
 	}
 	return release, true, nil
 }
	// Copyright 2023 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package server

	import (
	"context"
	"fmt"
	"math/rand"
	"os"
	"path/filepath"
	"strconv"
	"testing"
	"time"

	"golang.org/x/telemetry"
	"golang.org/x/telemetry/counter"
	"golang.org/x/tools/gopls/internal/protocol"
	"golang.org/x/tools/internal/event"
	)

	// promptTimeout is the amount of time we wait for an ongoing prompt before
	// prompting again. This gives the user time to reply. However, at some point
	// we must assume that the client is not displaying the prompt, the user is
	// ignoring it, or the prompt has been disrupted in some way (e.g. by a gopls
	// crash).
	const promptTimeout = 24 * time.Hour

	// gracePeriod is the amount of time we wait before sufficient telemetry data
	// is accumulated in the local directory, so users can have time to review
	// what kind of information will be collected and uploaded when prompting starts.
	const gracePeriod = 7 * 24 * time.Hour

	// samplesPerMille is the prompt probability.
	// Token is an integer between [1, 1000] and is assigned when maybePromptForTelemetry
	// is called first time. Only the user with a token ∈ [1, samplesPerMille]
	// will be considered for prompting.
	const samplesPerMille = 10 // 1% sample rate

	// The following constants are used for testing telemetry integration.
	const (
	TelemetryPromptWorkTitle = "Checking telemetry prompt" // progress notification title, for awaiting in tests
	GoplsConfigDirEnvvar = "GOPLS_CONFIG_DIR" // overridden for testing
	FakeTelemetryModefileEnvvar = "GOPLS_FAKE_TELEMETRY_MODEFILE" // overridden for testing
	FakeSamplesPerMille = "GOPLS_FAKE_SAMPLES_PER_MILLE" // overridden for testing
	TelemetryYes = "Yes, I'd like to help."
	TelemetryNo = "No, thanks."
	)

	// The following environment variables may be set by the client.
	// Exported for testing telemetry integration.
	const (
	GoTelemetryGoplsClientStartTimeEnvvar = "GOTELEMETRY_GOPLS_CLIENT_START_TIME" // telemetry start time recored in client
	GoTelemetryGoplsClientTokenEnvvar = "GOTELEMETRY_GOPLS_CLIENT_TOKEN" // sampling token
	)

	// getenv returns the effective environment variable value for the provided
	// key, looking up the key in the session environment before falling back on
	// the process environment.
	func (s *server) getenv(key string) string {
	if v, ok := s.Options().Env[key]; ok {
	return v
	}
	return os.Getenv(key)
	}

	// telemetryMode returns the current effective telemetry mode.
	// By default this is x/telemetry.Mode(), but it may be overridden for tests.
	func (s *server) telemetryMode() string {
	if fake := s.getenv(FakeTelemetryModefileEnvvar); fake != "" {
	if data, err := os.ReadFile(fake); err == nil {
	return string(data)
	}
	return "local"
	}
	return telemetry.Mode()
	}

	// setTelemetryMode sets the current telemetry mode.
	// By default this calls x/telemetry.SetMode, but it may be overridden for
	// tests.
	func (s *server) setTelemetryMode(mode string) error {
	if fake := s.getenv(FakeTelemetryModefileEnvvar); fake != "" {
	return os.WriteFile(fake, []byte(mode), 0666)
	}
	return telemetry.SetMode(mode)
	}

	// maybePromptForTelemetry checks for the right conditions, and then prompts
	// the user to ask if they want to enable Go telemetry uploading. If the user
	// responds 'Yes', the telemetry mode is set to "on".
	//
	// The actual conditions for prompting are defensive, erring on the side of not
	// prompting.
	// If enabled is false, this will not prompt the user in any condition,
	// but will send work progress reports to help testing.
	func (s *server) maybePromptForTelemetry(ctx context.Context, enabled bool) {
	if s.Options().VerboseWorkDoneProgress {
	work := s.progress.Start(ctx, TelemetryPromptWorkTitle, "Checking if gopls should prompt about telemetry...", nil, nil)
	defer work.End(ctx, "Done.")
	}

	errorf := func(format string, args ...any) {
	err := fmt.Errorf(format, args...)
	event.Error(ctx, "telemetry prompt failed", err)
	}

	// Only prompt if we can read/write the prompt config file.
	configDir := s.getenv(GoplsConfigDirEnvvar) // set for testing
	if configDir == "" && testing.Testing() {
	// Unless tests set GoplsConfigDirEnvvar, the prompt is a no op.
	// We don't want tests to interact with os.UserConfigDir().
	return
	}
	if configDir == "" {
	userDir, err := os.UserConfigDir()
	if err != nil {
	errorf("unable to determine user config dir: %v", err)
	return
	}
	configDir = filepath.Join(userDir, "gopls")
	}

	// Read the current prompt file.

	var (
	promptDir = filepath.Join(configDir, "prompt") // prompt configuration directory
	promptFile = filepath.Join(promptDir, "telemetry") // telemetry prompt file
	)

	// prompt states, stored in the prompt file
	const (
	pUnknown = "" // first time
	pNotReady = "-" // user is not asked yet (either not sampled or not past the grace period)
	pYes = "yes" // user said yes
	pNo = "no" // user said no
	pPending = "pending" // current prompt is still pending
	pFailed = "failed" // prompt was asked but failed
	)
	validStates := map[string]bool{
	pNotReady: true,
	pYes: true,
	pNo: true,
	pPending: true,
	pFailed: true,
	}

	// Parse the current prompt file.
	var (
	state = pUnknown
	attempts = 0 // number of times we've asked already

	// the followings are recorded after gopls v0.17+.
	token = 0 // valid token is [1, 1000]
	creationTime int64 // unix time sec
	)
	if content, err := os.ReadFile(promptFile); err == nil {
	if n, _ := fmt.Sscanf(string(content), "%s %d %d %d", &state, &attempts, &creationTime, &token); (n == 2 \|\| n == 4) && validStates[state] {
	// successfully parsed!
	// ~ v0.16: must have only two fields, state and attempts.
	// v0.17 ~: must have all four fields.
	} else {
	state, attempts, creationTime, token = pUnknown, 0, 0, 0
	// TODO(hyangah): why do we want to present this as an error to user?
	errorf("malformed prompt result %q", string(content))
	}
	} else if !os.IsNotExist(err) {
	errorf("reading prompt file: %v", err)
	// Something went wrong. Since we don't know how many times we've asked the
	// prompt, err on the side of not asking.
	//
	// But record this in telemetry, in case some users enable telemetry by
	// other means.
	counter.New("gopls/telemetryprompt/corrupted").Inc()
	return
	}

	counter.New(fmt.Sprintf("gopls/telemetryprompt/attempts:%d", attempts)).Inc()

	// Check terminal conditions.

	if state == pYes {
	// Prompt has been accepted.
	//
	// We record this counter for every gopls session, rather than when the
	// prompt actually accepted below, because if we only recorded it in the
	// counter file at the time telemetry is enabled, we'd never upload it,
	// because we exclude any counter files that overlap with a time period
	// that has telemetry uploading is disabled.
	counter.New("gopls/telemetryprompt/accepted").Inc()
	return
	}
	if state == pNo {
	// Prompt has been declined. In most cases, this means we'll never see the
	// counter below, but it's possible that the user may enable telemetry by
	// other means later on. If we see a significant number of users that have
	// accepted telemetry but declined the prompt, it may be an indication that
	// the prompt is not working well.
	counter.New("gopls/telemetryprompt/declined").Inc()
	return
	}
	if attempts >= 5 { // pPending or pFailed
	// We've tried asking enough; give up. Record that the prompt expired, in
	// case the user decides to enable telemetry by other means later on.
	// (see also the pNo case).
	counter.New("gopls/telemetryprompt/expired").Inc()
	return
	}

	// We only check enabled after (1) the work progress is started, and (2) the
	// prompt file has been read. (1) is for testing purposes, and (2) is so that
	// we record the "gopls/telemetryprompt/accepted" counter for every session.
	if !enabled {
	return // prompt is disabled
	}

	if s.telemetryMode() == "on" \|\| s.telemetryMode() == "off" {
	// Telemetry is already on or explicitly off -- nothing to ask about.
	return
	}

	// Transition: pUnknown -> pNotReady
	if state == pUnknown {
	// First time; we need to make the prompt dir.
	if err := os.MkdirAll(promptDir, 0777); err != nil {
	errorf("creating prompt dir: %v", err)
	return
	}
	state = pNotReady
	}

	// Correct missing values.
	if creationTime == 0 {
	creationTime = time.Now().Unix()
	if v := s.getenv(GoTelemetryGoplsClientStartTimeEnvvar); v != "" {
	if sec, err := strconv.ParseInt(v, 10, 64); err == nil && sec > 0 {
	creationTime = sec
	}
	}
	}
	if token == 0 {
	token = rand.Intn(1000) + 1
	if v := s.getenv(GoTelemetryGoplsClientTokenEnvvar); v != "" {
	if tok, err := strconv.Atoi(v); err == nil && 1 <= tok && tok <= 1000 {
	token = tok
	}
	}
	}

	// Transition: pNotReady -> pPending if sampled
	if state == pNotReady {
	threshold := samplesPerMille
	if v := s.getenv(FakeSamplesPerMille); v != "" {
	if t, err := strconv.Atoi(v); err == nil {
	threshold = t
	}
	}
	if token <= threshold && time.Now().Unix()-creationTime > gracePeriod.Milliseconds()/1000 {
	state = pPending
	}
	}

	// Acquire the lock and write the updated state to the prompt file before actually
	// prompting.
	//
	// This ensures that the prompt file is writeable, and that we increment the
	// attempt counter before we prompt, so that we don't end up in a failure
	// mode where we keep prompting and then failing to record the response.

	release, ok, err := acquireLockFile(promptFile)
	if err != nil {
	errorf("acquiring prompt: %v", err)
	return
	}
	if !ok {
	// Another process is making decision.
	return
	}
	defer release()

	if state != pNotReady { // pPending or pFailed
	attempts++
	}

	pendingContent := []byte(fmt.Sprintf("%s %d %d %d", state, attempts, creationTime, token))
	if err := os.WriteFile(promptFile, pendingContent, 0666); err != nil {
	errorf("writing pending state: %v", err)
	return
	}

	if state == pNotReady {
	return
	}

	var prompt = `Go telemetry helps us improve Go by periodically sending anonymous metrics and crash reports to the Go team. Learn more at https://go.dev/doc/telemetry.

	Would you like to enable Go telemetry?
	`
	if s.Options().LinkifyShowMessage {
	prompt = `Go telemetry helps us improve Go by periodically sending anonymous metrics and crash reports to the Go team. Learn more at [go.dev/doc/telemetry](https://go.dev/doc/telemetry).

	Would you like to enable Go telemetry?
	`
	}
	// TODO(rfindley): investigate a "tell me more" action in combination with ShowDocument.
	params := &protocol.ShowMessageRequestParams{
	Type: protocol.Info,
	Message: prompt,
	Actions: []protocol.MessageActionItem{
	{Title: TelemetryYes},
	{Title: TelemetryNo},
	},
	}

	item, err := s.client.ShowMessageRequest(ctx, params)
	if err != nil {
	errorf("ShowMessageRequest failed: %v", err)
	// Defensive: ensure item == nil for the logic below.
	item = nil
	}

	message := func(typ protocol.MessageType, msg string) {
	if !showMessage(ctx, s.client, typ, msg) {
	// Make sure we record that "telemetry prompt failed".
	errorf("showMessage failed: %v", err)
	}
	}

	result := pFailed
	if item == nil {
	// e.g. dialog was dismissed
	errorf("no response")
	} else {
	// Response matches MessageActionItem.Title.
	switch item.Title {
	case TelemetryYes:
	result = pYes
	if err := s.setTelemetryMode("on"); err == nil {
	message(protocol.Info, telemetryOnMessage(s.Options().LinkifyShowMessage))
	} else {
	errorf("enabling telemetry failed: %v", err)
	msg := fmt.Sprintf("Failed to enable Go telemetry: %v\nTo enable telemetry manually, please run `go run golang.org/x/telemetry/cmd/gotelemetry@latest on`", err)
	message(protocol.Error, msg)
	}

	case TelemetryNo:
	result = pNo
	default:
	errorf("unrecognized response %q", item.Title)
	message(protocol.Error, fmt.Sprintf("Unrecognized response %q", item.Title))
	}
	}
	resultContent := []byte(fmt.Sprintf("%s %d %d %d", result, attempts, creationTime, token))
	if err := os.WriteFile(promptFile, resultContent, 0666); err != nil {
	errorf("error writing result state to prompt file: %v", err)
	}
	}

	func telemetryOnMessage(linkify bool) string {
	format := `Thank you. Telemetry uploading is now enabled.

	To disable telemetry uploading, run %s.
	`
	var runCmd = "`go run golang.org/x/telemetry/cmd/gotelemetry@latest local`"
	if linkify {
	runCmd = "[gotelemetry local](https://golang.org/x/telemetry/cmd/gotelemetry)"
	}
	return fmt.Sprintf(format, runCmd)
	}

	// acquireLockFile attempts to "acquire a lock" for writing to path.
	//
	// This is achieved by creating an exclusive lock file at <path>.lock. Lock
	// files expire after a period, at which point acquireLockFile will remove and
	// recreate the lock file.
	//
	// acquireLockFile fails if path is in a directory that doesn't exist.
	func acquireLockFile(path string) (func(), bool, error) {
	lockpath := path + ".lock"
	fi, err := os.Stat(lockpath)
	if err == nil {
	if time.Since(fi.ModTime()) > promptTimeout {
	_ = os.Remove(lockpath) // ignore error
	} else {
	return nil, false, nil
	}
	} else if !os.IsNotExist(err) {
	return nil, false, fmt.Errorf("statting lockfile: %v", err)
	}

	f, err := os.OpenFile(lockpath, os.O_CREATE\|os.O_EXCL, 0666)
	if err != nil {
	if os.IsExist(err) {
	return nil, false, nil
	}
	return nil, false, fmt.Errorf("creating lockfile: %v", err)
	}
	fi, err = f.Stat()
	if err != nil {
	return nil, false, err
	}
	release := func() {
	_ = f.Close() // ignore error
	fi2, err := os.Stat(lockpath)
	if err == nil && os.SameFile(fi, fi2) {
	// Only clean up the lockfile if it's the same file we created.
	// Otherwise, our lock has expired and something else has the lock.
	//
	// There's a race here, in that the file could have changed since the
	// stat above; but given that we've already waited 24h this is extremely
	// unlikely, and acceptable.
	_ = os.Remove(lockpath)
	}
	}
	return release, true, nil
	}