gtsocial-umbx

invoke.go (10526B)

---

 // Copyright 2020 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 gocommand is a helper for calling the go command.
 package gocommand
 
 import (
 	"bytes"
 	"context"
 	"fmt"
 	"io"
 	"log"
 	"os"
 	"regexp"
 	"runtime"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
 
 	exec "golang.org/x/sys/execabs"
 
 	"golang.org/x/tools/internal/event"
 )
 
 // An Runner will run go command invocations and serialize
 // them if it sees a concurrency error.
 type Runner struct {
 	// once guards the runner initialization.
 	once sync.Once
 
 	// inFlight tracks available workers.
 	inFlight chan struct{}
 
 	// serialized guards the ability to run a go command serially,
 	// to avoid deadlocks when claiming workers.
 	serialized chan struct{}
 }
 
 const maxInFlight = 10
 
 func (runner *Runner) initialize() {
 	runner.once.Do(func() {
 		runner.inFlight = make(chan struct{}, maxInFlight)
 		runner.serialized = make(chan struct{}, 1)
 	})
 }
 
 // 1.13: go: updates to go.mod needed, but contents have changed
 // 1.14: go: updating go.mod: existing contents have changed since last read
 var modConcurrencyError = regexp.MustCompile(`go:.*go.mod.*contents have changed`)
 
 // Run is a convenience wrapper around RunRaw.
 // It returns only stdout and a "friendly" error.
 func (runner *Runner) Run(ctx context.Context, inv Invocation) (*bytes.Buffer, error) {
 	stdout, _, friendly, _ := runner.RunRaw(ctx, inv)
 	return stdout, friendly
 }
 
 // RunPiped runs the invocation serially, always waiting for any concurrent
 // invocations to complete first.
 func (runner *Runner) RunPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) error {
 	_, err := runner.runPiped(ctx, inv, stdout, stderr)
 	return err
 }
 
 // RunRaw runs the invocation, serializing requests only if they fight over
 // go.mod changes.
 func (runner *Runner) RunRaw(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
 	// Make sure the runner is always initialized.
 	runner.initialize()
 
 	// First, try to run the go command concurrently.
 	stdout, stderr, friendlyErr, err := runner.runConcurrent(ctx, inv)
 
 	// If we encounter a load concurrency error, we need to retry serially.
 	if friendlyErr == nil || !modConcurrencyError.MatchString(friendlyErr.Error()) {
 		return stdout, stderr, friendlyErr, err
 	}
 	event.Error(ctx, "Load concurrency error, will retry serially", err)
 
 	// Run serially by calling runPiped.
 	stdout.Reset()
 	stderr.Reset()
 	friendlyErr, err = runner.runPiped(ctx, inv, stdout, stderr)
 	return stdout, stderr, friendlyErr, err
 }
 
 func (runner *Runner) runConcurrent(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
 	// Wait for 1 worker to become available.
 	select {
 	case <-ctx.Done():
 		return nil, nil, nil, ctx.Err()
 	case runner.inFlight <- struct{}{}:
 		defer func() { <-runner.inFlight }()
 	}
 
 	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
 	friendlyErr, err := inv.runWithFriendlyError(ctx, stdout, stderr)
 	return stdout, stderr, friendlyErr, err
 }
 
 func (runner *Runner) runPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) (error, error) {
 	// Make sure the runner is always initialized.
 	runner.initialize()
 
 	// Acquire the serialization lock. This avoids deadlocks between two
 	// runPiped commands.
 	select {
 	case <-ctx.Done():
 		return nil, ctx.Err()
 	case runner.serialized <- struct{}{}:
 		defer func() { <-runner.serialized }()
 	}
 
 	// Wait for all in-progress go commands to return before proceeding,
 	// to avoid load concurrency errors.
 	for i := 0; i < maxInFlight; i++ {
 		select {
 		case <-ctx.Done():
 			return nil, ctx.Err()
 		case runner.inFlight <- struct{}{}:
 			// Make sure we always "return" any workers we took.
 			defer func() { <-runner.inFlight }()
 		}
 	}
 
 	return inv.runWithFriendlyError(ctx, stdout, stderr)
 }
 
 // An Invocation represents a call to the go command.
 type Invocation struct {
 	Verb       string
 	Args       []string
 	BuildFlags []string
 
 	// If ModFlag is set, the go command is invoked with -mod=ModFlag.
 	ModFlag string
 
 	// If ModFile is set, the go command is invoked with -modfile=ModFile.
 	ModFile string
 
 	// If Overlay is set, the go command is invoked with -overlay=Overlay.
 	Overlay string
 
 	// If CleanEnv is set, the invocation will run only with the environment
 	// in Env, not starting with os.Environ.
 	CleanEnv   bool
 	Env        []string
 	WorkingDir string
 	Logf       func(format string, args ...interface{})
 }
 
 func (i *Invocation) runWithFriendlyError(ctx context.Context, stdout, stderr io.Writer) (friendlyError error, rawError error) {
 	rawError = i.run(ctx, stdout, stderr)
 	if rawError != nil {
 		friendlyError = rawError
 		// Check for 'go' executable not being found.
 		if ee, ok := rawError.(*exec.Error); ok && ee.Err == exec.ErrNotFound {
 			friendlyError = fmt.Errorf("go command required, not found: %v", ee)
 		}
 		if ctx.Err() != nil {
 			friendlyError = ctx.Err()
 		}
 		friendlyError = fmt.Errorf("err: %v: stderr: %s", friendlyError, stderr)
 	}
 	return
 }
 
 func (i *Invocation) run(ctx context.Context, stdout, stderr io.Writer) error {
 	log := i.Logf
 	if log == nil {
 		log = func(string, ...interface{}) {}
 	}
 
 	goArgs := []string{i.Verb}
 
 	appendModFile := func() {
 		if i.ModFile != "" {
 			goArgs = append(goArgs, "-modfile="+i.ModFile)
 		}
 	}
 	appendModFlag := func() {
 		if i.ModFlag != "" {
 			goArgs = append(goArgs, "-mod="+i.ModFlag)
 		}
 	}
 	appendOverlayFlag := func() {
 		if i.Overlay != "" {
 			goArgs = append(goArgs, "-overlay="+i.Overlay)
 		}
 	}
 
 	switch i.Verb {
 	case "env", "version":
 		goArgs = append(goArgs, i.Args...)
 	case "mod":
 		// mod needs the sub-verb before flags.
 		goArgs = append(goArgs, i.Args[0])
 		appendModFile()
 		goArgs = append(goArgs, i.Args[1:]...)
 	case "get":
 		goArgs = append(goArgs, i.BuildFlags...)
 		appendModFile()
 		goArgs = append(goArgs, i.Args...)
 
 	default: // notably list and build.
 		goArgs = append(goArgs, i.BuildFlags...)
 		appendModFile()
 		appendModFlag()
 		appendOverlayFlag()
 		goArgs = append(goArgs, i.Args...)
 	}
 	cmd := exec.Command("go", goArgs...)
 	cmd.Stdout = stdout
 	cmd.Stderr = stderr
 	// On darwin the cwd gets resolved to the real path, which breaks anything that
 	// expects the working directory to keep the original path, including the
 	// go command when dealing with modules.
 	// The Go stdlib has a special feature where if the cwd and the PWD are the
 	// same node then it trusts the PWD, so by setting it in the env for the child
 	// process we fix up all the paths returned by the go command.
 	if !i.CleanEnv {
 		cmd.Env = os.Environ()
 	}
 	cmd.Env = append(cmd.Env, i.Env...)
 	if i.WorkingDir != "" {
 		cmd.Env = append(cmd.Env, "PWD="+i.WorkingDir)
 		cmd.Dir = i.WorkingDir
 	}
 	defer func(start time.Time) { log("%s for %v", time.Since(start), cmdDebugStr(cmd)) }(time.Now())
 
 	return runCmdContext(ctx, cmd)
 }
 
 // DebugHangingGoCommands may be set by tests to enable additional
 // instrumentation (including panics) for debugging hanging Go commands.
 //
 // See golang/go#54461 for details.
 var DebugHangingGoCommands = false
 
 // runCmdContext is like exec.CommandContext except it sends os.Interrupt
 // before os.Kill.
 func runCmdContext(ctx context.Context, cmd *exec.Cmd) error {
 	if err := cmd.Start(); err != nil {
 		return err
 	}
 	resChan := make(chan error, 1)
 	go func() {
 		resChan <- cmd.Wait()
 	}()
 
 	// If we're interested in debugging hanging Go commands, stop waiting after a
 	// minute and panic with interesting information.
 	if DebugHangingGoCommands {
 		select {
 		case err := <-resChan:
 			return err
 		case <-time.After(1 * time.Minute):
 			HandleHangingGoCommand(cmd.Process)
 		case <-ctx.Done():
 		}
 	} else {
 		select {
 		case err := <-resChan:
 			return err
 		case <-ctx.Done():
 		}
 	}
 
 	// Cancelled. Interrupt and see if it ends voluntarily.
 	cmd.Process.Signal(os.Interrupt)
 	select {
 	case err := <-resChan:
 		return err
 	case <-time.After(time.Second):
 	}
 
 	// Didn't shut down in response to interrupt. Kill it hard.
 	// TODO(rfindley): per advice from bcmills@, it may be better to send SIGQUIT
 	// on certain platforms, such as unix.
 	if err := cmd.Process.Kill(); err != nil && DebugHangingGoCommands {
 		// Don't panic here as this reliably fails on windows with EINVAL.
 		log.Printf("error killing the Go command: %v", err)
 	}
 
 	// See above: don't wait indefinitely if we're debugging hanging Go commands.
 	if DebugHangingGoCommands {
 		select {
 		case err := <-resChan:
 			return err
 		case <-time.After(10 * time.Second): // a shorter wait as resChan should return quickly following Kill
 			HandleHangingGoCommand(cmd.Process)
 		}
 	}
 	return <-resChan
 }
 
 func HandleHangingGoCommand(proc *os.Process) {
 	switch runtime.GOOS {
 	case "linux", "darwin", "freebsd", "netbsd":
 		fmt.Fprintln(os.Stderr, `DETECTED A HANGING GO COMMAND
 
 The gopls test runner has detected a hanging go command. In order to debug
 this, the output of ps and lsof/fstat is printed below.
 
 See golang/go#54461 for more details.`)
 
 		fmt.Fprintln(os.Stderr, "\nps axo ppid,pid,command:")
 		fmt.Fprintln(os.Stderr, "-------------------------")
 		psCmd := exec.Command("ps", "axo", "ppid,pid,command")
 		psCmd.Stdout = os.Stderr
 		psCmd.Stderr = os.Stderr
 		if err := psCmd.Run(); err != nil {
 			panic(fmt.Sprintf("running ps: %v", err))
 		}
 
 		listFiles := "lsof"
 		if runtime.GOOS == "freebsd" || runtime.GOOS == "netbsd" {
 			listFiles = "fstat"
 		}
 
 		fmt.Fprintln(os.Stderr, "\n"+listFiles+":")
 		fmt.Fprintln(os.Stderr, "-----")
 		listFilesCmd := exec.Command(listFiles)
 		listFilesCmd.Stdout = os.Stderr
 		listFilesCmd.Stderr = os.Stderr
 		if err := listFilesCmd.Run(); err != nil {
 			panic(fmt.Sprintf("running %s: %v", listFiles, err))
 		}
 	}
 	panic(fmt.Sprintf("detected hanging go command (pid %d): see golang/go#54461 for more details", proc.Pid))
 }
 
 func cmdDebugStr(cmd *exec.Cmd) string {
 	env := make(map[string]string)
 	for _, kv := range cmd.Env {
 		split := strings.SplitN(kv, "=", 2)
 		if len(split) == 2 {
 			k, v := split[0], split[1]
 			env[k] = v
 		}
 	}
 
 	var args []string
 	for _, arg := range cmd.Args {
 		quoted := strconv.Quote(arg)
 		if quoted[1:len(quoted)-1] != arg || strings.Contains(arg, " ") {
 			args = append(args, quoted)
 		} else {
 			args = append(args, arg)
 		}
 	}
 	return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v GOPROXY=%v PWD=%v %v", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["GOPROXY"], env["PWD"], strings.Join(args, " "))
 }