--- /dev/null
+// 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"
+ "os"
+ "os/exec"
+ "regexp"
+ "strings"
+ "sync"
+ "time"
+
+ "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
+ ModFlag string
+ ModFile string
+ 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)
+ }
+ }
+
+ 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()
+ 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.
+ cmd.Env = append(os.Environ(), 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)
+}
+
+// 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()
+ }()
+
+ 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.
+ cmd.Process.Kill()
+ return <-resChan
+}
+
+func cmdDebugStr(cmd *exec.Cmd) string {
+ env := make(map[string]string)
+ for _, kv := range cmd.Env {
+ split := strings.Split(kv, "=")
+ k, v := split[0], split[1]
+ env[k] = v
+ }
+
+ return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v GOPROXY=%v PWD=%v go %v", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["GOPROXY"], env["PWD"], cmd.Args)
+}
projects / dotfiles / .git / blobdiff