diff options
Diffstat (limited to 'vendor/golang.org/x/tools/internal/gocommand/invoke.go')
-rw-r--r-- | vendor/golang.org/x/tools/internal/gocommand/invoke.go | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/internal/gocommand/invoke.go b/vendor/golang.org/x/tools/internal/gocommand/invoke.go new file mode 100644 index 0000000..f516e17 --- /dev/null +++ b/vendor/golang.org/x/tools/internal/gocommand/invoke.go @@ -0,0 +1,230 @@ +// 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 + 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} + switch i.Verb { + case "mod": + // mod needs the sub-verb before build flags. + goArgs = append(goArgs, i.Args[0]) + goArgs = append(goArgs, i.BuildFlags...) + goArgs = append(goArgs, i.Args[1:]...) + case "env": + // env doesn't take build flags. + goArgs = append(goArgs, i.Args...) + default: + goArgs = append(goArgs, i.BuildFlags...) + 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) +} |