Lock by flock to prevent parallel runs (#812)

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/fatih/color v1.7.0
 	github.com/go-critic/go-critic v0.3.5-0.20190904082202-d79a9f0c64db
 	github.com/go-lintpack/lintpack v0.5.2
+	github.com/gofrs/flock v0.0.0-20190320160742-5135e617513b
 	github.com/golangci/check v0.0.0-20180506172741-cfe4005ccda2
 	github.com/golangci/dupl v0.0.0-20180902072040-3e9179ac440a
 	github.com/golangci/errcheck v0.0.0-20181223084120-ef45e06d44b6

go.sum

@@ -66,6 +66,8 @@ github.com/go-toolsmith/typep v1.0.0 h1:zKymWyA1TRYvqYrYDrfEMZULyrhcnGY3x7LDKU2X
 github.com/go-toolsmith/typep v1.0.0/go.mod h1:JSQCQMUPdRlMZFswiq3TGpNp1GMktqkR2Ns5AIQkATU=
 github.com/gobwas/glob v0.2.3 h1:A4xDbljILXROh+kObIiy5kIaPYD8e96x1tgBhUI5J+Y=
 github.com/gobwas/glob v0.2.3/go.mod h1:d3Ez4x06l9bZtSvzIay5+Yzi0fmZzPgnTbPcKjJAkT8=
+github.com/gofrs/flock v0.0.0-20190320160742-5135e617513b h1:ekuhfTjngPhisSjOJ0QWKpPQE8/rbknHaes6WVJj5Hw=
+github.com/gofrs/flock v0.0.0-20190320160742-5135e617513b/go.mod h1:F1TvTiK9OcQqauNUHlbJvyl9Qa1QvF/gOUDKA14jxHU=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.2.1 h1:/s5zKNz0uPFCZ5hddgPdo2TK2TVrUNMn0OOX8/aZMTE=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=

pkg/commands/executor.go

@@ -2,11 +2,13 @@ package commands
 
 import (
 	"bytes"
+	"context"
 	"crypto/sha256"
 	"encoding/json"
 	"fmt"
 	"io"
 	"os"
+	"time"
 
 	"github.com/golangci/golangci-lint/internal/cache"
 
@@ -15,6 +17,8 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 
+	"github.com/gofrs/flock"
+
 	"github.com/golangci/golangci-lint/internal/pkgcache"
 	"github.com/golangci/golangci-lint/pkg/config"
 	"github.com/golangci/golangci-lint/pkg/fsutils"
@@ -48,6 +52,7 @@ type Executor struct {
 	sw                *timeutils.Stopwatch
 
 	loadGuard *load.Guard
+	flock     *flock.Flock
 }
 
 func NewExecutor(version, commit, date string) *Executor {
@@ -62,6 +67,9 @@ func NewExecutor(version, commit, date string) *Executor {
 
 	e.debugf("Starting execution...")
 	e.log = report.NewLogWrapper(logutils.NewStderrLog(""), &e.reportData)
+	if ok := e.acquireFileLock(); !ok {
+		e.log.Fatalf("Parallel golangci-lint is running")
+	}
 
 	// to setup log level early we need to parse config from command line extra time to
 	// find `-v` option
@@ -195,3 +203,24 @@ func computeConfigSalt(cfg *config.Config) ([]byte, error) {
 	}
 	return h.Sum(nil), nil
 }
+
+func (e *Executor) acquireFileLock() bool {
+	lockFile := os.TempDir() + "/golangci-lint.lock"
+	e.debugf("Locking on file %s...", lockFile)
+	f := flock.New(lockFile)
+	ctx, finish := context.WithTimeout(context.Background(), time.Minute)
+	defer finish()
+
+	if ok, _ := f.TryLockContext(ctx, time.Second*3); !ok {
+		return false
+	}
+
+	e.flock = f
+	return true
+}
+
+func (e *Executor) releaseFileLock() {
+	if err := e.flock.Unlock(); err != nil {
+		e.debugf("Failed to unlock on file: %s", err)
+	}
+}

pkg/commands/root.go

@@ -73,6 +73,7 @@ func (e *Executor) persistentPostRun(_ *cobra.Command, _ []string) {
 		trace.Stop()
 	}
 
+	e.releaseFileLock()
 	os.Exit(e.exitCode)
 }
 

pkg/commands/run.go

@@ -453,7 +453,6 @@ func watchResources(ctx context.Context, done chan struct{}, logger logutils.Log
 	const MB = 1024 * 1024
 
 	track := func() {
-		debugf("Starting memory tracing iteration ...")
 		var m runtime.MemStats
 		runtime.ReadMemStats(&m)