From 1a2a672644c2146ff2f6efd1e42076555f80765d Mon Sep 17 00:00:00 2001
From: Romanos <rski@arista.com>
Date: Fri, 28 Aug 2020 07:06:28 +0100
Subject: [PATCH] Allow for serializing multiple golangci-lint invocations
 (#1302)

By default, golangci-lint fails after five seconds if another instance
is running. It is possible to disable that, but the discussion around
whether the cache is safe to use concurrently is not exactly full of
confidence. Add a flag that allows golangci-lint to wait forever
instead of failing.

see #1301
---
 pkg/commands/executor.go | 10 +++++++---
 pkg/commands/run.go      |  3 +++
 pkg/config/config.go     |  1 +
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/pkg/commands/executor.go b/pkg/commands/executor.go
index 9581acab..0becc990 100644
--- a/pkg/commands/executor.go
+++ b/pkg/commands/executor.go
@@ -218,11 +218,15 @@ func (e *Executor) acquireFileLock() bool {
 	lockFile := filepath.Join(os.TempDir(), "golangci-lint.lock")
 	e.debugf("Locking on file %s...", lockFile)
 	f := flock.New(lockFile)
-	const totalTimeout = 5 * time.Second
 	const retryDelay = time.Second
-	ctx, finish := context.WithTimeout(context.Background(), totalTimeout)
-	defer finish()
 
+	ctx := context.Background()
+	if !e.cfg.Run.AllowSerialRunners {
+		const totalTimeout = 5 * time.Second
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, totalTimeout)
+		defer cancel()
+	}
 	if ok, _ := f.TryLockContext(ctx, retryDelay); !ok {
 		return false
 	}
diff --git a/pkg/commands/run.go b/pkg/commands/run.go
index 3cd4381c..57cb5471 100644
--- a/pkg/commands/run.go
+++ b/pkg/commands/run.go
@@ -111,6 +111,9 @@ func initFlagSet(fs *pflag.FlagSet, cfg *config.Config, m *lintersdb.Manager, is
 	const allowParallelDesc = "Allow multiple parallel golangci-lint instances running. " +
 		"If false (default) - golangci-lint acquires file lock on start."
 	fs.BoolVar(&rc.AllowParallelRunners, "allow-parallel-runners", false, wh(allowParallelDesc))
+	const allowSerialDesc = "Allow multiple golangci-lint instances running, but serialize them	around a lock. " +
+		"If false (default) - golangci-lint exits with an error if it fails to acquire file lock on start."
+	fs.BoolVar(&rc.AllowSerialRunners, "allow-serial-runners", false, wh(allowSerialDesc))
 
 	// Linters settings config
 	lsc := &cfg.LintersSettings
diff --git a/pkg/config/config.go b/pkg/config/config.go
index bf7641f2..9689ea09 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -152,6 +152,7 @@ type Run struct {
 	UseDefaultSkipDirs bool     `mapstructure:"skip-dirs-use-default"`
 
 	AllowParallelRunners bool `mapstructure:"allow-parallel-runners"`
+	AllowSerialRunners   bool `mapstructure:"allow-serial-runners"`
 }
 
 type LintersSettings struct {