Revert "Cross-platform multi process support (eksctl-io#2230)"

This reverts commit 7af3408.

This broke eksctl on windows again, unfortunately.

go.mod

@@ -19,7 +19,6 @@ require (
 	github.com/fluxcd/helm-operator/pkg/install v0.0.0-20200407140510-8d71b0072a3e // helm-operator 1.0.0
 	github.com/github-release/github-release v0.8.1
 	github.com/gobwas/glob v0.2.3
-	github.com/gofrs/flock v0.7.1
 	github.com/golangci/golangci-lint v1.27.0
 	github.com/google/go-github/v31 v31.0.0
 	github.com/goreleaser/goreleaser v0.136.0

go.sum

@@ -358,9 +358,8 @@ 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/godbus/dbus v4.1.0+incompatible/go.mod h1:/YcGZj5zSblfDWMMoOzV4fas9FZnQYTkDnsGvmh2Grw=
 github.com/gofrs/flock v0.0.0-20190320160742-5135e617513b/go.mod h1:F1TvTiK9OcQqauNUHlbJvyl9Qa1QvF/gOUDKA14jxHU=
+github.com/gofrs/flock v0.7.0 h1:pGFUjl501gafK9HBt1VGL1KCOd/YhIooID+xgyJCf3g=
 github.com/gofrs/flock v0.7.0/go.mod h1:F1TvTiK9OcQqauNUHlbJvyl9Qa1QvF/gOUDKA14jxHU=
-github.com/gofrs/flock v0.7.1 h1:DP+LD/t0njgoPBvT5MJLeliUIVQR03hiKR6vezdwHlc=
-github.com/gofrs/flock v0.7.1/go.mod h1:F1TvTiK9OcQqauNUHlbJvyl9Qa1QvF/gOUDKA14jxHU=
 github.com/gogo/protobuf v0.0.0-20171007142547-342cbe0a0415/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.2.0/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=

pkg/utils/kubeconfig/kubeconfig.go

@@ -4,16 +4,15 @@ import (
 	"fmt"
 	"os"
 	"path"
-	"path/filepath"
 	"strings"
 
+	"github.com/weaveworks/eksctl/pkg/utils/file"
+
 	"os/exec"
 
-	"github.com/gofrs/flock"
 	"github.com/kris-nova/logger"
 	"github.com/pkg/errors"
 	api "github.com/weaveworks/eksctl/pkg/apis/eksctl.io/v1alpha5"
-	"github.com/weaveworks/eksctl/pkg/utils/file"
 	"k8s.io/client-go/tools/clientcmd"
 	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
 )
@@ -180,62 +179,12 @@ func AppendAuthenticator(config *clientcmdapi.Config, clusterMeta *api.ClusterMe
 	}
 }
 
-// ensureDirectory should probably be handled in flock
-func ensureDirectory(filePath string) error {
-	dir := filepath.Dir(filePath)
-	if _, err := os.Stat(dir); os.IsNotExist(err) {
-		if err = os.MkdirAll(dir, 0755); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func lockConfigFile(filePath string) error {
-	// Make sure the directory exists, otherwise flock fails
-	if err := ensureDirectory(filePath); err != nil {
-		return err
-	}
-	flock := flock.New(filePath)
-	err := flock.Lock()
-	if err != nil {
-		return errors.Wrap(err, "flock: failed to obtain exclusive lock on kubeconfig file")
-	}
-
-	return nil
-}
-
-func unlockConfigFile(filePath string) error {
-	// Make sure the directory exists, otherwise flock fails
-	if err := ensureDirectory(filePath); err != nil {
-		return err
-	}
-	flock := flock.New(filePath)
-	err := flock.Unlock()
-	if err != nil {
-		return errors.Wrap(err, "flock: failed to release exclusive lock on kubeconfig file")
-	}
-
-	return nil
-}
-
 // Write will write Kubernetes client configuration to a file.
 // If path isn't specified then the path will be determined by client-go.
 // If file pointed to by path doesn't exist it will be created.
 // If the file already exists then the configuration will be merged with the existing file.
 func Write(path string, newConfig clientcmdapi.Config, setContext bool) (string, error) {
 	configAccess := getConfigAccess(path)
-	configFileName := configAccess.GetDefaultFilename()
-	err := lockConfigFile(configFileName)
-	if err != nil {
-		return "", err
-	}
-
-	defer func() {
-		if err := unlockConfigFile(configFileName); err != nil {
-			logger.Critical(err.Error())
-		}
-	}()
 
 	config, err := configAccess.GetStartingConfig()
 	if err != nil {
@@ -254,7 +203,7 @@ func Write(path string, newConfig clientcmdapi.Config, setContext bool) (string,
 		return "", errors.Wrapf(err, "unable to modify kubeconfig %s", path)
 	}
 
-	return configFileName, nil
+	return configAccess.GetDefaultFilename(), nil
 }
 
 func getConfigAccess(explicitPath string) clientcmd.ConfigAccess {
@@ -314,17 +263,6 @@ func MaybeDeleteConfig(meta *api.ClusterMeta) {
 	p := AutoPath(meta.Name)
 
 	if file.Exists(p) {
-		err := lockConfigFile(p)
-		if err != nil {
-			logger.Critical(err.Error())
-		}
-
-		defer func() {
-			if err := unlockConfigFile(p); err != nil {
-				logger.Critical(err.Error())
-			}
-		}()
-
 		if err := isValidConfig(p, meta.Name); err != nil {
 			logger.Debug(err.Error())
 			return
@@ -336,18 +274,6 @@ func MaybeDeleteConfig(meta *api.ClusterMeta) {
 	}
 
 	configAccess := getConfigAccess(DefaultPath())
-	defaultFilename := configAccess.GetDefaultFilename()
-	err := lockConfigFile(defaultFilename)
-	if err != nil {
-		logger.Critical(err.Error())
-	}
-
-	defer func() {
-		if err := unlockConfigFile(defaultFilename); err != nil {
-			logger.Critical(err.Error())
-		}
-	}()
-
 	config, err := configAccess.GetStartingConfig()
 	if err != nil {
 		logger.Debug("error reading kubeconfig file %q: %s", DefaultPath(), err.Error())

pkg/utils/kubeconfig/kubeconfig_test.go

@@ -4,7 +4,6 @@ import (
 	"io/ioutil"
 	"os"
 	"path"
-	"sync"
 
 	eksctlapi "github.com/weaveworks/eksctl/pkg/apis/eksctl.io/v1alpha5"
 	"github.com/weaveworks/eksctl/pkg/utils/kubeconfig"
@@ -309,44 +308,4 @@ var _ = Describe("Kubeconfig", func() {
 			Expect(configFileAsBytes).To(MatchYAML(twoClustersAsBytes), "Should not change")
 		})
 	})
-
-	It("safely handles concurrent read-modify-write operations", func() {
-		var (
-			oneClusterAsBytes  []byte
-			twoClustersAsBytes []byte
-		)
-		ChangeKubeconfig()
-
-		var err error
-
-		if oneClusterAsBytes, err = ioutil.ReadFile("testdata/one_cluster.golden"); err != nil {
-			GinkgoT().Fatalf("failed reading .golden: %v", err)
-		}
-
-		if twoClustersAsBytes, err = ioutil.ReadFile("testdata/two_clusters.golden"); err != nil {
-			GinkgoT().Fatalf("failed reading .golden: %v", err)
-		}
-
-		var wg sync.WaitGroup
-		multiplier := 3
-		iters := 100
-		for i := 0; i < multiplier; i++ {
-			for k := 0; k < iters; k++ {
-				wg.Add(2)
-				go func() {
-					defer wg.Done()
-					_, err := configFile.Write(oneClusterAsBytes)
-					Expect(err).To(BeNil())
-				}()
-				go func() {
-					defer wg.Done()
-					_, err := configFile.Write(twoClustersAsBytes)
-					Expect(err).To(BeNil())
-				}()
-			}
-		}
-
-		wg.Wait()
-
-	})
 })