Make plugin utils package.

api/internal/plugins/utils/utils.go

@@ -0,0 +1,115 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package utils
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"time"
+
+	"sigs.k8s.io/kustomize/api/filesys"
+	"sigs.k8s.io/kustomize/api/konfig"
+)
+
+func GoBin() string {
+	return filepath.Join(runtime.GOROOT(), "bin", "go")
+}
+
+// DeterminePluginSrcRoot guesses where the user
+// has her ${g}/${v}/$lower(${k})/${k}.go files.
+func DeterminePluginSrcRoot(fSys filesys.FileSystem) (string, error) {
+	return konfig.FirstDirThatExistsElseError(
+		"source directory", fSys, []konfig.NotedFunc{
+			{
+				Note: "relative to unit test",
+				F: func() string {
+					return filepath.Clean(
+						filepath.Join(
+							os.Getenv("PWD"),
+							"..", "..",
+							konfig.RelPluginHome))
+				},
+			},
+			{
+				Note: "relative to unit test (internal pkg)",
+				F: func() string {
+					return filepath.Clean(
+						filepath.Join(
+							os.Getenv("PWD"),
+							"..", "..", "..", "..",
+							konfig.RelPluginHome))
+				},
+			},
+			{
+				Note: "relative to api package",
+				F: func() string {
+					return filepath.Clean(
+						filepath.Join(
+							os.Getenv("PWD"),
+							"..", "..", "..",
+							konfig.RelPluginHome))
+				},
+			},
+			{
+				Note: "old style $GOPATH",
+				F: func() string {
+					return filepath.Join(
+						os.Getenv("GOPATH"),
+						"src", konfig.DomainName,
+						konfig.ProgramName, konfig.RelPluginHome)
+				},
+			},
+			{
+				Note: "HOME with literal 'gopath'",
+				F: func() string {
+					return filepath.Join(
+						konfig.HomeDir(), "gopath",
+						"src", konfig.DomainName,
+						konfig.ProgramName, konfig.RelPluginHome)
+				},
+			},
+			{
+				Note: "home directory",
+				F: func() string {
+					return filepath.Join(
+						konfig.HomeDir(), konfig.DomainName,
+						konfig.ProgramName, konfig.RelPluginHome)
+				},
+			},
+		})
+}
+
+// FileYoungerThan returns true if the file both exists and has an
+// age is <= the Duration argument.
+func FileYoungerThan(path string, d time.Duration) bool {
+	fi, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false
+		}
+	}
+	return time.Since(fi.ModTime()) <= d
+}
+
+// FileModifiedAfter returns true if the file both exists and was
+// modified after the given time..
+func FileModifiedAfter(path string, t time.Time) bool {
+	fi, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false
+		}
+	}
+	return fi.ModTime().After(t)
+}
+
+func FileExists(path string) bool {
+	if _, err := os.Stat(path); err != nil {
+		if os.IsNotExist(err) {
+			return false
+		}
+	}
+	return true
+}

api/internal/plugins/utils/utils_test.go

@@ -0,0 +1,26 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package utils
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"sigs.k8s.io/kustomize/api/filesys"
+	"sigs.k8s.io/kustomize/api/konfig"
+)
+
+func TestDeterminePluginSrcRoot(t *testing.T) {
+	actual, err := DeterminePluginSrcRoot(filesys.MakeFsOnDisk())
+	if err != nil {
+		t.Error(err)
+	}
+	if !filepath.IsAbs(actual) {
+		t.Errorf("expected absolute path, but got '%s'", actual)
+	}
+	if !strings.HasSuffix(actual, konfig.RelPluginHome) {
+		t.Errorf("expected suffix '%s' in '%s'", konfig.RelPluginHome, actual)
+	}
+}