Make api/plugins

api/plugins/compiler/compiler.go

@@ -0,0 +1,146 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package compiler
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"time"
+
+	"sigs.k8s.io/kustomize/v3/api/pgmconfig"
+	"sigs.k8s.io/kustomize/v3/api/plugins/config"
+)
+
+// Compiler creates Go plugin object files.
+//
+// Source code is read from
+//   ${srcRoot}/${g}/${v}/${k}.go
+//
+// Object code is written to
+//   ${objRoot}/${g}/${v}/${k}.so
+type Compiler struct {
+	srcRoot string
+	objRoot string
+}
+
+// DefaultSrcRoot guesses where the user
+// has her ${g}/${v}/$lower(${k})/${k}.go files.
+func DefaultSrcRoot() (string, error) {
+	var nope []string
+	var root string
+
+	root = filepath.Join(
+		os.Getenv("GOPATH"), "src",
+		config.DomainName, pgmconfig.ProgramName, config.PluginRoot)
+	if FileExists(root) {
+		return root, nil
+	}
+	nope = append(nope, root)
+
+	root = config.DefaultPluginConfig().DirectoryPath
+	if FileExists(root) {
+		return root, nil
+	}
+	nope = append(nope, root)
+
+	root = filepath.Join(
+		config.HomeDir(), pgmconfig.ProgramName, config.PluginRoot)
+	if FileExists(root) {
+		return root, nil
+	}
+	nope = append(nope, root)
+
+	return "", fmt.Errorf(
+		"no default src root; tried %v", nope)
+}
+
+// NewCompiler returns a new compiler instance.
+func NewCompiler(srcRoot, objRoot string) *Compiler {
+	return &Compiler{srcRoot: srcRoot, objRoot: objRoot}
+}
+
+// ObjRoot is root of compilation target tree.
+func (b *Compiler) ObjRoot() string {
+	return b.objRoot
+}
+
+// SrcRoot is where to find src.
+func (b *Compiler) SrcRoot() string {
+	return b.srcRoot
+}
+
+func goBin() string {
+	return filepath.Join(runtime.GOROOT(), "bin", "go")
+}
+
+// Compile reads ${srcRoot}/${g}/${v}/${k}.go
+//    and writes ${objRoot}/${g}/${v}/${k}.so
+func (b *Compiler) Compile(g, v, k string) error {
+	lowK := strings.ToLower(k)
+	objDir := filepath.Join(b.objRoot, g, v, lowK)
+	objFile := filepath.Join(objDir, k) + ".so"
+	if RecentFileExists(objFile) {
+		// Skip rebuilding it.
+		return nil
+	}
+	err := os.MkdirAll(objDir, os.ModePerm)
+	if err != nil {
+		return err
+	}
+	srcFile := filepath.Join(b.srcRoot, g, v, lowK, k) + ".go"
+	if !FileExists(srcFile) {
+		// Handy for tests of lone plugins.
+		s := k + ".go"
+		if !FileExists(s) {
+			return fmt.Errorf(
+				"cannot find source at '%s' or '%s'", srcFile, s)
+
+		}
+		srcFile = s
+	}
+	commands := []string{
+		"build",
+		"-buildmode",
+		"plugin",
+		"-o", objFile, srcFile,
+	}
+	goBin := goBin()
+	if !FileExists(goBin) {
+		return fmt.Errorf(
+			"cannot find go compiler %s", goBin)
+	}
+	cmd := exec.Command(goBin, commands...)
+	cmd.Env = os.Environ()
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf(
+			"compiler error building %s: %v", srcFile, err)
+	}
+	return nil
+}
+
+// True if file less than 3 minutes old, i.e. not
+// accidentally left over from some earlier build.
+func RecentFileExists(path string) bool {
+	fi, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false
+		}
+	}
+	age := time.Now().Sub(fi.ModTime())
+	return age.Minutes() < 3
+}
+
+func FileExists(name string) bool {
+	if _, err := os.Stat(name); err != nil {
+		if os.IsNotExist(err) {
+			return false
+		}
+	}
+	return true
+}

api/plugins/compiler/compiler_test.go

@@ -0,0 +1,66 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package compiler_test
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	. "sigs.k8s.io/kustomize/v3/api/plugins/compiler"
+)
+
+// Regression coverage over compiler behavior.
+func TestCompiler(t *testing.T) {
+	configRoot, err := ioutil.TempDir("", "kustomize-compiler-test")
+	if err != nil {
+		t.Errorf("failed to make temp dir: %v", err)
+	}
+	srcRoot, err := DefaultSrcRoot()
+	if err != nil {
+		t.Error(err)
+	}
+	c := NewCompiler(srcRoot, configRoot)
+	if configRoot != c.ObjRoot() {
+		t.Errorf("unexpected objRoot %s", c.ObjRoot())
+	}
+
+	expectObj := filepath.Join(
+		c.ObjRoot(),
+		"someteam.example.com", "v1", "dateprefixer", "DatePrefixer.so")
+	if FileExists(expectObj) {
+		t.Errorf("obj file should not exist yet: %s", expectObj)
+	}
+	err = c.Compile("someteam.example.com", "v1", "DatePrefixer")
+	if err != nil {
+		t.Error(err)
+	}
+	if !RecentFileExists(expectObj) {
+		t.Errorf("didn't find expected obj file %s", expectObj)
+	}
+
+	expectObj = filepath.Join(
+		c.ObjRoot(),
+		"builtin", "", "secretgenerator", "SecretGenerator.so")
+	if FileExists(expectObj) {
+		t.Errorf("obj file should not exist yet: %s", expectObj)
+	}
+	err = c.Compile("builtin", "", "SecretGenerator")
+	if err != nil {
+		t.Error(err)
+	}
+	if !RecentFileExists(expectObj) {
+		t.Errorf("didn't find expected obj file %s", expectObj)
+	}
+
+	err = os.RemoveAll(c.ObjRoot())
+	if err != nil {
+		t.Errorf(
+			"removing temp dir: %s %v", c.ObjRoot(), err)
+	}
+	if FileExists(expectObj) {
+		t.Errorf("cleanup failed; still see: %s", expectObj)
+	}
+}