Remove static cling in plugin development flow.

api/internal/plugins/compiler/compiler.go

@@ -6,6 +6,7 @@ package compiler
 import (
 	"bytes"
 	"fmt"
+	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -16,61 +17,74 @@ import (
 )
 
 // 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
+	// pluginRoot is where the user
+	// has her ${g}/${v}/$lower(${k})/${k}.go files.
+	pluginRoot string
+	// Where compilation happens.
+	workDir string
+	// Used as the root file name for src and object.
+	rawKind string
+	// Capture compiler output.
+	stderr bytes.Buffer
+	// Capture compiler output.
+	stdout bytes.Buffer
 }
 
 // NewCompiler returns a new compiler instance.
-func NewCompiler(srcRoot, objRoot string) *Compiler {
-	return &Compiler{srcRoot: srcRoot, objRoot: objRoot}
+func NewCompiler(root string) *Compiler {
+	return &Compiler{pluginRoot: root}
 }
 
-// ObjRoot is root of compilation target tree.
-func (b *Compiler) ObjRoot() string {
-	return b.objRoot
+// Set GVK converts g,v,k tuples to file path components.
+func (b *Compiler) SetGVK(g, v, k string) {
+	b.rawKind = k
+	b.workDir = filepath.Join(b.pluginRoot, g, v, strings.ToLower(k))
 }
 
-// SrcRoot is where to find src.
-func (b *Compiler) SrcRoot() string {
-	return b.srcRoot
+func (b *Compiler) srcPath() string {
+	return filepath.Join(b.workDir, b.rawKind+".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 FileYoungerThan(objFile, time.Minute) {
-		// Skip rebuilding it.
+func (b *Compiler) objFile() string {
+	return b.rawKind + ".so"
+}
+
+// Absolute path to the compiler output (the .so file).
+func (b *Compiler) ObjPath() string {
+	return filepath.Join(b.workDir, b.objFile())
+}
+
+// Cleanup provides a hook to delete the .so file.
+// Ignore errors.
+func (b *Compiler) Cleanup() {
+	_ = os.Remove(b.ObjPath())
+}
+
+// Compile changes its working directory to
+// ${pluginRoot}/${g}/${v}/$lower(${k} and places
+// object code next to source code.
+func (b *Compiler) Compile() error {
+	if FileYoungerThan(b.ObjPath(), 8*time.Second) {
+		// Skip rebuilding it, to save time in a plugin test file
+		// that has many distinct calls to make a harness and compile
+		// the plugin (only the first compile will happen).
+		// Make it a short time to avoid tricking someone who's actively
+		// developing a plugin.
 		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
+	if !FileExists(b.srcPath()) {
+		return fmt.Errorf("cannot  find source at '%s'", b.srcPath())
 	}
+	// If you use an IDE, make sure it's go build and test flags
+	// match those used below.  Same goes for Makefile targets.
 	commands := []string{
 		"build",
+		// "-trimpath",  This flag used to make it better, now it makes it worse,
+		//               see https://github.com/golang/go/issues/31354
 		"-buildmode",
 		"plugin",
-		"-o", objFile, srcFile,
+		"-o", b.objFile(),
 	}
 	goBin := goBin()
 	if !FileExists(goBin) {
@@ -78,12 +92,26 @@ func (b *Compiler) Compile(g, v, k string) error {
 			"cannot find go compiler %s", goBin)
 	}
 	cmd := exec.Command(goBin, commands...)
-	var stderr bytes.Buffer
-	cmd.Stderr = &stderr
+	b.stderr.Reset()
+	cmd.Stderr = &b.stderr
+	b.stdout.Reset()
+	cmd.Stdout = &b.stdout
 	cmd.Env = os.Environ()
+	cmd.Dir = b.workDir
 	if err := cmd.Run(); err != nil {
+		b.report()
 		return errors.Wrapf(
-			err, "cannot compile %s:\nSTDERR\n%s\n", srcFile, stderr.String())
+			err, "cannot compile %s:\nSTDERR\n%s\n",
+			b.srcPath(), b.stderr.String())
 	}
 	return nil
 }
+
+func (b *Compiler) report() {
+	log.Println("stdout:  -------")
+	log.Println(b.stdout.String())
+	log.Println("----------------")
+	log.Println("stderr:  -------")
+	log.Println(b.stderr.String())
+	log.Println("----------------")
+}

api/internal/plugins/compiler/compiler_test.go

@@ -4,8 +4,6 @@
 package compiler_test
 
 import (
-	"io/ioutil"
-	"os"
 	"path/filepath"
 	"testing"
 	"time"
@@ -16,53 +14,46 @@ import (
 
 // 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 := DeterminePluginSrcRoot(filesys.MakeFsOnDisk())
 	if err != nil {
 		t.Error(err)
 	}
-	c := NewCompiler(srcRoot, configRoot)
-	if configRoot != c.ObjRoot() {
-		t.Errorf("unexpected objRoot %s", c.ObjRoot())
-	}
+	c := NewCompiler(srcRoot)
 
+	c.SetGVK("someteam.example.com", "v1", "DatePrefixer")
 	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)
+		srcRoot, "someteam.example.com", "v1", "dateprefixer", "DatePrefixer.so")
+	if expectObj != c.ObjPath() {
+		t.Errorf("Expected '%s', got '%s'", expectObj, c.ObjPath())
 	}
-	err = c.Compile("someteam.example.com", "v1", "DatePrefixer")
+	err = c.Compile()
 	if err != nil {
 		t.Error(err)
 	}
 	if !FileYoungerThan(expectObj, time.Second) {
 		t.Errorf("didn't find expected obj file %s", expectObj)
 	}
+	c.Cleanup()
+	if FileExists(expectObj) {
+		t.Errorf("obj file '%s' should be gone", expectObj)
+	}
 
+	c.SetGVK("builtin", "", "SecretGenerator")
 	expectObj = filepath.Join(
-		c.ObjRoot(),
+		srcRoot,
 		"builtin", "", "secretgenerator", "SecretGenerator.so")
-	if FileExists(expectObj) {
-		t.Errorf("obj file should not exist yet: %s", expectObj)
+	if expectObj != c.ObjPath() {
+		t.Errorf("Expected '%s', got '%s'", expectObj, c.ObjPath())
 	}
-	err = c.Compile("builtin", "", "SecretGenerator")
+	err = c.Compile()
 	if err != nil {
 		t.Error(err)
 	}
 	if !FileYoungerThan(expectObj, time.Second) {
 		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)
-	}
+	c.Cleanup()
 	if FileExists(expectObj) {
-		t.Errorf("cleanup failed; still see: %s", expectObj)
+		t.Errorf("obj file '%s' should be gone", expectObj)
 	}
 }