cmd/entc: support custom target on codegen (#189)

Summary:
Pull Request resolved: https://github.com/facebookincubator/ent/pull/189

Fixes #61

Reviewed By: alexsn

Differential Revision: D18676988

fbshipit-source-id: 00d415e14d1278a45edea49c69abe4916303f55d

cmd/entc/entc.go

@@ -95,6 +95,13 @@ func main() {
 						for _, tmpl := range template {
 							opts = append(opts, entc.TemplateDir(tmpl))
 						}
+						// If the target directory is not inferred from
+						// the schema path, resolve its package path.
+						if cfg.Target != "" {
+							pkgPath, err := PkgPath(DefaultConfig, cfg.Target)
+							failOnErr(err)
+							cfg.Package = pkgPath
+						}
 						cfg.IDType = &field.TypeInfo{Type: field.Type(idtype)}
 						err := entc.Generate(path[0], &cfg, opts...)
 						failOnErr(err)

cmd/entc/packages.go

@@ -20,27 +20,32 @@ func PkgPath(config *packages.Config, target string) (string, error) {
 	if config == nil {
 		config = DefaultConfig
 	}
-	abs, err := filepath.Abs(target)
+	pathCheck, err := filepath.Abs(target)
 	if err != nil {
 		return "", err
 	}
-	pathCheck := abs
+	var parts []string
 	if _, err := os.Stat(pathCheck); os.IsNotExist(err) {
-		pathCheck = filepath.Dir(abs)
+		parts = append(parts, filepath.Base(pathCheck))
+		pathCheck = filepath.Dir(pathCheck)
 	}
-	pkgs, err := packages.Load(config, pathCheck)
-	if err != nil {
-		return "", fmt.Errorf("load package info: %v", err)
+	// Try maximum 2 directories above the given target
+	// to find the root packages or module.
+	for i := 0; i < 2; i++ {
+		pkgs, err := packages.Load(config, pathCheck)
+		if err != nil {
+			return "", fmt.Errorf("load package info: %v", err)
+		}
+		if len(pkgs) == 0 || len(pkgs[0].Errors) != 0 {
+			parts = append(parts, filepath.Base(pathCheck))
+			pathCheck = filepath.Dir(pathCheck)
+			continue
+		}
+		pkgPath := pkgs[0].PkgPath
+		for j := len(parts) - 1; j >= 0; j-- {
+			pkgPath = path.Join(pkgPath, parts[j])
+		}
+		return pkgPath, nil
 	}
-	if len(pkgs) == 0 {
-		return "", fmt.Errorf("no package was found for: %s", pathCheck)
-	}
-	if errs := pkgs[0].Errors; len(errs) != 0 {
-		return "", errs[0]
-	}
-	pkgPath := pkgs[0].PkgPath
-	if abs != pathCheck {
-		pkgPath = path.Join(pkgPath, filepath.Base(abs))
-	}
-	return pkgPath, nil
+	return "", fmt.Errorf("root package or module was not found for: %s", target)
 }

cmd/entc/packages_test.go

@@ -35,6 +35,11 @@ func testPkgPath(t *testing.T, x packagestest.Exporter) {
 
 	target = filepath.Join(e.Config.Dir, "z/ent")
 	pkgPath, err = PkgPath(e.Config, target)
+	require.NoError(t, err)
+	require.Equal(t, "golang.org/x/y/z/ent", pkgPath)
+
+	target = filepath.Join(e.Config.Dir, "z/e/n/t")
+	pkgPath, err = PkgPath(e.Config, target)
 	require.Error(t, err)
 	require.Empty(t, pkgPath)
 }