better error handling in gen package (#134)

cbusbey · cbusbey · commit 464c601a487c · 2016-05-13T09:19:51.000-05:00
diff --git a/gen/generate-components/main.go b/gen/generate-components/main.go
@@ -66,13 +66,13 @@ func genGroupDeclarations(name string, fields []datadictionary.MessagePart) (fil
 	return
 }
 
-func genHeader(header *datadictionary.MessageDef) {
+func genHeader(header *datadictionary.MessageDef) error {
 	writer := new(bytes.Buffer)
 	if err := gen.WritePackage(writer, pkg); err != nil {
-		panic(err)
+		return err
 	}
 	if err := gen.WriteComponentImports(writer, pkg, header.Parts); err != nil {
-		panic(err)
+		return err
 	}
 
 	fileOut := writer.String()
@@ -84,20 +84,20 @@ func genHeader(header *datadictionary.MessageDef) {
 
 	writer = new(bytes.Buffer)
 	if err := gen.WriteFieldSetters(writer, "Header", header.Parts); err != nil {
-		panic(err)
+		return err
 	}
 	fileOut += writer.String()
 
-	gen.WriteFile(path.Join(pkg, "header.go"), fileOut)
+	return gen.WriteFile(path.Join(pkg, "header.go"), fileOut)
 }
 
-func genTrailer(trailer *datadictionary.MessageDef) {
+func genTrailer(trailer *datadictionary.MessageDef) error {
 	writer := new(bytes.Buffer)
 	if err := gen.WritePackage(writer, pkg); err != nil {
-		panic(err)
+		return err
 	}
 	if err := gen.WriteComponentImports(writer, pkg, trailer.Parts); err != nil {
-		panic(err)
+		return err
 	}
 	fileOut := writer.String()
 
@@ -108,24 +108,24 @@ func genTrailer(trailer *datadictionary.MessageDef) {
 
 	writer = new(bytes.Buffer)
 	if err := gen.WriteFieldSetters(writer, "Trailer", trailer.Parts); err != nil {
-		panic(err)
+		return err
 	}
 	fileOut += writer.String()
 
-	gen.WriteFile(path.Join(pkg, "trailer.go"), fileOut)
+	return gen.WriteFile(path.Join(pkg, "trailer.go"), fileOut)
 }
 
-func genComponent(name string, component *datadictionary.ComponentType) {
+func genComponent(name string, component *datadictionary.ComponentType) error {
 	writer := new(bytes.Buffer)
 	if err := gen.WritePackage(writer, strings.ToLower(name)); err != nil {
-		panic(err)
+		return err
 	}
 	if err := gen.WriteComponentImports(writer, pkg, component.Parts()); err != nil {
-		panic(err)
+		return err
 	}
 
 	if err := gen.WriteNewComponent(writer, *component); err != nil {
-		panic(err)
+		return err
 	}
 
 	fileOut := writer.String()
@@ -136,7 +136,7 @@ func genComponent(name string, component *datadictionary.ComponentType) {
 	fileOut += "}\n"
 	fileOut += genComponentSetters(component)
 
-	gen.WriteFile(path.Join(pkg, strings.ToLower(name), name+".go"), fileOut)
+	return gen.WriteFile(path.Join(pkg, strings.ToLower(name), name+".go"), fileOut)
 }
 
 func genComponentSetters(component *datadictionary.ComponentType) string {
@@ -173,15 +173,18 @@ func main() {
 		panic(pkg + "/ is not a directory")
 	}
 
+	var h gen.ErrorHandler
 	switch pkg {
 	//uses fixt11 header/trailer
 	case "fix50", "fix50sp1", "fix50sp2":
 	default:
-		genHeader(fixSpec.Header)
-		genTrailer(fixSpec.Trailer)
+		h.Handle(genHeader(fixSpec.Header))
+		h.Handle(genTrailer(fixSpec.Trailer))
 	}
 
 	for name, component := range fixSpec.ComponentTypes {
-		genComponent(name, component)
+		h.Handle(genComponent(name, component))
 	}
+
+	os.Exit(h.ReturnCode)
 }
diff --git a/gen/generate-fields/main.go b/gen/generate-fields/main.go
@@ -22,7 +22,7 @@ func usage() {
 	os.Exit(2)
 }
 
-func genEnums() {
+func genEnums() error {
 	fileOut := "package enum\n"
 
 	for _, fieldName := range sortedTags {
@@ -48,10 +48,10 @@ func genEnums() {
 		fileOut += ")\n"
 	}
 
-	gen.WriteFile("enum/enums.go", fileOut)
+	return gen.WriteFile("enum/enums.go", fileOut)
 }
 
-func genFields() {
+func genFields() error {
 	fileOut := "package field\n"
 	fileOut += "import(\n"
 	fileOut += "\"github.com/quickfixgo/quickfix\"\n"
@@ -140,7 +140,7 @@ func genFields() {
 			goType = "float64"
 
 		default:
-			fmt.Printf("Unknown type '%v' for tag '%v'\n", field.Type, tag)
+			return fmt.Errorf("Unknown type '%v' for tag '%v'\n", field.Type, tag)
 		}
 
 		fileOut += fmt.Sprintf("//%vField is a %v field\n", field.Name(), field.Type)
@@ -157,10 +157,10 @@ func genFields() {
 		}
 	}
 
-	gen.WriteFile("field/fields.go", fileOut)
+	return gen.WriteFile("field/fields.go", fileOut)
 }
 
-func genTags() {
+func genTags() error {
 	fileOut := "package tag\n"
 	fileOut += "import(\"github.com/quickfixgo/quickfix\")\n"
 
@@ -170,7 +170,7 @@ func genTags() {
 	}
 	fileOut += ")\n"
 
-	gen.WriteFile("tag/tag_numbers.go", fileOut)
+	return gen.WriteFile("tag/tag_numbers.go", fileOut)
 }
 
 func main() {
@@ -231,7 +231,9 @@ func main() {
 	}
 	sort.Strings(sortedTags)
 
-	genTags()
-	genFields()
-	genEnums()
+	var h gen.ErrorHandler
+	h.Handle(genTags())
+	h.Handle(genFields())
+	h.Handle(genEnums())
+	os.Exit(h.ReturnCode)
 }
diff --git a/gen/generate-messages/main.go b/gen/generate-messages/main.go
@@ -34,12 +34,6 @@ func initPackage() {
 	}
 }
 
-func genMessages() {
-	for _, m := range fixSpec.Messages {
-		genMessagePkg(m)
-	}
-}
-
 type group struct {
 	parent string
 	field  *datadictionary.FieldDef
@@ -138,16 +132,16 @@ func Route(router RouteOut) (string,string,quickfix.MessageRoute) {
 	return fileOut
 }
 
-func genMessagePkg(msg *datadictionary.MessageDef) {
+func genMessagePkg(msg *datadictionary.MessageDef) error {
 	pkgName := strings.ToLower(msg.Name)
 	fileOut := fmt.Sprintf("//Package %v msg type = %v.\n", pkgName, msg.MsgType)
 
 	writer := new(bytes.Buffer)
 	if err := gen.WritePackage(writer, pkgName); err != nil {
-		panic(err)
+		return err
 	}
 	if err := gen.WriteMessageImports(writer, pkg, msg.Parts); err != nil {
-		panic(err)
+		return err
 	}
 	fileOut += writer.String()
 	fileOut += genGroupDeclarations(msg)
@@ -156,7 +150,7 @@ func genMessagePkg(msg *datadictionary.MessageDef) {
 	fileOut += genMessageSetters(msg)
 	fileOut += genMessageRoute(msg)
 
-	gen.WriteFile(path.Join(pkg, strings.ToLower(msg.Name), msg.Name+".go"), fileOut)
+	return gen.WriteFile(path.Join(pkg, strings.ToLower(msg.Name), msg.Name+".go"), fileOut)
 }
 
 func main() {
@@ -193,5 +187,9 @@ func main() {
 		panic(pkg + "/ is not a directory")
 	}
 
-	genMessages()
+	var h gen.ErrorHandler
+	for _, m := range fixSpec.Messages {
+		h.Handle(genMessagePkg(m))
+	}
+	os.Exit(h.ReturnCode)
 }
diff --git a/gen/generate.go b/gen/generate.go
@@ -12,38 +12,73 @@ import (
 
 var (
 	tabWidth    = 8
-	printerMode printer.Mode
+	printerMode = printer.UseSpaces | printer.TabIndent
 )
 
-func init() {
-	initPrinterMode()
+//ParseError indicates generated go source is invalid
+type ParseError struct {
+	path string
+	err  error
 }
 
-func initPrinterMode() {
-	printerMode = printer.UseSpaces | printer.TabIndent
+func (e ParseError) Error() string {
+	return fmt.Sprintf("Error parsing %v: %v", e.path, e.err)
 }
 
-func WriteFile(filePath, fileOut string) {
-	fset := token.NewFileSet()
-	f, err := parser.ParseFile(fset, "", fileOut, parser.ParseComments)
-	if err != nil {
-		fmt.Println("Failed to parse:\n", fileOut)
+//ErrorHandler is a convenience struct for interpretting generation Errors
+type ErrorHandler struct {
+	ReturnCode int
+}
+
+//Handle interprets the generation error. Proceeds with setting returnCode, or panics depending on error type
+func (h *ErrorHandler) Handle(err error) {
+	switch err := err.(type) {
+	case nil:
+	//do nothing
+	case ParseError:
+		fmt.Println(err)
+		h.ReturnCode = 1
+	default:
 		panic(err)
 	}
+}
 
-	ast.SortImports(fset, f)
-
-	//create parentdir if it doesn't exist
+func write(filePath string, fset *token.FileSet, f *ast.File) error {
 	if parentdir := path.Dir(filePath); parentdir != "." {
 		if err := os.MkdirAll(parentdir, os.ModePerm); err != nil {
-			panic(err)
+			return err
 		}
 	}
 
-	if file, err := os.Create(filePath); err == nil {
-		defer file.Close()
-		(&printer.Config{Mode: printerMode, Tabwidth: tabWidth}).Fprint(file, fset, f)
-	} else {
-		panic(err)
+	file, err := os.Create(filePath)
+	if err != nil {
+		return err
 	}
+
+	ast.SortImports(fset, f)
+	err = (&printer.Config{Mode: printerMode, Tabwidth: tabWidth}).Fprint(file, fset, f)
+	_ = file.Close()
+	return err
+}
+
+//WriteFile parses the generated code in fileOut and writes the code out to filePath.
+//Function performs some import clean up and gofmts the code before writing
+//Returns ParseError if the generated source is invalid but is written to filePath
+func WriteFile(filePath, fileOut string) error {
+	fset := token.NewFileSet()
+	f, pErr := parser.ParseFile(fset, "", fileOut, parser.ParseComments)
+	if f == nil {
+		return pErr
+	}
+
+	//write out the file regardless of parseFile errors
+	if err := write(filePath, fset, f); err != nil {
+		return err
+	}
+
+	if pErr != nil {
+		return ParseError{path: filePath, err: pErr}
+	}
+
+	return nil
 }

Original file line number	Diff line number	Diff line change
`@@ -66,13 +66,13 @@ func genGroupDeclarations(name string, fields []datadictionary.MessagePart) (fil`
`66`	`66`	`return`
`67`	`67`	`}`
`68`	`68`
`69`		`-func genHeader(header *datadictionary.MessageDef) {`
	`69`	`+func genHeader(header *datadictionary.MessageDef) error {`
`70`	`70`	`writer := new(bytes.Buffer)`
`71`	`71`	`if err := gen.WritePackage(writer, pkg); err != nil {`
`72`		`- panic(err)`
	`72`	`+ return err`
`73`	`73`	`}`
`74`	`74`	`if err := gen.WriteComponentImports(writer, pkg, header.Parts); err != nil {`
`75`		`- panic(err)`
	`75`	`+ return err`
`76`	`76`	`}`
`77`	`77`
`78`	`78`	`fileOut := writer.String()`
`@@ -84,20 +84,20 @@ func genHeader(header *datadictionary.MessageDef) {`
`84`	`84`
`85`	`85`	`writer = new(bytes.Buffer)`
`86`	`86`	`if err := gen.WriteFieldSetters(writer, "Header", header.Parts); err != nil {`
`87`		`- panic(err)`
	`87`	`+ return err`
`88`	`88`	`}`
`89`	`89`	`fileOut += writer.String()`
`90`	`90`
`91`		`- gen.WriteFile(path.Join(pkg, "header.go"), fileOut)`
	`91`	`+ return gen.WriteFile(path.Join(pkg, "header.go"), fileOut)`
`92`	`92`	`}`
`93`	`93`
`94`		`-func genTrailer(trailer *datadictionary.MessageDef) {`
	`94`	`+func genTrailer(trailer *datadictionary.MessageDef) error {`
`95`	`95`	`writer := new(bytes.Buffer)`
`96`	`96`	`if err := gen.WritePackage(writer, pkg); err != nil {`
`97`		`- panic(err)`
	`97`	`+ return err`
`98`	`98`	`}`
`99`	`99`	`if err := gen.WriteComponentImports(writer, pkg, trailer.Parts); err != nil {`
`100`		`- panic(err)`
	`100`	`+ return err`
`101`	`101`	`}`
`102`	`102`	`fileOut := writer.String()`
`103`	`103`
`@@ -108,24 +108,24 @@ func genTrailer(trailer *datadictionary.MessageDef) {`
`108`	`108`
`109`	`109`	`writer = new(bytes.Buffer)`
`110`	`110`	`if err := gen.WriteFieldSetters(writer, "Trailer", trailer.Parts); err != nil {`
`111`		`- panic(err)`
	`111`	`+ return err`
`112`	`112`	`}`
`113`	`113`	`fileOut += writer.String()`
`114`	`114`
`115`		`- gen.WriteFile(path.Join(pkg, "trailer.go"), fileOut)`
	`115`	`+ return gen.WriteFile(path.Join(pkg, "trailer.go"), fileOut)`
`116`	`116`	`}`
`117`	`117`
`118`		`-func genComponent(name string, component *datadictionary.ComponentType) {`
	`118`	`+func genComponent(name string, component *datadictionary.ComponentType) error {`
`119`	`119`	`writer := new(bytes.Buffer)`
`120`	`120`	`if err := gen.WritePackage(writer, strings.ToLower(name)); err != nil {`
`121`		`- panic(err)`
	`121`	`+ return err`
`122`	`122`	`}`
`123`	`123`	`if err := gen.WriteComponentImports(writer, pkg, component.Parts()); err != nil {`
`124`		`- panic(err)`
	`124`	`+ return err`
`125`	`125`	`}`
`126`	`126`
`127`	`127`	`if err := gen.WriteNewComponent(writer, *component); err != nil {`
`128`		`- panic(err)`
	`128`	`+ return err`
`129`	`129`	`}`
`130`	`130`
`131`	`131`	`fileOut := writer.String()`
`@@ -136,7 +136,7 @@ func genComponent(name string, component *datadictionary.ComponentType) {`
`136`	`136`	`fileOut += "}\n"`
`137`	`137`	`fileOut += genComponentSetters(component)`
`138`	`138`
`139`		`- gen.WriteFile(path.Join(pkg, strings.ToLower(name), name+".go"), fileOut)`
	`139`	`+ return gen.WriteFile(path.Join(pkg, strings.ToLower(name), name+".go"), fileOut)`
`140`	`140`	`}`
`141`	`141`
`142`	`142`	`func genComponentSetters(component *datadictionary.ComponentType) string {`
`@@ -173,15 +173,18 @@ func main() {`
`173`	`173`	`panic(pkg + "/ is not a directory")`
`174`	`174`	`}`
`175`	`175`
	`176`	`+ var h gen.ErrorHandler`
`176`	`177`	`switch pkg {`
`177`	`178`	`//uses fixt11 header/trailer`
`178`	`179`	`case "fix50", "fix50sp1", "fix50sp2":`
`179`	`180`	`default:`
`180`		`- genHeader(fixSpec.Header)`
`181`		`- genTrailer(fixSpec.Trailer)`
	`181`	`+ h.Handle(genHeader(fixSpec.Header))`
	`182`	`+ h.Handle(genTrailer(fixSpec.Trailer))`
`182`	`183`	`}`
`183`	`184`
`184`	`185`	`for name, component := range fixSpec.ComponentTypes {`
`185`		`- genComponent(name, component)`
	`186`	`+ h.Handle(genComponent(name, component))`
`186`	`187`	`}`
	`188`	`+`
	`189`	`+ os.Exit(h.ReturnCode)`
`187`	`190`	`}`
Original file line number	Diff line number	Diff line change
`@@ -22,7 +22,7 @@ func usage() {`
`22`	`22`	`os.Exit(2)`
`23`	`23`	`}`
`24`	`24`
`25`		`-func genEnums() {`
	`25`	`+func genEnums() error {`
`26`	`26`	`fileOut := "package enum\n"`
`27`	`27`
`28`	`28`	`for _, fieldName := range sortedTags {`
`@@ -48,10 +48,10 @@ func genEnums() {`
`48`	`48`	`fileOut += ")\n"`
`49`	`49`	`}`
`50`	`50`
`51`		`- gen.WriteFile("enum/enums.go", fileOut)`
	`51`	`+ return gen.WriteFile("enum/enums.go", fileOut)`
`52`	`52`	`}`
`53`	`53`
`54`		`-func genFields() {`
	`54`	`+func genFields() error {`
`55`	`55`	`fileOut := "package field\n"`
`56`	`56`	`fileOut += "import(\n"`
`57`	`57`	`fileOut += "\"github.com/quickfixgo/quickfix\"\n"`
`@@ -140,7 +140,7 @@ func genFields() {`
`140`	`140`	`goType = "float64"`
`141`	`141`
`142`	`142`	`default:`
`143`		`- fmt.Printf("Unknown type '%v' for tag '%v'\n", field.Type, tag)`
	`143`	`+ return fmt.Errorf("Unknown type '%v' for tag '%v'\n", field.Type, tag)`
`144`	`144`	`}`
`145`	`145`
`146`	`146`	`fileOut += fmt.Sprintf("//%vField is a %v field\n", field.Name(), field.Type)`
`@@ -157,10 +157,10 @@ func genFields() {`
`157`	`157`	`}`
`158`	`158`	`}`
`159`	`159`
`160`		`- gen.WriteFile("field/fields.go", fileOut)`
	`160`	`+ return gen.WriteFile("field/fields.go", fileOut)`
`161`	`161`	`}`
`162`	`162`
`163`		`-func genTags() {`
	`163`	`+func genTags() error {`
`164`	`164`	`fileOut := "package tag\n"`
`165`	`165`	`fileOut += "import(\"github.com/quickfixgo/quickfix\")\n"`
`166`	`166`
`@@ -170,7 +170,7 @@ func genTags() {`
`170`	`170`	`}`
`171`	`171`	`fileOut += ")\n"`
`172`	`172`
`173`		`- gen.WriteFile("tag/tag_numbers.go", fileOut)`
	`173`	`+ return gen.WriteFile("tag/tag_numbers.go", fileOut)`
`174`	`174`	`}`
`175`	`175`
`176`	`176`	`func main() {`
`@@ -231,7 +231,9 @@ func main() {`
`231`	`231`	`}`
`232`	`232`	`sort.Strings(sortedTags)`
`233`	`233`
`234`		`- genTags()`
`235`		`- genFields()`
`236`		`- genEnums()`
	`234`	`+ var h gen.ErrorHandler`
	`235`	`+ h.Handle(genTags())`
	`236`	`+ h.Handle(genFields())`
	`237`	`+ h.Handle(genEnums())`
	`238`	`+ os.Exit(h.ReturnCode)`
`237`	`239`	`}`
Original file line number	Diff line number	Diff line change
`@@ -34,12 +34,6 @@ func initPackage() {`
`34`	`34`	`}`
`35`	`35`	`}`
`36`	`36`
`37`		`-func genMessages() {`
`38`		`- for _, m := range fixSpec.Messages {`
`39`		`- genMessagePkg(m)`
`40`		`- }`
`41`		`-}`
`42`		`-`
`43`	`37`	`type group struct {`
`44`	`38`	`parent string`
`45`	`39`	`field *datadictionary.FieldDef`
`@@ -138,16 +132,16 @@ func Route(router RouteOut) (string,string,quickfix.MessageRoute) {`
`138`	`132`	`return fileOut`
`139`	`133`	`}`
`140`	`134`
`141`		`-func genMessagePkg(msg *datadictionary.MessageDef) {`
	`135`	`+func genMessagePkg(msg *datadictionary.MessageDef) error {`
`142`	`136`	`pkgName := strings.ToLower(msg.Name)`
`143`	`137`	`fileOut := fmt.Sprintf("//Package %v msg type = %v.\n", pkgName, msg.MsgType)`
`144`	`138`
`145`	`139`	`writer := new(bytes.Buffer)`
`146`	`140`	`if err := gen.WritePackage(writer, pkgName); err != nil {`
`147`		`- panic(err)`
	`141`	`+ return err`
`148`	`142`	`}`
`149`	`143`	`if err := gen.WriteMessageImports(writer, pkg, msg.Parts); err != nil {`
`150`		`- panic(err)`
	`144`	`+ return err`
`151`	`145`	`}`
`152`	`146`	`fileOut += writer.String()`
`153`	`147`	`fileOut += genGroupDeclarations(msg)`
`@@ -156,7 +150,7 @@ func genMessagePkg(msg *datadictionary.MessageDef) {`
`156`	`150`	`fileOut += genMessageSetters(msg)`
`157`	`151`	`fileOut += genMessageRoute(msg)`
`158`	`152`
`159`		`- gen.WriteFile(path.Join(pkg, strings.ToLower(msg.Name), msg.Name+".go"), fileOut)`
	`153`	`+ return gen.WriteFile(path.Join(pkg, strings.ToLower(msg.Name), msg.Name+".go"), fileOut)`
`160`	`154`	`}`
`161`	`155`
`162`	`156`	`func main() {`
`@@ -193,5 +187,9 @@ func main() {`
`193`	`187`	`panic(pkg + "/ is not a directory")`
`194`	`188`	`}`
`195`	`189`
`196`		`- genMessages()`
	`190`	`+ var h gen.ErrorHandler`
	`191`	`+ for _, m := range fixSpec.Messages {`
	`192`	`+ h.Handle(genMessagePkg(m))`
	`193`	`+ }`
	`194`	`+ os.Exit(h.ReturnCode)`
`197`	`195`	`}`