feat(codegen): Add a flag to force field generation as pointers to ma…

…ke validations work (#260)

Co-authored-by: Gildas Lebel <[email protected]>

README.md

@@ -31,6 +31,7 @@ to the application/user. Just plug your application to your favorite message bro
   * [Versioning](#versioning)
   * [Extensions](#specification-extensions)
   * [ErrorHandler](#errorhandler)
+  * [Validations](#validations)
 * [Contributing and support](#contributing-and-support)
 
 ## Supported functionalities
@@ -779,6 +780,25 @@ func(ctx context.Context, topic string, msg *extensions.AcknowledgeableBrokerMes
 }
 ```
 
+### Validations
+
+You can use [go-playground/validator](https://github.com/go-playground/validator) to validate the fields content against the contract.
+
+The following tags are currently supported:
+
+| Asyncapi         | Validator tag  | Comment                                                      |
+|------------------|----------------|--------------------------------------------------------------|
+| required         | required       | For a full support, the flag `--force-pointers` is necessary |
+| minLength        | min            |                                                              |
+| maxLength        | max            |                                                              |
+| minimum          | gte            |                                                              |
+| maximum          | lte            |                                                              |
+| exclusiveMinimum | gt             |                                                              |
+| exclusiveMaximum | lt             |                                                              |
+| uniqueItems      | unique         | Only for arrays                                              |
+| enum             | oneof          | Only string enum are supported                               |    
+
+
 ## Contributing and support
 
 If you find any bug or lacking a feature, please raise an issue on the Github repository!

cmd/asyncapi-codegen/config.go

@@ -46,6 +46,9 @@ type Flags struct {
 
 	// IgnoreStringFormat states whether the properties' format (date, date-time) should impact the type in types
 	IgnoreStringFormat bool
+
+	// ForcePointers can be used to force all struct fields to be generated as pointers
+	ForcePointers bool
 }
 
 // SetToCommand adds the flags to a cobra command.
@@ -63,6 +66,7 @@ func (f *Flags) SetToCommand(cmd *cobra.Command) {
 		"Naming scheme for generated golang elements.\nSupported values: camel, none.")
 	cmd.Flags().BoolVar(&f.IgnoreStringFormat, "ignore-string-format", false,
 		"Ignores the format (date, date-time) on string properties, generating golang string, instead of dates")
+	cmd.Flags().BoolVar(&f.ForcePointers, "force-pointers", false, "Forces all struct fields to be generated as pointers")
 }
 
 // ToCodegenOptions processes command line flags structure to code generation tool options.
@@ -74,6 +78,7 @@ func (f Flags) ToCodegenOptions() (options.Options, error) {
 		ConvertKeys:        f.ConvertKeys,
 		NamingScheme:       f.NamingScheme,
 		IgnoreStringFormat: f.IgnoreStringFormat,
+		ForcePointers:      f.ForcePointers,
 	}
 
 	if f.Generate != "" {

pkg/codegen/codegen.go

@@ -10,7 +10,9 @@ import (
 	asyncapiv2 "github.com/lerenn/asyncapi-codegen/pkg/asyncapi/v2"
 	asyncapiv3 "github.com/lerenn/asyncapi-codegen/pkg/asyncapi/v3"
 	generatorv2 "github.com/lerenn/asyncapi-codegen/pkg/codegen/generators/v2"
+	templatesv2 "github.com/lerenn/asyncapi-codegen/pkg/codegen/generators/v2/templates"
 	generatorv3 "github.com/lerenn/asyncapi-codegen/pkg/codegen/generators/v3"
+	templatesv3 "github.com/lerenn/asyncapi-codegen/pkg/codegen/generators/v3/templates"
 	"github.com/lerenn/asyncapi-codegen/pkg/codegen/options"
 	"github.com/lerenn/asyncapi-codegen/pkg/utils/template"
 	"golang.org/x/tools/imports"
@@ -91,6 +93,10 @@ func (cg CodeGen) Generate(opt options.Options) error {
 	if opt.IgnoreStringFormat {
 		template.DisableDateOrTimeGeneration()
 	}
+	if opt.ForcePointers {
+		templatesv2.ForcePointerOnFields()
+		templatesv3.ForcePointerOnFields()
+	}
 
 	// Process specification
 	if err := cg.specification.Process(); err != nil {

pkg/codegen/generators/helpers.go

@@ -30,9 +30,9 @@ func GenerateJSONTags[T any](schema asyncapi.Validations[T], field string) strin
 
 // GenerateValidateTags returns the "validate" tag for a given field in a struct, based on the asyncapi contract.
 // This tag can then be used by go-playground/validator/v10 to validate the struct's content.
-func GenerateValidateTags[T any](schema asyncapi.Validations[T]) string {
+func GenerateValidateTags[T any](schema asyncapi.Validations[T], isPointer bool, schemaType string) string {
 	var directives []string
-	if schema.IsRequired {
+	if schema.IsRequired && (isPointer || schemaType == "array") {
 		directives = append(directives, "required")
 	}
 

pkg/codegen/generators/v2/templates/helpers.go

@@ -141,13 +141,25 @@ func OperationName(channel asyncapi.Channel) string {
 	return templateutil.Namify(name)
 }
 
+var isFieldPointer = func(parent asyncapi.Schema, field string, schema asyncapi.Schema) bool {
+	return !IsRequired(parent, field) && schema.Type != "array"
+}
+
+// ForcePointerOnFields is used to force the generation of all fields as pointers, except for arrays.
+func ForcePointerOnFields() {
+	isFieldPointer = func(parent asyncapi.Schema, field string, schema asyncapi.Schema) bool {
+		return schema.Type != "array"
+	}
+}
+
 // HelpersFunctions returns the functions that can be used as helpers
 // in a golang template.
 func HelpersFunctions() template.FuncMap {
 	return template.FuncMap{
 		"getChildrenObjectSchemas":       GetChildrenObjectSchemas,
 		"channelToMessage":               ChannelToMessage,
 		"isRequired":                     IsRequired,
+		"isFieldPointer":                 isFieldPointer,
 		"generateChannelPath":            GenerateChannelPath,
 		"referenceToStructAttributePath": ReferenceToStructAttributePath,
 		"operationName":                  OperationName,

pkg/codegen/generators/v2/templates/schema_definition.tmpl

@@ -15,7 +15,7 @@ type {{ namify .Name }} struct {
     {{else if and $value.ReferenceTo $value.ReferenceTo.Description}}
     // Description: {{multiLineComment $value.ReferenceTo.Description}}
     {{end -}}
-    {{namify $key}} {{if and (not (isRequired $ $key)) (ne $value.Type "array")}}*{{end}}{{template "schema-name" $value}} `{{generateJSONTags $value.Validations $key}}{{generateValidateTags $value.Validations}}`
+    {{namify $key}} {{if isFieldPointer $ $key $value }}*{{end}}{{template "schema-name" $value}} `{{generateJSONTags $value.Validations $key}}{{generateValidateTags $value.Validations (isFieldPointer $ $key $value) $value.Type }}`
     {{end -}}
 
     {{- if .AdditionalProperties}}

pkg/codegen/generators/v3/templates/helpers.go

@@ -127,6 +127,17 @@ func GenerateChannelAddr(ch *asyncapi.Channel) string {
 	return sprint[:len(sprint)-1] + ")"
 }
 
+var isFieldPointer = func(parent asyncapi.Schema, field string, schema asyncapi.Schema) bool {
+	return !IsRequired(parent, field) && schema.Type != "array"
+}
+
+// ForcePointerOnFields is used to force the generation of all fields as pointers, except for arrays.
+func ForcePointerOnFields() {
+	isFieldPointer = func(parent asyncapi.Schema, field string, schema asyncapi.Schema) bool {
+		return schema.Type != "array"
+	}
+}
+
 // HelpersFunctions returns the functions that can be used as helpers
 // in a golang template.
 func HelpersFunctions() template.FuncMap {
@@ -136,6 +147,7 @@ func HelpersFunctions() template.FuncMap {
 		"opToMsgTypeName":                OpToMsgTypeName,
 		"opToChannelTypeName":            OpToChannelTypeName,
 		"isRequired":                     IsRequired,
+		"isFieldPointer":                 isFieldPointer,
 		"generateChannelAddr":            GenerateChannelAddr,
 		"generateChannelAddrFromOp":      GenerateChannelAddrFromOp,
 		"referenceToStructAttributePath": ReferenceToStructAttributePath,

pkg/codegen/generators/v3/templates/schema_definition.tmpl

@@ -15,7 +15,7 @@ type {{ namify .Name }} struct {
     {{else if and $value.ReferenceTo $value.ReferenceTo.Description}}
     // Description: {{multiLineComment $value.ReferenceTo.Description}}
     {{end -}}
-    {{namify $key}} {{if and (not (isRequired $ $key)) (ne $value.Type "array")}}*{{end}}{{template "schema-name" $value}} `{{generateJSONTags $value.Validations $key}}{{generateValidateTags $value.Validations}}`
+    {{namify $key}} {{if isFieldPointer $ $key $value }}*{{end}}{{template "schema-name" $value}} `{{generateJSONTags $value.Validations $key}}{{generateValidateTags $value.Validations (isFieldPointer $ $key $value) $value.Type }}`
     {{end -}}
 
     {{- if .AdditionalProperties}}

pkg/codegen/options/options.go

@@ -35,4 +35,7 @@ type Options struct {
 
 	// IgnoreStringFormat states whether the properties' format (date, date-time) should impact the type in types
 	IgnoreStringFormat bool
+
+	// ForcePointers can be used to force all struct fields to be generated as pointers
+	ForcePointers bool
 }

test/v2/issues/131/suite_test.go

@@ -92,13 +92,6 @@ func (suite *Suite) TestFloat() {
 	assert.Error(suite.T(), validator.New().Struct(tooLarge))
 }
 
-func (suite *Suite) TestRequired() {
-	invalidAbsent := ValidTestSchema()
-	invalidAbsent.RequiredProp = ""
-
-	assert.Error(suite.T(), validator.New().Struct(invalidAbsent))
-}
-
 func (suite *Suite) TestArray() {
 	empty := ValidTestSchema()
 	empty.ArrayProp = []string{}

test/v2/issues/259/asyncapi.yaml

@@ -0,0 +1,27 @@
+asyncapi: 2.6.0
+info:
+  title: Sample App
+  version: 1.2.3
+
+components:
+  messages:
+    Test:
+      payload:
+        type: object
+        required:
+          - reqField
+          - reqArray
+        properties:
+          reqField:
+            type: string
+          nonReqField:
+            type: string
+          reqArray:
+            type: array
+            items:
+              type: string
+          nonReqArray:
+            type: array
+            items:
+              type: string
+