Update code generation templates and configurations

- Added new templates for handling various code generation scenarios, including validation and transformation for different data types.
- Refactored existing templates to improve readability and maintainability.
- Updated the .golangci.yml configuration to include specific checks for static analysis.
- Bumped dependencies in go.mod and updated go.sum accordingly.
- Removed obsolete staticcheck configuration file.

This commit enhances the code generation process and ensures better compliance with coding standards.

Author: raphael

.golangci.yml

@@ -4,4 +4,11 @@ linters:
     - errorlint
     - errcheck
     - staticcheck
+    - unparam      # Detects unused parameters
+    - unused       # Detects unused constants, variables, functions and types
+    - ineffassign  # Detects ineffectual assignments
+  settings:
+    staticcheck:
+      checks:
+        - "-ST1001"
 

README.md

@@ -98,7 +98,7 @@ Traditional API development suffers from:
 Goa solves these problems by:
 - Generating 30-50% of your codebase directly from your design
 - Ensuring perfect alignment between design, code, and documentation
-- Supporting multiple transports (HTTP and gRPC) from a single design
+- Supporting multiple transports (HTTP, gRPC, and JSON-RPC) from a single design
 - Maintaining a clean separation between business logic and transport details
 
 ## 🌟 Key Features
@@ -107,12 +107,13 @@ Goa solves these problems by:
 - **Comprehensive Code Generation**:
   - Type-safe server interfaces that enforce your design
   - Client packages with full error handling
-  - Transport layer adapters (HTTP/gRPC) with routing and encoding
+  - Transport layer adapters (HTTP/gRPC/JSON-RPC) with routing and encoding
   - OpenAPI/Swagger documentation that's always in sync
   - CLI tools for testing your services
-- **Multi-Protocol Support**: Generate HTTP REST and gRPC endpoints from a single design
+- **Multi-Protocol Support**: Generate HTTP REST, gRPC, and JSON-RPC endpoints from a single design
 - **Clean Architecture**: Business logic remains separate from transport concerns
 - **Enterprise Ready**: Supports authentication, authorization, CORS, logging, and more
+- **Comprehensive Testing**: Includes extensive unit and integration test suites ensuring quality and reliability
 
 ## 🔄 How It Works
 
@@ -177,7 +178,32 @@ The example above:
 2. Generates server and client code
 3. Starts a server that logs requests server-side (without displaying any client output)
 
-## 📚 Documentation
+### JSON-RPC Alternative
+
+For a JSON-RPC service, simply add a `JSONRPC` expression to the method:
+
+```go
+Method("say_hello", func() {
+    Payload(func() {
+        Field(1, "name", String)
+        Required("name")
+    })
+    Result(String)
+
+    JSONRPC(func() {
+        POST("/jsonrpc")
+    })
+})
+```
+
+Then test with:
+```bash
+curl -X POST http://localhost:8000/jsonrpc \
+  -H "Content-Type: application/json" \
+  -d '{"jsonrpc":"2.0","method":"hello.say_hello","params":{"name":"world"},"id":"1"}'
+```
+
+## Documentation
 
 Our completely redesigned documentation site at [goa.design](https://goa.design) provides comprehensive guides and references:
 
@@ -188,7 +214,7 @@ Our completely redesigned documentation site at [goa.design](https://goa.design)
 - **[Real-World Guide](https://goa.design/docs/5-real-world/)**: Follow best practices for production services
 - **[Advanced Topics](https://goa.design/docs/6-advanced/)**: Explore advanced features and techniques
 
-## 🛠️ Real-World Examples
+##  Real-World Examples
 
 The [examples repository](https://github.com/goadesign/examples) contains complete, working examples demonstrating:
 
@@ -202,7 +228,7 @@ The [examples repository](https://github.com/goadesign/examples) contains comple
 - **Interceptors**: Request/response processing middleware
 - **Multipart**: Handling multipart form submissions
 - **Security**: Authentication and authorization examples
-- **Streaming**: Implementing streaming endpoints
+- **Streaming**: Implementing streaming endpoints (HTTP, WebSocket, JSON-RPC SSE)
 - **Tracing**: Integrating with observability tools
 - **TUS**: Resumable file uploads implementation
 
@@ -220,12 +246,21 @@ The [examples repository](https://github.com/goadesign/examples) contains comple
 - Report issues on [GitHub](https://github.com/goadesign/goa/issues)
 - Find answers with the [Goa Guru](https://gurubase.io/g/goa) AI assistant
 
-## 📣 What's New
+## What's New
+
+**June 2025:** Goa now includes comprehensive **JSON-RPC 2.0 support** as a
+first-class transport alongside HTTP and gRPC! Generate complete JSON-RPC
+services with streaming support (WebSocket and SSE), client/server code, CLI
+tools, and full type safety - all from a single design.
 
-**Jan 2024:** Goa's powerful design DSL is now accessible through the [Goa Design Wizard](https://chat.openai.com/g/g-mLuQDGyro-goa-design-wizard), a specialized AI trained on Goa. Generate service designs through natural language conversations!
+**February 2025:** The Goa website has been completely redesigned with extensive
+new documentation, tutorials, and guides to help you build better services.
 
-**February 2025:** The Goa website has been completely redesigned with extensive new documentation, tutorials, and guides to help you build better services.
+**Jan 2024:** Goa's powerful design DSL is now accessible through the
+[Goa Design Wizard](https://chat.openai.com/g/g-mLuQDGyro-goa-design-wizard), a
+specialized AI trained on Goa. Generate service designs through natural language
+conversations!
 
-## 📄 License
+## License
 
 MIT License - see [LICENSE](LICENSE) for details.

codegen/cli/cli.go

@@ -262,7 +262,7 @@ func UsageCommands(data []*CommandData) *codegen.SectionTemplate {
 		usages[i] = fmt.Sprintf("%s %s%s%s", cmd.Name, lp, strings.Join(subs, "|"), rp)
 	}
 
-	return &codegen.SectionTemplate{Source: usageT, Data: usages}
+	return &codegen.SectionTemplate{Source: cliTemplates.Read(usageCommandsT), Data: usages}
 }
 
 // UsageExamples builds a section template that generates a help text showing
@@ -275,7 +275,7 @@ func UsageExamples(data []*CommandData) *codegen.SectionTemplate {
 		}
 	}
 
-	return &codegen.SectionTemplate{Source: exampleT, Data: examples}
+	return &codegen.SectionTemplate{Source: cliTemplates.Read(usageExamplesT), Data: examples}
 }
 
 // FlagsCode returns a string containing the code that parses the command-line
@@ -285,7 +285,7 @@ func UsageExamples(data []*CommandData) *codegen.SectionTemplate {
 func FlagsCode(data []*CommandData) string {
 	section := codegen.SectionTemplate{
 		Name:    "parse-endpoint-flags",
-		Source:  parseFlagsT,
+		Source:  cliTemplates.Read(parseFlagsT),
 		Data:    data,
 		FuncMap: map[string]any{"printDescription": printDescription},
 	}
@@ -303,7 +303,7 @@ func FlagsCode(data []*CommandData) string {
 func CommandUsage(data *CommandData) *codegen.SectionTemplate {
 	return &codegen.SectionTemplate{
 		Name:    "cli-command-usage",
-		Source:  commandUsageT,
+		Source:  cliTemplates.Read(commandUsageT),
 		Data:    data,
 		FuncMap: map[string]any{"printDescription": printDescription},
 	}
@@ -314,7 +314,7 @@ func CommandUsage(data *CommandData) *codegen.SectionTemplate {
 func PayloadBuilderSection(buildFunction *BuildFunctionData) *codegen.SectionTemplate {
 	return &codegen.SectionTemplate{
 		Name:   "cli-build-payload",
-		Source: buildPayloadT,
+		Source: cliTemplates.Read(buildPayloadT),
 		Data:   buildFunction,
 		FuncMap: map[string]any{
 			"fieldCode": fieldCode,
@@ -606,166 +606,3 @@ func fieldCode(init *PayloadInitData) string {
 	return c
 }
 
-// input: []string
-const usageT = `// UsageCommands returns the set of commands and sub-commands using the format
-//
-//    command (subcommand1|subcommand2|...)
-//
-func UsageCommands() string {
-	return ` + "`" + `{{ range . }}{{ . }}
-{{ end }}` + "`" + `
-}
-`
-
-// input: []string
-const exampleT = `// UsageExamples produces an example of a valid invocation of the CLI tool.
-func UsageExamples() string {
-	return {{ range . }}os.Args[0] + ` + "`" + ` {{ . }}` + "`" + ` + "\n" +
-	{{ end }}""
-}
-`
-
-// input: []commandData
-const parseFlagsT = `var (
-		{{- range . }}
-		{{ .VarName }}Flags = flag.NewFlagSet("{{ .Name }}", flag.ContinueOnError)
-		{{ range .Subcommands }}
-		{{ .FullName }}Flags = flag.NewFlagSet("{{ .Name }}", flag.ExitOnError)
-		{{- $sub := . }}
-		{{- range .Flags }}
-		{{ .FullName }}Flag = {{ $sub.FullName }}Flags.String("{{ .Name }}", "{{ if .Default }}{{ .Default }}{{ else if .Required }}REQUIRED{{ end }}", {{ printf "%q" .Description }})
-		{{- end }}
-		{{ end }}
-		{{- end }}
-	)
-	{{ range . -}}
-	{{ $cmd := . -}}
-	{{ .VarName }}Flags.Usage = {{ .VarName }}Usage
-	{{ range .Subcommands -}}
-	{{ .FullName }}Flags.Usage = {{ .FullName }}Usage
-	{{ end }}
-	{{ end }}
-	if err := flag.CommandLine.Parse(os.Args[1:]); err != nil {
-		return nil, nil, err
-	}
-
-	if flag.NArg() < 2 { // two non flag args are required: SERVICE and ENDPOINT (aka COMMAND)
-		return nil, nil, fmt.Errorf("not enough arguments")
-	}
-
-	var (
-		svcn string
-		svcf *flag.FlagSet
-	)
-	{
-		svcn = flag.Arg(0)
-		switch svcn {
-	{{- range . }}
-		case "{{ .Name }}":
-			svcf = {{ .VarName }}Flags
-	{{- end }}
-		default:
-			return nil, nil, fmt.Errorf("unknown service %q", svcn)
-		}
-	}
-	if err := svcf.Parse(flag.Args()[1:]); err != nil {
-		return nil, nil, err
-	}
-
-	var (
-		epn string
-		epf *flag.FlagSet
-	)
-	{
-		epn = svcf.Arg(0)
-		switch svcn {
-	{{- range . }}
-		case "{{ .Name }}":
-			switch epn {
-		{{- range .Subcommands }}
-			case "{{ .Name }}":
-				epf = {{ .FullName }}Flags
-		{{ end }}
-			}
-	{{ end }}
-		}
-	}
-	if epf == nil {
-		return nil, nil, fmt.Errorf("unknown %q endpoint %q", svcn, epn)
-	}
-
-	// Parse endpoint flags if any
-	if svcf.NArg() > 1 {
-		if err := epf.Parse(svcf.Args()[1:]); err != nil {
-			return nil, nil, err
-		}
-	}
-`
-
-// input: commandData
-const commandUsageT = `
-{{ printf "%sUsage displays the usage of the %s command and its subcommands." .VarName .Name | comment }}
-func {{ .VarName }}Usage() {
-	fmt.Fprintf(os.Stderr, ` + "`" + `{{ printDescription .Description }}
-Usage:
-    %[1]s [globalflags] {{ .Name }} COMMAND [flags]
-
-COMMAND:
-    {{- range .Subcommands }}
-    {{ .Name }}: {{ printDescription .Description }}
-    {{- end }}
-
-Additional help:
-    %[1]s {{ .Name }} COMMAND --help
-` + "`" + `, os.Args[0])
-}
-
-{{- range .Subcommands }}
-func {{ .FullName }}Usage() {
-	fmt.Fprintf(os.Stderr, ` + "`" + `%[1]s [flags] {{ $.Name }} {{ .Name }}{{range .Flags }} -{{ .Name }} {{ .Type }}{{ end }}
-
-{{ printDescription .Description}}
-	{{- range .Flags }}
-    -{{ .Name }} {{ .Type }}: {{ .Description }}
-	{{- end }}
-
-Example:
-    %[1]s {{ .Example }}
-` + "`" + `, os.Args[0])
-}
-{{ end }}
-`
-
-// input: buildFunctionData
-const buildPayloadT = `{{ printf "%s builds the payload for the %s %s endpoint from CLI flags." .Name .ServiceName .MethodName | comment }}
-func {{ .Name }}({{ range .FormalParams }}{{ . }} string, {{ end }}) ({{ .ResultType }}, error) {
-{{- if .CheckErr }}
-	var err error
-{{- end }}
-{{- range .Fields }}
-	{{- if .VarName }}
-		var {{ .VarName }} {{ .TypeRef }}
-		{
-			{{ .Init }}
-		}
-	{{- end }}
-{{- end }}
-{{- with .PayloadInit }}
-	{{- if .Code }}
-		{{ .Code }}
-		{{- if .ReturnTypeAttribute }}
-			res := &{{ .ReturnTypeName }}{
-				{{ .ReturnTypeAttribute }}: {{ if .ReturnTypeAttributePointer }}&{{ end }}v,
-			}
-		{{- end }}
-	{{- end }}
-	{{- if .ReturnIsStruct }}
-		{{- if not .Code }}
-		{{ if .ReturnTypeAttribute }}res{{ else }}v{{ end }} := &{{ .ReturnTypeName }}{}
-		{{- end }}
-		{{ fieldCode . }}
-	{{- end }}
-	return {{ if .ReturnTypeAttribute }}res{{ else }}v{{ end }}, nil
-{{- end }}
-}
-`

codegen/cli/templates.go

@@ -0,0 +1,22 @@
+package cli
+
+import (
+	"embed"
+
+	"goa.design/goa/v3/codegen/template"
+)
+
+// Template constants
+const (
+	usageCommandsT = "usage_commands"
+	usageExamplesT = "usage_examples"
+	parseFlagsT    = "parse_flags"
+	commandUsageT  = "command_usage"
+	buildPayloadT  = "build_payload"
+)
+
+//go:embed templates/*.go.tpl
+var templateFS embed.FS
+
+// cliTemplates is the shared template reader for the cli package.
+var cliTemplates = &template.TemplateReader{FS: templateFS}

codegen/cli/templates/build_payload.go.tpl

@@ -0,0 +1,31 @@
+{{ printf "%s builds the payload for the %s %s endpoint from CLI flags." .Name .ServiceName .MethodName | comment }}
+func {{ .Name }}({{ range .FormalParams }}{{ . }} string, {{ end }}) ({{ .ResultType }}, error) {
+{{- if .CheckErr }}
+	var err error
+{{- end }}
+{{- range .Fields }}
+	{{- if .VarName }}
+		var {{ .VarName }} {{ .TypeRef }}
+		{
+			{{ .Init }}
+		}
+	{{- end }}
+{{- end }}
+{{- with .PayloadInit }}
+	{{- if .Code }}
+		{{ .Code }}
+		{{- if .ReturnTypeAttribute }}
+			res := &{{ .ReturnTypeName }}{
+				{{ .ReturnTypeAttribute }}: {{ if .ReturnTypeAttributePointer }}&{{ end }}v,
+			}
+		{{- end }}
+	{{- end }}
+	{{- if .ReturnIsStruct }}
+		{{- if not .Code }}
+		{{ if .ReturnTypeAttribute }}res{{ else }}v{{ end }} := &{{ .ReturnTypeName }}{}
+		{{- end }}
+		{{ fieldCode . }}
+	{{- end }}
+	return {{ if .ReturnTypeAttribute }}res{{ else }}v{{ end }}, nil
+{{- end }}
+}