feat(server/v2): add swagger server component (#23486)

server/v2/api/swagger/config.go

@@ -0,0 +1,34 @@
+package swagger
+
+// Config defines the configuration for the Swagger UI server
+type Config struct {
+	// Enable enables/disables the Swagger UI server
+	Enable bool `mapstructure:"enable" toml:"enable" comment:"Enable enables/disables the Swagger UI server"`
+	// Address defines the server address to bind to
+	Address string `mapstructure:"address" toml:"address" comment:"Address defines the server address to bind to"`
+}
+
+// DefaultConfig returns the default configuration
+func DefaultConfig() *Config {
+	return &Config{
+		Enable:  true,
+		Address: "localhost:8090",
+	}
+}
+
+// CfgOption defines a function for configuring the settings
+type CfgOption func(*Config)
+
+// OverwriteDefaultConfig overwrites the default config with the new config.
+func OverwriteDefaultConfig(newCfg *Config) CfgOption {
+	return func(cfg *Config) {
+		*cfg = *newCfg
+	}
+}
+
+// Disable the grpc server by default (default enabled).
+func Disable() CfgOption {
+	return func(cfg *Config) {
+		cfg.Enable = false
+	}
+}

server/v2/api/swagger/doc.go

@@ -0,0 +1,14 @@
+/*
+Package swagger provides Swagger UI server/v2 component.
+
+Example usage in commands.go:
+
+	swaggerServer, err := swaggerv2.New[T](
+		logger.With(log.ModuleKey, "swagger"),
+		deps.GlobalConfig,
+		swaggerv2.CfgOption(func(cfg *swaggerv2.Config) {
+			cfg.SwaggerUI = docs.SwaggerUI
+		}),
+	)
+*/
+package swagger

server/v2/api/swagger/handler.go

@@ -0,0 +1,22 @@
+package swagger
+
+import (
+	"io/fs"
+	"net/http"
+)
+
+type swaggerHandler struct {
+	swaggerFS fs.FS
+}
+
+func (h *swaggerHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// CORS headers
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+	w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, OPTIONS")
+
+	if r.Method == http.MethodOptions {
+		return
+	}
+
+	http.StripPrefix("/swagger/", http.FileServer(http.FS(h.swaggerFS))).ServeHTTP(w, r)
+}

server/v2/api/swagger/server.go

@@ -0,0 +1,110 @@
+package swagger
+
+import (
+	"context"
+	"fmt"
+	"io/fs"
+	"net/http"
+
+	"cosmossdk.io/core/server"
+	"cosmossdk.io/core/transaction"
+	"cosmossdk.io/log"
+	serverv2 "cosmossdk.io/server/v2"
+)
+
+var (
+	_ serverv2.ServerComponent[transaction.Tx] = (*Server[transaction.Tx])(nil)
+	_ serverv2.HasConfig                       = (*Server[transaction.Tx])(nil)
+)
+
+const ServerName = "swagger"
+
+// Server represents a Swagger UI server
+type Server[T transaction.Tx] struct {
+	logger     log.Logger
+	config     *Config
+	cfgOptions []CfgOption
+
+	server *http.Server
+}
+
+// New creates a new Swagger UI server
+func New[T transaction.Tx](
+	logger log.Logger,
+	swaggerUI fs.FS,
+	config server.ConfigMap,
+	cfgOptions ...CfgOption,
+) (*Server[T], error) {
+	s := &Server[T]{
+		logger:     logger.With(log.ModuleKey, ServerName),
+		cfgOptions: cfgOptions,
+	}
+
+	serverCfg := s.Config().(*Config)
+	if len(config) > 0 {
+		if err := serverv2.UnmarshalSubConfig(config, s.Name(), &serverCfg); err != nil {
+			return s, fmt.Errorf("failed to unmarshal config: %w", err)
+		}
+	}
+	s.config = serverCfg
+
+	mux := http.NewServeMux()
+	mux.Handle("/swagger/", &swaggerHandler{
+		swaggerFS: swaggerUI,
+	})
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, "/swagger/", http.StatusMovedPermanently)
+	})
+
+	s.server = &http.Server{
+		Addr:    s.config.Address,
+		Handler: mux,
+	}
+
+	return s, nil
+}
+
+// Name returns the server's name
+func (s *Server[T]) Name() string {
+	return ServerName
+}
+
+// Config returns the server configuration
+func (s *Server[T]) Config() any {
+	if s.config == nil || s.config.Address == "" {
+		cfg := DefaultConfig()
+		// overwrite the default config with the provided options
+		for _, opt := range s.cfgOptions {
+			opt(cfg)
+		}
+
+		return cfg
+	}
+
+	return s.config
+}
+
+// Start starts the server
+func (s *Server[T]) Start(ctx context.Context) error {
+	if !s.config.Enable {
+		s.logger.Info(fmt.Sprintf("%s server is disabled via config", s.Name()))
+		return nil
+	}
+
+	s.logger.Info("starting swagger server...", "address", s.config.Address)
+	if err := s.server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+		return fmt.Errorf("failed to start swagger server: %w", err)
+	}
+
+	return nil
+}
+
+// Stop stops the server
+func (s *Server[T]) Stop(ctx context.Context) error {
+	if !s.config.Enable {
+		return nil
+	}
+
+	s.logger.Info("stopping swagger server...", "address", s.config.Address)
+	return s.server.Shutdown(ctx)
+}