feat(server/v2): Add Swagger UI support for server/v2

server/v2/api/swagger/config.go

@@ -0,0 +1,23 @@
+package swagger
+
+import (
+    "cosmossdk.io/core/server"
+)
+
+const ServerName = "swagger"
+
+type Config struct {
+    Enable  bool   `toml:"enable" mapstructure:"enable"`
+    Address string `toml:"address" mapstructure:"address"`
+    Path    string `toml:"path" mapstructure:"path"`
+}
+
+func DefaultConfig() *Config {
+    return &Config{
+        Enable:  true,
+        Address: "localhost:8080",
+        Path:    "/swagger/",
+    }
+}
+
+type CfgOption func(*Config)

server/v2/api/swagger/handler.go

@@ -0,0 +1,46 @@
+package swagger
+
+import (
+    "net/http"
+    "path"
+    "path/filepath"
+    "strings"
+
+    "github.com/rakyll/statik/fs"
+)
+
+// Handler returns an HTTP handler that serves the Swagger UI files
+func Handler(statikFS http.FileSystem) http.HandlerFunc {
+    return func(w http.ResponseWriter, r *http.Request) {
+        // If the path is empty or "/", show index.html
+        if r.URL.Path == "/" || r.URL.Path == "" {
+            r.URL.Path = "/index.html"
+        }
+
+        // Clearing the path
+        urlPath := path.Clean(r.URL.Path)
+
+        // Opening the file from statikFS
+        f, err := statikFS.Open(urlPath)
+        if err != nil {
+            w.WriteHeader(http.StatusNotFound)
+            return
+        }
+        defer f.Close()
+
+        // Determining the content-type
+        ext := strings.ToLower(filepath.Ext(urlPath))
+        switch ext {
+        case ".html":
+            w.Header().Set("Content-Type", "text/html")
+        case ".css":
+            w.Header().Set("Content-Type", "text/css")
+        case ".js":
+            w.Header().Set("Content-Type", "application/javascript")
+        case ".json":
+            w.Header().Set("Content-Type", "application/json")
+        }
+
+        http.ServeContent(w, r, urlPath, time.Time{}, f)
+    }
+} 

server/v2/api/swagger/server.go

@@ -0,0 +1,75 @@
+package swagger
+
+import (
+    "context"
+    "fmt"
+    "net/http"
+
+    "cosmossdk.io/core/server"
+    "cosmossdk.io/core/transaction"
+    "cosmossdk.io/log"
+    serverv2 "cosmossdk.io/server/v2"
+)
+
+type Server[T transaction.Tx] struct {
+    logger     log.Logger
+    config     *Config
+    cfgOptions []CfgOption
+    server     *http.Server
+}
+
+func New[T transaction.Tx](
+    logger log.Logger,
+    cfg server.ConfigMap,
+    cfgOptions ...CfgOption,
+) (*Server[T], error) {
+    srv := &Server[T]{
+        logger:     logger.With(log.ModuleKey, ServerName),
+        cfgOptions: cfgOptions,
+    }
+
+    serverCfg := srv.Config().(*Config)
+    if len(cfg) > 0 {
+        if err := serverv2.UnmarshalSubConfig(cfg, srv.Name(), &serverCfg); err != nil {
+            return nil, fmt.Errorf("failed to unmarshal config: %w", err)
+        }
+    }
+    srv.config = serverCfg
+
+    mux := http.NewServeMux()
+    mux.Handle(srv.config.Path, NewSwaggerHandler())
+
+    srv.server = &http.Server{
+        Addr:    srv.config.Address,
+        Handler: mux,
+    }
+
+    return srv, nil
+}
+
+func (s *Server[T]) Name() string {
+    return ServerName
+}
+
+func (s *Server[T]) Start(ctx context.Context) error {
+    if !s.config.Enable {
+        s.logger.Info("swagger server is disabled via config")
+        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
+}
+
+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)
+}

server/v2/server.go

@@ -8,12 +8,14 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/cosmos/cosmos-sdk/server/v2/api/swagger"
 	"github.com/pelletier/go-toml/v2"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 
 	"cosmossdk.io/core/transaction"
 	"cosmossdk.io/log"
+	"github.com/rakyll/statik/fs"
 )
 
 // ServerComponent is a server component that can be started and stopped.
@@ -73,6 +75,7 @@ var _ ServerComponent[transaction.Tx] = (*Server[transaction.Tx])(nil)
 type Server[T transaction.Tx] struct {
 	components []ServerComponent[T]
 	config     ServerConfig
+	router     *http.ServeMux
 }
 
 func NewServer[T transaction.Tx](
@@ -82,6 +85,7 @@ func NewServer[T transaction.Tx](
 	return &Server[T]{
 		config:     config,
 		components: components,
+		router:     http.NewServeMux(),
 	}
 }
 
@@ -242,3 +246,18 @@ func (s *Server[T]) StartFlags() []*pflag.FlagSet {
 
 	return flags
 }
+
+func (s *Server[T]) setupSwagger() error {
+	cfg := s.config.API.Swagger
+	if !cfg.Enable {
+		return nil
+	}
+
+	statikFS, err := fs.New()
+	if err != nil {
+		return err
+	}
+
+	s.router.PathPrefix(cfg.Path).Handler(swagger.Handler(statikFS))
+	return nil
+}