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internal/mcp: rename ClientConnection to ServerConnection

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It's too confusing that you send server requests through the Client, and
send client requests through the ClientConnection. Rename
ClientConnection to ServerConnection, so that the types on the
server side of the control diagram start with 'Server'.

Change-Id: Idfd27af464a9296a2341cd23b2075cd9d0eb6b45
Reviewed-on: https://go-review.googlesource.com/c/tools/+/670538
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Robert Findley <rfindley@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
This commit is contained in:
Rob Findley 2025-05-07 16:43:03 +00:00 • committed by Gopher Robot
commit 347a1a0078
1 changed files with 65 additions and 63 deletions
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60
mcp/server.go
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@ -28,7 +28,7 @@ type Server struct {
mu sync.Mutex
prompts []*Prompt
tools []*Tool
clients []*ClientConnection
conns []*ServerConnection
}
// ServerOptions is used to configure behavior of the server.
@ -74,14 +74,14 @@ func (s *Server) AddTools(tools ...*Tool) {
// Clients returns an iterator that yields the current set of client
// connections.
func (s *Server) Clients() iter.Seq[*ClientConnection] {
func (s *Server) Clients() iter.Seq[*ServerConnection] {
s.mu.Lock()
clients := slices.Clone(s.clients)
clients := slices.Clone(s.conns)
s.mu.Unlock()
return slices.Values(clients)
}
func (s *Server) listPrompts(_ context.Context, _ *ClientConnection, params *protocol.ListPromptsParams) (*protocol.ListPromptsResult, error) {
func (s *Server) listPrompts(_ context.Context, _ *ServerConnection, params *protocol.ListPromptsParams) (*protocol.ListPromptsResult, error) {
s.mu.Lock()
defer s.mu.Unlock()
@ -92,7 +92,7 @@ func (s *Server) listPrompts(_ context.Context, _ *ClientConnection, params *pro
return res, nil
}
func (s *Server) getPrompt(ctx context.Context, cc *ClientConnection, params *protocol.GetPromptParams) (*protocol.GetPromptResult, error) {
func (s *Server) getPrompt(ctx context.Context, cc *ServerConnection, params *protocol.GetPromptParams) (*protocol.GetPromptResult, error) {
s.mu.Lock()
var prompt *Prompt
if i := slices.IndexFunc(s.prompts, func(t *Prompt) bool {
@ -108,7 +108,7 @@ func (s *Server) getPrompt(ctx context.Context, cc *ClientConnection, params *pr
return prompt.Handler(ctx, cc, params.Arguments)
}
func (s *Server) listTools(_ context.Context, _ *ClientConnection, params *protocol.ListToolsParams) (*protocol.ListToolsResult, error) {
func (s *Server) listTools(_ context.Context, _ *ServerConnection, params *protocol.ListToolsParams) (*protocol.ListToolsResult, error) {
s.mu.Lock()
defer s.mu.Unlock()
@ -119,7 +119,7 @@ func (s *Server) listTools(_ context.Context, _ *ClientConnection, params *proto
return res, nil
}
func (s *Server) callTool(ctx context.Context, cc *ClientConnection, params *protocol.CallToolParams) (*protocol.CallToolResult, error) {
func (s *Server) callTool(ctx context.Context, cc *ServerConnection, params *protocol.CallToolParams) (*protocol.CallToolResult, error) {
s.mu.Lock()
var tool *Tool
if i := slices.IndexFunc(s.tools, func(t *Tool) bool {
@ -146,22 +146,22 @@ func (s *Server) Run(ctx context.Context, t Transport, opts *ConnectionOptions)
return cc.Wait()
}
// bind implements the binder[*ClientConnection] interface, so that Servers can
// bind implements the binder[*ServerConnection] interface, so that Servers can
// be connected using [connect].
func (s *Server) bind(conn *jsonrpc2.Connection) *ClientConnection {
cc := &ClientConnection{conn: conn, server: s}
func (s *Server) bind(conn *jsonrpc2.Connection) *ServerConnection {
cc := &ServerConnection{conn: conn, server: s}
s.mu.Lock()
s.clients = append(s.clients, cc)
s.conns = append(s.conns, cc)
s.mu.Unlock()
return cc
}
// disconnect implements the binder[*ClientConnection] interface, so that
// disconnect implements the binder[*ServerConnection] interface, so that
// Servers can be connected using [connect].
func (s *Server) disconnect(cc *ClientConnection) {
func (s *Server) disconnect(cc *ServerConnection) {
s.mu.Lock()
defer s.mu.Unlock()
s.clients = slices.DeleteFunc(s.clients, func(cc2 *ClientConnection) bool {
s.conns = slices.DeleteFunc(s.conns, func(cc2 *ServerConnection) bool {
return cc2 == cc
})
}
@ -172,15 +172,17 @@ func (s *Server) disconnect(cc *ClientConnection) {
// It returns a connection object that may be used to terminate the connection
// (with [Connection.Close]), or await client termination (with
// [Connection.Wait]).
func (s *Server) Connect(ctx context.Context, t Transport, opts *ConnectionOptions) (*ClientConnection, error) {
func (s *Server) Connect(ctx context.Context, t Transport, opts *ConnectionOptions) (*ServerConnection, error) {
return connect(ctx, t, opts, s)
}
// A ClientConnection is a connection with an MCP client.
// A ServerConnection is a connection from a single MCP client. Its methods can
// be used to send requests or notifications to the client. Create a connection
// by calling [Server.Connect].
//
// It handles messages from the client, and can be used to send messages to the
// client. Create a connection by calling [Server.Connect].
type ClientConnection struct {
// Call [ServerConnection.Close] to close the connection, or await client
// termination with [ServerConnection.Wait].
type ServerConnection struct {
server *Server
conn *jsonrpc2.Connection
@ -190,11 +192,11 @@ type ClientConnection struct {
}
// Ping makes an MCP "ping" request to the client.
func (cc *ClientConnection) Ping(ctx context.Context) error {
func (cc *ServerConnection) Ping(ctx context.Context) error {
return call(ctx, cc.conn, "ping", nil, nil)
}
func (cc *ClientConnection) handle(ctx context.Context, req *jsonrpc2.Request) (any, error) {
func (cc *ServerConnection) handle(ctx context.Context, req *jsonrpc2.Request) (any, error) {
cc.mu.Lock()
initialized := cc.initialized
cc.mu.Unlock()
@ -210,7 +212,7 @@ func (cc *ClientConnection) handle(ctx context.Context, req *jsonrpc2.Request) (
}
}
// TODO: embed the incoming request ID in the ClientContext (or, more likely,
// TODO: embed the incoming request ID in the client context (or, more likely,
// a wrapper around it), so that we can correlate responses and notifications
// to the handler; this is required for the new session-based transport.
@ -239,7 +241,7 @@ func (cc *ClientConnection) handle(ctx context.Context, req *jsonrpc2.Request) (
return nil, jsonrpc2.ErrNotHandled
}
func (cc *ClientConnection) initialize(ctx context.Context, _ *ClientConnection, params *protocol.InitializeParams) (*protocol.InitializeResult, error) {
func (cc *ServerConnection) initialize(ctx context.Context, _ *ServerConnection, params *protocol.InitializeParams) (*protocol.InitializeResult, error) {
cc.mu.Lock()
cc.initializeParams = params
cc.mu.Unlock()
@ -274,15 +276,15 @@ func (cc *ClientConnection) initialize(ctx context.Context, _ *ClientConnection,
}, nil
}
// Close performs a graceful close of the connection, preventing new requests
// from being handled, and waiting for ongoing requests to return. Close then
// terminates the connection.
func (cc *ClientConnection) Close() error {
// Close performs a graceful shutdown of the connection, preventing new
// requests from being handled, and waiting for ongoing requests to return.
// Close then terminates the connection.
func (cc *ServerConnection) Close() error {
return cc.conn.Close()
}
// Wait waits for the connection to be closed by the client.
func (cc *ClientConnection) Wait() error {
func (cc *ServerConnection) Wait() error {
return cc.conn.Wait()
}
@ -290,7 +292,7 @@ func (cc *ClientConnection) Wait() error {
//
// Importantly, it returns nil if the handler returned an error, which is a
// requirement of the jsonrpc2 package.
func dispatch[TConn, TParams, TResult any](ctx context.Context, conn TConn, req *jsonrpc2.Request, f func(context.Context, TConn, TParams) (TResult, error)) (any, error) {
func dispatch[TParams, TResult any](ctx context.Context, conn *ServerConnection, req *jsonrpc2.Request, f func(context.Context, *ServerConnection, TParams) (TResult, error)) (any, error) {
var params TParams
if err := json.Unmarshal(req.Params, &params); err != nil {
return nil, err