464 lines
19 KiB
GDScript
Vendored
464 lines
19 KiB
GDScript
Vendored
@tool
|
||
class_name McpDispatcher
|
||
extends RefCounted
|
||
|
||
## Routes incoming commands to handlers and manages the command queue
|
||
## with a per-frame time budget.
|
||
|
||
var _command_queue: Array[Dictionary] = []
|
||
var _handlers: Dictionary = {} # command_name -> Callable
|
||
## Lazy handler registration (#736): plugin.gd registers command names
|
||
## against a handler key plus a per-handler script path and constructor
|
||
## args, and the handler script is load()ed and instantiated at the FIRST
|
||
## dispatch of one of its commands. This keeps the ~30 handler scripts
|
||
## (and everything they preload) out of plugin.gd's eager compile
|
||
## closure, which stalled "Initializing plugins" on every editor boot.
|
||
## Materialized commands are promoted into `_handlers`, so the lazy dicts
|
||
## are only consulted on the first call per command.
|
||
var _lazy_handler_specs: Dictionary = {} # handler_key -> {path: String, args: Array}
|
||
var _lazy_handler_cache: Dictionary = {} # handler_key -> handler instance
|
||
var _lazy_commands: Dictionary = {} # command_name -> {handler: String, method: StringName}
|
||
var _pending_deferred: Dictionary = {} # request_id -> {command, started_ms, timeout_ms}
|
||
var _log_buffer
|
||
var _surfaced_error_tracker
|
||
## The McpConnection whose pause_processing handlers flip around unsafe
|
||
## editor operations (#288 guard). Set by plugin.gd; untyped to honor the
|
||
## self-update field-storage policy. When set, _call_handler restores the
|
||
## pause depth a crashed handler left unbalanced (#712) — without this a
|
||
## single handler crash inside a pause window freezes the transport
|
||
## forever (pause has no watchdog or disconnect reset by design).
|
||
var pause_target
|
||
var mcp_logging := true
|
||
var deferred_timeout_overrides_ms: Dictionary = {}
|
||
|
||
const DEFAULT_DEFERRED_TIMEOUT_MS := 4500
|
||
const DEFERRED_TIMEOUT_MS_BY_COMMAND := {
|
||
"create_script": 4500,
|
||
## Fresh-`.gd` writes defer through the same import-settle window as
|
||
## create_script (#714) — same headroom over IMPORT_SETTLE_MAX_MSEC.
|
||
"write_file": 4500,
|
||
"stop_project": 4500,
|
||
"run_project": 6000,
|
||
"take_screenshot": 30000,
|
||
"check_client_status": 30000,
|
||
"game_eval": 15000,
|
||
"game_command": 15000,
|
||
"scan_filesystem": 30000,
|
||
}
|
||
const ErrorCodes := preload("res://addons/godot_ai/utils/error_codes.gd")
|
||
const FuzzySuggestions := preload("res://addons/godot_ai/utils/fuzzy_suggestions.gd")
|
||
|
||
|
||
func _init(log_buffer: McpLogBuffer, surfaced_error_tracker = null) -> void:
|
||
_log_buffer = log_buffer
|
||
_surfaced_error_tracker = surfaced_error_tracker
|
||
|
||
|
||
## Register a command handler. The callable receives (params: Dictionary) -> Dictionary.
|
||
func register(command_name: String, handler: Callable) -> void:
|
||
_handlers[command_name] = handler
|
||
|
||
|
||
## Declare a lazily-constructed handler (#736). `script_path` is load()ed
|
||
## and instantiated with `ctor_args` at the first dispatch of any command
|
||
## registered against `handler_key` via register_lazy. `ctor_args` may hold
|
||
## plugin-lifetime objects (connection, buffers, the dispatcher itself for
|
||
## batch); clear() drops them so teardown ordering matches the old eager
|
||
## registration (#46).
|
||
func register_lazy_handler(handler_key: String, script_path: String, ctor_args: Array) -> void:
|
||
_lazy_handler_specs[handler_key] = {"path": script_path, "args": ctor_args}
|
||
|
||
|
||
## Register a command that resolves to `method` on the lazily-constructed
|
||
## handler declared under `handler_key`. Same dispatch semantics as
|
||
## register(); only construction timing differs.
|
||
func register_lazy(command_name: String, handler_key: String, method: StringName) -> void:
|
||
_lazy_commands[command_name] = {"handler": handler_key, "method": method}
|
||
|
||
|
||
## Drop registered handlers, queued commands, and the log buffer ref so
|
||
## plugin.gd can release RefCounted handlers before Godot reloads their
|
||
## class_name scripts (issue #46). After clear(), the dispatcher is inert.
|
||
func clear() -> void:
|
||
## Stop lazy handlers before releasing the cache. Handler-owned polling
|
||
## coroutines retain any in-flight worker and deferred-response connection
|
||
## across frames, then join only after the worker is no longer alive.
|
||
for instance in _lazy_handler_cache.values():
|
||
if is_instance_valid(instance) and instance.has_method("prepare_for_teardown"):
|
||
instance.call("prepare_for_teardown")
|
||
_handlers.clear()
|
||
## Release lazily-constructed handler instances (and the ctor args that
|
||
## reference plugin-lifetime objects) at the same teardown point where
|
||
## eager handler Callables used to be dropped — their destructors must
|
||
## run while their scripts are still loaded (#46). This also breaks the
|
||
## dispatcher -> batch handler -> dispatcher ref cycle.
|
||
_lazy_handler_specs.clear()
|
||
_lazy_handler_cache.clear()
|
||
_lazy_commands.clear()
|
||
_command_queue.clear()
|
||
_pending_deferred.clear()
|
||
_log_buffer = null
|
||
_surfaced_error_tracker = null
|
||
pause_target = null
|
||
## Drop queued-but-unexecuted commands. Called by the connection on
|
||
## disconnect (#712): commands queued by the previous connection must not
|
||
## execute under the next one — the requester is gone, its in-flight
|
||
## futures were already failed server-side, and a mutation landing after
|
||
## reconnect is a surprise write nobody can correlate. Deferred bookkeeping
|
||
## has its own reset (clear_deferred_responses).
|
||
func clear_command_queue() -> void:
|
||
_command_queue.clear()
|
||
|
||
|
||
## Invoke a registered handler directly by name. Returns the handler's raw
|
||
## response dict (no request_id or status wrapping). Returns an UNKNOWN_COMMAND
|
||
## error dict if the command is not registered. Used by batch_execute.
|
||
func dispatch_direct(command: String, params: Dictionary) -> Dictionary:
|
||
if not has_command(command):
|
||
return ErrorCodes.make(ErrorCodes.UNKNOWN_COMMAND, "Unknown command: %s" % command)
|
||
## Strip the reserved deferred-reply key: only _dispatch may thread it.
|
||
## A caller-supplied _request_id (e.g. inside a batch_execute
|
||
## sub-command's params) would flip a deferred-capable handler into
|
||
## deferred mode against a request id the dispatcher never registered —
|
||
## the direct caller would get the DEFERRED sentinel instead of a result
|
||
## and the out-of-band reply would be dropped as expired.
|
||
if params.has("_request_id"):
|
||
params = params.duplicate()
|
||
params.erase("_request_id")
|
||
return _call_handler(command, params)
|
||
|
||
|
||
## Whether a command is registered (eagerly or lazily).
|
||
func has_command(command: String) -> bool:
|
||
return _handlers.has(command) or _lazy_commands.has(command)
|
||
|
||
|
||
## Rank registered commands by similarity to `cmd_name` and return the top `limit`
|
||
## matches. Uses Godot's built-in String.similarity() (0.0–1.0). Returns an empty
|
||
## array if no candidates clear the threshold. Used by batch_execute to surface
|
||
## "did you mean" suggestions when an unknown command is passed.
|
||
func suggest_similar(cmd_name: String, limit: int = 3, threshold: float = 0.5) -> Array[String]:
|
||
return FuzzySuggestions.rank(cmd_name, _registered_command_names(), limit, threshold, 0.0, 0.0)
|
||
|
||
|
||
## Union of eagerly-registered and lazily-registered command names.
|
||
## Materialized lazy commands live in both dicts, so dedupe via keys.
|
||
func _registered_command_names() -> Array:
|
||
var names: Dictionary = {}
|
||
for command in _handlers:
|
||
names[command] = true
|
||
for command in _lazy_commands:
|
||
names[command] = true
|
||
return names.keys()
|
||
|
||
|
||
## Enqueue a raw command dict received from the WebSocket.
|
||
func enqueue(cmd: Dictionary) -> void:
|
||
_command_queue.append(cmd)
|
||
|
||
|
||
func pending_deferred_count() -> int:
|
||
return _pending_deferred.size()
|
||
|
||
|
||
func clear_deferred_responses() -> void:
|
||
_pending_deferred.clear()
|
||
|
||
|
||
func has_pending_deferred_response(request_id: String) -> bool:
|
||
return request_id.is_empty() or _pending_deferred.has(request_id)
|
||
|
||
|
||
func complete_deferred_response(request_id: String) -> bool:
|
||
if request_id.is_empty():
|
||
return true
|
||
if not _pending_deferred.has(request_id):
|
||
return false
|
||
_pending_deferred.erase(request_id)
|
||
return true
|
||
|
||
|
||
## Handlers whose response flows out-of-band (e.g. debugger-channel capture)
|
||
## return this marker so tick() skips auto-sending a response. The handler is
|
||
## responsible for pushing the final response via McpConnection._send_json when
|
||
## the async operation completes. The dispatcher tracks the request_id and emits
|
||
## DEFERRED_TIMEOUT if the out-of-band response never arrives. The request_id is
|
||
## threaded through params under the "_request_id" key so the handler can
|
||
## correlate the response.
|
||
const DEFERRED_RESPONSE := {"_deferred": true}
|
||
|
||
|
||
## Process queued commands within a frame budget (milliseconds).
|
||
## Returns an array of response dictionaries to send back.
|
||
func tick(budget_ms: float = 4.0) -> Array[Dictionary]:
|
||
var responses: Array[Dictionary] = _collect_deferred_timeouts()
|
||
var start := Time.get_ticks_msec()
|
||
var idx := 0
|
||
|
||
while idx < _command_queue.size() and (Time.get_ticks_msec() - start) < budget_ms:
|
||
var cmd: Dictionary = _command_queue[idx]
|
||
var response := _dispatch(cmd)
|
||
if not response.get("_deferred", false):
|
||
responses.append(response)
|
||
idx += 1
|
||
|
||
if idx > 0:
|
||
_command_queue = _command_queue.slice(idx)
|
||
|
||
return responses
|
||
|
||
|
||
func _dispatch(cmd: Dictionary) -> Dictionary:
|
||
var request_id: String = cmd.get("request_id", "")
|
||
var command: String = cmd.get("command", "")
|
||
var raw_params: Dictionary = cmd.get("params", {})
|
||
## Duplicate so the internal _request_id key we thread through doesn't
|
||
## mutate the queued command's params (which is the same dict we're
|
||
## about to JSON-log below, and which later readers like batch_execute
|
||
## shouldn't see dispatcher-internal metadata from).
|
||
var params: Dictionary = raw_params.duplicate()
|
||
params["_request_id"] = request_id
|
||
|
||
if mcp_logging:
|
||
_log_buffer.log("[recv] %s(%s)" % [command, JSON.stringify(raw_params)])
|
||
|
||
var result: Dictionary
|
||
|
||
if has_command(command):
|
||
result = _call_handler(command, params)
|
||
else:
|
||
result = ErrorCodes.make(ErrorCodes.UNKNOWN_COMMAND, "Unknown command: %s" % command)
|
||
|
||
if result.get("_deferred", false):
|
||
## A handler may attach `_deferred_timeout_ms` to its deferred sentinel
|
||
## to claim a per-request budget larger than its command's shared entry
|
||
## (e.g. game_command's `input_sequence`, which steps frames well past
|
||
## the 15s that suits one-shot game ops). 0/absent falls back to the
|
||
## per-command table.
|
||
_register_deferred(request_id, command, int(result.get("_deferred_timeout_ms", 0)))
|
||
if mcp_logging:
|
||
_log_buffer.log("[defer] %s (request %s)" % [command, request_id])
|
||
return result
|
||
|
||
result["request_id"] = request_id
|
||
if not result.has("status"):
|
||
result["status"] = "ok"
|
||
## Stamp live editor readiness onto every command-response envelope so
|
||
## the server's `Session.readiness` cache self-heals on the very next
|
||
## tool call. Without this, a single dropped `readiness_changed` event
|
||
## (or a one-frame race around `pause_processing`) leaves the cache
|
||
## stuck at "playing" / "importing" long after the editor has settled,
|
||
## and write tools fail with EDITOR_NOT_READY against a writable editor.
|
||
## See connection.gd::send_deferred_response for the deferred-response
|
||
## counterpart, which stamps the same field.
|
||
result["readiness"] = McpConnection.get_readiness()
|
||
_stamp_error_watermark(result)
|
||
|
||
if mcp_logging:
|
||
var status: String = result.get("status", "ok")
|
||
if status == "ok":
|
||
_log_buffer.log("[send] %s -> ok" % command)
|
||
else:
|
||
var err_msg: String = result.get("error", {}).get("message", "unknown")
|
||
_log_buffer.log("[send] %s -> error: %s" % [command, err_msg])
|
||
|
||
return result
|
||
|
||
|
||
## Truncate JSON-stringified args at this many chars when stuffing them into
|
||
## a malformed-result error message — large dicts shouldn't bloat the
|
||
## response, but a few hundred chars usually pinpoints which param was the
|
||
## wrong shape.
|
||
const _MALFORMED_ARGS_MAX := 400
|
||
|
||
|
||
func _call_handler(command: String, params: Dictionary) -> Dictionary:
|
||
if not _handlers.has(command):
|
||
var materialize_error := _materialize_lazy_command(command)
|
||
if not materialize_error.is_empty():
|
||
return materialize_error
|
||
## #712: a handler that crashes between pause_processing = true and its
|
||
## matching false leaves the pause depth unbalanced — GDScript swallows
|
||
## the error, the dispatcher reports "malformed result", and the
|
||
## transport stays paused FOREVER (no watchdog, no disconnect reset).
|
||
## Restore balance at this boundary: the depth a handler leaves behind
|
||
## must equal the depth it started with.
|
||
var pause_depth_before: int = pause_target.pause_depth() if pause_target != null else 0
|
||
var result: Dictionary = _handlers[command].call(params)
|
||
if pause_target != null and pause_target.pause_depth() > pause_depth_before:
|
||
var leaked: int = pause_target.pause_depth() - pause_depth_before
|
||
while pause_target.pause_depth() > pause_depth_before:
|
||
pause_target.resume()
|
||
if mcp_logging and _log_buffer != null:
|
||
_log_buffer.log(
|
||
"[error] %s leaked %d pause_processing level(s) — restored (handler crash?)"
|
||
% [command, leaked]
|
||
)
|
||
## Handlers must return {"data": ...} on success or {"error": ...} on failure.
|
||
## Anything else (null, empty, missing keys) means the handler crashed
|
||
## mid-call — GDScript swallows the error and returns an empty dict.
|
||
if result == null or not (result.has("data") or result.has("error") or result.has("_deferred")):
|
||
var safe_params := params.duplicate()
|
||
safe_params.erase("_request_id")
|
||
var args_json := JSON.stringify(safe_params)
|
||
if args_json.length() > _MALFORMED_ARGS_MAX:
|
||
args_json = args_json.substr(0, _MALFORMED_ARGS_MAX) + "..."
|
||
var backtrace := _capture_compact_backtrace()
|
||
var msg := (
|
||
"Handler '%s' returned malformed result — likely a runtime error in the handler "
|
||
+ "(e.g. param type mismatch). Args received: %s"
|
||
) % [command, args_json]
|
||
if not backtrace.is_empty():
|
||
msg += "\nBacktrace:\n%s" % backtrace
|
||
if mcp_logging and _log_buffer != null:
|
||
var compact_backtrace := backtrace.replace("\n", " | ")
|
||
_log_buffer.log(
|
||
"[error] %s -> malformed result; args=%s; backtrace=%s"
|
||
% [command, args_json, compact_backtrace]
|
||
)
|
||
return ErrorCodes.make(ErrorCodes.INTERNAL_ERROR, msg)
|
||
return result
|
||
|
||
|
||
## Resolve a lazily-registered command into a live Callable in `_handlers`.
|
||
## Loads + constructs the owning handler on first use (cached per handler
|
||
## key, so one load() covers every command the handler serves). Returns an
|
||
## empty dict on success or a protocol error dict on failure — a missing
|
||
## script or method is a plugin packaging bug and must surface loudly, not
|
||
## as a silent no-op.
|
||
func _materialize_lazy_command(command: String) -> Dictionary:
|
||
var command_spec: Dictionary = _lazy_commands.get(command, {})
|
||
if command_spec.is_empty():
|
||
return ErrorCodes.make(ErrorCodes.UNKNOWN_COMMAND, "Unknown command: %s" % command)
|
||
var handler_key: String = command_spec["handler"]
|
||
var instance = _lazy_handler_cache.get(handler_key)
|
||
if instance == null:
|
||
var handler_spec: Dictionary = _lazy_handler_specs.get(handler_key, {})
|
||
if handler_spec.is_empty():
|
||
return ErrorCodes.make(
|
||
ErrorCodes.INTERNAL_ERROR,
|
||
"No lazy handler '%s' declared for command '%s'" % [handler_key, command]
|
||
)
|
||
## Existence-check first so a missing script surfaces as one clean
|
||
## protocol error instead of also spraying engine load errors.
|
||
if not ResourceLoader.exists(handler_spec["path"]):
|
||
return ErrorCodes.make(
|
||
ErrorCodes.INTERNAL_ERROR,
|
||
"Missing handler script '%s' for command '%s'" % [handler_spec["path"], command]
|
||
)
|
||
var script := load(handler_spec["path"]) as GDScript
|
||
if script == null:
|
||
return ErrorCodes.make(
|
||
ErrorCodes.INTERNAL_ERROR,
|
||
"Failed to load handler script '%s' for command '%s'" % [handler_spec["path"], command]
|
||
)
|
||
instance = script.callv("new", handler_spec["args"])
|
||
if instance == null:
|
||
return ErrorCodes.make(
|
||
ErrorCodes.INTERNAL_ERROR,
|
||
"Failed to construct handler '%s' for command '%s'" % [handler_key, command]
|
||
)
|
||
_lazy_handler_cache[handler_key] = instance
|
||
var method: StringName = command_spec["method"]
|
||
if not instance.has_method(method):
|
||
return ErrorCodes.make(
|
||
ErrorCodes.INTERNAL_ERROR,
|
||
"Handler '%s' has no method '%s' for command '%s'" % [handler_key, method, command]
|
||
)
|
||
_handlers[command] = Callable(instance, method)
|
||
return {}
|
||
|
||
|
||
func _register_deferred(request_id: String, command: String, timeout_override_ms: int = 0) -> void:
|
||
if request_id.is_empty():
|
||
return
|
||
## A positive per-request override wins over the per-command table so a
|
||
## single deferred call can claim more headroom without globally widening
|
||
## the command's budget (see _dispatch: input_sequence needs ~30s, but the
|
||
## other game_command ops must keep their tight 15s).
|
||
var timeout_ms: int = (
|
||
timeout_override_ms if timeout_override_ms > 0
|
||
else _deferred_timeout_ms_for_command(command)
|
||
)
|
||
_pending_deferred[request_id] = {
|
||
"command": command,
|
||
"started_ms": Time.get_ticks_msec(),
|
||
"timeout_ms": timeout_ms,
|
||
}
|
||
|
||
|
||
func _deferred_timeout_ms_for_command(command: String) -> int:
|
||
if deferred_timeout_overrides_ms.has(command):
|
||
return int(deferred_timeout_overrides_ms[command])
|
||
return int(DEFERRED_TIMEOUT_MS_BY_COMMAND.get(command, DEFAULT_DEFERRED_TIMEOUT_MS))
|
||
|
||
|
||
func _collect_deferred_timeouts() -> Array[Dictionary]:
|
||
var responses: Array[Dictionary] = []
|
||
if _pending_deferred.is_empty():
|
||
return responses
|
||
var now := Time.get_ticks_msec()
|
||
for request_id in _pending_deferred.keys():
|
||
var entry: Dictionary = _pending_deferred[request_id]
|
||
var timeout_ms: int = entry.get("timeout_ms", DEFAULT_DEFERRED_TIMEOUT_MS)
|
||
var elapsed_ms := now - int(entry.get("started_ms", now))
|
||
if elapsed_ms < timeout_ms:
|
||
continue
|
||
_pending_deferred.erase(request_id)
|
||
var command: String = entry.get("command", "")
|
||
var response := ErrorCodes.make(
|
||
ErrorCodes.DEFERRED_TIMEOUT,
|
||
"Deferred response for '%s' timed out after %dms" % [command, timeout_ms]
|
||
)
|
||
response["request_id"] = request_id
|
||
response["error"]["data"] = {
|
||
"command": command,
|
||
"elapsed_ms": elapsed_ms,
|
||
"timeout_ms": timeout_ms,
|
||
}
|
||
## Same envelope-level readiness stamp as `_dispatch` — keep the
|
||
## self-heal channel symmetric across every reply shape the
|
||
## dispatcher emits so the server cache can't drift just because
|
||
## the editor happened to time out a deferred command.
|
||
response["readiness"] = McpConnection.get_readiness()
|
||
_stamp_error_watermark(response)
|
||
responses.append(response)
|
||
if mcp_logging and _log_buffer != null:
|
||
_log_buffer.log("[defer] %s (request %s) -> timeout" % [command, request_id])
|
||
return responses
|
||
|
||
|
||
func _stamp_error_watermark(response: Dictionary) -> void:
|
||
McpSurfacedErrorTracker.stamp_watermark(response, _surfaced_error_tracker)
|
||
|
||
|
||
static func _capture_compact_backtrace(max_frames: int = 8) -> String:
|
||
var traces: Array = Engine.capture_script_backtraces(false)
|
||
for bt in traces:
|
||
if bt != null and not bt.is_empty():
|
||
return _trim_backtrace_string(bt.format(0, 2), max_frames)
|
||
return _format_stack_frames(get_stack(), max_frames)
|
||
|
||
|
||
static func _trim_backtrace_string(text: String, max_frames: int) -> String:
|
||
var lines := text.strip_edges().split("\n")
|
||
var kept: Array[String] = []
|
||
for i in range(min(lines.size(), max_frames)):
|
||
kept.append(lines[i].strip_edges())
|
||
return "\n".join(kept)
|
||
|
||
|
||
static func _format_stack_frames(frames: Array, max_frames: int) -> String:
|
||
var lines: Array[String] = []
|
||
for i in range(min(frames.size(), max_frames)):
|
||
var frame: Dictionary = frames[i]
|
||
lines.append(
|
||
"%s:%s in %s"
|
||
% [
|
||
frame.get("source", "?"),
|
||
frame.get("line", 0),
|
||
frame.get("function", "?"),
|
||
]
|
||
)
|
||
return "\n".join(lines)
|