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tekton/addons/godot_ai/clients/_cli_finder.gd
T

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GDScript

@tool
class_name McpCliFinder
extends RefCounted
## Generic three-tier CLI resolution for clients whose binary lives somewhere
## a GUI-launched Godot's minimal PATH won't see:
## 1. Well-known install locations (~/.local/bin, /opt/homebrew/bin, ...)
## 2. Login shell lookup (`bash -lc 'command -v <exe>'`) — picks up .zshrc / .bashrc
## 3. Plain `which` / `where` against the inherited PATH
## Caches per-exe so repeated dock refreshes don't fork a shell every frame.
##
## Thread safety: `find()` runs on action-worker threads
## (`_run_client_action_worker` in `mcp_dock.gd`), and `invalidate()` runs on
## the main thread (manual Refresh path). Godot `Dictionary` is not safe for
## concurrent mutation, so `_cache` / `_searched` access is guarded by
## `_mutex`. The mutex is held only across dictionary read/write — the slow
## `_resolve()` path (FileAccess + bounded subprocess lookup) runs unlocked, so a
## main-thread `invalidate()` can never block on a worker's subprocess.
## Two workers racing the same exe both call `_resolve()` and both write
## back the same answer; that's wasted work, not corruption.
static var _mutex: Mutex = Mutex.new()
static var _cache: Dictionary = {} # exe_name -> resolved path (or "")
static var _searched: Dictionary = {}
const _LOOKUP_TIMEOUT_MS := 3000
## Find any of the supplied exe names; returns the first hit.
## On Windows pass the .exe variant in `exe_names` if relevant.
static func find(exe_names: Array[String]) -> String:
for name in exe_names:
var hit := _find_one(name)
if not hit.is_empty():
return hit
return ""
## Drop cache for one exe (call after the user installs / reinstalls).
static func invalidate(exe_name: String = "") -> void:
_mutex.lock()
if exe_name.is_empty():
_cache.clear()
_searched.clear()
else:
_cache.erase(exe_name)
_searched.erase(exe_name)
_mutex.unlock()
static func _find_one(exe_name: String) -> String:
_mutex.lock()
var already_searched: bool = _searched.get(exe_name, false)
var cached: String = _cache.get(exe_name, "")
_mutex.unlock()
if already_searched:
return cached
# `_resolve()` does FileAccess + bounded subprocess lookup (forks
# `bash -lc` / `which`), which can take 100ms-1s. Holding the mutex across that
# would let a concurrent `invalidate()` on the main thread freeze the
# editor for the duration of the subprocess — which defeats the whole
# point of running CLI lookup off the main thread.
var hit := _resolve(exe_name)
_mutex.lock()
_cache[exe_name] = hit
_searched[exe_name] = true
_mutex.unlock()
return hit
static func _resolve(exe_name: String) -> String:
var is_windows := OS.get_name() == "Windows"
# 1. Well-known locations
for dir in _well_known_dirs():
var full := dir.path_join(exe_name)
if FileAccess.file_exists(full):
return full
# 2. Login shell lookup (Unix only)
if not is_windows:
var shell := OS.get_environment("SHELL")
if shell.is_empty():
shell = "/bin/bash"
var stripped := exe_name.trim_suffix(".exe")
var login_result := McpCliExec.run(shell, ["-lc", "command -v %s" % stripped], _LOOKUP_TIMEOUT_MS, false)
if int(login_result.get("exit_code", -1)) == 0:
var login_found: String = str(login_result.get("stdout", "")).strip_edges()
if not login_found.is_empty() and FileAccess.file_exists(login_found):
return login_found
# 3. which / where with inherited PATH
var lookup := "where" if is_windows else "which"
var result := McpCliExec.run(lookup, [exe_name], _LOOKUP_TIMEOUT_MS, false)
if int(result.get("exit_code", -1)) == 0:
var output := str(result.get("stdout", ""))
var lines := PackedStringArray(output.split("\n"))
var found := _pick_best_path(lines) if is_windows else lines[0].strip_edges()
if not found.is_empty():
return found
return ""
## Executable extensions Windows' CreateProcessW can launch from a path
## (after the cmd.exe wrap in `_cli_exec.gd`). Order is preference: `.exe`
## is a native PE binary; `.cmd` / `.bat` go through the shell; `.com` is
## the legacy COM-format executable that some shims still ship.
const _WINDOWS_EXEC_EXTS := [".exe", ".cmd", ".bat", ".com"]
## Pick the best path from `where` output on Windows.
##
## npm-installed Node CLIs ship as BOTH `<dir>/<name>` (a POSIX bash shim
## for WSL / Git Bash users) AND `<dir>/<name>.cmd` (the actual Windows
## wrapper). `where <name>` lists both. CreateProcessW — the underlying
## syscall behind `OS.execute_with_pipe` — refuses to launch the
## extensionless POSIX shim, surfacing as
## `ERROR: Could not create child process: "...\claude" mcp list`
## in Godot's output log (#251). Picking a path with a real executable
## extension dodges that entirely.
##
## Extension scan is the OUTER loop so the order in `_WINDOWS_EXEC_EXTS`
## drives preference — `.exe` wins over `.cmd` even when the `.cmd` shows
## up first in `where` output (one fewer process per shell-out). Falls
## back to the first non-empty line when no entry has a recognised
## extension, so we never come up empty when `where` returned *something*.
static func _pick_best_path(lines: PackedStringArray) -> String:
var stripped := PackedStringArray()
for raw in lines:
var line := raw.strip_edges()
if not line.is_empty():
stripped.append(line)
if stripped.is_empty():
return ""
for ext in _WINDOWS_EXEC_EXTS:
for candidate in stripped:
if candidate.to_lower().ends_with(ext):
return candidate
return stripped[0]
static func _well_known_dirs() -> Array[String]:
var home := OS.get_environment("HOME")
if home.is_empty():
home = OS.get_environment("USERPROFILE")
match OS.get_name():
"macOS":
return [
home.path_join(".local/bin"),
home.path_join(".claude/local"),
home.path_join(".cargo/bin"),
"/opt/homebrew/bin",
"/usr/local/bin",
]
"Windows":
var local := OS.get_environment("LOCALAPPDATA")
var prog := OS.get_environment("ProgramFiles")
var paths: Array[String] = []
if not home.is_empty():
paths.append(home.path_join(".claude/local"))
paths.append(home.path_join(".local/bin"))
paths.append(home.path_join(".cargo/bin"))
paths.append(home.path_join("AppData/Local/Programs/uv"))
if not local.is_empty():
paths.append(local.path_join("Programs/uv"))
if not prog.is_empty():
paths.append(prog.path_join("uv"))
return paths
_:
return [
home.path_join(".local/bin"),
home.path_join(".claude/local"),
home.path_join(".cargo/bin"),
"/usr/local/bin",
]