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| 1 | +"""OpenSpace MCP Server — bootstrap, FastMCP creation, and entry point. |
| 2 | +
|
| 3 | +Extracted from ``mcp_server.py`` (Epic 4.9) to consolidate all MCP server |
| 4 | +concerns under ``openspace/mcp/``. |
| 5 | +
|
| 6 | +Sections: |
| 7 | + 1. _MCPSafeStdout — stdout wrapper for MCP stdio transport |
| 8 | + 2. Logging/stderr bootstrap — Windows pipe deadlock prevention |
| 9 | + 3. create_mcp_app() — FastMCP factory with tool handler registration |
| 10 | + 4. run_mcp_server() — CLI entry point with transport + auth setup |
| 11 | +""" |
| 12 | + |
| 13 | +from __future__ import annotations |
| 14 | + |
| 15 | +import atexit |
| 16 | +import inspect |
| 17 | +import logging |
| 18 | +import os |
| 19 | +import sys |
| 20 | +from pathlib import Path |
| 21 | + |
| 22 | + |
| 23 | +# --------------------------------------------------------------------------- |
| 24 | +# 1. Stdout wrapper for MCP stdio transport |
| 25 | +# --------------------------------------------------------------------------- |
| 26 | +class _MCPSafeStdout: |
| 27 | + """Stdout wrapper: binary (.buffer) → real stdout, text (.write) → stderr. |
| 28 | +
|
| 29 | + MCP stdio transport requires stdout for JSON-RPC messages only. |
| 30 | + Any text written by application code (print, warnings) must go to stderr. |
| 31 | + """ |
| 32 | + |
| 33 | + def __init__(self, real_stdout, stderr): |
| 34 | + self._real = real_stdout |
| 35 | + self._stderr = stderr |
| 36 | + |
| 37 | + @property |
| 38 | + def buffer(self): |
| 39 | + return self._real.buffer |
| 40 | + |
| 41 | + def fileno(self): |
| 42 | + return self._real.fileno() |
| 43 | + |
| 44 | + def write(self, s): |
| 45 | + return self._stderr.write(s) |
| 46 | + |
| 47 | + def writelines(self, lines): |
| 48 | + return self._stderr.writelines(lines) |
| 49 | + |
| 50 | + def flush(self): |
| 51 | + self._stderr.flush() |
| 52 | + self._real.flush() |
| 53 | + |
| 54 | + def isatty(self): |
| 55 | + return self._stderr.isatty() |
| 56 | + |
| 57 | + @property |
| 58 | + def encoding(self): |
| 59 | + return self._stderr.encoding |
| 60 | + |
| 61 | + @property |
| 62 | + def errors(self): |
| 63 | + return self._stderr.errors |
| 64 | + |
| 65 | + @property |
| 66 | + def closed(self): |
| 67 | + return self._stderr.closed |
| 68 | + |
| 69 | + def readable(self): |
| 70 | + return False |
| 71 | + |
| 72 | + def writable(self): |
| 73 | + return True |
| 74 | + |
| 75 | + def seekable(self): |
| 76 | + return False |
| 77 | + |
| 78 | + def __getattr__(self, name): |
| 79 | + return getattr(self._stderr, name) |
| 80 | + |
| 81 | + |
| 82 | +# --------------------------------------------------------------------------- |
| 83 | +# 2. Logging / stderr bootstrap |
| 84 | +# --------------------------------------------------------------------------- |
| 85 | +_LOG_DIR = Path(__file__).resolve().parent.parent.parent / "logs" |
| 86 | +_LOG_DIR.mkdir(parents=True, exist_ok=True) |
| 87 | + |
| 88 | +_real_stdout = sys.stdout |
| 89 | + |
| 90 | +# Windows pipe buffers are small. When using stdio MCP transport, |
| 91 | +# the parent process only reads stdout for MCP messages and does NOT |
| 92 | +# drain stderr. Heavy log/print output during execute_task fills the stderr |
| 93 | +# pipe buffer, blocking this process on write() → deadlock → timeout. |
| 94 | +# Redirect stderr to a log file on Windows to prevent this. |
| 95 | +_stderr_file = None |
| 96 | +if os.name == "nt": |
| 97 | + _stderr_file = open(_LOG_DIR / "mcp_stderr.log", "a", encoding="utf-8", buffering=1) |
| 98 | + sys.stderr = _stderr_file |
| 99 | + |
| 100 | +sys.stdout = _MCPSafeStdout(_real_stdout, sys.stderr) |
| 101 | + |
| 102 | +_log_file_handler = logging.FileHandler(_LOG_DIR / "mcp_server.log") |
| 103 | +logging.basicConfig( |
| 104 | + level=logging.INFO, |
| 105 | + format="%(asctime)s - %(name)s - %(levelname)s - %(message)s", |
| 106 | + handlers=[_log_file_handler], |
| 107 | +) |
| 108 | +logger = logging.getLogger("openspace.mcp_server") |
| 109 | + |
| 110 | + |
| 111 | +def _cleanup_file_handles(): |
| 112 | + """Clean up file handles on exit.""" |
| 113 | + global _stderr_file, _log_file_handler |
| 114 | + if _stderr_file: |
| 115 | + _stderr_file.close() |
| 116 | + _stderr_file = None |
| 117 | + if _log_file_handler: |
| 118 | + _log_file_handler.close() |
| 119 | + |
| 120 | + |
| 121 | +atexit.register(_cleanup_file_handles) |
| 122 | + |
| 123 | + |
| 124 | +# --------------------------------------------------------------------------- |
| 125 | +# 3. FastMCP app factory |
| 126 | +# --------------------------------------------------------------------------- |
| 127 | +def create_mcp_app(): |
| 128 | + """Create and return a configured FastMCP instance with all tools registered. |
| 129 | +
|
| 130 | + This is the single factory for the MCP application. Tool handlers are |
| 131 | + wired via ``register_handlers()`` from the tool_handlers module. |
| 132 | + """ |
| 133 | + from mcp.server.fastmcp import FastMCP |
| 134 | + |
| 135 | + from openspace.mcp.tool_handlers import register_handlers |
| 136 | + |
| 137 | + kwargs: dict = {} |
| 138 | + try: |
| 139 | + if "description" in inspect.signature(FastMCP.__init__).parameters: |
| 140 | + kwargs["description"] = "OpenSpace: Unite the Agents. Evolve the Mind. Rebuild the World." |
| 141 | + except (TypeError, ValueError): |
| 142 | + pass |
| 143 | + |
| 144 | + app = FastMCP("OpenSpace", **kwargs) |
| 145 | + register_handlers(app) |
| 146 | + return app |
| 147 | + |
| 148 | + |
| 149 | +# --------------------------------------------------------------------------- |
| 150 | +# 4. Server entry point |
| 151 | +# --------------------------------------------------------------------------- |
| 152 | +def run_mcp_server(mcp=None) -> None: |
| 153 | + """Console-script entry point for ``openspace-mcp``. |
| 154 | +
|
| 155 | + For HTTP transports (SSE, streamable-http), bearer token auth is |
| 156 | + REQUIRED. Set OPENSPACE_MCP_BEARER_TOKEN in the environment. |
| 157 | + The server refuses to start without it (fail-closed). |
| 158 | +
|
| 159 | + For stdio transport, auth is not applicable (local process IPC). |
| 160 | +
|
| 161 | + Args: |
| 162 | + mcp: Optional pre-created FastMCP instance. If None, creates one |
| 163 | + via ``create_mcp_app()``. |
| 164 | + """ |
| 165 | + import argparse |
| 166 | + |
| 167 | + import uvicorn |
| 168 | + |
| 169 | + from openspace.auth.bearer import ( |
| 170 | + BEARER_TOKEN_ENV, |
| 171 | + BearerTokenMiddleware, |
| 172 | + get_bearer_token, |
| 173 | + validate_token_strength, |
| 174 | + ) |
| 175 | + from openspace.auth.rate_limit import RateLimitMiddleware |
| 176 | + |
| 177 | + if mcp is None: |
| 178 | + mcp = create_mcp_app() |
| 179 | + |
| 180 | + parser = argparse.ArgumentParser(description="OpenSpace MCP Server") |
| 181 | + parser.add_argument( |
| 182 | + "--transport", |
| 183 | + choices=["stdio", "sse", "streamable-http"], |
| 184 | + default="stdio", |
| 185 | + ) |
| 186 | + parser.add_argument("--port", type=int, default=8080) |
| 187 | + parser.add_argument("--host", type=str, default="127.0.0.1") |
| 188 | + args = parser.parse_args() |
| 189 | + |
| 190 | + if args.transport == "stdio": |
| 191 | + mcp.run(transport="stdio") |
| 192 | + return |
| 193 | + |
| 194 | + # --- HTTP transports: enforce bearer token auth (fail-closed) --- |
| 195 | + token = get_bearer_token() |
| 196 | + if not token: |
| 197 | + logger.critical( |
| 198 | + "FAIL-CLOSED: %s not set. Refusing to start %s transport " |
| 199 | + "without authentication. Set the environment variable or " |
| 200 | + "use --transport stdio for local-only access.", |
| 201 | + BEARER_TOKEN_ENV, |
| 202 | + args.transport, |
| 203 | + ) |
| 204 | + sys.exit(1) |
| 205 | + |
| 206 | + token_ok, reason = validate_token_strength(token) |
| 207 | + if not token_ok: |
| 208 | + logger.critical("FAIL-CLOSED: %s — %s", BEARER_TOKEN_ENV, reason) |
| 209 | + sys.exit(1) |
| 210 | + |
| 211 | + if args.transport == "sse": |
| 212 | + starlette_app = mcp.sse_app() |
| 213 | + else: |
| 214 | + starlette_app = mcp.streamable_http_app() |
| 215 | + |
| 216 | + # Middleware chain: request → BearerAuth → RateLimit → MCP app |
| 217 | + rate_limited_app = RateLimitMiddleware(starlette_app) |
| 218 | + protected_app = BearerTokenMiddleware(rate_limited_app, token) |
| 219 | + |
| 220 | + logger.info( |
| 221 | + "Starting MCP server with bearer auth + rate limiting on %s:%d (%s transport)", |
| 222 | + args.host, |
| 223 | + args.port, |
| 224 | + args.transport, |
| 225 | + ) |
| 226 | + |
| 227 | + config = uvicorn.Config( |
| 228 | + protected_app, |
| 229 | + host=args.host, |
| 230 | + port=args.port, |
| 231 | + log_level="info", |
| 232 | + ) |
| 233 | + server = uvicorn.Server(config) |
| 234 | + import anyio |
| 235 | + |
| 236 | + anyio.run(server.serve) |
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