|
| 1 | +import contextlib |
| 2 | +import logging |
| 3 | +from uuid import uuid4 |
| 4 | + |
| 5 | +import anyio |
| 6 | +import click |
| 7 | +import mcp.types as types |
| 8 | +from mcp.server.lowlevel import Server |
| 9 | +from mcp.server.streamableHttp import StreamableHTTPServerTransport |
| 10 | +from starlette.applications import Starlette |
| 11 | +from starlette.routing import Mount |
| 12 | + |
| 13 | +# Configure logging |
| 14 | +logger = logging.getLogger(__name__) |
| 15 | + |
| 16 | +# Global task group that will be initialized in the lifespan |
| 17 | +task_group = None |
| 18 | + |
| 19 | + |
| 20 | +@contextlib.asynccontextmanager |
| 21 | +async def lifespan(app): |
| 22 | + """Application lifespan context manager for managing task group.""" |
| 23 | + global task_group |
| 24 | + |
| 25 | + async with anyio.create_task_group() as tg: |
| 26 | + task_group = tg |
| 27 | + logger.info("Application started, task group initialized!") |
| 28 | + try: |
| 29 | + yield |
| 30 | + finally: |
| 31 | + logger.info("Application shutting down, cleaning up resources...") |
| 32 | + if task_group: |
| 33 | + tg.cancel_scope.cancel() |
| 34 | + task_group = None |
| 35 | + logger.info("Resources cleaned up successfully.") |
| 36 | + |
| 37 | + |
| 38 | +@click.command() |
| 39 | +@click.option("--port", default=3000, help="Port to listen on for HTTP") |
| 40 | +@click.option( |
| 41 | + "--log-level", |
| 42 | + default="INFO", |
| 43 | + help="Logging level (DEBUG, INFO, WARNING, ERROR, CRITICAL)", |
| 44 | +) |
| 45 | +def main( |
| 46 | + port: int, |
| 47 | + log_level: str, |
| 48 | +) -> int: |
| 49 | + # Configure logging |
| 50 | + logging.basicConfig( |
| 51 | + level=getattr(logging, log_level.upper()), |
| 52 | + format="%(asctime)s - %(name)s - %(levelname)s - %(message)s", |
| 53 | + ) |
| 54 | + |
| 55 | + app = Server("mcp-streamable-http-demo") |
| 56 | + |
| 57 | + @app.call_tool() |
| 58 | + async def call_tool( |
| 59 | + name: str, arguments: dict |
| 60 | + ) -> list[types.TextContent | types.ImageContent | types.EmbeddedResource]: |
| 61 | + ctx = app.request_context |
| 62 | + interval = arguments.get("interval", 1.0) |
| 63 | + count = arguments.get("count", 5) |
| 64 | + caller = arguments.get("caller", "unknown") |
| 65 | + |
| 66 | + # Send the specified number of notifications with the given interval |
| 67 | + for i in range(count): |
| 68 | + await ctx.session.send_log_message( |
| 69 | + level="info", |
| 70 | + data=f"Notification {i+1}/{count} from caller: {caller}", |
| 71 | + logger="notification_stream", |
| 72 | + related_request_id=ctx.request_id, |
| 73 | + ) |
| 74 | + if i < count - 1: # Don't wait after the last notification |
| 75 | + await anyio.sleep(interval) |
| 76 | + |
| 77 | + return [ |
| 78 | + types.TextContent( |
| 79 | + type="text", |
| 80 | + text=( |
| 81 | + f"Sent {count} notifications with {interval}s interval" |
| 82 | + f" for caller: {caller}" |
| 83 | + ), |
| 84 | + ) |
| 85 | + ] |
| 86 | + |
| 87 | + @app.list_tools() |
| 88 | + async def list_tools() -> list[types.Tool]: |
| 89 | + return [ |
| 90 | + types.Tool( |
| 91 | + name="start-notification-stream", |
| 92 | + description=( |
| 93 | + "Sends a stream of notifications with configurable count" |
| 94 | + " and interval" |
| 95 | + ), |
| 96 | + inputSchema={ |
| 97 | + "type": "object", |
| 98 | + "required": ["interval", "count", "caller"], |
| 99 | + "properties": { |
| 100 | + "interval": { |
| 101 | + "type": "number", |
| 102 | + "description": "Interval between notifications in seconds", |
| 103 | + }, |
| 104 | + "count": { |
| 105 | + "type": "number", |
| 106 | + "description": "Number of notifications to send", |
| 107 | + }, |
| 108 | + "caller": { |
| 109 | + "type": "string", |
| 110 | + "description": ( |
| 111 | + "Identifier of the caller to include in notifications" |
| 112 | + ), |
| 113 | + }, |
| 114 | + }, |
| 115 | + }, |
| 116 | + ) |
| 117 | + ] |
| 118 | + |
| 119 | + # Create a Streamable HTTP transport |
| 120 | + http_transport = StreamableHTTPServerTransport( |
| 121 | + mcp_session_id=uuid4().hex, |
| 122 | + ) |
| 123 | + |
| 124 | + # We need to store the server instances between requests |
| 125 | + server_instances = {} |
| 126 | + |
| 127 | + # ASGI handler for streamable HTTP connections |
| 128 | + async def handle_streamable_http(scope, receive, send): |
| 129 | + if http_transport.mcp_session_id in server_instances: |
| 130 | + logger.debug("Session already exists, handling request directly") |
| 131 | + await http_transport.handle_request(scope, receive, send) |
| 132 | + else: |
| 133 | + # Start new server instance for this session |
| 134 | + async with http_transport.connect() as streams: |
| 135 | + read_stream, write_stream = streams |
| 136 | + |
| 137 | + async def run_server(): |
| 138 | + await app.run( |
| 139 | + read_stream, write_stream, app.create_initialization_options() |
| 140 | + ) |
| 141 | + |
| 142 | + if not task_group: |
| 143 | + raise RuntimeError("Task group is not initialized") |
| 144 | + |
| 145 | + task_group.start_soon(run_server) |
| 146 | + |
| 147 | + # For initialization requests, store the server reference |
| 148 | + if http_transport.mcp_session_id: |
| 149 | + server_instances[http_transport.mcp_session_id] = True |
| 150 | + |
| 151 | + # Handle the HTTP request and return the response |
| 152 | + await http_transport.handle_request(scope, receive, send) |
| 153 | + |
| 154 | + # Create an ASGI application using the transport |
| 155 | + starlette_app = Starlette( |
| 156 | + debug=True, |
| 157 | + routes=[ |
| 158 | + Mount("/mcp", app=handle_streamable_http), |
| 159 | + ], |
| 160 | + lifespan=lifespan, |
| 161 | + ) |
| 162 | + |
| 163 | + import uvicorn |
| 164 | + |
| 165 | + uvicorn.run(starlette_app, host="0.0.0.0", port=port) |
| 166 | + |
| 167 | + return 0 |
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