chore: import upstream snapshot with attribution

contributing/samples/mcp/mcp_streamablehttp_agent/filesystem_server.py

@@ -0,0 +1,100 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import asyncio
+import json
+import os
+from pathlib import Path
+import sys
+
+from mcp.server.fastmcp import FastMCP
+
+# Create an MCP server with a name
+mcp = FastMCP("Filesystem Server", host="localhost", port=3000)
+
+
+# Add a tool to read file contents
+@mcp.tool(description="Read contents of a file")
+def read_file(filepath: str) -> str:
+  """Read and return the contents of a file."""
+  with open(filepath, "r") as f:
+    return f.read()
+
+
+# Add a tool to list directory contents
+@mcp.tool(description="List contents of a directory")
+def list_directory(dirpath: str) -> list:
+  """List all files and directories in the given directory."""
+  return os.listdir(dirpath)
+
+
+# Add a tool to get current working directory
+@mcp.tool(description="Get current working directory")
+def get_cwd() -> str:
+  """Return the current working directory."""
+  return str(Path.cwd())
+
+
+# Add a resource for testing with JSON data
+@mcp.resource(
+    name="sample_data",
+    uri="file:///sample_data.json",
+    mime_type="application/json",
+)
+def sample_data() -> str:
+  data = {
+      "users": [
+          {"id": 1, "name": "Alice", "role": "admin"},
+          {"id": 2, "name": "Bob", "role": "user"},
+          {"id": 3, "name": "Charlie", "role": "user"},
+      ],
+      "settings": {"theme": "dark", "notifications": True},
+  }
+  return json.dumps(data, indent=2)
+
+
+# Graceful shutdown handler
+async def shutdown(signal, loop):
+  """Cleanup tasks tied to the service's shutdown."""
+  print(f"\nReceived exit signal {signal.name}...")
+
+  # Get all running tasks
+  tasks = [t for t in asyncio.all_tasks() if t is not asyncio.current_task()]
+
+  # Cancel all tasks
+  for task in tasks:
+    task.cancel()
+
+  print(f"Cancelling {len(tasks)} outstanding tasks")
+  await asyncio.gather(*tasks, return_exceptions=True)
+
+  # Stop the loop
+  loop.stop()
+  print("Shutdown complete!")
+
+
+# Main entry point with graceful shutdown handling
+if __name__ == "__main__":
+  try:
+    # The MCP run function ultimately uses asyncio.run() internally
+    mcp.run(transport="streamable-http")
+  except KeyboardInterrupt:
+    print("\nServer shutting down gracefully...")
+    # The asyncio event loop has already been stopped by the KeyboardInterrupt
+    print("Server has been shut down.")
+  except Exception as e:
+    print(f"Unexpected error: {e}")
+    sys.exit(1)
+  finally:
+    print("Thank you for using the Filesystem MCP Server!")