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6062397 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 | """MCP Client for connecting to FixMyNeighborhood MCP server.
Enhanced with:
- Request timeouts
- Automatic retry with exponential backoff
- Structured error handling
- Request logging for observability
"""
import sys
import io
import time
import threading
from typing import Optional, Dict, Any, Callable
from dataclasses import dataclass
from functools import wraps
from gradio_client import Client as GradioClient
from config import MCP_SERVER_URL
@dataclass
class RetryConfig:
"""Configuration for retry behavior."""
max_retries: int = 3
initial_delay: float = 1.0 # seconds
max_delay: float = 10.0
exponential_base: float = 2.0
timeout: float = 30.0 # seconds
@dataclass
class CallMetrics:
"""Metrics for a single tool call."""
tool_name: str
start_time: float
end_time: Optional[float] = None
success: bool = False
retries: int = 0
error: Optional[str] = None
@property
def duration(self) -> float:
if self.end_time:
return self.end_time - self.start_time
return 0.0
# Singleton client instance
_mcp_client: Optional["MCPClient"] = None
class MCPClient:
"""
MCP Tool Client using gradio_client to call remote Gradio MCP server.
Enhanced Features:
- Configurable request timeouts
- Automatic retry with exponential backoff
- Structured error responses
- Call metrics for observability
- Thread-safe operations
"""
# Tool parameter order (for positional args to Gradio API)
TOOL_PARAM_ORDER = {
"geo_search_address": ["lat", "lon"],
"validate_address": ["address"],
"cityinfra_lookup_asset": ["address", "asset_type"],
"get_nearby_reports": ["address", "issue_type", "radius_blocks"],
"weather_get_current": ["lat", "lon"],
"get_department_info": ["department_code"],
"pdf_generate_report": ["issue_type", "address", "urgency", "description"],
"sendgrid_send_email": ["to", "subject", "body", "api_key", "from_email", "report_id"]
}
def __init__(
self,
server_url: str = None,
retry_config: RetryConfig = None
):
self.server_url = server_url or MCP_SERVER_URL
self.retry_config = retry_config or RetryConfig()
self._client: Optional[GradioClient] = None
self._client_lock = threading.Lock()
self._call_history: list = []
self._max_history: int = 100
@property
def client(self) -> Optional[GradioClient]:
"""Lazy initialization of Gradio client with Windows encoding fix."""
if self._client is None:
with self._client_lock:
if self._client is None: # Double-check locking
self._init_client()
return self._client
def _init_client(self) -> None:
"""Initialize the Gradio client with suppressed output."""
old_stdout, old_stderr = sys.stdout, sys.stderr
try:
sys.stdout = io.StringIO()
sys.stderr = io.StringIO()
self._client = GradioClient(self.server_url)
print(f"[MCP] Connected to {self.server_url}")
except Exception as e:
sys.stdout, sys.stderr = old_stdout, old_stderr
print(f"[MCP] Connection failed: {e}")
finally:
sys.stdout, sys.stderr = old_stdout, old_stderr
def _with_timeout(
self,
func: Callable,
timeout: float,
*args,
**kwargs
) -> Any:
"""Execute a function with a timeout."""
result = [None]
error = [None]
def target():
try:
result[0] = func(*args, **kwargs)
except Exception as e:
error[0] = e
thread = threading.Thread(target=target)
thread.start()
thread.join(timeout=timeout)
if thread.is_alive():
# Thread is still running - timeout occurred
raise TimeoutError(f"Operation timed out after {timeout}s")
if error[0]:
raise error[0]
return result[0]
def call_tool(self, tool_name: str, **kwargs) -> dict:
"""
Call an MCP tool with retry and timeout support.
Args:
tool_name: Name of the tool to call
**kwargs: Tool parameters
Returns:
dict: Tool result or error response
"""
metrics = CallMetrics(tool_name=tool_name, start_time=time.time())
config = self.retry_config
for attempt in range(config.max_retries + 1):
try:
if self.client is None:
return self._fallback_response(tool_name, kwargs, "Client not initialized")
# Get ordered args for this tool
param_order = self.TOOL_PARAM_ORDER.get(tool_name, [])
args = [kwargs.get(param) for param in param_order]
# Execute with timeout
result = self._with_timeout(
self._execute_call,
config.timeout,
tool_name,
args
)
# Success
metrics.end_time = time.time()
metrics.success = True
metrics.retries = attempt
self._record_call(metrics)
return result if isinstance(result, dict) else {"result": result}
except TimeoutError as e:
metrics.error = f"Timeout: {e}"
print(f"[MCP] {tool_name} timeout (attempt {attempt + 1}/{config.max_retries + 1})")
except Exception as e:
metrics.error = str(e)
print(f"[MCP] {tool_name} error: {e} (attempt {attempt + 1}/{config.max_retries + 1})")
# Check if we should retry
if attempt < config.max_retries:
delay = min(
config.initial_delay * (config.exponential_base ** attempt),
config.max_delay
)
print(f"[MCP] Retrying in {delay:.1f}s...")
time.sleep(delay)
metrics.retries = attempt + 1
# All retries exhausted
metrics.end_time = time.time()
metrics.success = False
self._record_call(metrics)
return self._fallback_response(
tool_name,
kwargs,
f"Failed after {config.max_retries + 1} attempts: {metrics.error}"
)
def _execute_call(self, tool_name: str, args: list) -> Any:
"""Execute the actual API call with suppressed output."""
old_stdout, old_stderr = sys.stdout, sys.stderr
try:
sys.stdout = io.StringIO()
sys.stderr = io.StringIO()
return self.client.predict(
*args,
api_name=f"/{tool_name}"
)
finally:
sys.stdout, sys.stderr = old_stdout, old_stderr
def _fallback_response(
self,
tool_name: str,
inputs: dict,
error: str = None
) -> dict:
"""Return structured error response when MCP server is unavailable."""
return {
"error": "MCP server unavailable",
"error_detail": error,
"message": "The infrastructure tools service is temporarily unavailable. Please try again in a moment.",
"tool": tool_name,
"server_url": self.server_url,
"recoverable": True,
"retry_after": 30,
}
def _record_call(self, metrics: CallMetrics) -> None:
"""Record call metrics for observability."""
self._call_history.append({
"tool": metrics.tool_name,
"duration": metrics.duration,
"success": metrics.success,
"retries": metrics.retries,
"error": metrics.error,
"timestamp": metrics.start_time,
})
# Trim history
if len(self._call_history) > self._max_history:
self._call_history = self._call_history[-self._max_history:]
def get_metrics(self) -> Dict[str, Any]:
"""Get call metrics for observability."""
if not self._call_history:
return {"total_calls": 0}
successful = [c for c in self._call_history if c["success"]]
failed = [c for c in self._call_history if not c["success"]]
return {
"total_calls": len(self._call_history),
"successful": len(successful),
"failed": len(failed),
"success_rate": len(successful) / len(self._call_history) if self._call_history else 0,
"avg_duration": sum(c["duration"] for c in successful) / len(successful) if successful else 0,
"total_retries": sum(c["retries"] for c in self._call_history),
"by_tool": self._get_by_tool_metrics(),
}
def _get_by_tool_metrics(self) -> Dict[str, Dict[str, Any]]:
"""Get metrics grouped by tool."""
by_tool = {}
for call in self._call_history:
tool = call["tool"]
if tool not in by_tool:
by_tool[tool] = {"calls": 0, "success": 0, "total_duration": 0}
by_tool[tool]["calls"] += 1
if call["success"]:
by_tool[tool]["success"] += 1
by_tool[tool]["total_duration"] += call["duration"]
return by_tool
def health_check(self) -> Dict[str, Any]:
"""Check if MCP server is healthy."""
start = time.time()
try:
# Try a lightweight call
if self.client is None:
return {
"healthy": False,
"error": "Client not initialized",
"latency": None,
}
# Attempt connection
return {
"healthy": True,
"latency": time.time() - start,
"server_url": self.server_url,
}
except Exception as e:
return {
"healthy": False,
"error": str(e),
"latency": time.time() - start,
}
def get_mcp_client() -> Optional[MCPClient]:
"""Get singleton MCP client instance."""
global _mcp_client
if _mcp_client is None:
_mcp_client = MCPClient()
return _mcp_client
def reset_mcp_client() -> None:
"""Reset the MCP client (useful for testing or reconnection)."""
global _mcp_client
_mcp_client = None
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