decomposer: generate deliverable files for Define the service contract and project architecture for the FastAPI endpoint monitoring service.; Implement the typed monitor CRUD API and concurrency-safe in-memory state according to the service design.; Implement secure on-demand endpoint checks with status updates, latency measurement, robust error handling, and redacted structured logs.; Add operational API endpoints and environment-driven runtime configuration to the monitoring service.; Create automated tests for the monitoring service.; Package the service with Docker and developer documentation.; Validate the complete project.

app/security.py

@@ -2,7 +2,7 @@ import asyncio
 import ipaddress
 import socket
 from collections.abc import Awaitable, Callable
-from urllib.parse import urlsplit, urlunsplit
+from urllib.parse import urlsplit
 
 Resolver = Callable[[str, int], Awaitable[list[str]]]
 
@@ -11,45 +11,28 @@ class UnsafeTarget(ValueError):
     pass
 
 
-def redact_url(url: str) -> str:
-    parts = urlsplit(url)
-    host = parts.hostname or "invalid"
-    if ":" in host:
-        host = f"[{host}]"
-    port = f":{parts.port}" if parts.port else ""
-    return urlunsplit((parts.scheme, f"{host}{port}", parts.path, "", ""))
-
-
 async def system_resolver(host: str, port: int) -> list[str]:
-    def resolve() -> list[str]:
-        rows = socket.getaddrinfo(host, port, type=socket.SOCK_STREAM)
-        return list({row[4][0] for row in rows})
-
-    return await asyncio.to_thread(resolve)
+    loop = asyncio.get_running_loop()
+    records = await loop.getaddrinfo(host, port, type=socket.SOCK_STREAM)
+    return sorted({record[4][0] for record in records})
 
 
 async def validate_target(url: str, resolver: Resolver = system_resolver) -> None:
-    parts = urlsplit(url)
-    if parts.scheme not in {"http", "https"} or not parts.hostname:
-        raise UnsafeTarget("invalid_scheme_or_host")
-    if parts.username is not None or parts.password is not None:
+    parsed = urlsplit(url)
+    if parsed.scheme not in {"http", "https"} or not parsed.hostname:
+        raise UnsafeTarget("unsupported_target")
+    if parsed.username or parsed.password:
         raise UnsafeTarget("credentials_not_allowed")
-    host = parts.hostname.rstrip(".").lower()
-    if host == "localhost" or host.endswith(".localhost"):
-        raise UnsafeTarget("non_global_target")
-    port = parts.port or (443 if parts.scheme == "https" else 80)
+    port = parsed.port or (443 if parsed.scheme == "https" else 80)
     try:
-        literal = ipaddress.ip_address(host)
-        addresses = [str(literal)]
-    except ValueError:
-        try:
-            addresses = await resolver(host, port)
-        except (OSError, socket.gaierror) as exc:
-            raise UnsafeTarget("dns_resolution_failed") from exc
+        addresses = await resolver(parsed.hostname, port)
+    except (OSError, socket.gaierror) as exc:
+        raise UnsafeTarget("dns_resolution_failed") from exc
     if not addresses:
         raise UnsafeTarget("dns_resolution_failed")
     try:
-        if any(not ipaddress.ip_address(address).is_global for address in addresses):
-            raise UnsafeTarget("non_global_target")
+        safe = all(ipaddress.ip_address(address).is_global for address in addresses)
     except ValueError as exc:
-        raise UnsafeTarget("invalid_dns_answer") from exc
+        raise UnsafeTarget("dns_resolution_failed") from exc
+    if not safe:
+        raise UnsafeTarget("non_public_target")