Initial commit: LAN Checker

Network health monitoring script with MQTT reporting for Home Assistant.
- Ping, HTTP, and SNMP checkers
- MQTT Discovery for automatic entity creation
- Configurable check intervals

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

checkers/__init__.py

@@ -0,0 +1,9 @@
+from .ping import PingChecker
+from .http import HttpChecker
+from .snmp import SnmpChecker
+
+CHECKERS = {
+    "ping": PingChecker,
+    "http": HttpChecker,
+    "snmp": SnmpChecker,
+}

checkers/base.py

@@ -0,0 +1,21 @@
+from abc import ABC, abstractmethod
+from dataclasses import dataclass
+from typing import Any
+
+
+@dataclass
+class CheckResult:
+    success: bool
+    message: str
+    response_time: float | None = None
+    details: dict[str, Any] | None = None
+
+
+class BaseChecker(ABC):
+    def __init__(self, name: str, config: dict):
+        self.name = name
+        self.config = config
+
+    @abstractmethod
+    def check(self) -> CheckResult:
+        pass

checkers/http.py

@@ -0,0 +1,53 @@
+import time
+
+import requests
+
+from .base import BaseChecker, CheckResult
+
+
+class HttpChecker(BaseChecker):
+    def check(self) -> CheckResult:
+        url = self.config["url"]
+        method = self.config.get("method", "GET").upper()
+        timeout = self.config.get("timeout", 10)
+        expected_status = self.config.get("expected_status", 200)
+        verify_ssl = self.config.get("verify_ssl", True)
+        headers = self.config.get("headers", {})
+
+        start = time.time()
+        try:
+            response = requests.request(
+                method=method,
+                url=url,
+                timeout=timeout,
+                verify=verify_ssl,
+                headers=headers
+            )
+            response_time = (time.time() - start) * 1000  # ms
+
+            if response.status_code == expected_status:
+                return CheckResult(
+                    success=True,
+                    message=f"HTTP {response.status_code}",
+                    response_time=response_time,
+                    details={"status_code": response.status_code}
+                )
+            else:
+                return CheckResult(
+                    success=False,
+                    message=f"Unexpected status: {response.status_code} (expected {expected_status})",
+                    response_time=response_time,
+                    details={"status_code": response.status_code}
+                )
+        except requests.Timeout:
+            return CheckResult(
+                success=False,
+                message="HTTP timeout",
+                response_time=None
+            )
+        except requests.RequestException as e:
+            return CheckResult(
+                success=False,
+                message=f"HTTP error: {e}",
+                response_time=None
+            )

checkers/ping.py

@@ -0,0 +1,53 @@
+import subprocess
+import time
+import platform
+
+from .base import BaseChecker, CheckResult
+
+
+class PingChecker(BaseChecker):
+    def check(self) -> CheckResult:
+        host = self.config["host"]
+        count = self.config.get("count", 1)
+        timeout = self.config.get("timeout", 5)
+
+        # Adapt ping command for OS
+        if platform.system().lower() == "windows":
+            cmd = ["ping", "-n", str(count), "-w", str(timeout * 1000), host]
+        else:
+            cmd = ["ping", "-c", str(count), "-W", str(timeout), host]
+
+        start = time.time()
+        try:
+            result = subprocess.run(
+                cmd,
+                capture_output=True,
+                text=True,
+                timeout=timeout + 5
+            )
+            response_time = (time.time() - start) * 1000  # ms
+
+            if result.returncode == 0:
+                return CheckResult(
+                    success=True,
+                    message="Host is reachable",
+                    response_time=response_time
+                )
+            else:
+                return CheckResult(
+                    success=False,
+                    message="Host is unreachable",
+                    response_time=None
+                )
+        except subprocess.TimeoutExpired:
+            return CheckResult(
+                success=False,
+                message="Ping timeout",
+                response_time=None
+            )
+        except Exception as e:
+            return CheckResult(
+                success=False,
+                message=f"Ping error: {e}",
+                response_time=None
+            )

checkers/snmp.py

@@ -0,0 +1,62 @@
+import time
+
+from pysnmp.hlapi import (
+    SnmpEngine,
+    CommunityData,
+    UdpTransportTarget,
+    ContextData,
+    ObjectType,
+    ObjectIdentity,
+    getCmd,
+)
+
+from .base import BaseChecker, CheckResult
+
+
+class SnmpChecker(BaseChecker):
+    def check(self) -> CheckResult:
+        host = self.config["host"]
+        port = self.config.get("port", 161)
+        community = self.config.get("community", "public")
+        oid = self.config.get("oid", "1.3.6.1.2.1.1.1.0")  # sysDescr
+        timeout_val = self.config.get("timeout", 5)
+
+        start = time.time()
+        try:
+            iterator = getCmd(
+                SnmpEngine(),
+                CommunityData(community),
+                UdpTransportTarget((host, port), timeout=timeout_val, retries=1),
+                ContextData(),
+                ObjectType(ObjectIdentity(oid))
+            )
+
+            error_indication, error_status, error_index, var_binds = next(iterator)
+            response_time = (time.time() - start) * 1000  # ms
+
+            if error_indication:
+                return CheckResult(
+                    success=False,
+                    message=f"SNMP error: {error_indication}",
+                    response_time=None
+                )
+            elif error_status:
+                return CheckResult(
+                    success=False,
+                    message=f"SNMP error: {error_status.prettyPrint()}",
+                    response_time=None
+                )
+            else:
+                values = {str(oid): str(val) for oid, val in var_binds}
+                return CheckResult(
+                    success=True,
+                    message="SNMP response OK",
+                    response_time=response_time,
+                    details=values
+                )
+        except Exception as e:
+            return CheckResult(
+                success=False,
+                message=f"SNMP error: {e}",
+                response_time=None
+            )