Add CLI validation and DNS options to Connectivity Monitor

python/README.md

@@ -47,6 +47,10 @@ Options:
   --targets TARGETS       Comma-separated ping targets (e.g. 1.1.1.1,8.8.8.8)
   --poll SECONDS          Poll interval in seconds (default: 2)
   --threshold N           Consecutive failures to declare an outage (default: 4)
+  --lat-warn MS           High-latency warning threshold in milliseconds (default: 100)
+  --enable-dns            Force-enable DNS health checks (overrides saved config)
+  --disable-dns           Disable DNS health checks
+  --dns-target HOST       Hostname to resolve for DNS checks (default: google.com)
   --web-port PORT         Web dashboard port (default: 8080)
 ```
 
@@ -64,6 +68,9 @@ python3 -m connectivity_monitor --headless --targets 1.1.1.1,8.8.8.8 --web-port
 
 # Adjust poll interval and threshold
 python3 -m connectivity_monitor --headless --poll 5 --threshold 3
+
+# Tune latency alerts and DNS checks
+python3 -m connectivity_monitor --headless --lat-warn 80 --disable-dns --targets 1.1.1.1,9.9.9.9
 ```
 
 ## Web Dashboard & API

python/connectivity_monitor/__main__.py

@@ -3,7 +3,13 @@
 import argparse
 import sys
 
-from .config import load_config, interactive_setup, headless_config, ensure_dirs
+from .config import (
+    load_config,
+    interactive_setup,
+    headless_config,
+    ensure_dirs,
+    validate_config,
+)
 from .monitor import run_monitor
 
 
@@ -35,6 +41,23 @@ def main():
         "--threshold", type=int, default=None,
         help="Consecutive failures to declare an outage (default: 4)",
     )
+    parser.add_argument(
+        "--lat-warn", type=int, dest="lat_warn", default=None,
+        help="Latency threshold in ms for warning/high-latency events (default: 100)",
+    )
+    dns_group = parser.add_mutually_exclusive_group()
+    dns_group.add_argument(
+        "--enable-dns", dest="enable_dns", action="store_true", default=None,
+        help="Force-enable DNS health checks (overrides saved config)",
+    )
+    dns_group.add_argument(
+        "--disable-dns", dest="enable_dns", action="store_false",
+        help="Disable DNS health checks",
+    )
+    parser.add_argument(
+        "--dns-target", type=str, dest="dns_target", default=None,
+        help="Hostname to resolve for DNS checks (default: google.com)",
+    )
     parser.add_argument(
         "--web-port", type=int, default=None, dest="web_port",
         help="Web dashboard port (default: 8080)",
@@ -52,6 +75,11 @@ def main():
         cfg = interactive_setup(saved)
         cfg["headless"] = False
 
+    try:
+        cfg = validate_config(cfg)
+    except ValueError as exc:
+        parser.error(str(exc))
+
     run_monitor(cfg)
 
 

python/connectivity_monitor/config.py

@@ -17,6 +17,26 @@
 }
 
 
+def _normalize_targets(targets):
+    """Split and clean a comma-separated targets string."""
+    if not targets:
+        return []
+    return [t.strip() for t in str(targets).split(",") if t.strip()]
+
+
+def _require_positive_int(value, label, minimum=1, maximum=None):
+    """Validate integer bounds and return the coerced value."""
+    try:
+        num = int(value)
+    except (TypeError, ValueError):
+        raise ValueError("{} must be an integer.".format(label))
+    if num < minimum:
+        raise ValueError("{} must be at least {}.".format(label, minimum))
+    if maximum is not None and num > maximum:
+        raise ValueError("{} must be at most {}.".format(label, maximum))
+    return num
+
+
 def get_base_dir():
     """Return base directory for logs/reports/config."""
     home = os.path.expanduser("~")
@@ -134,7 +154,57 @@ def headless_config(args):
         cfg["poll"] = args.poll
     if args.threshold:
         cfg["threshold"] = args.threshold
+    if args.lat_warn is not None:
+        cfg["lat_warn"] = args.lat_warn
+    if args.enable_dns is not None:
+        cfg["enable_dns"] = args.enable_dns
+    if args.dns_target:
+        cfg["dns_target"] = args.dns_target
     if args.web_port is not None:
         cfg["web_port"] = args.web_port
 
     return cfg
+
+
+def validate_config(cfg):
+    """
+    Validate and normalize configuration.
+
+    Ensures numeric fields are positive, port is within range, targets are
+    present, and DNS settings are consistent. Returns the validated config
+    (mutating the original dict).
+    """
+    cfg["poll"] = _require_positive_int(
+        cfg.get("poll", DEFAULTS["poll"]), "Poll interval (seconds)"
+    )
+    cfg["threshold"] = _require_positive_int(
+        cfg.get("threshold", DEFAULTS["threshold"]),
+        "Failure threshold",
+    )
+    cfg["lat_warn"] = _require_positive_int(
+        cfg.get("lat_warn", DEFAULTS["lat_warn"]),
+        "Latency warning threshold (ms)",
+    )
+    cfg["web_port"] = _require_positive_int(
+        cfg.get("web_port", DEFAULTS["web_port"]),
+        "Web dashboard port",
+        maximum=65535,
+    )
+
+    targets = _normalize_targets(cfg.get("targets", DEFAULTS["targets"]))
+    if not targets:
+        raise ValueError("At least one ping target is required (e.g. 1.1.1.1).")
+    cfg["targets"] = ",".join(targets)
+
+    enable_dns = cfg.get("enable_dns", True)
+    if isinstance(enable_dns, str):
+        enable_dns = enable_dns.lower() not in ("false", "0", "no", "off")
+    cfg["enable_dns"] = bool(enable_dns)
+
+    if cfg["enable_dns"]:
+        dns_target = cfg.get("dns_target", DEFAULTS["dns_target"])
+        if not dns_target or not str(dns_target).strip():
+            raise ValueError("DNS health check is enabled but no DNS hostname is set.")
+        cfg["dns_target"] = str(dns_target).strip()
+
+    return cfg