Tentative first version

.gitignore

@@ -1,2 +1,3 @@
 *.sqlite3
 *.egg-info
+__pycache__

netmon/entry.py

@@ -0,0 +1,66 @@
+from .ping import Ping
+import time
+import typing as t
+import sqlite3
+import argparse
+import logging
+
+
+logger = logging.getLogger(__name__)
+
+
+def record(target: str, interval: int, outage_interval: int):
+    """Record errors while pinging `target` each `interval` seconds"""
+
+    ping = Ping(target)
+    db = sqlite3.connect("netmon.sqlite3")
+
+    outage: t.Optional[int] = None
+
+    try:
+        while True:
+            res = ping.ping()
+            if outage is None and not res:  # beginning of outage
+                outage = int(time.time())
+                logger.info("Could not reach target.")
+
+            elif outage is not None and res:  # end of outage
+                delta = int(time.time() - outage)
+                logger.info(
+                    "Could reach target again (out for %d min %d s)",
+                    delta // 60,
+                    delta % 60,
+                )
+                with db:
+                    db.execute(
+                        "INSERT INTO errors (from_time, to_time, host) VALUES (?, ?, ?);",
+                        (int(outage), int(time.time()), target),
+                    )
+            time.sleep(interval if outage is None else outage_interval)
+    except KeyboardInterrupt as exn:
+        if outage is not None:
+            with db:
+                db.execute(
+                    "INSERT INTO errors (from_time, to_time, host) VALUES (?, ?, ?);",
+                    (int(outage), int(time.time()), target),
+                )
+        raise exn
+
+
+def entry():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("host", help="Remote host to ping (IP address preferred)")
+    parser.add_argument("-i", "--interval", default=30, help="Time between two pings")
+    parser.add_argument(
+        "-I",
+        "--outage-interval",
+        default=2,
+        help="Time between two pings while the network is down",
+    )
+    args = parser.parse_args()
+
+    record(args.host, args.interval, args.outage_interval)
+
+
+if __name__ == "__main__":
+    entry()

netmon/ping.py

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+import subprocess
+
+
+class Ping:
+    host: str
+    _cmd: list[str]
+
+    def __init__(self, host: str):
+        self.host = host
+        self._cmd = ["/usr/bin/ping", "-c", "1", "-W", "1", "-qn", self.host]
+
+    def ping(self) -> bool:
+        try:
+            subprocess.run(
+                self._cmd,
+                shell=False,
+                check=True,
+                stdout=subprocess.DEVNULL,
+                stderr=subprocess.DEVNULL,
+            )
+            return True
+        except subprocess.CalledProcessError:
+            return False