Used isort to sort imports. Also added to the git pre-commit hook.

[python_utils.git] / arper.py

diff --git a/arper.py b/arper.py
index c0cc9f035af4367ce0c84a0e623a2ea6ae320699..ff1168ea4ef30b6f0ca16f5411e188b113548a0d 100644 (file)
--- a/arper.py
+++ b/arper.py
@@ -2,22 +2,23 @@
 
 """A caching layer around the kernel's network mapping between IPs and MACs"""
 
+
 import datetime
 import logging
 import os
-from typing import Any, Optional
 import warnings
+from typing import Any, Optional
 
 from overrides import overrides
 
 import argparse_utils
-from collect.bidict import BiDict
 import config
 import exec_utils
 import file_utils
 import persistent
-import string_utils
 import site_config
+import string_utils
+from collect.bidict import BiDict
 
 logger = logging.getLogger(__name__)
 
@@ -36,21 +37,19 @@ cfg.add_argument(
     type=argparse_utils.valid_duration,
     default=datetime.timedelta(seconds=60 * 15),
     metavar='DURATION',
-    help='Max acceptable age of the kernel arp table cache'
+    help='Max acceptable age of the kernel arp table cache',
 )
 cfg.add_argument(
     '--arper_min_entries_to_be_valid',
     type=int,
     default=site_config.get_config().arper_minimum_device_count,
-    help='Min number of arp entries to bother persisting.'
+    help='Min number of arp entries to bother persisting.',
 )
 
 
[email protected]_autoloaded_singleton()
[email protected]_autoloaded_singleton()  # type: ignore
 class Arper(persistent.Persistent):
-    def __init__(
-            self, cached_state: Optional[BiDict] = None
-    ) -> None:
+    def __init__(self, cached_state: Optional[BiDict] = None) -> None:
         self.state = BiDict()
         if cached_state is not None:
             logger.debug('Loading Arper map from cached state.')
@@ -60,14 +59,16 @@ class Arper(persistent.Persistent):
             self.update_from_arp_scan()
             self.update_from_arp()
         if len(self.state) < config.config['arper_min_entries_to_be_valid']:
-            raise Exception('Arper didn\'t find enough entries; only got {len(self.state)}.')
+            raise Exception(
+                f'Arper didn\'t find enough entries; only got {len(self.state)}.'
+            )
 
     def update_from_arp_scan(self):
         network_spec = site_config.get_config().network
         try:
             output = exec_utils.cmd(
                 f'/usr/local/bin/arp-scan --retry=6 --timeout 350 --backoff=1.4 --random --numeric --plain --ignoredups {network_spec}',
-                timeout_seconds=10.0
+                timeout_seconds=10.0,
             )
         except Exception as e:
             logger.exception(e)
@@ -75,24 +76,31 @@ class Arper(persistent.Persistent):
         for line in output.split('\n'):
             ip = string_utils.extract_ip_v4(line)
             mac = string_utils.extract_mac_address(line)
-            if ip is not None and mac is not None and mac != 'UNKNOWN' and ip != 'UNKNOWN':
+            if (
+                ip is not None
+                and mac is not None
+                and mac != 'UNKNOWN'
+                and ip != 'UNKNOWN'
+            ):
                 mac = mac.lower()
                 logger.debug(f'ARPER: {mac} => {ip}')
                 self.state[mac] = ip
 
     def update_from_arp(self):
         try:
-            output = exec_utils.cmd(
-                '/usr/sbin/arp -a',
-                timeout_seconds=10.0
-            )
+            output = exec_utils.cmd('/usr/sbin/arp -a', timeout_seconds=10.0)
         except Exception as e:
             logger.exception(e)
             return
         for line in output.split('\n'):
             ip = string_utils.extract_ip_v4(line)
             mac = string_utils.extract_mac_address(line)
-            if ip is not None and mac is not None and mac != 'UNKNOWN' and ip != 'UNKNOWN':
+            if (
+                ip is not None
+                and mac is not None
+                and mac != 'UNKNOWN'
+                and ip != 'UNKNOWN'
+            ):
                 mac = mac.lower()
                 logger.debug(f'ARPER: {mac} => {ip}')
                 self.state[mac] = ip
@@ -109,8 +117,8 @@ class Arper(persistent.Persistent):
     def load(cls) -> Any:
         cache_file = config.config['arper_cache_location']
         if persistent.was_file_written_within_n_seconds(
-                cache_file,
-                config.config['arper_cache_max_staleness'].total_seconds(),
+            cache_file,
+            config.config['arper_cache_max_staleness'].total_seconds(),
         ):
             logger.debug(f'Loading state from {cache_file}')
             cached_state = BiDict()
@@ -128,8 +136,8 @@ class Arper(persistent.Persistent):
                 return cls(cached_state)
             else:
                 msg = f'{cache_file} is invalid: only {len(cached_state)} entries.  Deleting it.'
-                warnings.warn(msg)
                 logger.warning(msg)
+                warnings.warn(msg, stacklevel=2)
                 os.remove(cache_file)
         logger.debug('No usable saved state found')
         return None
@@ -137,9 +145,7 @@ class Arper(persistent.Persistent):
     @overrides
     def save(self) -> bool:
         if len(self.state) > config.config['arper_min_entries_to_be_valid']:
-            logger.debug(
-                f'Persisting state to {config.config["arper_cache_location"]}'
-            )
+            logger.debug(f'Persisting state to {config.config["arper_cache_location"]}')
             with file_utils.FileWriter(config.config['arper_cache_location']) as wf:
                 for (mac, ip) in self.state.items():
                     mac = mac.lower()