Add a logging.Filter implementation

README.md

@@ -149,6 +149,30 @@ for line in data:
 
 ```
 
+
+### As a python logging.Filter
+
+```python
+import logging
+
+from anonip import AnonipFilter
+
+if __name__ == '__main__':
+    handler = logging.StreamHandler()
+    handler.addFilter(AnonipFilter())
+    logging.basicConfig(
+        level=logging.DEBUG,
+        format='%(asctime)s - %(levelname)s - %(message)s',
+        handlers=[handler]
+    )
+
+    logging.debug('192.0.2.123 - call from root logger')
+
+    logger = logging.getLogger('child')
+    logger.info('2001:db8:abcd:ef01:2345:6789:abcd:ef01 - call from child logger')
+```
+
+
 ### Python 2 or 3?
 For compatibility reasons, anonip uses the shebang `#! /usr/bin/env python`.
 This will default to python2 on all Linux distributions except for Arch Linux.

anonip.py

@@ -43,6 +43,7 @@
 import logging
 import sys
 from io import open
+from collections import abc
 
 try:
     import ipaddress
@@ -260,6 +261,50 @@ def truncate_address(self, ip):
         return ip.supernet(new_prefix=self._prefixes[ip.version])[0]
 
 
+class AnonipFilter:
+    def __init__(self, args=None, extra=None, anonip=None):
+        """
+        An implementation of Python logging.Filter using anonip.
+
+        :param args: list of log message args to filter. Defaults to []
+        :param extra: list of LogRecord attributes to filter. Defaults to []
+        :param anonip: dict of parameters for Anonip instance
+        """
+        self.args = [] if args is None else args
+        self.extra = [] if extra is None else extra
+        self.anonip = Anonip(**(anonip or {}))
+
+    def filter(self, record):
+        """
+        See logging.Filter.filter()
+        """
+        if record.name != "anonip":
+            for key in self.args:
+                if isinstance(record.args, abc.Mapping):
+                    if key in record.args:
+                        value = record.args[key]
+                        if isinstance(value, str):
+                            record.args[key] = self.anonip.process_line(value)
+                elif isinstance(record.args, abc.Sequence):
+                    if key < len(record.args):
+                        value = record.args[key]
+                        if isinstance(value, str):
+                            is_tuple = isinstance(record.args, tuple)
+                            if is_tuple:
+                                record.args = list(record.args)
+                            record.args[key] = self.anonip.process_line(value)
+                            if is_tuple:
+                                record.args = tuple(record.args)
+
+            for key in self.extra:
+                if hasattr(record, key):
+                    value = getattr(record, key)
+                    if (isinstance(value, str)):
+                        setattr(record, key, self.anonip.process_line(value))
+
+        return True
+
+
 def _validate_ipmask(mask, bits=32):
     """
     Verify if the supplied ip mask is valid.

tests.py

@@ -319,3 +319,80 @@ def test_properties_columns():
     assert a.columns == [0]
     a.columns = [5, 6]
     assert a.columns == [4, 5]
+
+
+def test_logging_filter_defaults(caplog):
+    logging.disable(logging.NOTSET)
+    logging.getLogger("anonip").setLevel(logging.CRITICAL)
+
+    logger = logging.getLogger("filter_defaults")
+    logger.addFilter(anonip.AnonipFilter())
+    logger.setLevel(logging.INFO)
+
+    logger.info("192.168.100.200 string")
+    logger.info("1.2.3.4 string")
+    logger.info("2001:0db8:85a3:0000:0000:8a2e:0370:7334 string")
+    logger.info("2a00:1450:400a:803::200e string")
+
+    assert caplog.record_tuples == [
+        ("filter_defaults", logging.INFO, "192.168.96.0 string"),
+        ("filter_defaults", logging.INFO, "1.2.0.0 string"),
+        ("filter_defaults", logging.INFO, "2001:db8:85a0:: string"),
+        ("filter_defaults", logging.INFO, "2a00:1450:4000:: string"),
+    ]
+
+    logging.disable(logging.CRITICAL)
+
+
+def test_logging_filter_args(caplog):
+    logging.disable(logging.NOTSET)
+    logging.getLogger("anonip").setLevel(logging.CRITICAL)
+
+    logger = logging.getLogger("filter_args")
+    logger.addFilter(anonip.AnonipFilter(args=["ip", "non-existing-attr"], extra=[]))
+    logger.setLevel(logging.INFO)
+
+    logger.info("%(ip)s string", {"ip": "192.168.100.200"})
+    logger.info("string %(ip)s", {"ip": "1.2.3.4"})
+    logger.info("%(ip)s string", {"ip": "2001:0db8:85a3:0000:0000:8a2e:0370:7334"})
+    logger.info("string")
+
+    assert caplog.record_tuples == [
+        ("filter_args", logging.INFO, "192.168.96.0 string"),
+        ("filter_args", logging.INFO, "string 1.2.0.0"),
+        ("filter_args", logging.INFO, "2001:db8:85a0:: string"),
+        ("filter_args", logging.INFO, "string"),
+    ]
+
+    logging.disable(logging.CRITICAL)
+
+
+def test_logging_filter_extra(caplog):
+    logging.disable(logging.NOTSET)
+    logging.getLogger("anonip").setLevel(logging.CRITICAL)
+
+    logger = logging.getLogger("filter_args")
+    logger.addFilter(
+        anonip.AnonipFilter(
+            extra=["ip", "non-existing-key"], anonip={"ipv4mask": 16, "ipv6mask": 64}
+        )
+    )
+    logger.setLevel(logging.INFO)
+
+    logger.info("string", extra={"ip": "192.168.100.200"})
+    logger.info("string", extra={"ip": "1.2.3.4"})
+    logger.info("string", extra={"ip": "2001:0db8:85a3:0000:0000:8a2e:0370:7334"})
+    logger.info("string", extra={"ip": "2a00:1450:400a:803::200e"})
+
+    expected = [
+        "192.168.0.0",
+        "1.2.0.0",
+        "2001:db8:85a3::",
+        "2a00:1450:400a:803::",
+    ]
+
+    actual = [record.ip for record in caplog.records]
+
+    assert actual == expected
+
+    logging.disable(logging.CRITICAL)