Convert tinydns and dnscache logs to human-readable form
"""
-import re
+import re, typing
from struct import pack
-from time import strftime, gmtime
from subprocess import Popen, PIPE
+from time import strftime, gmtime
## Regular expressions for matching tinydns/dnscache log lines. We
# tinydns can drop a query for one of three reasons; this dictionary
# maps the symbol that gets logged in each case to a human-readable
-# reason.
+# reason. We include the "+" case here, indicating that the query was
+# NOT dropped, to avoid a special case later on when we're formatting
+# the human-readable output.
query_drop_reason = {
+ "+": None,
"-": "no authority",
"I": "invalid query",
"C": "invalid class",
+ "/": "couldn't parse"
}
qt = words[i]
words[i] = query_type.get(int(qt), qt)
-def handle_dnscache_log(line, match):
+def handle_dnscache_log(line) -> typing.Optional[str]:
+ """
+ Handle a single log line if it matches the ``dnscache_log_re`` regex.
+
+ Parameters
+ ----------
+
+ line : string
+ The log line that might match ``dnscache_log_re``.
+
+ Returns
+ -------
+
+ Either the human-readable string if the log line was handled (that
+ is, if it was really a dnscache log line), or ``None`` if it was
+ not.
+
+ Examples
+ --------
+
+ >>> line = "2022-09-15 18:37:33.863805500 query 1 7f000001:a3db:4fb9 1 www.example.com."
+ >>> handle_dnscache_log(line)
+ '2022-09-15 18:37:33.863805500 query #1 127.0.0.1:41947 (id 20409) a www.example.com.'
+
+ >>> line = "2022-09-15 18:37:33.863874500 tx 0 1 www.example.com. . c0a80101"
+ >>> handle_dnscache_log(line)
+ '2022-09-15 18:37:33.863874500 tx g=0 a www.example.com. . 192.168.1.1'
+
+ >>> line = "2022-09-15 18:37:33.878529500 rr c0a80101 20865 1 www.example.com. 5db8d822"
+ >>> handle_dnscache_log(line)
+ '2022-09-15 18:37:33.878529500 rr 192.168.1.1 TTL=20865 a www.example.com. 93.184.216.34'
+
+ >>> line = "2022-09-15 18:37:33.878532500 stats 1 43 1 0"
+ >>> handle_dnscache_log(line)
+ '2022-09-15 18:37:33.878532500 stats count=1 motion=43 udp-active=1 tcp-active=0'
+
+ >>> line = "2022-09-15 18:37:33.878602500 sent 1 49"
+ >>> handle_dnscache_log(line)
+ '2022-09-15 18:37:33.878602500 sent #1 49'
+
+ >>> line = "this line is nonsense"
+ >>> handle_dnscache_log(line)
+
+ """
+ match = dnscache_log_re.match(line)
+ if not match:
+ return None
+
(timestamp, event, data) = match.groups()
words = data.split()
ellipsis = ""
length = int(response[0:2], 16)
chars = []
- for i in range(1, len(response)/2):
+ for i in range(1, len(response)//2):
chars.append(chr(int(response[2*i : (2*i)+2], 16)))
words[4] = "%d:\"%s%s\"" % (length, "".join(chars), ellipsis)
elif event in ("tcpopen", "tcpclose"):
decode_client(words, 0)
- print(timestamp, event, " ".join(words))
+ return f"{timestamp} {event} " + " ".join(words)
-def handle_tinydns_log(line : str, match: re.Match):
+
+def handle_tinydns_log(line : str) -> typing.Optional[str]:
"""
- Handle a line that matched the ``tinydns_log_re`` regex.
+ Handle a single log line if it matches the ``tinydns_log_re`` regex.
Parameters
----------
line : string
- The tinydns log line that matched ``tinydns_log_re``.
+ The log line that might match ``tinydns_log_re``.
+
+ Returns
+ -------
- match : re.Match
- The match object that was returned when ``line`` was
- tested against ``tinydns_log_re``.
+ Either the human-readable string if the log line was handled (that
+ is, if it was really a tinydns log line), or ``None`` if it was
+ not.
Examples
--------
>>> line = "2022-09-14 21:04:40.206516500 7f000001:9d61:be69 - 0001 www.example.com"
- >>> match = tinydns_log_re.match(line)
- >>> handle_tinydns_log(line, match)
- 2022-09-14 21:04:40.206516500 dropped query (no authority) from 127.0.0.1:40289 (id 48745): a www.example.com
+ >>> handle_tinydns_log(line)
+ '2022-09-14 21:04:40.206516500 dropped query (no authority) from 127.0.0.1:40289 (id 48745): a www.example.com'
+
+ >>> line = "this line is nonsense"
+ >>> handle_tinydns_log(line)
"""
+ match = tinydns_log_re.match(line)
+ if not match:
+ return None
+
(timestamp, ip, port, id, code, type, name) = match.groups()
ip = convert_ip(ip)
port = int(port, 16)
type = int(type, 16) # "001c" -> 28
type = query_type.get(type, type) # 28 -> "aaaa"
- print(timestamp, end=' ')
+ line_tpl = "{timestamp} "
+ reason = query_drop_reason[code]
if code == "+":
- print ("sent response to %s:%s (id %s): %s %s"
- % (ip, port, id, type, name))
- elif code in ("-", "I", "C"):
- reason = query_drop_reason[code]
- print ("dropped query (%s) from %s:%s (id %s): %s %s"
- % (reason, ip, port, id, type, name))
- elif code == "/":
- print ("dropped query (couldn't parse) from %s:%s"
- % (ip, port))
+ line_tpl += "sent response to {ip}:{port} (id {id}): {type} {name}"
else:
- print ("%s from %s:%s (id %s): %s %s"
- % (code, ip, port, id, type, name))
+ line_tpl += "dropped query ({reason}) from {ip}:{port}"
+ if code != "/":
+ # If the query can actually be parsed, the log line is a
+ # bit more informative than it would have been otherwise.
+ line_tpl += " (id {id}): {type} {name}"
+
+ return line_tpl.format(timestamp=timestamp,
+ reason=reason,
+ ip=ip,
+ port=port,
+ id=id,
+ type=type,
+ name=name)
+
+
+def parse_logfile(file : typing.TextIO):
+ r"""
+ Process a single log ``file``.
+
+ Parameters
+ ----------
+ file : typing.TextIO
+ An open log file, or stdin.
-def parse_logfile(file):
+ Examples
+ --------
+
+ >>> line = "@4000000063227a320c4f3114 7f000001:9d61:be69 - 0001 www.example.com\n"
+ >>> from tempfile import NamedTemporaryFile
+ >>> with NamedTemporaryFile(mode="w", delete=False) as f:
+ ... _ = f.write(line)
+ >>> f = open(f.name, 'r')
+ >>> parse_logfile(f)
+ 2022-09-14 21:04:40.206516500 dropped query (no authority) from 127.0.0.1:40289 (id 48745): a www.example.com
+ >>> f.close()
+ >>> from os import remove
+ >>> remove(f.name)
+
+ """
# Open pipe to tai64nlocal: we will write lines of our input (the
# raw log file) to it, and read log lines with readable timestamps
# from it.
tai.stdin.write(line)
line = tai.stdout.readline()
- match = tinydns_log_re.match(line)
- if match:
- handle_tinydns_log(line, match)
- continue
+ friendly_line = handle_tinydns_log(line)
+ if not friendly_line:
+ friendly_line = handle_dnscache_log(line)
+ if not friendly_line:
+ friendly_line = line
- match = dnscache_log_re.match(line)
- if match:
- handle_dnscache_log(line, match)
- continue
-
- print(line)
+ print(friendly_line)
def main():
+ r"""
+ The entry point to the program.
+
+ This function is responsible only for parsing any command-line
+ arguments, and then calling :func`parse_logfile` on them.
+ """
# Create an argument parser using the file's docsctring as its
# description.
from argparse import ArgumentParser, FileType
default=[stdin],
help="djbdns logfile to process (default: stdin)")
+ # Warning: argparse automatically opens its file arguments here,
+ # and they only get closed when the program terminates. There's no
+ # real benefit to closing them one-at-a-time after calling
+ # parse_logfile(), because the "scarce" resource of open file
+ # descriptors gets consumed immediately, before any processing has
+ # happened. In other words, if you're going to run out of file
+ # descriptors, it's going to happen right now.
+ #
+ # So anyway, don't run this on several million logfiles.
args = parser.parse_args()
for f in args.logfiles:
parse_logfile(f)
-
-
if __name__ == "__main__":
main()
projects / djbdns-logparse.git / blobdiff