Format timestamps using ISO 8601 formatting (e.g. "2018-02-28T12:34:56Z")

* Z is the zone designator for the zero UTC offset.
* T is the delimiter used to separate date and time.

This makes it clear for the end-user that the date/time logged is
specified in UTC and not in the local time zone.

test/functional/combine_logs.py

@@ -13,7 +13,7 @@ import re
 import sys
 
 # Matches on the date format at the start of the log event
-TIMESTAMP_PATTERN = re.compile(r"^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.\d{6}")
+TIMESTAMP_PATTERN = re.compile(r"^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{6}Z")
 
 LogEvent = namedtuple('LogEvent', ['timestamp', 'source', 'event'])
 

test/functional/test_framework/test_framework.py

@@ -358,7 +358,7 @@ class BitcoinTestFramework():
         ll = int(self.options.loglevel) if self.options.loglevel.isdigit() else self.options.loglevel.upper()
         ch.setLevel(ll)
         # Format logs the same as bitcoind's debug.log with microprecision (so log files can be concatenated and sorted)
-        formatter = logging.Formatter(fmt='%(asctime)s.%(msecs)03d000 %(name)s (%(levelname)s): %(message)s', datefmt='%Y-%m-%d %H:%M:%S')
+        formatter = logging.Formatter(fmt='%(asctime)s.%(msecs)03d000Z %(name)s (%(levelname)s): %(message)s', datefmt='%Y-%m-%dT%H:%M:%S')
         formatter.converter = time.gmtime
         fh.setFormatter(formatter)
         ch.setFormatter(formatter)