Further build-many-glibcs.py fixes for utcnow() deprecation

It turns out that the replacement of datetime.datetime.utcnow(), for a
warning produced early in running build-many-glibcs.py with Python
3.12, (a) wasn't complete (there were other uses elsewhere in the
script also needing updating) and (b) broke reading of build-time from
build-state.json, because an aware datetime was written out including
+00:00 for the timezone, which was not expected by the strptime call.

Fix the first by making the change to
datetime.datetime.now(datetime.timezone.utc) for all the remaining
utcnow() calls.  Fix the second by using strftime with an explicit
format instead of just str() when formatting build times for
build-state.json and and email subjects, and then setting the timezone
explicitly when reading from build-state.json.  (Other uses, in
particular messages output by the bot, continue to use str() as the
precise format should not matter in those cases; it shouldn't actually
matter for email subjects either but it seems a good idea to keep
those short.)

Tested with a bot-cycle run and checking the format of times in
build-state.json afterwards.

diff --git a/scripts/build-many-glibcs.py b/scripts/build-many-glibcs.py
index 9cdf3e682f5cf7a7af94006bdc5da3e9bc386ade..d08afc407428bf012a9cacdf28a8d5e8d18ae2c4 100755 (executable)
--- a/scripts/build-many-glibcs.py
+++ b/scripts/build-many-glibcs.py
@@ -1057,7 +1057,8 @@ class Context(object):
     def update_build_state(self, action, build_time, build_versions):
         """Update the build state after a build."""
         build_time = build_time.replace(microsecond=0)
-        self.build_state[action]['build-time'] = str(build_time)
+        self.build_state[action]['build-time'] = build_time.strftime(
+            '%Y-%m-%d %H:%M:%S')
         self.build_state[action]['build-versions'] = build_versions
         build_results = {}
         for log in self.status_log_list:
@@ -1103,15 +1104,17 @@ class Context(object):
         old_time_str = self.build_state[action]['build-time']
         if not old_time_str:
             return True
-        old_time = datetime.datetime.strptime(old_time_str,
-                                              '%Y-%m-%d %H:%M:%S')
-        new_time = datetime.datetime.utcnow()
+        old_time = datetime.datetime.strptime(
+            old_time_str, '%Y-%m-%d %H:%M:%S').replace(
+                tzinfo=datetime.timezone.utc)
+        new_time = datetime.datetime.now(datetime.timezone.utc)
         delta = new_time - old_time
         return delta.total_seconds() >= delay
 
     def bot_cycle(self):
         """Run a single round of checkout and builds."""
-        print('Bot cycle starting %s.' % str(datetime.datetime.utcnow()))
+        print('Bot cycle starting %s.'
+              % str(datetime.datetime.now(datetime.timezone.utc)))
         self.load_bot_config_json()
         actions = ('host-libraries', 'compilers', 'glibcs')
         self.bot_run_self(['--replace-sources'], 'checkout')
@@ -1163,12 +1166,13 @@ class Context(object):
             shutil.copytree(self.logsdir, self.logsdir_old)
         for a in actions:
             if must_build[a]:
-                build_time = datetime.datetime.utcnow()
+                build_time = datetime.datetime.now(datetime.timezone.utc)
                 print('Rebuilding %s at %s.' % (a, str(build_time)))
                 self.bot_run_self([], a)
                 self.load_build_state_json()
                 self.bot_build_mail(a, build_time)
-        print('Bot cycle done at %s.' % str(datetime.datetime.utcnow()))
+        print('Bot cycle done at %s.'
+              % str(datetime.datetime.now(datetime.timezone.utc)))
 
     def bot_build_mail(self, action, build_time):
         """Send email with the results of a build."""
@@ -1184,7 +1188,7 @@ class Context(object):
         build_time = build_time.replace(microsecond=0)
         subject = (self.bot_config['email-subject'] %
                    {'action': action,
-                    'build-time': str(build_time)})
+                    'build-time': build_time.strftime('%Y-%m-%d %H:%M:%S')})
         results = self.build_state[action]['build-results']
         changes = self.build_state[action]['result-changes']
         ever_passed = set(self.build_state[action]['ever-passed'])
@@ -1233,7 +1237,8 @@ class Context(object):
         msg['From'] = self.bot_config['email-from']
         msg['To'] = self.bot_config['email-to']
         msg['Message-ID'] = email.utils.make_msgid()
-        msg['Date'] = email.utils.format_datetime(datetime.datetime.utcnow())
+        msg['Date'] = email.utils.format_datetime(
+            datetime.datetime.now(datetime.timezone.utc))
         with smtplib.SMTP(self.bot_config['email-server']) as s:
             s.send_message(msg)