Merge ~hloeung/smtp-relay-charm:fgrepmail-logs into smtp-relay-charm:master

[Haw Loeung]

files/fgrepmail-logs.py: Fix searching logs by date

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[Paul Collins (pjdc)]

review: Approve (lgtm)

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision f71477065dce393246cd11557e4ac0d2aedad44e

diff --git a/files/fgrepmail-logs.py b/files/fgrepmail-logs.py
index 18a928a..2de498e 100755
--- a/files/fgrepmail-logs.py
+++ b/files/fgrepmail-logs.py
@@ -5,6 +5,7 @@
 #
 # Easily search mail logs pulling all associated lines for specific matches.
 
+import datetime
 import glob
 import os
 import re
@@ -40,17 +41,30 @@ def build_maillogs_list(logs=None):
             search_logs.append(name + '.gz')
             continue
 
-        # Support for just the date, e.g. 20210728 (mail.log-20210728).
-        name = '{}-{}'.format(default, log)
-        search_logs.append(name)
-        # Just the date and gzip compressed.
-        search_logs.append(name + '.gz')
-
-        # Date hyphened, `date -I`.
-        name = '{}-{}'.format(default, log.replace('-', ''))
-        search_logs.append(name)
-        # gzip compressed.
-        search_logs.append(name + '.gz')
+        # Date format (e.g. 20220209 or 2022-02-09).
+        if log.startswith('202'):
+            # Date hyphened, `date -I`.
+            date = log.replace('-', '')
+
+            # systemd logrotate.timer runs at 00:00 UTC so we need to use the day after.
+            date = '{}-{}-{}'.format(date[:4], date[4:6], date[6:8])
+            dt = datetime.date.fromisoformat(date)
+            daydelta = datetime.timedelta(days = 1)
+            after = dt + daydelta
+            # Current day is mail.log so include that if 202X-XX-XX is today.
+            if date == (str(datetime.date.today())):
+                include_default = True
+                continue
+            date = str(after).replace('-', '')
+
+            name = '{}-{}'.format(default, date)
+            search_logs.append(name)
+            # Just the date and gzip compressed.
+            search_logs.append(name + '.gz')
+            continue
+
+        print('Unsupported format {}'.format(log))
+        return []
 
     maillogs = []
     for log in search_logs: