Fix logs view and API

- We needed to use an engine-agnostic way to extract the days
- Joining with the LogEntryKind table has *horrible* performance in MySQL, so do it ourselves
- Limit to 50 logs per page

data/model/log.py

@@ -2,15 +2,14 @@ import json
 
 from peewee import JOIN_LEFT_OUTER, SQL, fn
 from datetime import datetime, timedelta, date
+from cachetools import lru_cache
 
-from data.database import LogEntry, LogEntryKind, User
+from data.database import LogEntry, LogEntryKind, User, db
 
 def _logs_query(selections, start_time, end_time, performer=None, repository=None, namespace=None):
   joined = (LogEntry
             .select(*selections)
             .switch(LogEntry)
-            .join(LogEntryKind)
-            .switch(LogEntry)
             .where(LogEntry.datetime >= start_time, LogEntry.datetime < end_time))
 
   if repository:
@@ -25,17 +24,27 @@ def _logs_query(selections, start_time, end_time, performer=None, repository=Non
   return joined
 
 
+@lru_cache(maxsize=1)
+def get_log_entry_kinds():
+  kind_map = {}
+  for kind in LogEntryKind.select():
+    kind_map[kind.id] = kind.name
+
+  return kind_map
+
+
 def get_aggregated_logs(start_time, end_time, performer=None, repository=None, namespace=None):
-  selections = [LogEntryKind, fn.date(LogEntry.datetime, '%d'), fn.Count(LogEntry.id).alias('count')]
+  date = db.extract_date('day', LogEntry.datetime)
+  selections = [LogEntry.kind, LogEntry.datetime, fn.Count(LogEntry.id).alias('count')]
   query = _logs_query(selections, start_time, end_time, performer, repository, namespace)
-  return query.group_by(fn.date(LogEntry.datetime, '%d'), LogEntryKind)
+  return query.group_by(date, LogEntry.kind)
 
 
 def list_logs(start_time, end_time, performer=None, repository=None, namespace=None, page=None,
               count=None):
 
   Performer = User.alias()
-  selections = [LogEntry, LogEntryKind, Performer]
+  selections = [LogEntry, Performer]
 
   query = _logs_query(selections, start_time, end_time, performer, repository, namespace)
   query = (query.switch(LogEntry)