Get timezone-aware datetime objects from database

reproserver/database.py

@@ -2,11 +2,12 @@
 from datetime import datetime, timezone
 import logging
 import os
-from sqlalchemy import Column, ForeignKey, create_engine
+from sqlalchemy import Column, ForeignKey, TypeDecorator, create_engine
 from sqlalchemy.exc import OperationalError
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import relationship, sessionmaker
-from sqlalchemy.types import Boolean, DateTime, Integer, String, Text
+from sqlalchemy.types import Boolean, DateTime as PlainDateTime, Integer, \
+    String, Text
 import sys
 import time
 
@@ -19,6 +20,26 @@
 Base = declarative_base()
 
 
+# https://docs.sqlalchemy.org/en/14/core/custom_types.html#store-timezone-aware-timestamps-as-timezone-naive-utc
+class DateTimeUtc(TypeDecorator):
+    impl = PlainDateTime
+    cache_ok = True
+
+    def process_bind_param(self, value, dialect):
+        if value is not None:
+            if not value.tzinfo:
+                raise TypeError("tzinfo is required")
+            if value.utcoffset() != 0:
+                logger.warning("tzinfo was not UTC")
+            value = value.astimezone(timezone.utc).replace(tzinfo=None)
+        return value
+
+    def process_result_value(self, value, dialect):
+        if value is not None:
+            value = value.replace(tzinfo=timezone.utc)
+        return value
+
+
 class Experiment(Base):
     """Experiments available on the server.
 
@@ -31,7 +52,7 @@ class Experiment(Base):
     __tablename__ = 'experiments'
 
     hash = Column(String(64), primary_key=True)
-    last_access = Column(DateTime, nullable=False,
+    last_access = Column(DateTimeUtc, nullable=False,
                          default=lambda: datetime.now(timezone.utc))
     size = Column(Integer, nullable=False)
     info = Column(Text, nullable=False)
@@ -84,7 +105,7 @@ class Upload(Base):
                               back_populates='uploads')
     submitted_ip = Column(Text, nullable=True)
     repository_key = Column(Text, nullable=True, index=True)
-    timestamp = Column(DateTime, nullable=False,
+    timestamp = Column(DateTimeUtc, nullable=False,
                        default=lambda: datetime.now(timezone.utc))
 
     @property
@@ -171,10 +192,10 @@ class Run(Base):
     upload_id = Column(Integer, ForeignKey('uploads.id',
                                            ondelete='RESTRICT'))
     upload = relationship('Upload', uselist=False)
-    submitted = Column(DateTime, nullable=False,
+    submitted = Column(DateTimeUtc, nullable=False,
                        default=lambda: datetime.now(timezone.utc))
-    started = Column(DateTime, nullable=True)
-    done = Column(DateTime, nullable=True)
+    started = Column(DateTimeUtc, nullable=True)
+    done = Column(DateTimeUtc, nullable=True)
 
     progress_percent = Column(Integer, nullable=False, default=0)
     progress_text = Column(Text, nullable=False, default='')
@@ -226,7 +247,7 @@ class RunLogLine(Base):
     id = Column(Integer, primary_key=True)
     run_id = Column(Integer, ForeignKey('runs.id', ondelete='CASCADE'))
     run = relationship('Run', uselist=False, back_populates='log')
-    timestamp = Column(DateTime, nullable=False,
+    timestamp = Column(DateTimeUtc, nullable=False,
                        default=lambda: datetime.now(timezone.utc))
     line = Column(Text, nullable=False)