fix(models,db): delegate timestamps to DB server and configure connection pool

- Replace default=datetime.utcnow with server_default=func.now() across all 16 models (17 columns) for consistent, timezone-aware timestamps from PostgreSQL

- Upgrade DateTime columns to DateTime(timezone=True) for timestamptz storage

- Configure SQLAlchemy engine pool: pool_size=20, max_overflow=10, pool_recycle=3600, pool_pre_ping=True

- Remove unused datetime imports from model files

backend/app/models/audit.py

@@ -1,7 +1,5 @@
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, DateTime, ForeignKey
+from sqlalchemy import Column, String, DateTime, ForeignKey, func
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 from sqlalchemy.orm import relationship
 
@@ -22,7 +20,7 @@ class AuditLog(Base):
     action = Column(String, nullable=False)
     entity_type = Column(String, nullable=True)
     entity_id = Column(String, nullable=True)
-    timestamp = Column(DateTime, default=datetime.utcnow)
+    timestamp = Column(DateTime(timezone=True), server_default=func.now())
     details = Column(JSONB, nullable=True)
 
     # Relationships

backend/app/models/campaign.py

@@ -5,11 +5,9 @@ enabling simulation of complete attack chains and APT emulations.
 """
 
 import uuid
-from datetime import datetime
-
 from sqlalchemy import (
     Column, String, Text, Integer, Boolean, DateTime,
-    ForeignKey, Index,
+    ForeignKey, Index, func,
 )
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 from sqlalchemy.orm import relationship
@@ -54,7 +52,7 @@ class Campaign(Base):
     completed_at = Column(DateTime, nullable=True)
     target_platform = Column(String, nullable=True)
     tags = Column(JSONB, nullable=True, default=[])
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     # Recurring scheduling fields
     is_recurring = Column(Boolean, default=False)

backend/app/models/compliance.py

@@ -5,11 +5,9 @@ MITRE ATT&CK techniques, enabling compliance gap analysis.
 """
 
 import uuid
-from datetime import datetime
-
 from sqlalchemy import (
     Column, String, Text, Boolean, DateTime,
-    ForeignKey, Index, UniqueConstraint,
+    ForeignKey, Index, UniqueConstraint, func,
 )
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
@@ -27,7 +25,7 @@ class ComplianceFramework(Base):
     description = Column(Text, nullable=True)
     url = Column(String, nullable=True)
     is_active = Column(Boolean, default=True)
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     # Relationships
     controls = relationship(

backend/app/models/coverage_snapshot.py

@@ -6,11 +6,9 @@ per technique per snapshot) to avoid bloated JSONB fields.
 """
 
 import uuid
-from datetime import datetime
-
 from sqlalchemy import (
     Column, String, Float, Integer, DateTime,
-    ForeignKey, Index,
+    ForeignKey, Index, func,
 )
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
@@ -37,7 +35,7 @@ class CoverageSnapshot(Base):
         ForeignKey("users.id", ondelete="SET NULL"),
         nullable=True,
     )
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     # Relationships
     creator = relationship("User", foreign_keys=[created_by])

backend/app/models/data_source.py

@@ -1,9 +1,7 @@
 """DataSource model — registry of external data sources for import."""
 
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Text, Boolean, DateTime, Index
+from sqlalchemy import Column, String, Text, Boolean, DateTime, Index, func
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 
 from app.database import Base
@@ -31,7 +29,7 @@ class DataSource(Base):
     last_sync_stats = Column(JSONB, nullable=True)                 # {"imported": X, "updated": Y, ...}
     sync_frequency = Column(String, nullable=True)                 # daily / weekly / monthly / manual
     config = Column(JSONB, nullable=True)                          # source-specific configuration
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     __table_args__ = (
         Index('ix_data_sources_type', 'type'),

backend/app/models/defensive_technique.py

@@ -5,11 +5,9 @@ ATT&CK techniques, enabling recommended countermeasure lookups.
 """
 
 import uuid
-from datetime import datetime
-
 from sqlalchemy import (
     Column, String, Text, DateTime,
-    ForeignKey, Index, UniqueConstraint,
+    ForeignKey, Index, UniqueConstraint, func,
 )
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
@@ -32,7 +30,7 @@ class DefensiveTechnique(Base):
     description = Column(Text, nullable=True)
     tactic = Column(String, nullable=True)                            # Detect, Isolate, Deceive, Evict, etc.
     d3fend_url = Column(String, nullable=True)
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     # Relationships
     attack_mappings = relationship(

backend/app/models/detection_rule.py

@@ -1,9 +1,7 @@
 """DetectionRule model — detection rules from multiple sources."""
 
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Text, Boolean, DateTime, Index
+from sqlalchemy import Column, String, Text, Boolean, DateTime, Index, func
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 
 from app.database import Base
@@ -33,7 +31,7 @@ class DetectionRule(Base):
     log_sources = Column(JSONB, nullable=True)                     # e.g. {"product": "windows", "service": "sysmon"}
     false_positive_rate = Column(String, nullable=True)            # low / medium / high
     is_active = Column(Boolean, default=True)
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     __table_args__ = (
         Index('ix_detection_rules_mitre_technique_id', 'mitre_technique_id'),

backend/app/models/evidence.py

@@ -1,7 +1,5 @@
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Text, DateTime, ForeignKey, Enum
+from sqlalchemy import Column, String, Text, DateTime, ForeignKey, Enum, func
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
 
@@ -27,7 +25,7 @@ class Evidence(Base):
     file_path = Column(String, nullable=False)  # Path in MinIO
     sha256_hash = Column(String, nullable=False)
     uploaded_by = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=True)
-    uploaded_at = Column(DateTime, default=datetime.utcnow)
+    uploaded_at = Column(DateTime(timezone=True), server_default=func.now())
     team = Column(Enum(TeamSide, name="teamside"), nullable=False, default=TeamSide.red)
     notes = Column(Text, nullable=True)
 

backend/app/models/intel.py

@@ -1,7 +1,5 @@
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Boolean, DateTime, ForeignKey
+from sqlalchemy import Column, String, Boolean, DateTime, ForeignKey, func
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
 
@@ -22,7 +20,7 @@ class IntelItem(Base):
     url = Column(String, nullable=False)
     title = Column(String, nullable=True)
     source = Column(String, nullable=True)
-    detected_at = Column(DateTime, default=datetime.utcnow)
+    detected_at = Column(DateTime(timezone=True), server_default=func.now())
     reviewed = Column(Boolean, default=False)
 
     # Relationships

backend/app/models/jira_link.py

@@ -2,9 +2,7 @@
 
 import enum
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, DateTime, ForeignKey, Enum as SQLEnum, Index
+from sqlalchemy import Column, String, DateTime, ForeignKey, Enum as SQLEnum, Index, func
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 from sqlalchemy.orm import relationship
 
@@ -45,8 +43,8 @@ class JiraLink(Base):
     last_synced_at = Column(DateTime)
     sync_metadata = Column(JSONB, default={})
     created_by = Column(UUID(as_uuid=True), ForeignKey("users.id"))
-    created_at = Column(DateTime, default=datetime.utcnow)
-    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
 
     creator = relationship("User", foreign_keys=[created_by])
 

backend/app/models/notification.py

@@ -1,9 +1,7 @@
 """Notification model — in-app notifications for user actions."""
 
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Text, Boolean, DateTime, ForeignKey, Index
+from sqlalchemy import Column, String, Text, Boolean, DateTime, ForeignKey, Index, func
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
 
@@ -27,7 +25,7 @@ class Notification(Base):
     entity_type = Column(String, nullable=True)
     entity_id = Column(UUID(as_uuid=True), nullable=True)
     read = Column(Boolean, default=False)
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     # Relationships
     user = relationship("User")

backend/app/models/osint_item.py

@@ -1,9 +1,7 @@
 """OSINT enrichment items — CVEs, blogs, PoCs, and advisories linked to techniques."""
 
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Text, Boolean, DateTime, ForeignKey
+from sqlalchemy import Column, String, Text, Boolean, DateTime, ForeignKey, func
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 from sqlalchemy.orm import relationship
 
@@ -32,7 +30,7 @@ class OsintItem(Base):
     title = Column(String(500), nullable=False)
     description = Column(Text, nullable=True)
     severity = Column(String(20), nullable=True)  # CRITICAL, HIGH, MEDIUM, LOW, UNKNOWN
-    discovered_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    discovered_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False)
     reviewed = Column(Boolean, default=False)
     metadata_ = Column("metadata", JSONB, default={})
 

backend/app/models/test.py

@@ -1,7 +1,5 @@
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Text, Boolean, Integer, DateTime, ForeignKey, Enum
+from sqlalchemy import Column, String, Text, Boolean, Integer, DateTime, ForeignKey, Enum, func
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
 
@@ -31,7 +29,7 @@ class Test(Base):
     created_by = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=True)
     result = Column(Enum(TestResult, name="testresult"), nullable=True)
     state = Column(Enum(TestState, name="teststate"), default=TestState.draft)
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     # ── Red Team fields ─────────────────────────────────────────────
     red_summary = Column(Text, nullable=True)

backend/app/models/test_template.py

@@ -1,9 +1,7 @@
 """TestTemplate model — predefined test catalog entries."""
 
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Text, Boolean, DateTime, Index
+from sqlalchemy import Column, String, Text, Boolean, DateTime, Index, func
 from sqlalchemy.dialects.postgresql import UUID
 
 from app.database import Base
@@ -36,7 +34,7 @@ class TestTemplate(Base):
     atomic_test_id = Column(String, nullable=True)               # ID in Atomic Red Team repo
     suggested_remediation = Column(Text, nullable=True)
     is_active = Column(Boolean, default=True)
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     __table_args__ = (
         Index('ix_test_templates_mitre_technique_id', 'mitre_technique_id'),

backend/app/models/threat_actor.py

@@ -5,11 +5,9 @@ techniques, imported from MITRE CTI (STIX 2.0).
 """
 
 import uuid
-from datetime import datetime
-
 from sqlalchemy import (
     Column, String, Text, Boolean, DateTime,
-    ForeignKey, Index, UniqueConstraint,
+    ForeignKey, Index, UniqueConstraint, func,
 )
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 from sqlalchemy.orm import relationship
@@ -40,7 +38,7 @@ class ThreatActor(Base):
     references = Column(JSONB, nullable=True, default=[])               # [{"url": "...", "description": "..."}]
     mitre_url = Column(String, nullable=True)
     is_active = Column(Boolean, default=True)
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     # Relationships
     techniques = relationship(

backend/app/models/user.py

@@ -1,7 +1,5 @@
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Boolean, DateTime
+from sqlalchemy import Column, String, Boolean, DateTime, func
 from sqlalchemy.dialects.postgresql import UUID
 
 from app.database import Base
@@ -28,5 +26,5 @@ class User(Base):
     role = Column(String, nullable=False, default="viewer")
     is_active = Column(Boolean, default=True)
     must_change_password = Column(Boolean, default=True)
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
     last_login = Column(DateTime, nullable=True)

backend/app/models/worklog.py

@@ -1,9 +1,7 @@
 """Worklog model — immutable internal time-tracking records."""
 
 import uuid
-from datetime import datetime
-
-from sqlalchemy import Column, String, Integer, DateTime, ForeignKey, Text, Index
+from sqlalchemy import Column, String, Integer, DateTime, ForeignKey, Text, Index, func
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 from sqlalchemy.orm import relationship
 
@@ -32,7 +30,7 @@ class Worklog(Base):
     tempo_synced = Column(DateTime)
     tempo_worklog_id = Column(String(100))
     integrity_hash = Column(String(64))
-    created_at = Column(DateTime, default=datetime.utcnow)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
     extra_metadata = Column("metadata", JSONB, default={})
 
     user = relationship("User", foreign_keys=[user_id])