retrieve latest annotation from db (#1723)

* add function to retrieve latest annotation from db, db updates

* dont create directory in s3

server/db/cellxgene_orm.py

@@ -1,11 +1,12 @@
-from datetime import datetime
+import uuid
 
 from sqlalchemy import (
     Column,
     DateTime,
     ForeignKey,
     String,
-)
+    func, JSON)
+from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import relationship
 
@@ -21,8 +22,8 @@ class CellxGeneUser(Base):
     __tablename__ = "cxguser"
 
     id = Column(String, primary_key=True)
-    created_at = Column(DateTime, nullable=False, default=datetime.utcnow)
-    updated_at = Column(DateTime, nullable=False, default=datetime.utcnow, onupdate=datetime.utcnow)
+    created_at = Column(DateTime, nullable=False, server_default=func.now())
+    updated_at = Column(DateTime, nullable=False, server_default=func.now(), onupdate=func.now())
 
     # Relationships
     annotations = relationship("Annotation", back_populates="cxguser")
@@ -36,12 +37,13 @@ class Annotation(Base):
 
     __tablename__ = "annotation"
 
-    id = Column(String, primary_key=True)
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, unique=True, nullable=False)
     tiledb_uri = Column(String)
     user_id = Column(String, ForeignKey("cxguser.id"), nullable=False)
-    dataset_id = Column(String, ForeignKey("cxgdataset.id"), nullable=False)
-    created_at = Column(DateTime, nullable=False, default=datetime.utcnow)
+    dataset_id = Column(UUID, ForeignKey("cxgdataset.id"), nullable=False)
 
+    created_at = Column(DateTime, nullable=False, server_default=func.now())
+    schema_hints = Column(JSON)
     # Relationships
     cxguser = relationship("CellxGeneUser", back_populates="annotations")
     dataset = relationship("CellxGeneDataset", back_populates="annotations")
@@ -49,12 +51,13 @@ class Annotation(Base):
 
 class CellxGeneDataset(Base):
     """
-    Datasets refer to cellxgene datasets stored in tiledb
+    Datasets refer to datasets stored by cellxgene
     """
 
     __tablename__ = "cxgdataset"
 
-    id = Column(String, primary_key=True)
-    name = Column(String)
-    created_at = Column(DateTime, nullable=False, default=datetime.utcnow)
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, unique=True, nullable=False)
+    name = Column(String, unique=True, index=True)
+
+    created_at = Column(DateTime, nullable=False, server_default=func.now())
     annotations = relationship("Annotation", back_populates="dataset")

server/db/db_utils.py

@@ -33,6 +33,9 @@ class DbUtils:
             else self.session.query(*table_args).all()
         )
 
+    def query_for_most_recent(self, table: Base, filter_args: typing.List[bool] = None) -> Base:
+        return self.session.query(table).filter(*filter_args).order_by(table.created_at.desc()).limit(1).all()[0]
+
 
 class DBSessionMaker:
     def __init__(self, database_uri):