Add timestamps to workflow and capability requests

 - Add columns to tables workflow_requests and capability_requests
 - Make the updated_at column auto-update in the database for both
 - Use in the __repr__ method for Python for human-friendliness

Manually verified that the timezone manipulations were correct

schema/versions/72cee10f1f0d_add_created_updated_timestamps_to_.py

+"""add created/updated timestamps to capability and workflow requests
+
+Revision ID: 72cee10f1f0d
+Revises: 50ff97fe0c2a
+Create Date: 2021-03-10 10:30:01.160958
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "72cee10f1f0d"
+down_revision = "50ff97fe0c2a"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.add_column(
+        "capability_requests",
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+    )
+    op.add_column(
+        "workflow_requests",
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+    )
+    op.add_column(
+        "capability_requests",
+        sa.Column(
+            "updated_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+    )
+    op.add_column(
+        "workflow_requests",
+        sa.Column(
+            "updated_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.func.now(),
+            nullable=False,
+        ),
+    )
+
+    op.execute(
+        """
+    create or replace function update_updated_at_timestamp() RETURNS trigger LANGUAGE plpgsql AS $$
+    BEGIN
+      NEW.updated_at := current_timestamp;
+      RETURN NEW;
+    END;
+    $$;"""
+    )
+
+    op.execute(
+        """
+    create trigger capability_request_updated 
+    before update on capability_requests
+    for each row execute function update_updated_at_timestamp();"""
+    )
+
+    op.execute(
+        """
+    create trigger workflow_request_updated 
+    before update on workflow_requests
+    for each row execute function update_updated_at_timestamp();"""
+    )
+
+
+def downgrade():
+    op.drop_column("capability_requests", "created_at")
+    op.drop_column("workflow_requests", "created_at")
+    op.drop_column("capability_requests", "updated_at")
+    op.drop_column("workflow_requests", "updated_at")
+    op.execute("drop trigger workflow_request_updated on workflow_requests")
+    op.execute("drop trigger capability_request_updated on capability_requests")
+    op.execute("drop function update_updated_at_timestamp")

shared/workspaces/workspaces/capability/schema.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 import json
 from typing import Dict, Tuple
 
+import pendulum
 import sqlalchemy as sa
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import relationship
@@ -154,6 +155,20 @@ class CapabilityRequest(Base, CapabilityRequestIF):
         "capability_name", sa.String, sa.ForeignKey("capabilities.capability_name")
     )
     parameters = sa.Column("parameters", sa.JSON)
+    created_at = sa.Column(
+        "created_at",
+        sa.DateTime(timezone=True),
+        server_default=sa.func.now(),
+        nullable=False,
+    )
+    updated_at = sa.Column(
+        "updated_at",
+        sa.DateTime(timezone=True),
+        server_default=sa.func.now(),
+        server_onupdate=sa.func.now(),
+        nullable=False,
+    )
+
     # FIXME: This needs to be changed to properly keep track of product locators.
     # future_products = sa.Column('future_products', sa.String)
     versions = relationship("CapabilityVersion", back_populates="request")
@@ -173,6 +188,22 @@ class CapabilityRequest(Base, CapabilityRequestIF):
             "parameters": self.parameters,
         }
 
+    @property
+    def created_at_ago(self) -> str:
+        return pendulum.instance(self.created_at).diff_for_humans()
+
+    @property
+    def updated_at_ago(self) -> str:
+        return pendulum.instance(self.updated_at).diff_for_humans()
+
+    def __repr__(self):
+        return (
+            f"<CapabilityRequest #{self.id} "
+            f"for capability {self.capability_name}, "
+            f"created {self.created_at_ago} and "
+            f"last updated {self.updated_at_ago})>"
+        )
+
 
 class CapabilityVersion(Base, CapabilityVersionIF):
     """

shared/workspaces/workspaces/workflow/schema.py

@@ -4,6 +4,7 @@ from pathlib import Path
 from typing import Dict, List
 
 import chevron
+import pendulum
 import sqlalchemy as sa
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import relationship
@@ -184,6 +185,27 @@ class WorkflowRequest(Base, WorkflowRequestIF):
     state = sa.Column("state", sa.String)
     results_dir = sa.Column("results_dir", sa.String)
     files = relationship("WorkflowRequestFile", backref="request")
+    created_at = sa.Column(
+        "created_at",
+        sa.DateTime(timezone=True),
+        server_default=sa.func.now(),
+        nullable=False,
+    )
+    updated_at = sa.Column(
+        "updated_at",
+        sa.DateTime(timezone=True),
+        server_default=sa.func.now(),
+        server_onupdate=sa.func.now(),
+        nullable=False,
+    )
+
+    @property
+    def created_at_ago(self) -> str:
+        return pendulum.instance(self.created_at).diff_for_humans()
+
+    @property
+    def updated_at_ago(self) -> str:
+        return pendulum.instance(self.updated_at).diff_for_humans()
 
     @property
     def request(self) -> AbstractRequest:
@@ -217,7 +239,11 @@ class WorkflowRequest(Base, WorkflowRequestIF):
         return self.files
 
     def __repr__(self):
-        return f"<WorkflowRequest workflow_request_id= {self.workflow_request_id}>"
+        return (
+            f"<WorkflowRequest workflow_request_id= {self.workflow_request_id}"
+            f"created {self.created_at_ago} and "
+            f"last updated {self.updated_at_ago})>"
+        )
 
 
 class WorkflowRequestFile(Base, WorkflowRequestFileIF):