move model forward: subsystems, dataclasses, uid base class

src/aramaki/server/alembic/versions/20240204_f342ec229dba.py

@@ -0,0 +1,66 @@
+"""add subsystems
+
+Revision ID: f342ec229dba
+Revises: d50e144e683a
+Create Date: 2024-02-04 09:00:59.137909
+
+"""
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "f342ec229dba"
+down_revision = "d50e144e683a"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table(
+        "subsystem",
+        sa.Column("system_id", sa.Uuid(), nullable=False),
+        sa.Column("subsystem_id", sa.Uuid(), nullable=False),
+        sa.ForeignKeyConstraint(
+            ["subsystem_id"],
+            ["system.id"],
+            name=op.f("fk_subsystem_subsystem_id_system"),
+        ),
+        sa.ForeignKeyConstraint(
+            ["system_id"],
+            ["system.id"],
+            name=op.f("fk_subsystem_system_id_system"),
+        ),
+        sa.PrimaryKeyConstraint(
+            "system_id", "subsystem_id", name=op.f("pk_subsystem")
+        ),
+    )
+    op.add_column("system", sa.Column("type_", sa.String(), nullable=False))
+    op.alter_column(
+        "system", "primary_instance", existing_type=sa.UUID(), nullable=False
+    )
+    op.alter_column(
+        "system",
+        "title",
+        existing_type=sa.TEXT(),
+        type_=sa.String(),
+        nullable=False,
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.alter_column(
+        "system",
+        "title",
+        existing_type=sa.String(),
+        type_=sa.TEXT(),
+        nullable=True,
+    )
+    op.alter_column(
+        "system", "primary_instance", existing_type=sa.UUID(), nullable=True
+    )
+    op.drop_column("system", "type_")
+    op.drop_table("subsystem")
+    # ### end Alembic commands ###

src/aramaki/server/models/meta.py

@@ -1,4 +1,12 @@
-from sqlalchemy.orm import DeclarativeBase
+import uuid
+
+from sqlalchemy import func
+from sqlalchemy.orm import (
+    DeclarativeBase,
+    Mapped,
+    MappedAsDataclass,
+    mapped_column,
+)
 from sqlalchemy.schema import MetaData
 
 # Recommended naming convention used by Alembic, as various different database
@@ -15,5 +23,16 @@
 metadata = MetaData(naming_convention=NAMING_CONVENTION)
 
 
-class Base(DeclarativeBase):
+class Base(MappedAsDataclass, DeclarativeBase):
     metadata = metadata
+
+
+class UIDBase(Base):
+    __abstract__ = True
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        init=False,
+        primary_key=True,
+        default_factory=uuid.uuid4,
+        server_default=func.gen_random_uuid(),
+    )

src/aramaki/server/models/system.py

@@ -1,24 +1,39 @@
 import uuid
 
-from sqlalchemy import func
-from sqlalchemy.orm import Mapped, mapped_column
+from sqlalchemy import Column, ForeignKey, Table
+from sqlalchemy.orm import Mapped, relationship
 
 from . import meta
 
+subsystem = Table(
+    "subsystem",
+    meta.Base.metadata,
+    Column("system_id", ForeignKey("system.id"), primary_key=True),
+    Column("subsystem_id", ForeignKey("system.id"), primary_key=True),
+)
 
-class System(meta.Base):
-    __tablename__ = "system"
-
-    id: Mapped[uuid.UUID] = mapped_column(
-        primary_key=True,
-        default=uuid.uuid4,
-        server_default=func.gen_random_uuid(),
-    )
 
-    title: Mapped[str]
+class System(meta.UIDBase):
+    __tablename__ = "system"
 
     # Make this a dictionary, use references
     type_: Mapped[str]
 
     # XXX Turn into relationship
     primary_instance: Mapped[uuid.UUID]
+
+    title: Mapped[str]
+
+    # Subsystems are designed specifically as an n-to-m relation ship with the
+    # idea that the subsystems itself should be quite independent and that this
+    # is an organizational relationship for the UI that should be flexible.
+    #
+    # To avoid too many implicit dependencies on attributes from the parents
+    # I'm currently not setting up the inverse relationship. We'll see how
+    # this goes and whether this can hold over time.
+    subsystems: Mapped[list["System"]] = relationship(
+        secondary=subsystem,
+        primaryjoin="system.c.id == subsystem.c.system_id",
+        secondaryjoin="system.c.id == subsystem.c.subsystem_id",
+        default_factory=list,
+    )

src/aramaki/server/tests/test_system.py

@@ -1,10 +1,22 @@
+import uuid
+
 from aramaki.server.models.system import System
 
 
 def test_system_basic():
-    system = System()
+    system = System(
+        type_="infrastructure", primary_instance="asdf", title="A system"
+    )
+
+    assert isinstance(system.id, uuid.UUID)
+    assert system.title == "A system"
+    assert system.type_ == "infrastructure"
+    assert system.primary_instance == "asdf"
+    assert system.subsystems == []
+
+    subsystem = System(
+        type_="infrastructure", primary_instance="asdf", title="A subsystem"
+    )
+    system.subsystems.append(subsystem)
 
-    assert system.id is None
-    assert system.title is None
-    assert system.type_ is None
-    assert system.primary_instance is None
+    assert system.subsystems == [subsystem]