use uow in services, flask app

hjwp · hjwp · commit 650d8e4c312b · 2019-11-20T21:08:45.000Z
diff --git a/src/allocation/config.py b/src/allocation/config.py
@@ -1,5 +1,6 @@
 import os
 
+
 def get_postgres_uri():
     host = os.environ.get('DB_HOST', 'localhost')
     port = 54321 if host == 'localhost' else 5432
diff --git a/src/allocation/flask_app.py b/src/allocation/flask_app.py
@@ -1,43 +1,35 @@
 from datetime import datetime
 from flask import Flask, jsonify, request
-from sqlalchemy import create_engine
-from sqlalchemy.orm import sessionmaker
 
-from allocation import config
-from allocation import orm
-from allocation import repository
+from allocation import unit_of_work
 from allocation import model
 from allocation import services
+from allocation import orm
 
-orm.start_mappers()
-get_session = sessionmaker(bind=create_engine(config.get_postgres_uri()))
 app = Flask(__name__)
+orm.start_mappers()
 
 
 @app.route("/add_batch", methods=['POST'])
 def add_batch():
-    session = get_session()
-    repo = repository.SqlAlchemyRepository(session)
     eta = request.json['eta']
     if eta is not None:
         eta = datetime.fromisoformat(eta).date()
     services.add_batch(
         request.json['ref'], request.json['sku'], request.json['qty'], eta,
-        repo, session
+        unit_of_work.SqlAlchemyUnitOfWork(),
     )
     return 'OK', 201
 
 
 @app.route("/allocate", methods=['POST'])
 def allocate_endpoint():
-    session = get_session()
-    repo = repository.SqlAlchemyRepository(session)
     try:
         batchref = services.allocate(
             request.json['orderid'],
             request.json['sku'],
             request.json['qty'],
-            repo, session
+            unit_of_work.SqlAlchemyUnitOfWork(),
         )
     except (model.OutOfStock, services.InvalidSku) as e:
         return jsonify({'message': str(e)}), 400
diff --git a/src/allocation/services.py b/src/allocation/services.py
@@ -3,8 +3,8 @@
 from datetime import date
 
 from allocation.model import OrderLine
-from allocation.repository import AbstractRepository
-from allocation import model
+from allocation import model, unit_of_work
+
 
 
 class InvalidSku(Exception):
@@ -17,19 +17,22 @@ def is_valid_sku(sku, batches):
 
 def add_batch(
         ref: str, sku: str, qty: int, eta: Optional[date],
-        repo: AbstractRepository, session,
+        uow: unit_of_work.AbstractUnitOfWork
 ):
-    repo.add(model.Batch(ref, sku, qty, eta))
-    session.commit()
+    with uow:
+        uow.batches.add(model.Batch(ref, sku, qty, eta))
+        uow.commit()
 
 
 def allocate(
-        orderid: str, sku: str, qty: int, repo: AbstractRepository, session
+        orderid: str, sku: str, qty: int,
+        uow: unit_of_work.AbstractUnitOfWork
 ) -> str:
     line = OrderLine(orderid, sku, qty)
-    batches = repo.list()
-    if not is_valid_sku(line.sku, batches):
-        raise InvalidSku(f'Invalid sku {line.sku}')
-    batchref = model.allocate(line, batches)
-    session.commit()
+    with uow:
+        batches = uow.batches.list()
+        if not is_valid_sku(line.sku, batches):
+            raise InvalidSku(f'Invalid sku {line.sku}')
+        batchref = model.allocate(line, batches)
+        uow.commit()
     return batchref
diff --git a/src/allocation/unit_of_work.py b/src/allocation/unit_of_work.py
@@ -1,6 +1,7 @@
 # pylint: disable=attribute-defined-outside-init
 from __future__ import annotations
 import abc
+from typing import Callable
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 from sqlalchemy.orm.session import Session
diff --git a/tests/unit/test_services.py b/tests/unit/test_services.py
@@ -1,5 +1,5 @@
 import pytest
-from allocation import repository, services
+from allocation import repository, services, unit_of_work
 
 
 class FakeRepository(repository.AbstractRepository):
@@ -17,38 +17,44 @@ def list(self):
         return list(self._batches)
 
 
-class FakeSession():
-    committed = False
+class FakeUnitOfWork(unit_of_work.AbstractUnitOfWork):
+
+    def __init__(self):
+        self.batches = FakeRepository([])
+        self.committed = False
 
     def commit(self):
         self.committed = True
 
+    def rollback(self):
+        pass
+
+
 
 def test_add_batch():
-    repo, session = FakeRepository([]), FakeSession()
-    services.add_batch("b1", "CRUNCHY-ARMCHAIR", 100, None, repo, session)
-    assert repo.get("b1") is not None
-    assert session.committed
+    uow = FakeUnitOfWork()
+    services.add_batch("b1", "CRUNCHY-ARMCHAIR", 100, None, uow)
+    assert uow.batches.get("b1") is not None
+    assert uow.committed
 
 
 def test_allocate_returns_allocation():
-    repo, session = FakeRepository([]), FakeSession()
-    services.add_batch("batch1", "COMPLICATED-LAMP", 100, None, repo, session)
-    result = services.allocate("o1", "COMPLICATED-LAMP", 10, repo, session)
+    uow = FakeUnitOfWork()
+    services.add_batch("batch1", "COMPLICATED-LAMP", 100, None, uow)
+    result = services.allocate("o1", "COMPLICATED-LAMP", 10, uow)
     assert result == "batch1"
 
 
 def test_allocate_errors_for_invalid_sku():
-    repo, session = FakeRepository([]), FakeSession()
-    services.add_batch("b1", "AREALSKU", 100, None, repo, session)
+    uow = FakeUnitOfWork()
+    services.add_batch("b1", "AREALSKU", 100, None, uow)
 
     with pytest.raises(services.InvalidSku, match="Invalid sku NONEXISTENTSKU"):
-        services.allocate("o1", "NONEXISTENTSKU", 10, repo, FakeSession())
+        services.allocate("o1", "NONEXISTENTSKU", 10, uow)
 
 
-def test_commits():
-    repo, session = FakeRepository([]), FakeSession()
-    session = FakeSession()
-    services.add_batch("b1", "OMINOUS-MIRROR", 100, None, repo, session)
-    services.allocate("o1", "OMINOUS-MIRROR", 10, repo, session)
-    assert session.committed is True
+def test_allocate_commits():
+    uow = FakeUnitOfWork()
+    services.add_batch("b1", "OMINOUS-MIRROR", 100, None, uow)
+    services.allocate("o1", "OMINOUS-MIRROR", 10, uow)
+    assert uow.committed
