rework cli app example

Author: pgorecki

src/cli/__main__.py

@@ -1,20 +1,20 @@
-import copy
 import uuid
 
-from sqlalchemy.orm import Session
-
-from config.container import Container
+from config.container import TopLevelContainer
+from modules.catalog.application.command import CreateListingDraftCommand
+from modules.catalog.application.query import GetAllListings
+from modules.catalog.domain.repositories import ListingRepository
 from modules.catalog.infrastructure.listing_repository import Base
+from seedwork.domain.value_objects import Money
 from seedwork.infrastructure.logging import LoggerFactory, logger
-from seedwork.infrastructure.request_context import request_context
 
 # a sample command line script to print all listings
 # run with "cd src && python -m cli"
 
 # configure logger prior to first usage
 LoggerFactory.configure(logger_name="cli")
 
-container = Container()
+container = TopLevelContainer()
 container.config.from_dict(
     dict(
         # DATABASE_URL="sqlite+pysqlite:///:memory:",
@@ -24,85 +24,39 @@
     )
 )
 
-engine = container.db().engine()
+# let's create the database schema
+engine = container.db_engine()
 Base.metadata.create_all(engine)
 
+# let's create a new application instance
+app = container.application()
+
+
+# let's query the listings, this method implicitly creates a transaction context and then executes a query
+# see `get_all_listings` query handler in `src/modules/catalog/application/query/get_all_listings.py`
+query_result = app.execute_query(GetAllListings())
+
+# now let's print the listings
+listings = query_result.payload
+print("Listings:")
+for listing in listings:
+    print(f"{listing['id']} - {listing['title']}")
+
+# now we are explicitly creating a transaction context, this time we want to execute a command
+with app.transaction_context() as ctx:
+    # see `create_listing_draft` command handler in `src/modules/catalog/application/command/create_listing_draft.py`
+    ctx.execute_command(
+        CreateListingDraftCommand(
+            listing_id=uuid.uuid4(),
+            title="First listing",
+            description="...",
+            ask_price=Money(100),
+            seller_id=uuid.UUID(int=1),
+        )
+    )
 
-from seedwork.spike.test_scratch import (
-    ActivateUserCommand,
-    Application,
-    CommandResult,
-    DependencyProvider,
-    TransactionContext,
-)
-
-
-class CustomDependencyProvider(DependencyProvider):
-    def __init__(self, ioc_container):
-        self.ioc_container = ioc_container
-
-
-provider = CustomDependencyProvider(container)
-app = Application(provider)
-
-
-@app.on_enter_transaction_context
-def on_enter_transaction_context(context: TransactionContext):
-    db_session = Session(engine)
-    correlation_id = uuid.uuid4()
-    context.dependency_provider = copy.deepcopy(app.dependency_provider)
-    context.dependency_provider["correlation_id"] = correlation_id
-    context.dependency_provider["db_session"] = db_session
-
-
-@app.on_exit_transaction_context
-def on_exit_transaction_context(context: TransactionContext, exc_type, exc_val, exc_tb):
-    db_session = context.dependency_provider["db_session"]
-    if exc_val is None:
-        db_session.commit()
-    else:
-        db_session.rollback()
-    context.dependency_provider["db_session"].close()
-
-
-@app.transaction_middleware
-def logging_middleware(next: callable, context: TransactionContext, task):
-    correlation_id = context.dependency_provider["correlation_id"]
-    request_context.correlation_id.set(correlation_id)
-    logger.info(f"transaction started for {task}")
-    result = next()
-    logger.info(f"transaction finished with {result}")
-    return result
-
-
-@app.transaction_middleware
-def sql_alchemy_session_middleware(next: callable, context: TransactionContext, task):
-    db_session = context.dependency_provider["db_session"]
-    logger.debug(f"session {db_session} started")
-    try:
-        result = next()
-        db_session.commit()
-        logger.debug(f"session {db_session} committed")
-        return result
-    except:
-        db_session.rollback()
-        logger.debug(f"session {db_session} rolled back")
-    finally:
-        db_session.close()
-
-
-@app.command_handler(ActivateUserCommand)
-def activate_user(
-    command: ActivateUserCommand, user_repository, db_session
-) -> CommandResult:
-    logger.info(f"activate_user {db_session} {user_repository}")
-    try:
-        user = user_repository.get_by_id(command.user_id)
-    except:
-        user = None
-    return CommandResult(user)
-
-
-with app.transaction_context(correlation_id="foo") as ctx:
-    ctx.execute_command(ActivateUserCommand(user_id=uuid.UUID(int=1)))
-    ctx.execute_command(ActivateUserCommand(user_id=uuid.UUID(int=2)))
+# use transaction context to acccess any dependency (i.e a repository, a service, etc.)
+with app.transaction_context() as ctx:
+    listing_repository = ctx.get_service(ListingRepository)
+    listing_count = listing_repository.count()
+    logger.info(f"There are {listing_count} listings in the database")