def test_di_methods():
""" Test how DI works with classes """
# A dependency to provide
@di.signature()
def current_user():
return User(email='*****@*****.**')
# A class that uses it
@di.kwargs(current_user=current_user)
class Actions:
def __init__(self, current_user: User):
self.user = current_user
@di.kwargs()
def method(self):
return self.user.email
# Test
with di.Injector() as root:
root.provide(current_user, current_user)
# Try to use a class
actions = root.invoke(Actions)
ret = root.invoke(actions.method)
assert ret == '*****@*****.**'
def test_di_cleanup_when_everything_fails():
""" Test how cleanup behaves when there are multiple failures """
cleaned_up = []
root = di.Injector()
# Init 5 providers
# Get 5 instances
for n in range(5):
@di.depends()
@contextmanager
def failing_provider(n=n):
try:
yield n
finally:
cleaned_up.append(n)
raise AssertionError
root.provide(n, failing_provider)
assert root.get(n) == n
# Now we have 5 clean-ups waiting to be executed
# Quit. They will all fail, but report their numbers into `cleaned_up`
with pytest.raises(AssertionError):
root.close()
# See that all 5 clean-ups have had a chance to run.
assert cleaned_up == [4, 3, 2, 1, 0]
def test_complex_dependencies():
""" Test low-level: nested dependencies """
root = di.Injector()
# "Z" depends on "A" and "B'
root.register_provider(
di.Provider(
'Z',
lambda a, b: f'a={a},b={b}',
deps_kw={
'a': di.Dependency('A'),
'b': di.Dependency('B')
},
))
# "A" depends on "C"
root.register_provider(
di.Provider('A',
lambda c: f'one before {c}',
deps_kw={'c': di.Dependency('C')}))
# "B" depends on "D"
root.register_provider(
di.Provider('B',
lambda d: f'one before {d}',
deps_kw={'d': di.Dependency('D')}))
# "C", "D" are regular
root.register_provider(di.Provider('C', lambda: 'cee'))
root.register_provider(di.Provider('D', lambda: 'dee'))
# The whole tree is resolved
assert root.get('Z') == 'a=one before cee,b=one before dee'
# Done
root.close()
def test_di_cleanup():
""" Test how cleanup works """
# Only one connection is available. The Injector should be able to reuse it
connection_pool = ['connection-1']
@di.signature()
@contextmanager
def get_connection():
try:
# Get a connection
connection = connection_pool.pop()
yield connection
finally:
# Clean-up
connection_pool.append(connection)
@di.kwargs(ssn='connection')
def save_to_db(ssn):
pass
with di.Injector() as root:
# I'm lazy. Let's use a custom token
root.provide('connection', get_connection)
root.get('connection')
root.get('connection')
root.get('connection')
root.get('connection')
# The only connection is in use
assert len(connection_pool) == 0
# Clean-up returned it to the pool
assert len(connection_pool) == 1
def main():
# Try out @operation-decorated business logic with an Injector DI and class-based CRUD
with di.Injector() as root:
root.provide(authenticated_user, authenticated_user)
# Call some operations
assert call_operation(root, 'whoami') == 'kolypto'
assert call_operation(root, 'user/list') == []
assert call_operation(root, 'user/create', login='******') == None
assert call_operation(root, 'user/list') == [User(login='******', created_by=User(login='******'))]
assert call_operation(root, 'user/delete', index=0) == None
assert call_operation(root, 'user/list') == []
def test_di_overrides():
""" Test how overrides work with DI """
# NOTE: it does not!
@di.kwargs(user='******')
def authenticated_user_email(user: Optional[User]):
if user is None:
return None
else:
return user.email
with di.Injector() as request:
request.provide_value('authenticated_user',
User(email='*****@*****.**'))
request.provide('email', authenticated_user_email)
# User authenticated ok
assert request.get('email') == '*****@*****.**'
# Now relogin as another user
with di.Injector(parent=request) as anonymized:
anonymized.provide_value('authenticated_user',
User(email='anonymous@localhost'))
# The higher-level injector still sees the old value
assert request.get('email') == '*****@*****.**'
# NOTE: at this level, we don't see any changes.
# Currently, this is the expected behavior: you can't override higher-level things from down below.
# assert anonymized.get('email') == 'anonymous@localhost' # not implemented
assert anonymized.get(
'email') == '*****@*****.**' # ❗ not overridden!
# And it's immediately lost when the `anonymized` context quits
assert request.get('email') == '*****@*****.**'
def __init__(self, *, debug: bool = False, fully_documented: bool = True, **kwargs):
"""
Args:
debug: Debug mode; will make extra consistency and quality checks
fully_documented: Ensure that every function, parameter, and result, has a description and annotation.
This parameter is dearly loved by documentation freaks, but is probably a curse to everyone else ... :)
**kwargs: Keyword arguments for the APIRouter, if you for some reason want to tune it to your taste
"""
super().__init__(**kwargs)
# Debug mode
self.debug: bool = debug
# Do we want all operations fully documented?
self.fully_documented: bool = fully_documented
# Init
self.injector = di.Injector()
self.func_operations: List[Callable] = []
self.class_operations: List[type] = []
def test_injector_low_level_api():
""" Test low level: Injector.add_provider() """
# Use the following scenario:
# "root" will be an application-wide injector with global stuff.
# When a user connects via WebSockets, they are authenticated and get a connection-level injector.
# When a user calls a function, a request-level injector is created.
# Root injector.
# Application-wide
with di.Injector() as root:
root.register_provider(
di.Provider(
token=Application,
func=lambda: Application(title='App'),
))
# A connected session injector.
# For every connected user. Imagine WebSockets
with di.Injector(parent=root) as connection:
connection.register_provider(
di.Provider(
token=User,
func=lambda: User(email='*****@*****.**'),
))
# A request injector.
# For every command the user sends, an injector is created to keep the context
with di.Injector(parent=connection) as request:
request.register_provider(
di.Provider(
token=DatabaseSession,
func=session_maker,
deps_kw={
# Function argument
'connection': di.Dependency(token=Connection)
},
))
request.register_provider(
di.Provider(token=Connection,
func=lambda: Connection(url='localhost')))
# Get Application: root injector
app = request.get(Application)
assert isinstance(app, Application)
assert app.title == 'App'
# Get Application again; get the very same instance
assert request.get(Application) is app
# Get User: request injector (parent)
user = request.get(User)
assert isinstance(user,
User) and user.email == '*****@*****.**'
# Get DB session
# Local injector + dependencies
ssn = request.get(DatabaseSession)
assert isinstance(ssn, DatabaseSession)
assert isinstance(
ssn.connection, Connection
) and ssn.connection.url == 'localhost' # got its dependency
assert ssn.closed == False
# Request quit. Make sure context managers cleaned up
assert ssn.closed == True # magic
# Cannot reuse the same injector because it's been closed
with pytest.raises(di.exc.ClosedInjectorError):
with request:
pass
# Copy its providers
def new_request():
return copy(request)
# ### Test: InjectFlags.SELF
with new_request() as request:
# Can get local things
assert request.has(DatabaseSession, di.SELF) == True
assert request.get(DatabaseSession, di.SELF)
assert request.get(DatabaseSession,
di.SELF) is not ssn # a different object!
# Cannot go upwards
assert request.has(Application, di.SELF) == False
with pytest.raises(di.NoProviderError):
request.get(Application, di.SELF)
# Optional works though
assert request.has(Application, di.SELF | di.OPTIONAL) == False
assert request.get(Application,
di.SELF | di.OPTIONAL,
default='Z') == 'Z'
# ### Test: InjectFlags.SKIP_SELF
with new_request() as request:
# Can find things on parents
assert request.has(Application, di.SKIP_SELF) == True
assert request.get(Application, di.SKIP_SELF)
# Can't find things on self
assert request.has(DatabaseSession, di.SKIP_SELF) == False
with pytest.raises(di.NoProviderError):
request.get(DatabaseSession, di.SKIP_SELF)
# ### Test: InjectFlags.OPTIONAL
with new_request() as request:
assert request.get('NONEXISTENT',
default=123) == 123 # no error
def test_di_functions():
""" Test DI with functions: automatic dependency reading from a function's signature """
# Prepare some resolvables
@di.signature(exclude=['debug']
) # exclude an argument from DI consideration
def init_application(debug: bool = False) -> Application:
""" Provider: Application """
return Application(title='App')
@di.signature()
def authenticate_user(app: Application) -> User:
""" Provider: User """
assert app.title == 'App'
return User(email='*****@*****.**')
@di.signature()
def db_connect(app: Application) -> Connection:
""" Provider: DB connection """
assert app.title == 'App'
return Connection(url='localhost')
@di.signature('connection') # pick one argument
@contextmanager
def db_session(connection: Connection,
connect: bool = True) -> DatabaseSession:
""" Provider: DB session """
connection = DatabaseSession(connection=connection, closed=False)
try:
yield connection
finally:
connection.closed = True
@di.signature()
def authenticated(user: User):
""" Provider: anonymous requirement to be signed in (guard) """
if user.email != '*****@*****.**':
raise Unauthenticated('Unauthenticated')
# Prepare an injector
with di.Injector() as root:
root.provide(Application, init_application)
root.provide(Connection, db_connect)
root.provide(DatabaseSession, db_session)
# Authenticate
with di.Injector(parent=root) as client:
client.provide(User, authenticate_user)
client.provide(authenticated, authenticated)
# Run a function
@di.kwargs(app=Application, ssn=DatabaseSession) # explicit kwargs
@di.depends(authenticated) # double-depends
def hello_app(
greeting: str, app, ssn
): # `greeting` is not provided; it's a required argument
""" The function to invoke """
if not ssn.closed:
return f'{greeting} {app.title}'
ret = client.invoke(hello_app, greeting='hello')
assert ret == 'hello App'
# Authenticate as another user
with di.Injector(parent=root) as client:
root.provide_value(User, User(email='anonymous'))
client.provide(authenticated, authenticated)
# See that authenticated() reports an error
with pytest.raises(Unauthenticated):
client.invoke(authenticated)
# See that user_func() fails with it
with pytest.raises(Unauthenticated):
client.invoke(hello_app, greeting='hello')
