async def test_stream_paging():
output = TeeQueue()
convo = IterStreamEvents("my-stream")
response = proto.ReadStreamEventsCompleted()
response.result = msg.ReadEventResult.Success
response.next_event_number = 10
response.last_event_number = 9
response.is_end_of_stream = False
response.last_commit_position = 8
await convo.respond_to(
msg.InboundMessage(
uuid4(),
msg.TcpCommand.ReadStreamEventsForwardCompleted,
response.SerializeToString(),
),
output,
)
reply = await output.get()
body = proto.ReadStreamEvents()
body.ParseFromString(reply.payload)
assert body.from_event_number == 10
async def test_stream_not_found():
output = TeeQueue()
convo = IterStreamEvents("my-stream")
response = proto.ReadStreamEventsCompleted()
response.result = msg.ReadStreamResult.NoStream
response.is_end_of_stream = False
response.next_event_number = 0
response.last_event_number = 0
response.last_commit_position = 0
await convo.respond_to(
msg.InboundMessage(
uuid4(),
msg.TcpCommand.ReadStreamEventsForwardCompleted,
response.SerializeToString(),
),
output,
)
with pytest.raises(exceptions.StreamNotFound) as exn:
await convo.result
assert exn.stream == "my-stream"
assert exn.conversation_id == convo.conversation_id
assert not output.items
async def test_end_of_stream():
output = TeeQueue()
event_1_id = uuid4()
event_2_id = uuid4()
convo = IterStreamEvents("my-stream")
response = proto.ReadStreamEventsCompleted()
response.result = msg.ReadEventResult.Success
response.next_event_number = 10
response.last_event_number = 9
response.is_end_of_stream = True
response.last_commit_position = 8
event_1 = proto.ResolvedIndexedEvent()
event_1.event.event_stream_id = "stream-123"
event_1.event.event_number = 32
event_1.event.event_id = event_1_id.bytes_le
event_1.event.event_type = "event-type"
event_1.event.data_content_type = msg.ContentType.Json
event_1.event.metadata_content_type = msg.ContentType.Binary
event_1.event.data = """
{
'color': 'red',
'winner': true
}
""".encode(
"UTF-8"
)
event_2 = proto.ResolvedIndexedEvent()
event_2.CopyFrom(event_1)
event_2.event.event_type = "event-2-type"
event_2.event.event_id = event_2_id.bytes_le
event_2.event.event_number = 33
response.events.extend([event_1, event_2])
await convo.respond_to(
msg.InboundMessage(
uuid4(), msg.TcpCommand.ReadEventCompleted, response.SerializeToString()
),
output,
)
# Todo: Use a slice here so that we can give information
# to the iterator about its position in the stream?
# assert isinstance(reply.result, msg.StreamSlice)
result = await convo.result
[event_1, event_2] = [e async for e in result]
assert event_1.event.stream == "stream-123"
assert event_1.event.id == event_1_id
assert event_1.event.type == "event-type"
assert event_1.event.event_number == 32
assert event_2.event.stream == "stream-123"
assert event_2.event.id == event_2_id
assert event_2.event.type == "event-2-type"
assert event_2.event.event_number == 33
async def test_when_a_stream_iterator_fails_midway():
"""
Sometimes bad things happen. What happens if we're iterating a stream and
some anarchist decides to delete it from under our feet? Well, I guess we
should return an error to the caller and stop the iterator.
"""
dispatcher = MessageDispatcher()
output_queue = TeeQueue()
conversation = IterStreamEvents("my-stream")
first_msg = read_stream_events_completed(
conversation.conversation_id, "my-stream",
[NewEvent("event", data={"x": 1})])
second_msg = read_stream_events_failure(conversation.conversation_id,
ReadStreamResult.StreamDeleted)
future = await dispatcher.start_conversation(conversation)
await dispatcher.dispatch(first_msg, output_queue)
await dispatcher.dispatch(second_msg, output_queue)
iterator = await asyncio.wait_for(future, 1)
event = await anext(iterator)
assert event.event.json()["x"] == 1
with pytest.raises(StreamDeleted):
await anext(iterator)
assert not dispatcher.has_conversation(conversation.conversation_id)
async def test_reconnect_at_last_event_number():
output = TeeQueue()
event_1_id = uuid4()
event_2_id = uuid4()
convo = IterStreamEvents("my-stream", from_event=32)
await convo.start(output)
response = proto.ReadStreamEventsCompleted()
response.result = msg.ReadEventResult.Success
response.next_event_number = 32
response.last_event_number = 31
response.is_end_of_stream = False
response.last_commit_position = 31
event_1 = proto.ResolvedIndexedEvent()
event_1.event.event_stream_id = "stream-123"
event_1.event.event_number = 32
event_1.event.event_id = event_1_id.bytes_le
event_1.event.event_type = "event-type"
event_1.event.data_content_type = msg.ContentType.Json
event_1.event.metadata_content_type = msg.ContentType.Binary
event_1.event.data = """
{
'color': 'red',
'winner': true
}
""".encode("UTF-8")
event_2 = proto.ResolvedIndexedEvent()
event_2.CopyFrom(event_1)
event_2.event.event_type = "event-2-type"
event_2.event.event_id = event_2_id.bytes_le
event_2.event.event_number = 33
response.events.extend([event_1, event_2])
await convo.respond_to(
msg.InboundMessage(
uuid4(),
msg.TcpCommand.ReadStreamEventsForwardCompleted,
response.SerializeToString(),
),
output,
)
await convo.start(output)
request = output.items[-1]
body = proto.ReadStreamEvents()
body.ParseFromString(request.payload)
assert request.command is msg.TcpCommand.ReadStreamEventsForward
assert body.event_stream_id == "my-stream"
assert body.from_event_number == 33
assert body.resolve_link_tos is True
assert body.require_master is False
assert body.max_count == 100
async def test_when_dispatching_stream_iterators():
"""
When we're dealing with iterators, the first message should result
in a StreamingIterator being returned to the caller; subsequent messages
should push new events to the caller, and the final message should
terminate iteration.
"""
conversation = IterStreamEvents("my-stream")
first_msg = read_stream_events_completed(
conversation.conversation_id, "my-stream",
[NewEvent("event", data={"x": 1})])
second_msg = read_stream_events_completed(
conversation.conversation_id,
"my-stream",
[NewEvent("event", data={"x": 2}),
NewEvent("event", data={"x": 3})],
)
final_msg = read_stream_events_completed(
conversation.conversation_id,
"my-stream",
[NewEvent("event", data={"x": 4})],
end_of_stream=True,
)
dispatcher = MessageDispatcher()
output_queue = TeeQueue()
future = await dispatcher.start_conversation(conversation)
# The first message should result in an iterator being returned to the caller
# with one event. The conversation should still be active.
await dispatcher.dispatch(first_msg, output_queue)
iterator = await asyncio.wait_for(future, 1)
e = await anext(iterator)
assert e.event.json()["x"] == 1
assert dispatcher.has_conversation(conversation.conversation_id)
# The second message should result in two events on the iterator.
# The conversation should still be active.
await dispatcher.dispatch(second_msg, output_queue)
e = await anext(iterator)
assert e.event.json()["x"] == 2
e = await anext(iterator)
assert e.event.json()["x"] == 3
assert dispatcher.has_conversation(conversation.conversation_id)
# The final message should result in one event and the iterator terminating
await dispatcher.dispatch(final_msg, output_queue)
[e] = [e async for e in iterator]
assert e.event.json()["x"] == 4
assert not dispatcher.has_conversation(conversation.conversation_id)
async def test_read_stream_request():
output = TeeQueue()
convo = IterStreamEvents("my-stream")
await convo.start(output)
request = await output.get()
body = proto.ReadStreamEvents()
body.ParseFromString(request.payload)
assert request.command is msg.TcpCommand.ReadStreamEventsForward
assert body.event_stream_id == "my-stream"
assert body.from_event_number == 0
assert body.resolve_link_tos is True
assert body.require_master is False
assert body.max_count == 100
async def test_when_a_stream_iterator_fails_at_the_first_hurdle():
"""
If we receive an error in reply to the first message in an iterator
conversation, then we ought to raise the error instead of returning
an iterator.
"""
dispatcher = MessageDispatcher()
conversation = IterStreamEvents("my-stream")
first_msg = read_stream_events_failure(conversation.conversation_id,
ReadStreamResult.StreamDeleted)
future = await dispatcher.start_conversation(conversation)
await dispatcher.dispatch(first_msg, None)
with pytest.raises(StreamDeleted):
await asyncio.wait_for(future, 1)
assert not dispatcher.has_conversation(conversation.conversation_id)
async def test_error_mid_stream():
output = TeeQueue()
convo = IterStreamEvents("my-stream")
response = proto.ReadStreamEventsCompleted()
response.result = msg.ReadStreamResult.Success
response.is_end_of_stream = False
response.next_event_number = 0
response.last_event_number = 0
response.last_commit_position = 0
await convo.respond_to(
msg.InboundMessage(
uuid4(),
msg.TcpCommand.ReadStreamEventsForwardCompleted,
response.SerializeToString(),
),
output,
)
response.result = msg.ReadStreamResult.AccessDenied
await convo.respond_to(
msg.InboundMessage(
uuid4(),
msg.TcpCommand.ReadStreamEventsForwardCompleted,
response.SerializeToString(),
),
output,
)
iterator = await convo.result
with pytest.raises(exceptions.AccessDenied) as exn:
await iterator.anext()
assert exn.conversation_id == convo.conversation_id
assert exn.conversation_type == "IterStreamEvents"
assert len(output.items) == 1