From d102032c36edbe625762ee012b3b5c685264ca30 Mon Sep 17 00:00:00 2001
From: Daniel K Lyons <dlyons@nrao.edu>
Date: Fri, 11 Sep 2020 13:55:07 -0600
Subject: [PATCH] Second try at typing this module
---
shared/channels/src/channels/amqp_helpers.py | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/shared/channels/src/channels/amqp_helpers.py b/shared/channels/src/channels/amqp_helpers.py
index 82a554bba..b075ac372 100644
--- a/shared/channels/src/channels/amqp_helpers.py
+++ b/shared/channels/src/channels/amqp_helpers.py
@@ -1,5 +1,5 @@
from abc import ABC, abstractmethod
-from typing import Callable, Any, Optional, Union, TypeVar, Protocol
+from typing import Callable, Any, Optional, Union, TypeVar, Protocol, Generic
import pika
from marshmallow import Schema
@@ -8,10 +8,10 @@ from pycapo import CapoConfig
from workspaces.json import WorkflowEventSchema
from workspaces.schema import WorkflowEvent
-T = TypeVar('T')
+T = TypeVar('T', contravariant=True)
-class ChannelDefinition(ABC, Protocol[T]):
+class ChannelDefinition(Protocol[T]):
@abstractmethod
def routing_key_for(self, message: T) -> str:
pass
@@ -49,10 +49,13 @@ class WorkflowEventChannel(ChannelDefinition[WorkflowEvent]):
return self.EXCHANGE
-class Channel(Protocol[T]):
- CONNECTION = None
- CHANNEL = None
- CONFIG = None
+ChannelDef = TypeVar('ChannelDef', bound=ChannelDefinition, covariant=True)
+
+
+class Channel(Generic[ChannelDef]):
+ CONNECTION : pika.BlockingConnection = None
+ CHANNEL : BlockingChannel = None
+ CONFIG : CapoConfig = None
def __init__(self, definition: ChannelDefinition[T]):
self.definition = definition
@@ -137,4 +140,4 @@ class Channel(Protocol[T]):
# Predefined event channels for ease of use
-workflow_events = Channel(WorkflowEventChannel())
+workflow_events : Channel[WorkflowEvent] = Channel(WorkflowEventChannel())
--
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