De-couple Msg from private Subscriber implementation #196
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Currently, Msg's Ack() method assumes that its Subcriber is typed as the internal subscription structure and will panic is such is not the case. This makes using a mock subscriber unsafe and impossible without type checking code forks. Since the code within Msg's Ack() is intrinsically tied to the subscriber struct, it made sense to convert that code into a method of subscriber. Msg will now be acknowledged based on the definition of its Subscriber.
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I was mentioning the OP to use that in this code. If it was part of the API it would be (I like the idea to have the Ack() part of the subscription and not the message. Actually, in the C NATS Streaming Client, this is what I did, not a function of the message but the subscription). |
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I made With it being un-exported, it felt alright to use the proto structure since that's all we need to make the If you would rather make it a public method, then taking a |
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Actually, it's true that there would be a risk of acknowledging a message that was not receive by this subscription, which is bad. Again, at this point I don't think I will merge this PR. I am not too happy with the current API (namely, we should not have passed a NATS connection, but options, we have added NATS Subscriptions APIs to surface the internals because a user needed that, etc), and adding this does help in making it cleaner. As described in other PR, you can use an helper if you want to use a mocked subscription. |
Based on the comments made on this Pull request: https://github.com/nats-io/go-nats-streaming/pull/195#issuecomment-411948113
This allows making use of the Subscription interface for message acknowledgment.