JetStream: lot of changes #794
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They will be described in the release notes, but gist: Added: - `DeliverSubject()` option to configure the deliver subject of a JetStream consumer created by the `js.Subscribe()` call (and variants) - `BindDeliverSubject()` option to subscribe directly to a JetStream consumer deliver subject (bypassing any lookup or JetStream consumer creation) - Fields `DeliverGroup` in `ConsumerConfig`, `PushBound` in `ConsumerInfo`. They help making prevent incorrect subscriptions to JetStream consumers - Field `Last` in `SequencePair` Changed: - With a `PullSubscription`, calling `NextMsg()` or `NextMsgWithContext()` will now return `ErrTypeSubscription`. You must use the `Fetch()` API - If the library created internally a JetStream consumer, the consumer will be deleted on `Unsubscribe()` or when the `Drain()` completes - Fail multiple instances of a subscription on the same durable push consumer (only one active at a time). Also, consumers now have the concept of `DeliverGroup`, which is the queue group name they are created for. Only queue member from the same group can attach to this consumer, and a non queue subscription cannot attach to it. Note that this requires server v2.3.5 - Attempting to create a queue subscription with a consumer configuration that has idle heartbeats and/or flow control will now result in an error Fixed: - Possible lock inversion - JetStream consumers could be incorrectly deleted on subscription's `Unsubscribe()` Resolves #785 Resolves #776 Resolves #775 Resolves #748 Resolves #747 Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
matthiashanel
approved these changes
Aug 16, 2021
example_test.go
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| @@ -323,7 +323,8 @@ func ExampleJetStream() { | |||
| }, nats.ManualAck()) | |||
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| // Async queue subscription where members load balance the | |||
| // received messages together. | |||
| // received messages together. Since no consumer name is specified, | |||
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Maybe expand on: since no consumer name is specified
Arguably I'm asking this because it's first up in the review, but it's also an example...
Perhaps add (as additional argument)
nats.go
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| // error will be returned. | ||
| // If you do not wish the JetStream consumer to be automatically deleted, | ||
| // ensure that the consumer is not created by the library, which means | ||
| // create the consumer with AddConsumer and bind to this consumer. |
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Maybe add a reference to the option name. (Using nats.Bind option)
| @@ -875,6 +877,21 @@ func (opt subOptFn) configureSubscribe(opts *subOpts) error { | |||
| } | |||
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| // Subscribe will create a subscription to the appropriate stream and consumer. | |||
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Maybe expand on appropriate?
The stream matching subject?
js.go
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| // This applies only in cases where the no consumer exists and it will be | ||
| // created by the library by the subscribe API. |
Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
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@matthiashanel I tried to address your comments on the last commit (e077154). If you could have another look and tell me if they need more tweaking. Thanks. |
As discussed with Matthias who came up with the idea, this is
better because then we make use of the provided subject. Otherwise
it was looking weird to have something which meaning was:
```
js.SubscribeSync("ignored", nats.BindDeliverSubject("p.d4"))
```
Instead you would now have:
```
sub, err = js.SubscribeSync("p.d4", nats.SubjectIsDelivery())
```
Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
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They will be described in the release notes, but gist:
Added:
DeliverSubject()option to configure the deliver subject of a JetStream consumer created by thejs.Subscribe()call (and variants)BindDeliverSubject()option to subscribe directly to a JetStream consumer deliver subject (bypassing any lookup or JetStream consumer creation)DeliverGroupinConsumerConfig,PushBoundinConsumerInfo. They help making prevent incorrect subscriptions to JetStream consumersLastinSequencePairChanged:
PullSubscription, callingNextMsg()orNextMsgWithContext()will now returnErrTypeSubscription. You must use theFetch()APIUnsubscribe()or when theDrain()completesDeliverGroup, which is the queue group name they are created for. Only queue member from the same group can attach to this consumer, and a non queue subscription cannot attach to it. Note that this requires server v2.3.5Fixed:
Unsubscribe()Resolves #785
Resolves #776
Resolves #775
Resolves #748
Resolves #747
Signed-off-by: Ivan Kozlovic ivan@synadia.com