Akka.Cluster.Sharding GetEntityLocation Query
#6101
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designed to make it easier for testing and telemetry, the new `GetEntityLocation` is an `IShardRegionQuery` that checks for the presence of an entity in a given `ShardRegion` and reports back if this entity is able to be located. This query is not designed to be supported over the network and is meant to be local-only.
| default: | ||
| Unhandled(query); | ||
| break; | ||
| } | ||
| } | ||
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| private void ReplyToGetEntityLocationQuery(GetEntityLocation getEntityLocation, IActorRef sender) |
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This is where the meat of these changes are
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| var shardId = ExtractShardId(new StartEntity(getEntityLocation.EntityId)); |
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One thing that is awkward about this query is that the ShardExtractor has to support the ShardRegion.StartEntity type in order for this to work - the reason being is that even though we already know what the entity id is, the extractors that resolve the ShardId are looking for an input message to generate the ShardId, not the EntityId. Therefore I have to smuggle the EnttityId back through a ShardRegion.StartEntity message. That makes this a bit hacky but it's the best compromise I could make.
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| // ShardRegion exists, but shard is not homed | ||
| // NOTE: in the event that we're querying a shard's location from a ShardRegionProxy |
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Validated this during our unit tests.
| /// In order for this query to work, the <see cref="MessageExtractor"/> must support <see cref="ShardRegion.StartEntity"/>, | ||
| /// which is also used when remember-entities=on. | ||
| /// </remarks> | ||
| public sealed class GetEntityLocation : IShardRegionQuery |
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This message never gets sent over the wire, so it doesn't require any changes to the wire type nor does it need to support IClusterShardingSerializable.
That's correct - I went for the "least bad" solution here. I don't expect many users to actually use this query much in production, but the one problematic issue here is what we're going to do inside Petabridge.Cmd.... |
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Going to do what we discussed in discord and see if I can eliminate the |
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Sigh - looks like there's no easy way to do this without |
Changes
Designed to make it easier for testing and telemetry, the new
GetEntityLocationis anIShardRegionQuerythat checks for the presence of an entity in a givenShardRegionand reports back if this entity is able to be located.This query is not designed to be supported over the network and is meant to be local-only.
I've added this primary for testing and telemetry purposes - as we're going to look at using this inside the
pbm cluster-shardingpalette for Petabridge.Cmd.Checklist
For significant changes, please ensure that the following have been completed (delete if not relevant):