Flesh out the slice API for the user code #9
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An EventEnvelope specifically for the commit log has been introduced, along with the start of one for gRPC. The commit log adapter for persistence will adapt between the entity manager's envelope and its own.
Sets up the source provider using slices.
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| assert_eq!(jdk_string_hashcode(""), 0); | ||
| assert_eq!(jdk_string_hashcode("howtodoinjava.com"), 1894145264); | ||
| assert_eq!(jdk_string_hashcode("hello world"), 1794106052); | ||
| } |
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These were taken from a JDK example.
| #[test] | ||
| fn test_slice_ranges() { | ||
| assert_eq!(slice_ranges(4), vec![0..256, 256..512, 512..768, 768..1024]); | ||
| } |
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Note that Range is non-inclusive in terms of its max i.e. it is "upto". I could've used RangeInclusive instead, but then I'd have do an additional subtraction when constructing each range. :-)
akka-persistence-rs/src/lib.rs
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| Self::with_separator(entity_type, entity_id, '|') | ||
| } | ||
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| pub fn with_separator(entity_type: EntityType, entity_id: EntityId, separator: char) -> Self { |
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In practise we only support the | separator on the jvm side. I think we should remove the option to use another separator since we would anyway have to translate it to | in all persistenceIds sent to jvm.
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Removed in commit 045b1e9
akka-persistence-rs/src/lib.rs
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| /// evenly distribute all persistence ids over the slices and be able to query the | ||
| /// events for a range of slices. | ||
| pub fn slice_for_persistence_id(persistence_id: &PersistenceId) -> u32 { | ||
| jdk_string_hashcode(&persistence_id.to_string()) % NUMBER_OF_SLICES |
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note that hashCode can be negative and to be compatible with jvm this should correspond to:
math.abs(persistenceId.hashCode % numberOfSlices)
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Now using an i32 per commit 6a1febf
akka-persistence-rs/src/lib.rs
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| // Implementation of the JDK8 string hashcode: | ||
| // https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#hashCode | ||
| fn jdk_string_hashcode(s: &str) -> u32 { |
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good, important that we use the same
As per PR feedback
| SmolStr::from("some-entity-type"), | ||
| SmolStr::from("some-entity-id") | ||
| )), | ||
| 451 |
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I have verified that it's the same slice in jvm
This PR fleshes out the slice API from a user code perspective. While the source provider is presently sourcing a local commit log, it doesn't make sense to have multiple projection instances i.e. there's no cluster. However, we have this API so that we can start up projection instances on the cloud side when communicating over gRPC.
An EventEnvelope specifically for the commit log has also been introduced, along with the start of one for gRPC. The commit log adapter for persistence will adapt between the entity manager's envelope and its own.
Finally, I had fun implementing some partition id functions, particularly the JDK string hashing one. :-)