feat: ADR-038 Part 2: StreamingService interface, file writing implementation, and configuration (#8664)

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## Description

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Hello 👋 this PR introduces the second stage of changes to support [ADR-038](https://github.com/cosmos/cosmos-sdk/pull/8012) state listening. This is rebased on top of the [first segment](https://github.com/cosmos/cosmos-sdk/pull/8551), which introduces the low level changes to the MultiStore and KVStore interfaces and implementations, the new WriteListener types, and the new listen.KVStore type.

In this segment we introduce the StreamingService interface, an implementation that writes out to files, and it's integration and configuration at the BaseApp level.

The idea was to have the first segment reviewed independently first but if people think it is easier/more time efficient to review both at the same time then we could start here.

Thanks!



This work is towards satisfying [ADR-038](https://github.com/cosmos/cosmos-sdk/blob/master/docs/architecture/adr-038-state-listening.md)

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- [x] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [x] Wrote unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [x] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
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This commit is contained in:
Ian Norden
2021-10-24 21:37:37 +00:00
committed by GitHub
parent 8d70efa799
commit 1326fa2a7d
16 changed files with 1222 additions and 86 deletions
+10
View File
@@ -222,6 +222,16 @@ When `Store.{Get, Set}()` is called, the store forwards the call to its parent,
When `Store.Iterator()` is called, it does not simply prefix the `Store.prefix`, since it does not work as intended. In that case, some of the elements are traversed even they are not starting with the prefix.
### `ListenKv` Store
`listenkv.Store` is a wrapper `KVStore` which provides state listening capabilities over the underlying `KVStore`.
It is applied automatically by the Cosmos SDK on any `KVStore` whose `StoreKey` is specified during state streaming configuration.
Additional information about state streaming configuration can be found in the [store/streaming/README.md](../../store/streaming/README.md).
+++ https://github.com/cosmos/cosmos-sdk/blob/v0.44.1/store/listenkv/store.go#L11-L18
When `KVStore.Set` or `KVStore.Delete` methods are called, `listenkv.Store` automatically writes the operations to the set of `Store.listeners`.
## New Store package (`store/v2`)
The SDK is in the process of transitioning to use the types listed here as the default interface for state storage. At the time of writing, these cannot be used within an application and are not directly compatible with the `CommitMultiStore` and related types.