29 lines
907 B
Markdown
29 lines
907 B
Markdown
# KvCas contracts (strong consistency)
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## CompareAndSwap
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- **RPC**: `kvrpc.KvCas/CompareAndSwap`
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- **Request**:
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- `namespace: string` (empty => `default`)
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- `key: bytes`
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- `value: bytes`
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- `expected_version: uint64`
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- **Response**:
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- `success: bool`
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- `current_version: uint64`
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- `new_version: uint64`
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- **Semantics**:
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- Allowed only for `strong` namespaces; returns `FailedPrecondition` otherwise or when not leader (redirect required).
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- Proposes via Raft; state machine applies with LWW timestamp wrapper.
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## Get
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- **RPC**: `kvrpc.KvCas/Get`
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- **Request**:
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- `namespace: string` (empty => `default`)
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- `key: bytes`
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- **Response**:
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- `found: bool`
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- `value: bytes`
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- `version: uint64`
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- **Semantics**:
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- Allowed only for `strong` namespaces; returns `FailedPrecondition` if not leader.
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- Reads versioned value (timestamp-prefixed) and returns decoded value plus version.
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