nimbus-eth1/nimbus/db/kvt/kvt_init/persistent.nim

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Nim

# nimbus-eth1
# Copyright (c) 2023-2024 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
# http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
# http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed
# except according to those terms.
## Persistent constructor for Kvt DB
## ====================================
##
## This module automatically pulls in the persistent backend library at the
## linking stage (e.g. `rocksdb`) which can be avoided for pure memory DB
## applications by importing `./kvt_init/memory_only` (rather than
## `./kvt_init/persistent`.)
##
{.push raises: [].}
import
results,
../../aristo,
../../opts,
../kvt_desc,
"."/[rocks_db, memory_only]
export
RdbBackendRef,
memory_only
# ------------------------------------------------------------------------------
# Private helpers
# ------------------------------------------------------------------------------
func toErr0(err: (KvtError,string)): KvtError =
err[0]
# ------------------------------------------------------------------------------
# Public database constuctors, destructor
# ------------------------------------------------------------------------------
proc init*(
T: type KvtDbRef;
B: type RdbBackendRef;
basePath: string;
opts: DbOptions;
): Result[KvtDbRef,KvtError] =
## Generic constructor for `RocksDb` backend
##
ok KvtDbRef(
top: LayerRef.init(),
backend: ? rocksDbKvtBackend(basePath, opts).mapErr toErr0)
proc init*(
T: type KvtDbRef;
B: type RdbBackendRef;
adb: AristoDbRef;
opts: DbOptions;
): Result[KvtDbRef,KvtError] =
## Constructor for `RocksDb` backend which piggybacks on the `Aristo`
## backend. The following changes will occur after successful instantiation:
##
## * When invoked, the function `kvt_tx.persistent()` will always return an
## error. If everything is all right (e.g. saving is possible), the error
## returned will be `TxPersistDelayed`. This indicates that the save
## request was queued, waiting for being picked up by an event handler.
##
## * There should be an invocation of `aristo_tx.persistent()` immediately
## follwing the `kvt_tx.persistent()` call (some `KVT` functions might
## return `RdbBeDelayedLocked` or similar errors while the save request
## is pending.) Once successful, the`aristo_tx.persistent()` function will
## also have commited the pending save request mentioned above.
##
## * The function `kvt_init/memory_only.finish()` does nothing.
##
## * The function `aristo_init/memory_only.finish()` will close both
## sessions, the one for `KVT` and the other for `Aristo`.
##
## * The functiond `kvt_delta.deltaUpdate()` and `tx_stow.tcStow()` should
## not be invoked directly (they will stop with an error most of the time,
## anyway.)
##
ok KvtDbRef(
top: LayerRef.init(),
backend: ? rocksDbKvtTriggeredBackend(adb, opts).mapErr toErr0)
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------