In this commit, we add a new sub-package to the walletdb package:
migration. In this package, we define a new interface, Manager, which
will expose all of the necessary functions required to abstract the
migration logic of different sub-services within the wallet, like the
address and transaction managers. The implementations of this interface
will then be able to use the migration logic within the Upgrade
function with no additional complexity.
This changes the database access APIs and each of the "manager"
packages (waddrmgr/wstakemgr) so that transactions are opened (only)
by the wallet package and the namespace buckets that each manager
expects to operate on are passed in as parameters.
This helps improve the atomicity situation as it means that many
calls to these APIs can be grouped together into a single
database transaction.
This change does not attempt to completely fix the "half-processed"
block problem. Mined transactions are still added to the wallet
database under their own database transaction as this is how they are
notified by the consensus JSON-RPC server (as loose transactions,
without the rest of the block that contains them). It will make
updating to a fixed notification model significantly easier, as the
same "manager" APIs can still be used, but grouped into a single
atomic transaction.
This fixes a deadlock where failed transactions due to the namespaces'
bucket being missing would cause deadlocks due to bolt's mmap rwmutex
still being read or write locked (and no way to unlock it, since the
underlying bolt tx was not returned on failure).
This changes the wallet.Open function signature to remove the database
namespace parameters. This is done so that the wallet package itself
is responsible for the location and opening of these namespaces from
the database, rather than requiring the caller to open these ahead of
time.
A new wallet.Create function has also been added. This function
initializes a new wallet in an empty database, using the same
namespaces as wallet.Open will eventually use. This relieves the
caller from needing to manage wallet database namespaces explicitly.
Fixes#397.
This commit implements a new namespaced db package which is intended to
be used be wallet and any sub-packages as its data storage mechanism.
- Key/value store
- Namespace support
- Allows multiple packages to have their own area in the database without
worrying about conflicts
- Read-only and read-write transactions with both manual and managed modes
- Nested buckets
- Supports registration of backend databases
- Comprehensive test coverage
