Safe Haskell	None
Language	Haskell2010

Ouroboros.Consensus.Node.DbLock

Contents

Defaults
For testing purposes

Synopsis

newtype DbLocked = DbLocked FilePath
withLockDB ∷ MountPoint → IO a → IO a
dbLockFsPath ∷ FsPath
dbLockTimeout ∷ DiffTime
withLockDB_ ∷ (IOLike m, MonadTimer m) ⇒ FileLock m → MountPoint → FsPath → DiffTime → m a → m a

Documentation

newtype DbLocked Source #

Constructors

DbLocked FilePath

Instances

Instances details

Eq DbLocked Source #
Instance details Defined in Ouroboros.Consensus.Node.DbLock Methods (==) ∷ DbLocked → DbLocked → Bool # (/=) ∷ DbLocked → DbLocked → Bool #
Exception DbLocked Source #
Instance details Defined in Ouroboros.Consensus.Node.DbLock Methods toException ∷ DbLocked → SomeException # fromException ∷ SomeException → Maybe DbLocked # displayException ∷ DbLocked → String # backtraceDesired ∷ DbLocked → Bool #
Show DbLocked Source #
Instance details Defined in Ouroboros.Consensus.Node.DbLock Methods showsPrec ∷ Int → DbLocked → ShowS # show ∷ DbLocked → String # showList ∷ [DbLocked] → ShowS #

withLockDB ∷ MountPoint → IO a → IO a Source #

We use an empty file (dbLockFsPath) as a lock of the database so that the database cannot be opened by more than one process. We wait up to dbLockTimeout to take the lock, before timing out and throwing a DbLocked exception.

Defaults

dbLockFsPath ∷ FsPath Source #

The default lock file

dbLockTimeout ∷ DiffTime Source #

Default time to wait on the lock

For testing purposes

withLockDB_ Source #

Arguments

∷ (IOLike m, MonadTimer m)
⇒ FileLock m
→ MountPoint	Root of the path
→ FsPath	File to lock
→ DiffTime	Timeout
→ m a
→ m a

We use the given FsPath in the MountPoint as a lock of the database so that the database cannot be opened by more than one process. We wait the given DiffTime on the thread taking the lock. In case of a timeout, we throw a DbLocked exception.

Some systems may delete the empty file when all its handles are closed. This is not an issue, since the file is created if it doesn't exist.