Safe Haskell	None
Language	Haskell2010

Eventful.Store.Class

Contents

EventStore
Utility types
Utility functions

Synopsis

EventStore

data EventStore serialized m Source #

The EventStore is the core type of eventful. A store operates in some monad m and stores events by serializing them to the type serialized.

Constructors

EventStore

Fields

getLatestVersion :: UUID -> m EventVersion
Gets the latest EventVersion for a given Projection.
getEvents :: UUID -> Maybe EventVersion -> m [StoredEvent serialized]
Retrieves all the events for a given Projection using that projection's UUID. If an event version is provided then all events with a version greater than or equal to that version are returned.
storeEvents :: ExpectedVersion -> UUID -> [serialized] -> m (Maybe EventWriteError)
Stores the events for a given Projection using that projection's UUID.

newtype GloballyOrderedEventStore serialized m Source #

Gets all the events ordered starting with a given SequenceNumber, and ordered by SequenceNumber. This is used when replaying all the events in a store.

Constructors

GloballyOrderedEventStore
Fields getSequencedEvents :: SequenceNumber -> m [GloballyOrderedEvent (StoredEvent serialized)]

data ExpectedVersion Source #

ExpectedVersion is used to assert the event stream is at a certain version number. This is used when multiple writers are concurrently writing to the event store. If the expected version is incorrect, then storing fails.

Constructors

AnyVersion	Used when the writer doesn't care what version the stream is at.
NoStream	The stream shouldn't exist yet.
StreamExists	The stream should already exist.
ExactVersion EventVersion	Used to assert the stream is at a particular version.

Instances

Eq ExpectedVersion Source #
Methods (==) :: ExpectedVersion -> ExpectedVersion -> Bool # (/=) :: ExpectedVersion -> ExpectedVersion -> Bool #
Show ExpectedVersion Source #
Methods showsPrec :: Int -> ExpectedVersion -> ShowS # show :: ExpectedVersion -> String # showList :: [ExpectedVersion] -> ShowS #

data EventWriteError Source #

Constructors

EventStreamNotAtExpectedVersion EventVersion

Instances

Eq EventWriteError Source #
Methods (==) :: EventWriteError -> EventWriteError -> Bool # (/=) :: EventWriteError -> EventWriteError -> Bool #
Show EventWriteError Source #
Methods showsPrec :: Int -> EventWriteError -> ShowS # show :: EventWriteError -> String # showList :: [EventWriteError] -> ShowS #

Utility types

data StoredEvent event Source #

A StoredEvent is an event with associated storage metadata.

Constructors

StoredEvent
Fields storedEventProjectionId :: UUID The UUID of the `Projection` that the event belongs to. storedEventVersion :: EventVersion The version of the Projection corresponding to this event. storedEventEvent :: event The actual event type. Note that this can be a serialized event or the actual Haskell event type.

Instances

Functor StoredEvent Source #
Methods fmap :: (a -> b) -> StoredEvent a -> StoredEvent b # (<$) :: a -> StoredEvent b -> StoredEvent a #
Foldable StoredEvent Source #
Methods fold :: Monoid m => StoredEvent m -> m # foldMap :: Monoid m => (a -> m) -> StoredEvent a -> m # foldr :: (a -> b -> b) -> b -> StoredEvent a -> b # foldr' :: (a -> b -> b) -> b -> StoredEvent a -> b # foldl :: (b -> a -> b) -> b -> StoredEvent a -> b # foldl' :: (b -> a -> b) -> b -> StoredEvent a -> b # foldr1 :: (a -> a -> a) -> StoredEvent a -> a # foldl1 :: (a -> a -> a) -> StoredEvent a -> a # toList :: StoredEvent a -> [a] # null :: StoredEvent a -> Bool # length :: StoredEvent a -> Int # elem :: Eq a => a -> StoredEvent a -> Bool # maximum :: Ord a => StoredEvent a -> a # minimum :: Ord a => StoredEvent a -> a # sum :: Num a => StoredEvent a -> a # product :: Num a => StoredEvent a -> a #
Traversable StoredEvent Source #
Methods traverse :: Applicative f => (a -> f b) -> StoredEvent a -> f (StoredEvent b) # sequenceA :: Applicative f => StoredEvent (f a) -> f (StoredEvent a) # mapM :: Monad m => (a -> m b) -> StoredEvent a -> m (StoredEvent b) # sequence :: Monad m => StoredEvent (m a) -> m (StoredEvent a) #
Eq event => Eq (StoredEvent event) Source #
Methods (==) :: StoredEvent event -> StoredEvent event -> Bool # (/=) :: StoredEvent event -> StoredEvent event -> Bool #
Show event => Show (StoredEvent event) Source #
Methods showsPrec :: Int -> StoredEvent event -> ShowS # show :: StoredEvent event -> String # showList :: [StoredEvent event] -> ShowS #

data GloballyOrderedEvent event Source #

A GloballyOrderedEvent is an event that has a global SequenceNumber.

Constructors

GloballyOrderedEvent
Fields globallyOrderedEventSequenceNumber :: SequenceNumber The global sequence number of this event. globallyOrderedEventEvent :: event The actual event type. Note that this can be a serialized event or the actual Haskell event type.

Instances

Functor GloballyOrderedEvent Source #
Methods fmap :: (a -> b) -> GloballyOrderedEvent a -> GloballyOrderedEvent b # (<$) :: a -> GloballyOrderedEvent b -> GloballyOrderedEvent a #
Foldable GloballyOrderedEvent Source #
Methods fold :: Monoid m => GloballyOrderedEvent m -> m # foldMap :: Monoid m => (a -> m) -> GloballyOrderedEvent a -> m # foldr :: (a -> b -> b) -> b -> GloballyOrderedEvent a -> b # foldr' :: (a -> b -> b) -> b -> GloballyOrderedEvent a -> b # foldl :: (b -> a -> b) -> b -> GloballyOrderedEvent a -> b # foldl' :: (b -> a -> b) -> b -> GloballyOrderedEvent a -> b # foldr1 :: (a -> a -> a) -> GloballyOrderedEvent a -> a # foldl1 :: (a -> a -> a) -> GloballyOrderedEvent a -> a # toList :: GloballyOrderedEvent a -> [a] # null :: GloballyOrderedEvent a -> Bool # length :: GloballyOrderedEvent a -> Int # elem :: Eq a => a -> GloballyOrderedEvent a -> Bool # maximum :: Ord a => GloballyOrderedEvent a -> a # minimum :: Ord a => GloballyOrderedEvent a -> a # sum :: Num a => GloballyOrderedEvent a -> a # product :: Num a => GloballyOrderedEvent a -> a #
Traversable GloballyOrderedEvent Source #
Methods traverse :: Applicative f => (a -> f b) -> GloballyOrderedEvent a -> f (GloballyOrderedEvent b) # sequenceA :: Applicative f => GloballyOrderedEvent (f a) -> f (GloballyOrderedEvent a) # mapM :: Monad m => (a -> m b) -> GloballyOrderedEvent a -> m (GloballyOrderedEvent b) # sequence :: Monad m => GloballyOrderedEvent (m a) -> m (GloballyOrderedEvent a) #
Eq event => Eq (GloballyOrderedEvent event) Source #
Methods (==) :: GloballyOrderedEvent event -> GloballyOrderedEvent event -> Bool # (/=) :: GloballyOrderedEvent event -> GloballyOrderedEvent event -> Bool #
Show event => Show (GloballyOrderedEvent event) Source #
Methods showsPrec :: Int -> GloballyOrderedEvent event -> ShowS # show :: GloballyOrderedEvent event -> String # showList :: [GloballyOrderedEvent event] -> ShowS #

newtype EventVersion Source #

Event versions are a strictly increasing series of integers for each projection. They allow us to order the events when they are replayed, and they also help as a concurrency check in a multi-threaded environment so services modifying the projection can be sure the projection didn't change during their execution.

Constructors

EventVersion
Fields unEventVersion :: Int

Instances

Enum EventVersion Source #
Methods succ :: EventVersion -> EventVersion # pred :: EventVersion -> EventVersion # toEnum :: Int -> EventVersion # fromEnum :: EventVersion -> Int # enumFrom :: EventVersion -> [EventVersion] # enumFromThen :: EventVersion -> EventVersion -> [EventVersion] # enumFromTo :: EventVersion -> EventVersion -> [EventVersion] # enumFromThenTo :: EventVersion -> EventVersion -> EventVersion -> [EventVersion] #
Eq EventVersion Source #
Methods (==) :: EventVersion -> EventVersion -> Bool # (/=) :: EventVersion -> EventVersion -> Bool #
Num EventVersion Source #
Methods (+) :: EventVersion -> EventVersion -> EventVersion # (-) :: EventVersion -> EventVersion -> EventVersion # (*) :: EventVersion -> EventVersion -> EventVersion # negate :: EventVersion -> EventVersion # abs :: EventVersion -> EventVersion # signum :: EventVersion -> EventVersion # fromInteger :: Integer -> EventVersion #
Ord EventVersion Source #
Methods compare :: EventVersion -> EventVersion -> Ordering # (<) :: EventVersion -> EventVersion -> Bool # (<=) :: EventVersion -> EventVersion -> Bool # (>) :: EventVersion -> EventVersion -> Bool # (>=) :: EventVersion -> EventVersion -> Bool # max :: EventVersion -> EventVersion -> EventVersion # min :: EventVersion -> EventVersion -> EventVersion #
Read EventVersion Source #
Methods readsPrec :: Int -> ReadS EventVersion # readList :: ReadS [EventVersion] # readPrec :: ReadPrec EventVersion # readListPrec :: ReadPrec [EventVersion] #
Show EventVersion Source #
Methods showsPrec :: Int -> EventVersion -> ShowS # show :: EventVersion -> String # showList :: [EventVersion] -> ShowS #
ToJSON EventVersion Source #
Methods toJSON :: EventVersion -> Value # toEncoding :: EventVersion -> Encoding # toJSONList :: [EventVersion] -> Value # toEncodingList :: [EventVersion] -> Encoding #
FromJSON EventVersion Source #
Methods parseJSON :: Value -> Parser EventVersion # parseJSONList :: Value -> Parser [EventVersion] #

newtype SequenceNumber Source #

The sequence number gives us a global ordering of events in a particular event store. Using sequence numbers is not strictly necessary for an event sourcing and CQRS system, but it makes it way easier to replay events consistently without having to use distributed transactions in an event bus. In SQL-based event stores, they are also very cheap to create.

Constructors

SequenceNumber
Fields unSequenceNumber :: Int

Instances

Enum SequenceNumber Source #
Methods succ :: SequenceNumber -> SequenceNumber # pred :: SequenceNumber -> SequenceNumber # toEnum :: Int -> SequenceNumber # fromEnum :: SequenceNumber -> Int # enumFrom :: SequenceNumber -> [SequenceNumber] # enumFromThen :: SequenceNumber -> SequenceNumber -> [SequenceNumber] # enumFromTo :: SequenceNumber -> SequenceNumber -> [SequenceNumber] # enumFromThenTo :: SequenceNumber -> SequenceNumber -> SequenceNumber -> [SequenceNumber] #
Eq SequenceNumber Source #
Methods (==) :: SequenceNumber -> SequenceNumber -> Bool # (/=) :: SequenceNumber -> SequenceNumber -> Bool #
Num SequenceNumber Source #
Methods (+) :: SequenceNumber -> SequenceNumber -> SequenceNumber # (-) :: SequenceNumber -> SequenceNumber -> SequenceNumber # (*) :: SequenceNumber -> SequenceNumber -> SequenceNumber # negate :: SequenceNumber -> SequenceNumber # abs :: SequenceNumber -> SequenceNumber # signum :: SequenceNumber -> SequenceNumber # fromInteger :: Integer -> SequenceNumber #
Ord SequenceNumber Source #
Methods compare :: SequenceNumber -> SequenceNumber -> Ordering # (<) :: SequenceNumber -> SequenceNumber -> Bool # (<=) :: SequenceNumber -> SequenceNumber -> Bool # (>) :: SequenceNumber -> SequenceNumber -> Bool # (>=) :: SequenceNumber -> SequenceNumber -> Bool # max :: SequenceNumber -> SequenceNumber -> SequenceNumber # min :: SequenceNumber -> SequenceNumber -> SequenceNumber #
Read SequenceNumber Source #
Methods readsPrec :: Int -> ReadS SequenceNumber # readList :: ReadS [SequenceNumber] # readPrec :: ReadPrec SequenceNumber # readListPrec :: ReadPrec [SequenceNumber] #
Show SequenceNumber Source #
Methods showsPrec :: Int -> SequenceNumber -> ShowS # show :: SequenceNumber -> String # showList :: [SequenceNumber] -> ShowS #
ToJSON SequenceNumber Source #
Methods toJSON :: SequenceNumber -> Value # toEncoding :: SequenceNumber -> Encoding # toJSONList :: [SequenceNumber] -> Value # toEncodingList :: [SequenceNumber] -> Encoding #
FromJSON SequenceNumber Source #
Methods parseJSON :: Value -> Parser SequenceNumber # parseJSONList :: Value -> Parser [SequenceNumber] #
ToHttpApiData SequenceNumber Source #
Methods toUrlPiece :: SequenceNumber -> Text # toEncodedUrlPiece :: SequenceNumber -> Builder # toHeader :: SequenceNumber -> ByteString # toQueryParam :: SequenceNumber -> Text #
FromHttpApiData SequenceNumber Source #
Methods parseUrlPiece :: Text -> Either Text SequenceNumber # parseHeader :: ByteString -> Either Text SequenceNumber # parseQueryParam :: Text -> Either Text SequenceNumber #
PathPiece SequenceNumber Source #
Methods fromPathPiece :: Text -> Maybe SequenceNumber # toPathPiece :: SequenceNumber -> Text #

Utility functions

transactionalExpectedWriteHelper :: Monad m => (UUID -> m EventVersion) -> (UUID -> [serialized] -> m ()) -> ExpectedVersion -> UUID -> [serialized] -> m (Maybe EventWriteError) Source #

Helper to create storeEventsRaw given a function to get the latest stream version and a function to write to the event store. **NOTE**: This only works if the monad m is transactional.