Safe Haskell	None
Language	GHC2024

Arbiter.Core.Codec

Contents

Column types
Row decoding
Parameter encoding
Bidirectional job write codec
Job codecs
Admission view codecs
Cron codecs
Worker codecs
Queue codecs

Description

Internal to the arbiter packages. Not covered by the PVP.

Typed encoding and decoding for PostgreSQL queries.

RowCodec decodes result rows. It is a free applicative that each backend (postgresql-simple, hasql, Orville) interprets natively.
Params is the typed parameter list for query execution.

Both use the same Col GADT.

Synopsis

data Col a where
- CInt4 :: Col Int32
- CInt8 :: Col Int64
- CText :: Col Text
- CBool :: Col Bool
- CTimestamptz :: Col UTCTime
- CJsonb :: Col Value
- CStored :: forall payload. Col (Stored payload)
- CFloat8 :: Col Double
- CUuid :: Col UUID
data NullCol a where
- NotNull :: forall a. Text -> Col a -> NullCol a
- Nullable :: forall a1. Text -> Col a1 -> NullCol (Maybe a1)
type RowCodec = Ap NullCol
col :: Text -> Col a -> RowCodec a
ncol :: Text -> Col a -> RowCodec (Maybe a)
runCodec :: Applicative f => (forall x. NullCol x -> f x) -> RowCodec a -> f a
codecColumns :: RowCodec a -> [Text]
joinColumns :: [Text] -> Text
data ParamType a where
- PScalar :: forall a. Col a -> ParamType a
- PNullable :: forall a1. Col a1 -> ParamType (Maybe a1)
- PArray :: forall a1. Col a1 -> ParamType [a1]
- PNullArray :: forall a1. Col a1 -> ParamType [Maybe a1]
data SomeParam where
- SomeParam :: forall a. ParamType a -> a -> SomeParam
type Params = [SomeParam]
pval :: Col a -> a -> SomeParam
pnul :: Col a -> Maybe a -> SomeParam
parr :: Col a -> [a] -> SomeParam
pnarr :: Col a -> [Maybe a] -> SomeParam
data Codec s a
cColumns :: Codec s a -> [(Text, Text)]
cScalar :: Codec s a -> s -> Params
cArray :: Codec s a -> [s] -> Params
jobCodec :: Text -> Codec (JobWriteSource payload) (JobRead (Stored stored))
payloadWriteCodec :: Codec (Value, PayloadColumns) PayloadKeys
data JobWriteSource payload = JobWriteSource {
- sourceJob :: JobWrite payload
- sourceEncoded :: Value
- sourceColumns :: PayloadColumns
- sourceParentId :: Maybe Int64
- sourceParentState :: Maybe Value
- sourceSuspended :: Bool
}
writeColumnNames :: [Text]
jobRowCodec :: Text -> RowCodec (JobRead (Stored payload))
dlqRowCodec :: Text -> RowCodec (Int64, UTCTime, JobRead (Stored payload))
archiveRowCodec :: Text -> RowCodec (Int64, UTCTime, JobRead (Stored payload), Maybe Value)
rateLimitPolicyViewCodec :: RowCodec RateLimitPolicyView
rateLimitBucketCodec :: RowCodec RateLimitBucketView
concurrencyPolicyViewCodec :: RowCodec ConcurrencyPolicyView
concurrencyKeyViewCodec :: RowCodec ConcurrencyKeyView
cronScheduleRowCodec :: RowCodec CronScheduleRow
workerRowWithHealthCodec :: RowCodec (WorkerRow, Text)
queueRowCodec :: RowCodec QueueRow

Column types

data Col a whereSource #

Scalar PostgreSQL column type. The GADT tag recovers the Haskell type.

Constructors

CInt4 :: Col Int32
CInt8 :: Col Int64
CText :: Col Text
CBool :: Col Bool
CTimestamptz :: Col UTCTime
CJsonb :: Col Value
CStored :: forall payload. Col (Stored payload)
CFloat8 :: Col Double
CUuid :: Col UUID

data NullCol a whereSource #

A named column with nullability. Carries the column name for backends that use name-based decoding, such as Orville.

Constructors

NotNull :: forall a. Text -> Col a -> NullCol a
Nullable :: forall a1. Text -> Col a1 -> NullCol (Maybe a1)

Row decoding

type RowCodec = Ap NullColSource #

Free applicative over NullCol. Backends interpret this into their native row parser by pattern-matching on each NullCol.

col :: Text -> Col a -> RowCodec aSource #

A non-nullable column.

ncol :: Text -> Col a -> RowCodec (Maybe a)Source #

A nullable column.

runCodec :: Applicative f => (forall x. NullCol x -> f x) -> RowCodec a -> f aSource #

Interpret a RowCodec by providing a natural transformation from NullCol to some Applicative.

codecColumns :: RowCodec a -> [Text]Source #

Extract the column names from a codec (in order).

joinColumns :: [Text] -> TextSource #

Column names as a comma-separated SQL list.

Parameter encoding

data ParamType a whereSource #

Parameter shape: scalar, nullable, or array.

Constructors

PScalar :: forall a. Col a -> ParamType a
PNullable :: forall a1. Col a1 -> ParamType (Maybe a1)
PArray :: forall a1. Col a1 -> ParamType [a1]
PNullArray :: forall a1. Col a1 -> ParamType [Maybe a1]

data SomeParam whereSource #

An existentially-typed parameter. A ParamType paired with its value.

Constructors

SomeParam :: forall a. ParamType a -> a -> SomeParam

type Params = [SomeParam]Source #

Positional query parameters.

pval :: Col a -> a -> SomeParamSource #

A non-null scalar parameter.

pnul :: Col a -> Maybe a -> SomeParamSource #

A nullable scalar parameter.

parr :: Col a -> [a] -> SomeParamSource #

A non-null array parameter.

pnarr :: Col a -> [Maybe a] -> SomeParamSource #

An array parameter with nullable elements.

Bidirectional job write codec

data Codec s aSource #

A profunctor codec. Writes source s to INSERT columns and params, decodes value a back.

Instances

Instances details

Applicative (Codec s) Source #
Instance details Defined in Arbiter.Core.Codec Methods pure :: a -> Codec s a# (<>) :: Codec s (a -> b) -> Codec s a -> Codec s b# liftA2 :: (a -> b -> c) -> Codec s a -> Codec s b -> Codec s c# (>) :: Codec s a -> Codec s b -> Codec s b# (<*) :: Codec s a -> Codec s b -> Codec s a#
Functor (Codec s) Source #
Instance details Defined in Arbiter.Core.Codec Methods fmap :: (a -> b) -> Codec s a -> Codec s b# (<$) :: a -> Codec s b -> Codec s a#

cColumns :: Codec s a -> [(Text, Text)]Source #

Writable (column name, PostgreSQL type) pairs, in order.

cScalar :: Codec s a -> s -> ParamsSource #

Single-row parameters, one per column.

cArray :: Codec s a -> [s] -> ParamsSource #

Batch parameters, one array per column.

jobCodec :: Text -> Codec (JobWriteSource payload) (JobRead (Stored stored))Source #

Main-table codec over a JobWriteSource.

payloadWriteCodec :: Codec (Value, PayloadColumns) PayloadKeysSource #

An encoded payload and the columns derived from it, as every job write stores them.

data JobWriteSource payloadSource #

The insert side of a job row. The payload encoding is built once by the caller.

Constructors

JobWriteSource
Fields sourceJob :: JobWrite payload The job to insert. sourceEncoded :: Value The encoded payload. sourceColumns :: PayloadColumns The columns the payload derives. sourceParentId :: Maybe Int64 The parent job id, if any. sourceParentState :: Maybe Value The initial rollup state. sourceSuspended :: Bool Whether the row is inserted suspended.