Hasql.Mover

Documentation

class (Typeable a, Show a) => Migration a where

A mapping from a singleton migration name to its up and down SQL

Methods

migration :: a

The name for this migration

up :: a -> Text

How to run this migration

down :: a -> Text

How to rollback this migration

data SomeMigration where

Constructors

SomeMigration :: Migration m => m -> SomeMigration

Declaration

declareMigration :: QuasiQuoter

Declare a migration with a nice syntax.

[declareMigration|
name = AddFoo

[up]
CREATE TABLE foo();

[down]
DROP TABLE foo();
|]

type Migrations = '[BaseMigration, AddFoo]

Checking and running migrations

Main functions

hasqlMover :: forall ms. All Migration ms => IO ()

Main function for running hasql-mover migrations

Example usage:

[declareMigration|
name = V0

[up]
CREATE TABLE foo ();

[down]
DROP TABLE foo CASCADE;
|]

type Migrations = '[V0]

main :: IO ()
main = hasqlMoverMain @Migrations

performMigrations :: forall migrations. All Migration migrations => MigrationCli -> IO (Either MigrationError ())

Perform the migrations according to some MigrationCli

Options

data MigrationCli

Options to supply to hasqlMover: a database connection and what migration command to run

Constructors

MigrationCli

Fields

• db :: MigrationDB
• cmd :: MigrationCmd

data MigrationCmd

A command for hasqlMover

Constructors

MigrateUp

Run pending migrations

MigrateDown

Rollback a migration

Fields

• undoDivergents :: Bool

  Are we allowed to undo a divergent migration? Default: No

• divergentUseOldDown :: Bool

  For a divergent migration, use the previous "down" SQL text, or the new one? Default: New down

MigrateStatus

Print the current status

MigrateForceUp Text

Force the up of a migration to run, regardless of its status or position in the migrations list

MigrateForceDown Text

Force the down of a migration to run, regardless of its status or position in the migrations list

Results

data MigrationError

Constructors

MigrationCheckError !QueryError

MigrationUpError !PendingMigration !QueryError

MigrationDownError !UpMigration !QueryError

MigrationForceUpError !SomeMigration !QueryError

MigrationForceDownError !SomeMigration !QueryError

MigrationDivergentDownError !DivergentMigration !QueryError

MigrationConnectError !ConnectionError

MigrationNothingToRollback

MigrationGotDivergents

MigrationException !SomeException

MigrationNotFound !Text

Checked migrations

data UpMigration

Constructors

forall m.Migration m => UpMigration

Fields

• migration :: m
• executedAt :: UTCTime

Instances

Show UpMigration

Defined in Hasql.Mover

Methods

showsPrec :: Int -> UpMigration -> ShowS

show :: UpMigration -> String

showList :: [UpMigration] -> ShowS

data PendingMigration

Constructors

forall m.Migration m => PendingMigration

Fields

• migration :: m

Instances

Show PendingMigration

Defined in Hasql.Mover

Methods

showsPrec :: Int -> PendingMigration -> ShowS

show :: PendingMigration -> String

showList :: [PendingMigration] -> ShowS

data DivergentMigration

Constructors

forall m.Migration m => DivergentMigration

Fields

• migration :: m
• oldUp, oldDown :: Text
• executedAt :: UTCTime

Settings

data MigrationDB

Encapsulates a way to run a hasql session; it could be through a pool, or through a connection directly.

Constructors

forall db. MigrationDB

Fields

• acquire :: IO (Either ConnectionError db)
• release :: db -> IO ()
• run :: forall a. Session a -> db -> IO (Either QueryError a)

migrationDBFromSettings :: Settings -> MigrationDB

Create a MigrationDB from a hasql settings - a PostgreSQL connection string as of writing

Integrating into an existing "main"

hasqlMoverOpts :: Parser MigrationCli

optparse-applicative options for hasql-mover; use hasqlMover to then run the parsed options