Database.Postgres.Temp.Internal.Core

This module provides the low level functionality for running initdb, postgres and createdb to make a database.

See initPlan for more details.

Documentation

data Event

Internal events for debugging

Constructors

StartPostgres

WaitForDB

Instances

Eq Event

Defined in Database.Postgres.Temp.Internal.Core

Methods

(==) :: Event -> Event -> Bool

(/=) :: Event -> Event -> Bool

Ord Event

Defined in Database.Postgres.Temp.Internal.Core

Methods

compare :: Event -> Event -> Ordering

(<) :: Event -> Event -> Bool

(<=) :: Event -> Event -> Bool

(>) :: Event -> Event -> Bool

(>=) :: Event -> Event -> Bool

max :: Event -> Event -> Event

min :: Event -> Event -> Event

Show Event

Defined in Database.Postgres.Temp.Internal.Core

Methods

showsPrec :: Int -> Event -> ShowS

show :: Event -> String

showList :: [Event] -> ShowS

data StartError

A list of failures that can occur when starting. This is not and exhaustive list but covers the errors that the system catches for the user.

Constructors

StartPostgresFailed ExitCode

postgres failed before a connection succeeded. Most likely this is due to invalid configuration

InitDbFailed ExitCode

initdb failed. This can be from invalid configuration or using a non-empty data directory

CreateDbFailed ExitCode

createdb failed. This can be from invalid configuration or the database might already exist.

CompletePlanFailed [String]

The PartialPlan was missing info and a complete Plan could not be created.

Instances

Eq StartError

Defined in Database.Postgres.Temp.Internal.Core

Methods

(==) :: StartError -> StartError -> Bool

(/=) :: StartError -> StartError -> Bool

Ord StartError

Defined in Database.Postgres.Temp.Internal.Core

Methods

compare :: StartError -> StartError -> Ordering

(<) :: StartError -> StartError -> Bool

(<=) :: StartError -> StartError -> Bool

(>) :: StartError -> StartError -> Bool

(>=) :: StartError -> StartError -> Bool

max :: StartError -> StartError -> StartError

min :: StartError -> StartError -> StartError

Show StartError

Defined in Database.Postgres.Temp.Internal.Core

Methods

showsPrec :: Int -> StartError -> ShowS

show :: StartError -> String

showList :: [StartError] -> ShowS

Exception StartError

Defined in Database.Postgres.Temp.Internal.Core

Methods

toException :: StartError -> SomeException

fromException :: SomeException -> Maybe StartError

displayException :: StartError -> String

type Logger = Event -> IO ()

A way to log internal Events

waitForDB :: Options -> IO ()

postgres is not ready until we are able to successfully connect. waitForDB attempts to connect over and over again and returns after the first successful connection.

data ProcessConfig

ProcessConfig contains the configuration necessary for starting a process. It is essentially a stripped down CreateProcess.

Constructors

ProcessConfig

Fields

• processConfigEnvVars :: [(String, String)]

  Environment variables

• processConfigCmdLine :: [String]

  Command line arguements

• processConfigStdIn :: Handle

  The Handle for standard input

• processConfigStdOut :: Handle

  The Handle for standard output

• processConfigStdErr :: Handle

  The Handle for standard error

startProcess

Arguments

:: String

Process name

-> ProcessConfig

Process config

-> IO ProcessHandle

Start a process interactively and return the ProcessHandle

executeProcess

Arguments

:: String

Process name

-> ProcessConfig

Process config

-> IO ExitCode

Start a process and block until it finishes return the ExitCode.

data PostgresPlan

PostgresPlan is used be startPostgresProcess to start the postgres and then attempt to connect to it.

Constructors

PostgresPlan

Fields

• postgresPlanProcessConfig :: ProcessConfig

  The process config for postgres

• postgresPlanClientConfig :: Options

  Connection options. Used to verify that postgres is ready.

data PostgresProcess

The output of calling startPostgresProcess.

Constructors

PostgresProcess

Fields

• postgresProcessClientConfig :: Options

  Connection options

• postgresProcessHandle :: ProcessHandle

  postgres process handle

terminateConnections :: Options -> IO ()

Force all connections to the database to close. Called during shutdown as well.

stopPostgresProcess :: PostgresProcess -> IO ExitCode

Stop the postgres process after attempting to terminate all the connections.

startPostgresProcess :: Logger -> PostgresPlan -> IO PostgresProcess

Start the postgres process and block until a successful connection occurs. A separate thread we continously check to see if the postgres process has crashed.

data Plan

Plan is the low level configuration necessary for creating a database starting postgres and creating a database. There is no validation done on the Plan. It is recommend that one use the higher level functions such as start which will generate plans that are valid. Plans are used internally but are exposed if the higher level plan generation is not sufficent.

Constructors

Plan

Fields

• planLogger :: Logger
• planInitDb :: Maybe ProcessConfig
• planCreateDb :: Maybe ProcessConfig
• planPostgres :: PostgresPlan
• planConfig :: String
• planDataDirectory :: FilePath

throwIfNotSuccess :: Exception e => (ExitCode -> e) -> ExitCode -> IO ()

A simple helper to throw ExitCodes when they are ExitFailure.

initPlan :: Plan -> IO PostgresProcess

initPlan optionally calls initdb, optionally calls createdb and unconditionally calls postgres. Additionally it writes a "postgresql.conf" and does not return until the postgres process is ready. See startPostgresProcess for more details.

shutdownPlan :: PostgresProcess -> IO ExitCode

Stop the postgres process. See stopPostgresProcess for more details.