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Handle for holding temporary resources, the postgres process handle and postgres connection information. The DB also includes the final plan used to start initdb, createdb and postgres. See toConnectionString or toConnectionOptions for converting a DB to postgresql connection string.

Convert a DB to a connection string. Alternatively one can access the Options using toConnectionOptions

Convert a DB to a connection Options type.

Access the data directory. This was either generated or specified explicitly when creating the Config

Make the data directory permanent. Useful for debugging. If you are using with or withConfig this function will not modify the DB that is passed for cleanup. You will need to setup your own bracket like

   bracket (fmap makeDataDirPermanent start) (either mempty stop)

Get the directory that is used to create other temporary directories

Default postgres options

The default configuration. This will create a database called "postgres" via initdb (it's default behavior). It will create a temporary directory for the data and a temporary directory for a unix socket on a random port. Additionally it will use the following "postgresql.conf" which is optimized for performance.

   shared_buffers = 12MB
   fsync = off
   synchronous_commit = off
   full_page_writes = off
   log_min_duration_statement = 0
   log_connections = on
   log_disconnections = on
   client_min_messages = ERROR

defaultConfig also passes the --no-sync flag to initdb.

If you would like to customize this behavior you can start with the defaultConfig and overwrite fields or combine a defaultConfig with another Config using <> (mappend).

Alternatively you can eschew defaultConfig altogether, however your postgres might start and run faster if you use defaultConfig.

defaultConfig also sets the initDbConfig to pure standardProcessConfig and postgresConfig to standardProcessConfig.

To append additional lines to "postgresql.conf" file create a custom Config like the following.

 custom = defaultConfig <> mempty
   { plan = mempty
     { postgresConfigFile =
         [ "wal_level = replica"
         , "archive_mode = on"
         , "max_wal_senders = 2"
         , "fsync = on"
         , "synchronous_commit = on"
         ]
     }
   }

Or using the provided lenses and your favorite lens library

 custom = defaultConfig & planL . postgresConfigFile <>~
   [ "wal_level = replica"
   , "archive_mode = on"
   , "max_wal_senders = 2"
   , "fsync = on"
   , "synchronous_commit = on"
   ]

This is common enough there is defaultPostgresConf which is a helper to do this.

As an alternative to using defaultConfig one could create a config from connections parameters using optionsToDefaultConfig

mappend the defaultConfig with a Config that provides additional "postgresql.conf" lines. Equivalent to

defaultPostgresConf extra = defaultConfig <> mempty
  { plan = mempty
    { postgresConfigFile = extra
    }
  }

or with lenses

defaultPostgresConf extra = defaultConfig & planL . postgresConfigFile <>~ extra

Create zero or more temporary resources and use them to make a Config.

The passed in config is inspected and a generated config is created. The final config is built by

  generated <> extra

Returns a DB that requires cleanup. startConfig should be used with a bracket and stop, e.g.

  withConfig :: Config -> (DB -> IO a) -> IO (Either StartError a)
  withConfig plan f = bracket (startConfig plan) (either mempty stop) $
     either (pure . Left) (fmap Right . f)

or just use withConfig. If you are calling startConfig you probably want withConfig anyway.

Based on the value of socketClass a "postgresql.conf" is created with

  listen_addresses = 'IP_ADDRESS'

if it is IpSocket. If is UnixSocket then the lines

  listen_addresses = ''
  unix_socket_directories = 'SOCKET_DIRECTORY'

are added.

Default start behavior. Equivalent to calling startConfig with the defaultConfig

Stop the postgres process and cleanup any temporary resources that might have been created.

Only stop the postgres process but leave any temporary resources. Useful for testing backup strategies when used in conjunction with restart or withRestart.

Restart the postgres from DB using the prior Plan

Reload the configuration file without shutting down. Calls pg_reload_conf().

Exception safe database create with options. See startConfig for more details. Calls stop even in the face of exceptions.

Default expectation safe interface. Equivalent to

  with = withConfig defaultConfig

Exception safe version of restart

Attempt to create a Config from a Options. Useful if you want to create a database owned by a specific user you will also login with among other use cases.

Display a Config.

Display a DB