{-|
Module : Config
Description : Manages PostgRESTWS configuration options.
This module provides a helper function to read the command line
arguments using the optparse-applicative and the AppConfig type to store
them. It also can be used to define other middleware configuration that
may be delegated to some sort of external configuration.
It currently includes a hardcoded CORS policy but this could easly be
turned in configurable behaviour if needed.
Other hardcoded options such as the minimum version number also belong here.
-}
module Config ( prettyVersion
, readOptions
, minimumPgVersion
, PgVersion (..)
, AppConfig (..)
)
where
import System.IO.Error (IOError)
import Control.Applicative
import qualified Data.ByteString as B
import qualified Data.Configurator as C
import qualified Data.Configurator.Types as C
import Data.Monoid
import Data.Text (intercalate, lines)
import Data.Text.Encoding (encodeUtf8)
import Data.Text.IO (hPutStrLn)
import Data.Version (versionBranch)
import Options.Applicative hiding (str)
import Paths_postgrest_ws (version)
import Text.Heredoc
import Text.PrettyPrint.ANSI.Leijen hiding ((<>), (<$>))
import qualified Text.PrettyPrint.ANSI.Leijen as L
import Protolude hiding (intercalate, (<>))
-- | Config file settings for the server
data AppConfig = AppConfig {
configDatabase :: Text
, configPath :: Text
, configHost :: Text
, configPort :: Int
, configAuditChannel :: Maybe Text
, configJwtSecret :: B.ByteString
, configJwtSecretIsBase64 :: Bool
, configPool :: Int
}
-- | User friendly version number
prettyVersion :: Text
prettyVersion = intercalate "." $ map show $ versionBranch version
-- | Function to read and parse options from the command line
readOptions :: IO AppConfig
readOptions = do
-- First read the config file path from command line
cfgPath <- customExecParser parserPrefs opts
-- Now read the actual config file
conf <- catch
(C.load [C.Required cfgPath])
configNotfoundHint
handle missingKeyHint $ do
-- db ----------------
cDbUri <- C.require conf "db-uri"
cPool <- C.lookupDefault 10 conf "db-pool"
-- server ------------
cPath <- C.require conf "server-root"
cHost <- C.lookupDefault "*4" conf "server-host"
cPort <- C.lookupDefault 3000 conf "server-port"
cAuditC <- C.lookup conf "audit-channel"
-- jwt ---------------
cJwtSec <- C.require conf "jwt-secret"
cJwtB64 <- C.lookupDefault False conf "secret-is-base64"
return $ AppConfig cDbUri cPath cHost cPort cAuditC (encodeUtf8 cJwtSec) cJwtB64 cPool
where
opts = info (helper <*> pathParser) $
fullDesc
<> progDesc (
"PostgREST "
<> toS prettyVersion
<> " / create a REST API to an existing Postgres database"
)
<> footerDoc (Just $
text "Example Config File:"
L.<> nest 2 (hardline L.<> exampleCfg)
)
parserPrefs = prefs showHelpOnError
configNotfoundHint :: IOError -> IO a
configNotfoundHint e = do
hPutStrLn stderr $
"Cannot open config file:\n\t" <> show e
exitFailure
missingKeyHint :: C.KeyError -> IO a
missingKeyHint (C.KeyError n) = do
hPutStrLn stderr $
"Required config parameter \"" <> n <> "\" is missing or of wrong type.\n" <>
"Documentation for configuration options available at\n" <>
"\thttp://postgrest.com/en/v0.4/admin.html#configuration\n\n" <>
"Try the --example-config option to see how to configure PostgREST."
exitFailure
exampleCfg :: Doc
exampleCfg = vsep . map (text . toS) . lines $
[str|db-uri = "postgres://user:pass@localhost:5432/dbname"
|db-pool = 10
|
|server-root = "./client-example"
|server-host = "*4"
|server-port = 3000
|
|## choose a secret to enable JWT auth
|## (use "@filename" to load from separate file)
|# jwt-secret = "foo"
|# secret-is-base64 = false
|]
pathParser :: Parser FilePath
pathParser =
strArgument $
metavar "FILENAME" <>
help "Path to configuration file"
data PgVersion = PgVersion {
pgvNum :: Int32
, pgvName :: Text
}
-- | Tells the minimum PostgreSQL version required by this version of PostgRESTWS
minimumPgVersion :: PgVersion
minimumPgVersion = PgVersion 90300 "9.3"