1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE QuantifiedConstraints #-}
{-# LANGUAGE ImpredicativeTypes #-}
{-# LANGUAGE OverloadedLists #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE RecordWildCards #-}
{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
module Conftrack
( Config(..)
, Warning(..)
, runFetchConfig
, readValue
, readOptionalValue
, readRequiredValue
, readNested
, readNestedOptional
, SomeSource
, ConfigError(..)
, Key(..)
, Value(..)
, configKeysOf
, key
) where
import Conftrack.Value (ConfigError(..), ConfigValue(..), Key (..), Origin(..), Value(..), KeyPart, prefixedWith, key)
import Conftrack.Source (SomeSource (..), ConfigSource (..))
import Prelude hiding (unzip)
import Control.Monad.State (StateT (..))
import Data.Functor ((<&>))
import Data.List.NonEmpty (NonEmpty, unzip)
import qualified Data.List.NonEmpty as NonEmpty
import Control.Monad (forM, (>=>))
import Data.Either (isRight)
import Data.Text (Text)
import qualified Data.Text as T
import Data.Maybe (isJust, mapMaybe)
import Data.Map (Map)
import qualified Data.Map.Strict as M
class Config a where
readConfig :: Fetch a
data FetcherState = FetcherState
{ fetcherSources :: [SomeSource]
, fetcherPrefix :: [KeyPart]
, fetcherOrigins :: Map Key [Origin]
, fetcherWarnings :: [Warning]
, fetcherErrors :: [ConfigError]
}
newtype Fetch a = Fetch (FetcherState -> IO (a, FetcherState))
deriving (Functor)
newtype Warning = Warning Text
deriving Show
instance Applicative Fetch where
pure a = Fetch (\s -> pure (a, s))
liftA2 f (Fetch m) (Fetch n) = Fetch $ \s -> do
(a, s2) <- m s
(b, s3) <- n s2
pure (f a b, s3)
runFetchConfig
:: forall a. Config a
=> NonEmpty SomeSource
-> IO (Either
[ConfigError]
(a, Map Key [Origin], [Warning]))
runFetchConfig sources = do
let (Fetch m) = readConfig @a
(result, FetcherState sources2 _ origins warnings errors) <- m (FetcherState (NonEmpty.toList sources) [] [] [] [])
unusedWarnings <- collectUnused sources2
if null errors
then pure $ Right (result, origins, unusedWarnings <> warnings)
else pure $ Left errors
configKeysOf :: forall a. Config a => IO [Key]
configKeysOf = do
let (Fetch m) = readConfig @a
(_, FetcherState _ _ _ _ errors) <- m (FetcherState [] [] [] [] [])
let keys = mapMaybe (\case {(NotPresent k) -> Just k; _ -> Nothing }) errors
pure keys
readOptionalValue :: forall a. ConfigValue a => Key -> Fetch (Maybe a)
readOptionalValue bareKey = Fetch $ \s1@FetcherState{..} -> do
let k = bareKey `prefixedWith` fetcherPrefix
stuff <- firstMatchInSources k fetcherSources
let (maybeValues, sources) = unzip stuff
let values = maybeValues <&> \case
Right (val, text) -> fromConfig @a val <&> (\a -> (a, [Origin a text]))
Left e -> Left e
val <- case fmap (\(Right a) -> a) $ filter isRight values of
[] -> pure (Nothing, [])
(value, origin):_ -> pure (Just value, origin)
pure (fst val, s1 { fetcherSources = sources
, fetcherOrigins = M.insertWith (<>) k (snd val) fetcherOrigins })
readRequiredValue :: ConfigValue a => Key -> Fetch a
readRequiredValue k =
let
Fetch m = readOptionalValue k
in
Fetch (m >=> (\(a, s) -> case a of
Nothing ->
let
dummy = error "A nonexisting config value was evaluated. This is a bug."
in
pure (dummy, s { fetcherErrors = NotPresent (k `prefixedWith` fetcherPrefix s) : fetcherErrors s })
Just v -> pure (v, s)))
readValue :: forall a. ConfigValue a => a -> Key -> Fetch a
readValue defaultValue k =
let
Fetch m = readOptionalValue @a k
in
Fetch (m >=> (\(a, s) -> case a of
Just val -> pure (val, s)
Nothing ->
let
origins = M.insertWith (<>)
(k `prefixedWith` fetcherPrefix s)
[Origin defaultValue "default value"]
(fetcherOrigins s)
in
pure (defaultValue, s { fetcherOrigins = origins })))
firstMatchInSources :: Key -> [SomeSource] -> IO [(Either ConfigError (Value, Text), SomeSource)]
firstMatchInSources _ [] = pure []
firstMatchInSources k (SomeSource (source, sourceState):sources) = do
(eitherValue, newState) <- runStateT (fetchValue k source) sourceState
case eitherValue of
Left _ -> do
firstMatchInSources k sources
<&> (\a -> (eitherValue, SomeSource (source, newState)) : a)
Right _ ->
pure $ (eitherValue, SomeSource (source, newState)) : fmap (Left Shadowed ,) sources
readNested :: forall a. Config a => Key -> Fetch a
readNested (Key prefix') = Fetch $ \s1 -> do
let (Fetch nested) = readConfig @a
(config, s2) <- nested (s1 { fetcherPrefix = fetcherPrefix s1 <> NonEmpty.toList prefix' })
pure (config, s2 { fetcherPrefix = fetcherPrefix s1 })
readNestedOptional :: forall a. Config a => Key -> Fetch (Maybe a)
readNestedOptional (Key prefix) = Fetch $ \s1 -> do
let (Fetch nested) = readConfig @a
(config, s2) <- nested (s1 { fetcherPrefix = fetcherPrefix s1 <> NonEmpty.toList prefix })
if null (fetcherErrors s2)
then pure (Just config, s2 { fetcherPrefix = fetcherPrefix s1 })
-- TODO: resetting errors like this makes configKeysOf less useful. Perhaps move nested errors to warnings?
else pure (Nothing, s2 { fetcherPrefix = fetcherPrefix s1
, fetcherErrors = fetcherErrors s1 })
collectUnused :: [SomeSource] -> IO [Warning]
collectUnused sources = do
forM sources (\(SomeSource (source, sourceState)) ->
runStateT (leftovers source) sourceState <&> fst)
<&> fmap (\(Just a) -> Warning $ "Unused Keys " <> T.pack (show a))
. filter (\(Just a) -> not (null a))
. filter isJust
|
