root / htools / Ganeti / HTools / Utils.hs @ 00152519
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1 | 525bfb36 | Iustin Pop | {-| Utility functions. -} |
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2 | e4f08c46 | Iustin Pop | |
3 | e2fa2baf | Iustin Pop | {- |
4 | e2fa2baf | Iustin Pop | |
5 | e8230242 | Iustin Pop | Copyright (C) 2009, 2010, 2011 Google Inc. |
6 | e2fa2baf | Iustin Pop | |
7 | e2fa2baf | Iustin Pop | This program is free software; you can redistribute it and/or modify |
8 | e2fa2baf | Iustin Pop | it under the terms of the GNU General Public License as published by |
9 | e2fa2baf | Iustin Pop | the Free Software Foundation; either version 2 of the License, or |
10 | e2fa2baf | Iustin Pop | (at your option) any later version. |
11 | e2fa2baf | Iustin Pop | |
12 | e2fa2baf | Iustin Pop | This program is distributed in the hope that it will be useful, but |
13 | e2fa2baf | Iustin Pop | WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | e2fa2baf | Iustin Pop | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
15 | e2fa2baf | Iustin Pop | General Public License for more details. |
16 | e2fa2baf | Iustin Pop | |
17 | e2fa2baf | Iustin Pop | You should have received a copy of the GNU General Public License |
18 | e2fa2baf | Iustin Pop | along with this program; if not, write to the Free Software |
19 | e2fa2baf | Iustin Pop | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
20 | e2fa2baf | Iustin Pop | 02110-1301, USA. |
21 | e2fa2baf | Iustin Pop | |
22 | e2fa2baf | Iustin Pop | -} |
23 | e2fa2baf | Iustin Pop | |
24 | 209b3711 | Iustin Pop | module Ganeti.HTools.Utils |
25 | 209b3711 | Iustin Pop | ( |
26 | 209b3711 | Iustin Pop | debug |
27 | adc5c176 | Iustin Pop | , debugFn |
28 | adc5c176 | Iustin Pop | , debugXy |
29 | 209b3711 | Iustin Pop | , sepSplit |
30 | 4715711d | Iustin Pop | , stdDev |
31 | 3d7cd10b | Iustin Pop | , commaJoin |
32 | 9ba5c28f | Iustin Pop | , readEitherString |
33 | 28f19313 | Iustin Pop | , JSRecord |
34 | 9ba5c28f | Iustin Pop | , loadJSArray |
35 | 9ba5c28f | Iustin Pop | , fromObj |
36 | a810ad21 | Iustin Pop | , fromObjWithDefault |
37 | f36a8028 | Iustin Pop | , maybeFromObj |
38 | 117dc2d8 | Iustin Pop | , tryFromObj |
39 | 117dc2d8 | Iustin Pop | , fromJVal |
40 | 3f6af65c | Iustin Pop | , asJSObject |
41 | 3f6af65c | Iustin Pop | , asObjectList |
42 | 942403e6 | Iustin Pop | , fromJResult |
43 | 5b763470 | Iustin Pop | , tryRead |
44 | c5f7412e | Iustin Pop | , formatTable |
45 | 117dc2d8 | Iustin Pop | , annotateResult |
46 | c4d98278 | Iustin Pop | , defaultGroupID |
47 | 209b3711 | Iustin Pop | ) where |
48 | e4f08c46 | Iustin Pop | |
49 | f36a8028 | Iustin Pop | import Control.Monad (liftM) |
50 | 29ac5975 | Iustin Pop | import Data.List |
51 | a810ad21 | Iustin Pop | import Data.Maybe (fromMaybe) |
52 | 942403e6 | Iustin Pop | import qualified Text.JSON as J |
53 | 9ba5c28f | Iustin Pop | import Text.Printf (printf) |
54 | e4f08c46 | Iustin Pop | |
55 | e4f08c46 | Iustin Pop | import Debug.Trace |
56 | e4f08c46 | Iustin Pop | |
57 | 117dc2d8 | Iustin Pop | import Ganeti.HTools.Types |
58 | 117dc2d8 | Iustin Pop | |
59 | 9188aeef | Iustin Pop | -- * Debug functions |
60 | 9188aeef | Iustin Pop | |
61 | e4f08c46 | Iustin Pop | -- | To be used only for debugging, breaks referential integrity. |
62 | e4f08c46 | Iustin Pop | debug :: Show a => a -> a |
63 | e4f08c46 | Iustin Pop | debug x = trace (show x) x |
64 | e4f08c46 | Iustin Pop | |
65 | 525bfb36 | Iustin Pop | -- | Displays a modified form of the second parameter before returning |
66 | 525bfb36 | Iustin Pop | -- it. |
67 | adc5c176 | Iustin Pop | debugFn :: Show b => (a -> b) -> a -> a |
68 | adc5c176 | Iustin Pop | debugFn fn x = debug (fn x) `seq` x |
69 | adc5c176 | Iustin Pop | |
70 | 525bfb36 | Iustin Pop | -- | Show the first parameter before returning the second one. |
71 | adc5c176 | Iustin Pop | debugXy :: Show a => a -> b -> b |
72 | adc5c176 | Iustin Pop | debugXy a b = debug a `seq` b |
73 | adc5c176 | Iustin Pop | |
74 | 525bfb36 | Iustin Pop | -- * Miscellaneous |
75 | 1b7cf8ca | Iustin Pop | |
76 | e4f08c46 | Iustin Pop | -- | Comma-join a string list. |
77 | e4f08c46 | Iustin Pop | commaJoin :: [String] -> String |
78 | e4f08c46 | Iustin Pop | commaJoin = intercalate "," |
79 | e4f08c46 | Iustin Pop | |
80 | 748d5d50 | Iustin Pop | -- | Split a list on a separator and return an array. |
81 | 748d5d50 | Iustin Pop | sepSplit :: Eq a => a -> [a] -> [[a]] |
82 | e4f08c46 | Iustin Pop | sepSplit sep s |
83 | 748d5d50 | Iustin Pop | | null s = [] |
84 | 748d5d50 | Iustin Pop | | null xs = [x] |
85 | 748d5d50 | Iustin Pop | | null ys = [x,[]] |
86 | 748d5d50 | Iustin Pop | | otherwise = x:sepSplit sep ys |
87 | e4f08c46 | Iustin Pop | where (x, xs) = break (== sep) s |
88 | e4f08c46 | Iustin Pop | ys = drop 1 xs |
89 | e4f08c46 | Iustin Pop | |
90 | 9188aeef | Iustin Pop | -- * Mathematical functions |
91 | 9188aeef | Iustin Pop | |
92 | 185297fa | Iustin Pop | -- Simple and slow statistical functions, please replace with better |
93 | 185297fa | Iustin Pop | -- versions |
94 | e4f08c46 | Iustin Pop | |
95 | 525bfb36 | Iustin Pop | -- | Standard deviation function. |
96 | 4715711d | Iustin Pop | stdDev :: [Double] -> Double |
97 | 4715711d | Iustin Pop | stdDev lst = |
98 | 7570569e | Iustin Pop | -- first, calculate the list length and sum lst in a single step, |
99 | 7570569e | Iustin Pop | -- for performance reasons |
100 | 7570569e | Iustin Pop | let (ll', sx) = foldl' (\(rl, rs) e -> |
101 | 7570569e | Iustin Pop | let rl' = rl + 1 |
102 | 7570569e | Iustin Pop | rs' = rs + e |
103 | 7570569e | Iustin Pop | in rl' `seq` rs' `seq` (rl', rs')) (0::Int, 0) lst |
104 | 7570569e | Iustin Pop | ll = fromIntegral ll'::Double |
105 | 7570569e | Iustin Pop | mv = sx / ll |
106 | 7570569e | Iustin Pop | av = foldl' (\accu em -> let d = em - mv in accu + d * d) 0.0 lst |
107 | 4715711d | Iustin Pop | in sqrt (av / ll) -- stddev |
108 | dd4c56ed | Iustin Pop | |
109 | 9188aeef | Iustin Pop | -- * JSON-related functions |
110 | 9188aeef | Iustin Pop | |
111 | 525bfb36 | Iustin Pop | -- | A type alias for the list-based representation of J.JSObject. |
112 | 28f19313 | Iustin Pop | type JSRecord = [(String, J.JSValue)] |
113 | 28f19313 | Iustin Pop | |
114 | 9188aeef | Iustin Pop | -- | Converts a JSON Result into a monadic value. |
115 | c96d44df | Iustin Pop | fromJResult :: Monad m => String -> J.Result a -> m a |
116 | c96d44df | Iustin Pop | fromJResult s (J.Error x) = fail (s ++ ": " ++ x) |
117 | c96d44df | Iustin Pop | fromJResult _ (J.Ok x) = return x |
118 | 50d26669 | Iustin Pop | |
119 | 9188aeef | Iustin Pop | -- | Tries to read a string from a JSON value. |
120 | 9188aeef | Iustin Pop | -- |
121 | 9188aeef | Iustin Pop | -- In case the value was not a string, we fail the read (in the |
122 | 9188aeef | Iustin Pop | -- context of the current monad. |
123 | 5aa48dbe | Iustin Pop | readEitherString :: (Monad m) => J.JSValue -> m String |
124 | 9ba5c28f | Iustin Pop | readEitherString v = |
125 | 9ba5c28f | Iustin Pop | case v of |
126 | 5aa48dbe | Iustin Pop | J.JSString s -> return $ J.fromJSString s |
127 | 5aa48dbe | Iustin Pop | _ -> fail "Wrong JSON type" |
128 | 9ba5c28f | Iustin Pop | |
129 | 9188aeef | Iustin Pop | -- | Converts a JSON message into an array of JSON objects. |
130 | c8b662f1 | Iustin Pop | loadJSArray :: (Monad m) |
131 | c8b662f1 | Iustin Pop | => String -- ^ Operation description (for error reporting) |
132 | c8b662f1 | Iustin Pop | -> String -- ^ Input message |
133 | c8b662f1 | Iustin Pop | -> m [J.JSObject J.JSValue] |
134 | c96d44df | Iustin Pop | loadJSArray s = fromJResult s . J.decodeStrict |
135 | 9ba5c28f | Iustin Pop | |
136 | f36a8028 | Iustin Pop | -- | Reads the value of a key in a JSON object. |
137 | 28f19313 | Iustin Pop | fromObj :: (J.JSON a, Monad m) => JSRecord -> String -> m a |
138 | e8230242 | Iustin Pop | fromObj o k = |
139 | 262f3e6c | Iustin Pop | case lookup k o of |
140 | 2befdc14 | Iustin Pop | Nothing -> fail $ printf "key '%s' not found, object contains only %s" |
141 | 2befdc14 | Iustin Pop | k (show (map fst o)) |
142 | f36a8028 | Iustin Pop | Just val -> fromKeyValue k val |
143 | f36a8028 | Iustin Pop | |
144 | f36a8028 | Iustin Pop | -- | Reads the value of an optional key in a JSON object. |
145 | e8230242 | Iustin Pop | maybeFromObj :: (J.JSON a, Monad m) => |
146 | 28f19313 | Iustin Pop | JSRecord -> String -> m (Maybe a) |
147 | e8230242 | Iustin Pop | maybeFromObj o k = |
148 | f36a8028 | Iustin Pop | case lookup k o of |
149 | f36a8028 | Iustin Pop | Nothing -> return Nothing |
150 | f36a8028 | Iustin Pop | Just val -> liftM Just (fromKeyValue k val) |
151 | f36a8028 | Iustin Pop | |
152 | a810ad21 | Iustin Pop | -- | Reads the value of a key in a JSON object with a default if missing. |
153 | a810ad21 | Iustin Pop | fromObjWithDefault :: (J.JSON a, Monad m) => |
154 | 28f19313 | Iustin Pop | JSRecord -> String -> a -> m a |
155 | a810ad21 | Iustin Pop | fromObjWithDefault o k d = liftM (fromMaybe d) $ maybeFromObj o k |
156 | a810ad21 | Iustin Pop | |
157 | 525bfb36 | Iustin Pop | -- | Reads a JValue, that originated from an object key. |
158 | f36a8028 | Iustin Pop | fromKeyValue :: (J.JSON a, Monad m) |
159 | f36a8028 | Iustin Pop | => String -- ^ The key name |
160 | f36a8028 | Iustin Pop | -> J.JSValue -- ^ The value to read |
161 | f36a8028 | Iustin Pop | -> m a |
162 | f36a8028 | Iustin Pop | fromKeyValue k val = |
163 | f36a8028 | Iustin Pop | fromJResult (printf "key '%s', value '%s'" k (show val)) (J.readJSON val) |
164 | 9ba5c28f | Iustin Pop | |
165 | 525bfb36 | Iustin Pop | -- | Annotate a Result with an ownership information. |
166 | 117dc2d8 | Iustin Pop | annotateResult :: String -> Result a -> Result a |
167 | 117dc2d8 | Iustin Pop | annotateResult owner (Bad s) = Bad $ owner ++ ": " ++ s |
168 | 117dc2d8 | Iustin Pop | annotateResult _ v = v |
169 | 117dc2d8 | Iustin Pop | |
170 | 117dc2d8 | Iustin Pop | -- | Try to extract a key from a object with better error reporting |
171 | 525bfb36 | Iustin Pop | -- than fromObj. |
172 | 117dc2d8 | Iustin Pop | tryFromObj :: (J.JSON a) => |
173 | 28f19313 | Iustin Pop | String -- ^ Textual "owner" in error messages |
174 | 28f19313 | Iustin Pop | -> JSRecord -- ^ The object array |
175 | 28f19313 | Iustin Pop | -> String -- ^ The desired key from the object |
176 | a083e855 | Iustin Pop | -> Result a |
177 | e8230242 | Iustin Pop | tryFromObj t o = annotateResult t . fromObj o |
178 | 117dc2d8 | Iustin Pop | |
179 | 117dc2d8 | Iustin Pop | -- | Small wrapper over readJSON. |
180 | 117dc2d8 | Iustin Pop | fromJVal :: (Monad m, J.JSON a) => J.JSValue -> m a |
181 | 117dc2d8 | Iustin Pop | fromJVal v = |
182 | 117dc2d8 | Iustin Pop | case J.readJSON v of |
183 | 39420403 | Iustin Pop | J.Error s -> fail ("Cannot convert value '" ++ show v ++ |
184 | 39420403 | Iustin Pop | "', error: " ++ s) |
185 | 117dc2d8 | Iustin Pop | J.Ok x -> return x |
186 | 117dc2d8 | Iustin Pop | |
187 | 9188aeef | Iustin Pop | -- | Converts a JSON value into a JSON object. |
188 | 5aa48dbe | Iustin Pop | asJSObject :: (Monad m) => J.JSValue -> m (J.JSObject J.JSValue) |
189 | 5aa48dbe | Iustin Pop | asJSObject (J.JSObject a) = return a |
190 | 5aa48dbe | Iustin Pop | asJSObject _ = fail "not an object" |
191 | 942403e6 | Iustin Pop | |
192 | 9188aeef | Iustin Pop | -- | Coneverts a list of JSON values into a list of JSON objects. |
193 | 5aa48dbe | Iustin Pop | asObjectList :: (Monad m) => [J.JSValue] -> m [J.JSObject J.JSValue] |
194 | 9f6dcdea | Iustin Pop | asObjectList = mapM asJSObject |
195 | 5b763470 | Iustin Pop | |
196 | 5b763470 | Iustin Pop | -- * Parsing utility functions |
197 | 5b763470 | Iustin Pop | |
198 | 525bfb36 | Iustin Pop | -- | Parse results from readsPrec. |
199 | 5b763470 | Iustin Pop | parseChoices :: (Monad m, Read a) => String -> String -> [(a, String)] -> m a |
200 | 5b763470 | Iustin Pop | parseChoices _ _ ((v, ""):[]) = return v |
201 | 5b763470 | Iustin Pop | parseChoices name s ((_, e):[]) = |
202 | 5b763470 | Iustin Pop | fail $ name ++ ": leftover characters when parsing '" |
203 | 5b763470 | Iustin Pop | ++ s ++ "': '" ++ e ++ "'" |
204 | 5b763470 | Iustin Pop | parseChoices name s _ = fail $ name ++ ": cannot parse string '" ++ s ++ "'" |
205 | 5b763470 | Iustin Pop | |
206 | 5b763470 | Iustin Pop | -- | Safe 'read' function returning data encapsulated in a Result. |
207 | 5b763470 | Iustin Pop | tryRead :: (Monad m, Read a) => String -> String -> m a |
208 | 5b763470 | Iustin Pop | tryRead name s = parseChoices name s $ reads s |
209 | c5f7412e | Iustin Pop | |
210 | 525bfb36 | Iustin Pop | -- | Format a table of strings to maintain consistent length. |
211 | c5f7412e | Iustin Pop | formatTable :: [[String]] -> [Bool] -> [[String]] |
212 | c5f7412e | Iustin Pop | formatTable vals numpos = |
213 | c5f7412e | Iustin Pop | let vtrans = transpose vals -- transpose, so that we work on rows |
214 | c5f7412e | Iustin Pop | -- rather than columns |
215 | c5f7412e | Iustin Pop | mlens = map (maximum . map length) vtrans |
216 | c5f7412e | Iustin Pop | expnd = map (\(flds, isnum, ml) -> |
217 | c5f7412e | Iustin Pop | map (\val -> |
218 | c5f7412e | Iustin Pop | let delta = ml - length val |
219 | c5f7412e | Iustin Pop | filler = replicate delta ' ' |
220 | c5f7412e | Iustin Pop | in if delta > 0 |
221 | c5f7412e | Iustin Pop | then if isnum |
222 | c5f7412e | Iustin Pop | then filler ++ val |
223 | c5f7412e | Iustin Pop | else val ++ filler |
224 | c5f7412e | Iustin Pop | else val |
225 | c5f7412e | Iustin Pop | ) flds |
226 | c5f7412e | Iustin Pop | ) (zip3 vtrans numpos mlens) |
227 | c5f7412e | Iustin Pop | in transpose expnd |
228 | 9b9da389 | Iustin Pop | |
229 | 525bfb36 | Iustin Pop | -- | Default group UUID (just a string, not a real UUID). |
230 | c4d98278 | Iustin Pop | defaultGroupID :: GroupID |
231 | c4d98278 | Iustin Pop | defaultGroupID = "00000000-0000-0000-0000-000000000000" |