| Safe Haskell | Safe-Infered |
|---|
Ganeti.Utils
Contents
Description
Utility functions.
- debug :: Show a => a -> a
- debugFn :: Show b => (a -> b) -> a -> a
- debugXy :: Show a => a -> b -> b
- applyIf :: Bool -> (a -> a) -> a -> a
- commaJoin :: [String] -> String
- sepSplit :: Eq a => a -> [a] -> [[a]]
- plural :: Int -> String -> String -> String
- ensureQuoted :: String -> String
- stdDev :: [Double] -> Double
- data Statistics
- = SumStatistics Double
- | StdDevStatistics Double Double Double
- getSumStatistics :: [Double] -> Statistics
- getStdDevStatistics :: [Double] -> Statistics
- getStatisticValue :: Statistics -> Double
- updateStatistics :: Statistics -> (Double, Double) -> Statistics
- if' :: Bool -> a -> a -> a
- parseChoices :: Monad m => String -> String -> [(a, String)] -> m a
- tryRead :: (Monad m, Read a) => String -> String -> m a
- formatTable :: [[String]] -> [Bool] -> [[String]]
- printTable :: String -> [String] -> [[String]] -> [Bool] -> String
- parseUnitValue :: Monad m => Bool -> String -> m Rational
- parseUnitEx :: (Monad m, Integral a, Read a) => Bool -> String -> m a
- parseUnit :: (Monad m, Integral a, Read a) => String -> m a
- parseUnitAssumeBinary :: (Monad m, Integral a, Read a) => String -> m a
- exitIfBad :: String -> Result a -> IO a
- exitErr :: String -> IO a
- exitWhen :: Bool -> String -> IO ()
- exitUnless :: Bool -> String -> IO ()
- logWarningIfBad :: String -> a -> Result a -> IO a
- tryAndLogIOError :: IO a -> String -> (a -> Result b) -> IO (Result b)
- warn :: String -> IO ()
- extractKey :: [Either Integer String] -> String -> ([Either Integer String], String)
- niceSort :: [String] -> [String]
- niceSortKey :: (a -> String) -> [a] -> [a]
- rStripSpace :: String -> String
- newUUID :: IO String
- getCurrentTime :: IO Integer
- getCurrentTimeUSec :: IO Integer
- clockTimeToString :: ClockTime -> String
- chompPrefix :: String -> String -> Maybe String
- wrap :: Int -> String -> [String]
- trim :: String -> String
- defaultHead :: a -> [a] -> a
- exitIfEmpty :: String -> [a] -> IO a
- monadicThe :: (Eq a, Monad m) => String -> [a] -> m a
- splitEithers :: [Either a b] -> ([a], [b], [Bool])
- recombineEithers :: (Show a, Show b) => [a] -> [b] -> [Bool] -> Result [Either a b]
- resolveAddrHints :: Maybe AddrInfo
- resolveAddr :: Int -> String -> IO (Result (Family, SockAddr))
- setOwnerAndGroupFromNames :: FilePath -> GanetiDaemon -> GanetiGroup -> IO ()
- formatOrdinal :: (Integral a, Show a) => a -> String
- atomicWriteFile :: FilePath -> String -> IO ()
- lockFile :: FilePath -> IO (Result ())
- type FStat = (EpochTime, FileID, FileOffset)
- nullFStat :: FStat
- buildFileStatus :: FileStatus -> FStat
- getFStat :: FilePath -> IO FStat
- getFStatSafe :: FilePath -> IO FStat
- needsReload :: FStat -> FilePath -> IO (Maybe FStat)
- watchFileEx :: (Eq a, Eq b) => Integer -> b -> IORef b -> a -> IO a -> IO a
- watchFile :: Eq a => FilePath -> Int -> a -> IO a -> IO a
- data FilePermissions = FilePermissions {
- fpOwner :: Maybe String
- fpGroup :: Maybe String
- fpPermissions :: FileMode
- ensurePermissions :: FilePath -> FilePermissions -> IO (Result ())
- safeRenameFile :: FilePermissions -> FilePath -> FilePath -> IO (Result ())
Debug functions
debugFn :: Show b => (a -> b) -> a -> aSource
Displays a modified form of the second parameter before returning it.
Miscellaneous
applyIf :: Bool -> (a -> a) -> a -> aSource
Apply the function if condition holds, otherwise use default value.
ensureQuoted :: String -> StringSource
Ensure a value is quoted if needed.
Mathematical functions
data Statistics Source
Abstract type of statistical accumulations. They behave as if the given statistics were computed on the list of values, but they allow a potentially more efficient update of a given value.
Constructors
| SumStatistics Double | |
| StdDevStatistics Double Double Double |
Instances
| Show Statistics |
getSumStatistics :: [Double] -> StatisticsSource
Get a statistics that sums up the values.
getStdDevStatistics :: [Double] -> StatisticsSource
Get a statistics for the standard deviation.
getStatisticValue :: Statistics -> DoubleSource
Obtain the value of a statistics.
updateStatistics :: Statistics -> (Double, Double) -> StatisticsSource
In a given statistics replace on value by another. This will only give meaningful results, if the original value was actually part of the statistics.
Logical functions
Arguments
| :: Bool | condition |
| -> a | "then" result |
| -> a | "else" result |
| -> a | "then" or else result depending on the condition |
"if" as a function, rather than as syntactic sugar.
Parsing utility functions
parseChoices :: Monad m => String -> String -> [(a, String)] -> m aSource
tryRead :: (Monad m, Read a) => String -> String -> m aSource
Safe read function returning data encapsulated in a Result.
formatTable :: [[String]] -> [Bool] -> [[String]]Source
Format a table of strings to maintain consistent length.
printTable :: String -> [String] -> [[String]] -> [Bool] -> StringSource
Constructs a printable table from given header and rows
parseUnitValue :: Monad m => Bool -> String -> m RationalSource
parseUnitEx :: (Monad m, Integral a, Read a) => Bool -> String -> m aSource
parseUnit :: (Monad m, Integral a, Read a) => String -> m aSource
Tries to extract number and scale from the given string.
Input must be in the format NUMBER+ SPACE* [UNIT]. If no unit is specified, it defaults to MiB. Return value is always an integral value in MiB.
parseUnitAssumeBinary :: (Monad m, Integral a, Read a) => String -> m aSource
Tries to extract a number and scale from a given string, taking all kilos to be binary.
exitWhen :: Bool -> String -> IO ()Source
Exits with an error message if the given boolean condition if true.
exitUnless :: Bool -> String -> IO ()Source
Exits with an error message unless the given boolean condition
if true, the opposite of exitWhen.
logWarningIfBad :: String -> a -> Result a -> IO aSource
tryAndLogIOError :: IO a -> String -> (a -> Result b) -> IO (Result b)Source
Try an IO interaction, log errors and unfold as a Result.
extractKey :: [Either Integer String] -> String -> ([Either Integer String], String)Source
niceSort :: [String] -> [String]Source
Sort a list of strings based on digit and non-digit groupings.
Given a list of names [ this function
will sort the list in the logical order a1, a10, a11, a2][.
a1, a2, a10, a11]
The sort algorithm breaks each name in groups of either only-digits or no-digits, and sorts based on each group.
Internally, this is not implemented via regexes (like the Python
version), but via actual splitting of the string in sequences of
either digits or everything else, and converting the digit sequences
in Left Integer and the non-digit ones in Right String, at which
point sorting becomes trivial due to the built-in Either ordering;
we only need one extra step of dropping the key at the end.
niceSortKey :: (a -> String) -> [a] -> [a]Source
Key-version of niceSort. We use sortBy and compare
since we don't want to add an ordering constraint on the a type,
hence the need to only compare the first element of the (key, a)
tuple.
on fst
rStripSpace :: String -> StringSource
Strip space characthers (including newline). As this is expensive, should only be run on small strings.
Returns a random UUID. This is a Linux-specific method as it uses the /proc filesystem.
getCurrentTime :: IO IntegerSource
Returns the current time as an Integer representing the number
of seconds from the Unix epoch.
getCurrentTimeUSec :: IO IntegerSource
Returns the current time as an Integer representing the number
of microseconds from the Unix epoch (hence the need for Integer).
clockTimeToString :: ClockTime -> StringSource
Convert a ClockTime into a (seconds-only) timestamp.
chompPrefix :: String -> String -> Maybe StringSource
Strip a prefix from a string, allowing the last character of the prefix (which is assumed to be a separator) to be absent from the string if the string terminates there.
>>> chompPrefix "foo:bar:" "a:b:c" Nothing
>>> chompPrefix "foo:bar:" "foo:bar:baz" Just "baz"
>>> chompPrefix "foo:bar:" "foo:bar:" Just ""
>>> chompPrefix "foo:bar:" "foo:bar" Just ""
>>> chompPrefix "foo:bar:" "foo:barbaz" Nothing
Arguments
| :: Int | maxWidth |
| -> String | string that needs wrapping |
| -> [String] | string "broken" in lines |
Breaks a string in lines with length <= maxWidth.
NOTE: The split is OK if:
- It doesn't break a word, i.e. the next line begins with space
(
isSpace . head $ rest) or the current line ends with space (null revExtra); - It breaks a very big word that doesn't fit anyway (
null revLine).
defaultHead :: a -> [a] -> aSource
A safer head version, with a default value.
exitIfEmpty :: String -> [a] -> IO aSource
A head version in the I/O monad, for validating parameters
without which we cannot continue.
monadicThe :: (Eq a, Monad m) => String -> [a] -> m aSource
Obtain the unique element of a list in an arbitrary monad.
splitEithers :: [Either a b] -> ([a], [b], [Bool])Source
Split an Either list into two separate lists (containing the
Left and Right elements, plus a "trail" list that allows
recombination later.
This is splitter; for recombination, look at recombineEithers.
The sum of "left" and "right" lists should be equal to the
original list length, and the trail list should be the same length
as well. The entries in the resulting lists are reversed in
comparison with the original list.
recombineEithers :: (Show a, Show b) => [a] -> [b] -> [Bool] -> Result [Either a b]Source
Recombines two "left" and "right" lists using a "trail"
list into a single Either list.
This is the counterpart to splitEithers. It does the opposite
transformation, and the output list will be the reverse of the
input lists. Since splitEithers also reverses the lists, calling
these together will result in the original list.
Mismatches in the structure of the lists (e.g. inconsistent
lengths) are represented via Bad; normally this function should
not fail, if lists are passed as generated by splitEithers.
resolveAddrHints :: Maybe AddrInfoSource
resolveAddr :: Int -> String -> IO (Result (Family, SockAddr))Source
Resolves a numeric address.
setOwnerAndGroupFromNames :: FilePath -> GanetiDaemon -> GanetiGroup -> IO ()Source
Set the owner and the group of a file (given as names, not numeric id).
formatOrdinal :: (Integral a, Show a) => a -> StringSource
Formats an integral number, appending a suffix.
atomicWriteFile :: FilePath -> String -> IO ()Source
Atomically write a file, by first writing the contents into a temporary file and then renaming it to the old position.
lockFile :: FilePath -> IO (Result ())Source
Attempt, in a non-blocking way, to obtain a lock on a given file; report back success.
buildFileStatus :: FileStatus -> FStatSource
getFStat :: FilePath -> IO FStatSource
Wrapper over buildFileStatus. This reads the data from the
filesystem and then builds our cache structure.
getFStatSafe :: FilePath -> IO FStatSource
Safe version of getFStat, that ignores IOErrors.
needsReload :: FStat -> FilePath -> IO (Maybe FStat)Source
Check if the file needs reloading
watchFileEx :: (Eq a, Eq b) => Integer -> b -> IORef b -> a -> IO a -> IO aSource
watchFile :: Eq a => FilePath -> Int -> a -> IO a -> IO aSource
Within the given timeout (in seconds), wait for for the output of the given method to change and return the new value; make use of the promise that the method will only change its value, if the given file changes on disk. If the file does not exist on disk, return immediately.
data FilePermissions Source
Type describing ownership and permissions of newly generated directories and files. All parameters are optional, with nothing meaning that the default value should be left untouched.
Constructors
| FilePermissions | |
Fields
| |
ensurePermissions :: FilePath -> FilePermissions -> IO (Result ())Source
Ensure that a given file or directory has the permissions, and possibly ownerships, as required.
safeRenameFile :: FilePermissions -> FilePath -> FilePath -> IO (Result ())Source
Safely rename a file, creating the target directory, if needed.