diff --git a/lib/System/Nagios/Plugin.hs b/lib/System/Nagios/Plugin.hs --- a/lib/System/Nagios/Plugin.hs +++ b/lib/System/Nagios/Plugin.hs @@ -5,219 +5,10 @@ module System.Nagios.Plugin ( - CheckStatus(..), - CheckResult, - UOM(..), - PerfValue(..), - NagiosPlugin, - runNagiosPlugin, - runNagiosPlugin', - addPerfDatum, - addResult, - checkStatus, - checkInfo, - worstResult, - PerfDatum, - finishState -) where - -import Control.Applicative -import Control.Monad.Catch -import Control.Monad.State.Lazy -import Data.Bifunctor -import Data.Int -import Data.Monoid -import Data.Nagios.Perfdata.Metric (UOM (..)) -import Data.Text (Text) -import qualified Data.Text as T -import qualified Data.Text.IO as T -import System.Exit - --- | Nagios plugin exit statuses. Ordered by priority - --- OK < Warning < Critical < Unknown, which correspond to plugin exit --- statuses of 0, 1, 2, and 3 respectively. -data CheckStatus = OK -- ^ Check executed successfully and - -- detected no service problems. - | Warning -- ^ Nothing's actually broken but this - -- should be followed up. - | Critical -- ^ Check executed successfully and detected - -- a service failure. - | Unknown -- ^ Check unable to determine service - -- status. - deriving (Enum, Eq, Ord) - -instance Show CheckStatus where - show OK = "OK" - show Warning = "WARNING" - show Critical = "CRITICAL" - show Unknown = "UNKNOWN" - --- | A CheckResult is the exit status of the plugin combined with the --- plugin's info text. A `NagiosPlugin` which exits with --- --- > CheckResult (Critical "entropy decreasing in closed system") --- --- as its peak-badness CheckResult (and no 'PerfDatum's) will a) exit with --- status 2 and b) output the text "CRITICAL: entropy decreasing in closed --- system". -newtype CheckResult = CheckResult - { unCheckResult :: (CheckStatus, Text) } - deriving (Eq, Ord, Show) - --- | Extract the return status from a 'CheckResult' -checkStatus :: CheckResult -> CheckStatus -checkStatus = fst . unCheckResult - --- | Extract the infotext from a 'CheckResult'. -checkInfo :: CheckResult -> Text -checkInfo = snd . unCheckResult - --- | Value of a performance metric. -data PerfValue = RealValue Double | IntegralValue Int64 - deriving Eq - -instance Show PerfValue where - show (RealValue x) = show x - show (IntegralValue x) = show x - --- | One performance metric. A plugin will output zero or more of these, --- whereupon Nagios generally passes them off to an external system such --- as or --- . --- The thresholds are purely informative (designed to be graphed), and --- do not affect alerting; likewise with `_min` and `_max`. -data PerfDatum = PerfDatum - { _label :: Text -- ^ Name of quantity being measured. - , _value :: PerfValue -- ^ Measured value, integral or real. - , _uom :: UOM -- ^ Unit of measure; 'NullUOM' is fine here. - , _min :: Maybe PerfValue -- ^ Measured quantity cannot be lower than this. - , _max :: Maybe PerfValue -- ^ Measured quantity cannot be higher than this. - , _warn :: Maybe PerfValue -- ^ Warning threshold for graphing. - , _crit :: Maybe PerfValue -- ^ Critical threshold for graphing. - } - deriving (Eq, Show) - --- | Current check results/perfdata. If the check suddenly dies, the --- 'worst' of the CheckResults (and all the PerfDatums) will be used --- to determine the exit state. -type CheckState = ([CheckResult], [PerfDatum]) - -newtype NagiosPlugin a = NagiosPlugin - { - unNagiosPlugin :: StateT CheckState IO a - } deriving (Functor, Applicative, Monad, MonadIO, MonadState CheckState, MonadCatch, MonadThrow) - --- | Execute a Nagios check. The program will terminate at the check's --- completion. A default status will provided if none is given. -runNagiosPlugin :: NagiosPlugin a -> IO () -runNagiosPlugin check = do - (_, st) <- runNagiosPlugin' $ catch check panic - finishWith st - where - panic :: SomeException -> NagiosPlugin a - panic = liftIO . finishWith . panicState - --- | Execute a Nagios check as with 'runNagiosPlugin', but return its --- final state rather than terminating. -runNagiosPlugin' :: NagiosPlugin a -> IO (a, CheckState) -runNagiosPlugin' a = runStateT (unNagiosPlugin a) mempty - --- | Insert a result. Only the 'CheckStatus' with the most 'badness' --- will determine the check's exit status. -addResult :: CheckStatus -> Text -> NagiosPlugin () -addResult s t = - modify (first (CheckResult (s, t) :)) - --- | Insert a performance metric into the list the check will output. -addPerfDatum :: - Text -- ^ Name of the quantity being measured. - -> PerfValue -- ^ Measured value. - -> UOM -- ^ Unit of the measured value. - -> Maybe PerfValue -- ^ Minimum threshold. - -> Maybe PerfValue -- ^ Maximum threshold. - -> Maybe PerfValue -- ^ Warning threshold. - -> Maybe PerfValue -- ^ Critical threshold. - -> NagiosPlugin () -addPerfDatum info val uom min' max' warn crit = - addPerfDatum' $ PerfDatum info val uom min' max' warn crit - where - addPerfDatum' pd = do - (rs, pds) <- get - put (rs, pd : pds) - --- | The result which will be used if no other results have been --- provided. -defaultResult :: CheckResult -defaultResult = CheckResult (Unknown, T.pack "no check result specified") - --- | The state the plugin will exit with if an uncaught exception occurs. --- within the plugin. -panicState :: SomeException -> CheckState -panicState = (,[]) . return . CheckResult . panicResult - where - panicResult e = (Critical, - T.pack ("unhandled exception: " ++ show e)) - --- | Returns result with greatest badness, or a default UNKNOWN result --- if no results have been specified. -worstResult :: [CheckResult] -> CheckResult -worstResult rs - | null rs = defaultResult - | otherwise = maximum rs - --- | Render a plugin's performance data according to the --- . -fmtPerfData :: [PerfDatum] -> Text -fmtPerfData = T.intercalate " " . map fmtPerfDatum - where - fmtPerfDatum PerfDatum{..} = T.concat - [ _label - , "=" - , T.pack (show _value) - , T.pack (show _uom) - , fmtThreshold _min - , fmtThreshold _max - , fmtThreshold _warn - , fmtThreshold _crit - ] - - fmtThreshold Nothing = ";" - fmtThreshold (Just t) = T.pack $ ";" <> show t - --- | Render a plugin's result according to the --- . --- --- FIXME: not actually true yet, need to implement verbose output. -fmtResults :: [CheckResult] -> Text -fmtResults = fmtResult . worstResult - where - fmtResult (CheckResult (s,t)) = - T.pack (show s) <> ": " <> t - --- | Given a check's final state, return the status and output it would --- exit with. -finishState :: CheckState -> (CheckStatus, Text) -finishState (rs, pds) = - let worst = worstResult rs - output = fmtResults rs <> perfdataPart pds - in (checkStatus worst, output) - where - perfdataPart [] = "" - perfdataPart xs = " | " <> fmtPerfData xs - --- | Calculate our final result, print output and then exit with the --- appropriate status. -finishWith :: MonadIO m => CheckState -> m a -finishWith = liftIO . exitWithStatus . finishState + module System.Nagios.Plugin.Check, + module System.Nagios.Plugin.Range --- | Output the final check result to stdout and then terminate the --- check program with the appropriate exit status. -exitWithStatus :: (CheckStatus, Text) -> IO a -exitWithStatus (OK, t) = T.putStrLn t >> exitSuccess -exitWithStatus (r, t) = T.putStrLn t >> exitWith (ExitFailure $ fromEnum r) +) where --- | A 'Range' is a combination of a lower boundary and an upper boundary (x,y). --- An 'AcceptableRange' asserts that measured values between x and y --- imply that nothing is wrong; an UnacceptableRange implies the inverse. -data Range = AcceptableRange PerfValue PerfValue - | UnacceptableRange PerfValue PerfValue +import System.Nagios.Plugin.Check +import System.Nagios.Plugin.Range diff --git a/lib/System/Nagios/Plugin/Check.hs b/lib/System/Nagios/Plugin/Check.hs new file mode 100644 --- /dev/null +++ b/lib/System/Nagios/Plugin/Check.hs @@ -0,0 +1,230 @@ +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE RecordWildCards #-} +{-# LANGUAGE TupleSections #-} + +module System.Nagios.Plugin.Check +( + CheckStatus(..), + CheckResult, + UOM(..), + PerfValue(..), + NagiosPlugin, + runNagiosPlugin, + runNagiosPlugin', + addPerfDatum, + addBarePerfDatum, + addResult, + checkStatus, + checkInfo, + worstResult, + PerfDatum, + finishState +) where + +import Control.Applicative +import Control.Monad.Catch +import Control.Monad.State.Lazy +import Data.Bifunctor +import Data.Int +import Data.Monoid +import Data.Nagios.Perfdata.Metric (UOM (..)) +import Data.Text (Text) +import qualified Data.Text as T +import qualified Data.Text.IO as T +import System.Exit + +-- | Nagios plugin exit statuses. Ordered by priority - +-- OK < Warning < Critical < Unknown, which correspond to plugin exit +-- statuses of 0, 1, 2, and 3 respectively. +data CheckStatus = OK -- ^ Check executed successfully and + -- detected no service problems. + | Warning -- ^ Nothing's actually broken but this + -- should be followed up. + | Critical -- ^ Check executed successfully and detected + -- a service failure. + | Unknown -- ^ Check unable to determine service + -- status. + deriving (Enum, Eq, Ord) + +instance Show CheckStatus where + show OK = "OK" + show Warning = "WARNING" + show Critical = "CRITICAL" + show Unknown = "UNKNOWN" + +-- | A CheckResult is the exit status of the plugin combined with the +-- plugin's info text. A `NagiosPlugin` which exits with +-- +-- > CheckResult (Critical "entropy decreasing in closed system") +-- +-- as its peak-badness CheckResult (and no 'PerfDatum's) will a) exit with +-- status 2 and b) output the text "CRITICAL: entropy decreasing in closed +-- system". +newtype CheckResult = CheckResult + { unCheckResult :: (CheckStatus, Text) } + deriving (Eq, Ord, Show) + +-- | Extract the return status from a 'CheckResult' +checkStatus :: CheckResult -> CheckStatus +checkStatus = fst . unCheckResult + +-- | Extract the infotext from a 'CheckResult'. +checkInfo :: CheckResult -> Text +checkInfo = snd . unCheckResult + +-- | Value of a performance metric. +data PerfValue = RealValue Double | IntegralValue Int64 + deriving Eq + +instance Show PerfValue where + show (RealValue x) = show x + show (IntegralValue x) = show x + +-- | One performance metric. A plugin will output zero or more of these, +-- whereupon Nagios generally passes them off to an external system such +-- as or +-- . +-- The thresholds are purely informative (designed to be graphed), and +-- do not affect alerting; likewise with `_min` and `_max`. +data PerfDatum = PerfDatum + { _label :: Text -- ^ Name of quantity being measured. + , _value :: PerfValue -- ^ Measured value, integral or real. + , _uom :: UOM -- ^ Unit of measure; 'NullUOM' is fine here. + , _min :: Maybe PerfValue -- ^ Measured quantity cannot be lower than this. + , _max :: Maybe PerfValue -- ^ Measured quantity cannot be higher than this. + , _warn :: Maybe PerfValue -- ^ Warning threshold for graphing. + , _crit :: Maybe PerfValue -- ^ Critical threshold for graphing. + } + deriving (Eq, Show) + +-- | Current check results/perfdata. If the check suddenly dies, the +-- 'worst' of the CheckResults (and all the PerfDatums) will be used +-- to determine the exit state. +type CheckState = ([CheckResult], [PerfDatum]) + +newtype NagiosPlugin a = NagiosPlugin + { + unNagiosPlugin :: StateT CheckState IO a + } deriving (Functor, Applicative, Monad, MonadIO, MonadState CheckState, MonadCatch, MonadThrow) + +-- | Execute a Nagios check. The program will terminate at the check's +-- completion. A default status will provided if none is given. +runNagiosPlugin :: NagiosPlugin a -> IO () +runNagiosPlugin check = do + (_, st) <- runNagiosPlugin' $ catch check panic + finishWith st + where + panic :: SomeException -> NagiosPlugin a + panic = liftIO . finishWith . panicState + +-- | Execute a Nagios check as with 'runNagiosPlugin', but return its +-- final state rather than terminating. +runNagiosPlugin' :: NagiosPlugin a -> IO (a, CheckState) +runNagiosPlugin' a = runStateT (unNagiosPlugin a) mempty + +-- | Insert a result. Only the 'CheckStatus' with the most 'badness' +-- will determine the check's exit status. +addResult :: CheckStatus -> Text -> NagiosPlugin () +addResult s t = + modify (first (CheckResult (s, t) :)) + +-- | Insert a performance metric into the list the check will output. +addPerfDatum :: + Text -- ^ Name of the quantity being measured. + -> PerfValue -- ^ Measured value. + -> UOM -- ^ Unit of the measured value. + -> Maybe PerfValue -- ^ Minimum threshold. + -> Maybe PerfValue -- ^ Maximum threshold. + -> Maybe PerfValue -- ^ Warning threshold. + -> Maybe PerfValue -- ^ Critical threshold. + -> NagiosPlugin () +addPerfDatum info val uom min' max' warn crit = + modify (second (PerfDatum info val uom min' max' warn crit :)) + +-- | Convenience function to insert a perfdatum without thresholds for +-- min, max, warn or crit. Note that unless the range of the metric is +-- actually unbounded, specifying explicit thresholds is considered +-- good practice (it makes life easier for authors of graphing +-- packages). +-- +-- FIXME: implement thresholds properly and default to negative and +-- positive infinity for min and max here. +addBarePerfDatum :: + Text -- ^ Name of the quantity being measured. + -> PerfValue -- ^ Measured value. + -> UOM -- ^ Unit of the measured value. + -> NagiosPlugin () +addBarePerfDatum info val uom = + addPerfDatum info val uom Nothing Nothing Nothing Nothing + +-- | The result which will be used if no other results have been +-- provided. +defaultResult :: CheckResult +defaultResult = CheckResult (Unknown, T.pack "no check result specified") + +-- | The state the plugin will exit with if an uncaught exception occurs. +-- within the plugin. +panicState :: SomeException -> CheckState +panicState = (,[]) . return . CheckResult . panicResult + where + panicResult e = (Critical, + T.pack ("unhandled exception: " ++ show e)) + +-- | Returns result with greatest badness, or a default UNKNOWN result +-- if no results have been specified. +worstResult :: [CheckResult] -> CheckResult +worstResult rs + | null rs = defaultResult + | otherwise = maximum rs + +-- | Render a plugin's performance data according to the +-- . +fmtPerfData :: [PerfDatum] -> Text +fmtPerfData = T.intercalate " " . map fmtPerfDatum + where + fmtPerfDatum PerfDatum{..} = T.concat + [ _label + , "=" + , T.pack (show _value) + , T.pack (show _uom) + , fmtThreshold _min + , fmtThreshold _max + , fmtThreshold _warn + , fmtThreshold _crit + ] + + fmtThreshold Nothing = ";" + fmtThreshold (Just t) = T.pack $ ";" <> show t + +-- | Render a plugin's result according to the +-- . +-- +-- FIXME: not actually true yet, need to implement verbose output. +fmtResults :: [CheckResult] -> Text +fmtResults = fmtResult . worstResult + where + fmtResult (CheckResult (s,t)) = + T.pack (show s) <> ": " <> t + +-- | Given a check's final state, return the status and output it would +-- exit with. +finishState :: CheckState -> (CheckStatus, Text) +finishState (rs, pds) = + let worst = worstResult rs + output = fmtResults rs <> perfdataPart pds + in (checkStatus worst, output) + where + perfdataPart [] = "" + perfdataPart xs = " | " <> fmtPerfData xs + +-- | Calculate our final result, print output and then exit with the +-- appropriate status. +finishWith :: MonadIO m => CheckState -> m a +finishWith = liftIO . exitWithStatus . finishState + +-- | Output the final check result to stdout and then terminate the +-- check program with the appropriate exit status. +exitWithStatus :: (CheckStatus, Text) -> IO a +exitWithStatus (OK, t) = T.putStrLn t >> exitSuccess +exitWithStatus (r, t) = T.putStrLn t >> exitWith (ExitFailure $ fromEnum r) diff --git a/lib/System/Nagios/Plugin/Range.hs b/lib/System/Nagios/Plugin/Range.hs new file mode 100644 --- /dev/null +++ b/lib/System/Nagios/Plugin/Range.hs @@ -0,0 +1,17 @@ +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE RecordWildCards #-} +{-# LANGUAGE TupleSections #-} + +module System.Nagios.Plugin.Range +( + Range +) where + +import System.Nagios.Plugin.Check (PerfValue) + +-- | A 'Range' is a combination of a lower boundary and an upper boundary (x,y). +-- An 'AcceptableRange' asserts that measured values between x and y +-- imply that nothing is wrong; an UnacceptableRange implies the inverse. +data Range = AcceptableRange PerfValue PerfValue + | UnacceptableRange PerfValue PerfValue diff --git a/nagios-check.cabal b/nagios-check.cabal --- a/nagios-check.cabal +++ b/nagios-check.cabal @@ -1,5 +1,5 @@ name: nagios-check -version: 0.1.0.0 +version: 0.2.0 synopsis: Package for writing monitoring plugins description: Implements Nagios plugin development guidelines within a Haskell framework for writing Nagios @@ -21,7 +21,9 @@ library exposed-modules: System.Nagios.Plugin - build-depends: base >=4.7 && <5, + other-modules: System.Nagios.Plugin.Check + System.Nagios.Plugin.Range + build-depends: base >=4.5 && <5, mtl, text, bifunctors,