+{-# LANGUAGE
+ ExistentialQuantification,
+ FlexibleContexts,
+ FlexibleInstances,
+ MultiParamTypeClasses,
+ OverlappingInstances,
+ TypeFamilies,
+ UndecidableInstances
+ #-}
+{-# LANGUAGE QuasiQuotes #-} -- DELETE THIS
module Database.RRDtool.Create
- ( DataSource(..)
+ ( DataSource
+ , ExternalDSType(..)
+ , ExternalDataSource(..)
+ , ComputedDataSource(..)
, createRRD
-- Data.HList
- , (.*.)
- , HNil(..)
+ , (.&.)
+ , Nil(..)
-- Database.RRDtool.Expression
, Constant(..)
- , IsVarName(..)
+ , IsVarName
, Variable(..)
, CommonUnaryOp(..)
, CommonBinaryOp(..)
where
import Data.HList
+import Data.HList.Graph
import Data.Time.Clock
import Data.Time.Clock.POSIX
import Database.RRDtool.Expression
+import Types.Data.Bool
-- |A single RRD can accept input from several data sources (DS), for
-- 32bit counter, DERIVE with @'dsMin' = 0@ is probably preferable. If
-- you are using a 64bit counter, just about any max setting will
-- eliminate the possibility of mistaking a reset for a counter wrap.
-data DataSource
- = -- |GAUGE is for things like temperatures or number of people in
- -- a room or the value of a RedHat share.
- GAUGE {
+class DataSource ds where
+ type DSName ds
+
+data ExternalDSType
+ = GAUGE -- ^GAUGE is for things like temperatures or number of
+ -- people in a room or the value of a RedHat share.
+ | COUNTER -- ^COUNTER is for continuous incrementing counters
+ -- like the ifInOctets counter in a router. The COUNTER
+ -- data source assumes that the counter never
+ -- decreases, except when a counter overflows. The
+ -- update function takes the overflow into account. The
+ -- counter is stored as a per-second rate. When the
+ -- counter overflows, RRDtool checks if the overflow
+ -- happened at the 32bit or 64bit border and acts
+ -- accordingly by adding an appropriate value to the
+ -- result.
+ | DERIVE -- ^DERIVE will store the derivative of the line going
+ -- from the last to the current value of the data
+ -- source. This can be useful for gauges, for example,
+ -- to measure the rate of people entering or leaving a
+ -- room. Internally, derive works exactly like COUNTER
+ -- but without overflow checks. So if your counter does
+ -- not reset at 32 or 64 bit you might want to use
+ -- DERIVE and combine it with a 'dsMin' value of 0.
+ | ABSOLUTE -- ^ABSOLUTE is for counters which get reset upon
+ -- reading. This is used for fast counters which tend
+ -- to overflow. So instead of reading them normally you
+ -- reset them after every read to make sure you have a
+ -- maximum time available before the next
+ -- overflow. Another usage is for things you count like
+ -- number of messages since the last update.
+ deriving (Show, Eq, Ord)
+
+data ExternalDataSource vn
+ = ExternalDataSource {
-- |The name you will use to reference this particular data
- -- source from an RRD. A ds-name must be 1 to 19 characters
+ -- source from an RRD. A ds name must be 1 to 19 characters
-- long in the characters @[a-zA-Z0-9_]@.
- dsName :: !String
- -- |Defines the maximum number of seconds that may
- -- pass between two updates of this data source before the
- -- value of the data source is assumed to be @*UNKNOWN*@.
- , dsHeartbeat :: !NominalDiffTime
- -- |'dsMin' and 'dsMax' Define the expected range values for
- -- data supplied by a data source. If 'dsMin' and\/or 'dsMax'
+ edsName :: !vn
+ -- |The type of this data source.
+ , edsType :: !ExternalDSType
+ -- |Defines the maximum number of seconds that may pass
+ -- between two updates of this data source before the value of
+ -- the data source is assumed to be @*UNKNOWN*@.
+ , edsHeartbeat :: !NominalDiffTime
+ -- |'edsMin' and 'edsMax' Define the expected range values for
+ -- data supplied by a data source. If 'edsMin' and\/or 'edsMax'
-- any value outside the defined range will be regarded as
- -- @*UNKNOWN*@. If you do not know or care about 'dsMin' and
- -- 'dsMax', set them to 'Nothing' for unknown. Note that
- -- 'dsMin' and 'dsMax' always refer to the processed values of
+ -- @*UNKNOWN*@. If you do not know or care about 'edsMin' and
+ -- 'edsMax', set them to 'Nothing' for unknown. Note that
+ -- 'edsMin' and 'edsMax' always refer to the processed values of
-- the DS. For a traffic-'COUNTER' type DS this would be the
-- maximum and minimum data-rate expected from the device.
--
-- available, always set the min and\/or max properties. This
-- will help RRDtool in doing a simple sanity check on the
-- data supplied when running update.
- , dsMin :: !(Maybe Double)
- -- |See 'dsMin'.
- , dsMax :: !(Maybe Double)
- }
- -- |COUNTER is for continuous incrementing counters like the
- -- ifInOctets counter in a router. The COUNTER data source assumes
- -- that the counter never decreases, except when a counter
- -- overflows. The update function takes the overflow into
- -- account. The counter is stored as a per-second rate. When the
- -- counter overflows, RRDtool checks if the overflow happened at
- -- the 32bit or 64bit border and acts accordingly by adding an
- -- appropriate value to the result.
- | COUNTER {
- dsName :: !String
- , dsHeartbeat :: !NominalDiffTime
- , dsMin :: !(Maybe Double)
- , dsMax :: !(Maybe Double)
- }
- -- |DERIVE will store the derivative of the line going from the
- -- last to the current value of the data source. This can be
- -- useful for gauges, for example, to measure the rate of people
- -- entering or leaving a room. Internally, derive works exactly
- -- like COUNTER but without overflow checks. So if your counter
- -- does not reset at 32 or 64 bit you might want to use DERIVE and
- -- combine it with a 'dsMin' value of 0.
- | DERIVE {
- dsName :: !String
- , dsHeartbeat :: !NominalDiffTime
- , dsMin :: !(Maybe Double)
- , dsMax :: !(Maybe Double)
- }
- -- |ABSOLUTE is for counters which get reset upon reading. This is
- -- used for fast counters which tend to overflow. So instead of
- -- reading them normally you reset them after every read to make
- -- sure you have a maximum time available before the next
- -- overflow. Another usage is for things you count like number of
- -- messages since the last update.
- | ABSOLUTE {
- dsName :: !String
- , dsHeartbeat :: !NominalDiffTime
- , dsMin :: !(Maybe Double)
- , dsMax :: !(Maybe Double)
- }
- -- |COMPUTE is for storing the result of a formula applied to
- -- other data sources in the RRD. This data source is not supplied
- -- a value on update, but rather its Primary Data Points (PDPs)
- -- are computed from the PDPs of the data sources according to the
- -- rpn-expression that defines the formula. Consolidation
- -- functions are then applied normally to the PDPs of the COMPUTE
- -- data source (that is the rpn-expression is only applied to
- -- generate PDPs). In database software, such data sets are
- -- referred to as \"virtual\" or \"computed\" columns.
- --
- -- FIXME: doc links
- | forall a. IsCommonExpr a => COMPUTE {
- dsName :: !String
+ , edsMin :: !(Maybe Double)
+ -- |See 'edsMin'.
+ , edsMax :: !(Maybe Double)
+ }
+ deriving (Show, Eq, Ord)
+
+instance ( IsVarName vn ~ True
+ )
+ => DataSource (ExternalDataSource vn)
+ where
+ type DSName (ExternalDataSource vn) = vn
+
+type instance MentionedVars (ExternalDataSource vn) = Nil
+
+-- |ComputedDataSource is for storing the result of a formula applied
+-- to other data sources in the RRD. This data source is not supplied
+-- a value on update, but rather its Primary Data Points (PDPs) are
+-- computed from the PDPs of the data sources according to the
+-- rpn-expression that defines the formula. Consolidation functions
+-- are then applied normally to the PDPs of the COMPUTE data source
+-- (that is the rpn-expression is only applied to generate PDPs). In
+-- database software, such data sets are referred to as \"virtual\" or
+-- \"computed\" columns.
+--
+-- FIXME: doc links
+data ComputedDataSource vn e
+ = ComputedDataSource {
+ -- |See 'edsName'
+ cdsName :: !vn
-- |rpn-expression defines the formula used to compute the
-- PDPs of a COMPUTE data source from other data sources in
-- the same \<RRD\>. It is similar to defining a CDEF argument
-- graph command.
--
-- FIXME: doc links
- , dsExpr :: !a
+ , cdsExpr :: !e
}
+ deriving (Show, Eq, Ord)
-dsTest :: DataSource
-dsTest = COMPUTE {
- dsName = "foo"
--- , dsExpr = Previous :<: Const 100
--- , dsExpr = Var "foo" :<: Const 100
- , dsExpr = AverageOf (Const 100 .*. Const 200 .*. HNil)
+instance ( IsVarName vn ~ True
+ , IsCommonExpr e ~ True
+ )
+ => DataSource (ComputedDataSource vn e)
+ where
+ type DSName (ComputedDataSource vn e) = vn
+
+type instance MentionedVars (ComputedDataSource vn e) = MentionedVars e
+
+{-
+dsTest = ComputedDataSource {
+ cdsName = "foo"
+-- , cdsExpr = Previous :<: Const 100
+-- , cdsExpr = Var "foo" :<: Const 100
+ , cdsExpr = AverageOf (Const 100 .*. Const 200 .*. Nil)
}
+-}
+
+-- |The name of the RRD you want to create. RRD files should end with
+-- the extension @.rrd@. However, RRDtool will accept any filename.
+newtype RRDPath = RRDPath FilePath
+
+-- |Do not clobber an existing file of the same name.
+data KeepOldRRD = KeepOldRRD
+
+-- |Specifies the time in seconds since @1970-01-01 UTC@ when the
+-- first value should be added to the RRD. RRDtool will not accept any
+-- data timed before or at the time specified. (default: @now - 10s@)
+newtype RRDStartTime = RRDStartTime POSIXTime
+
+-- |Specifies the base interval in seconds with which data will be fed
+-- into the RRD. (default: 300 sec)
+newtype RRDInterval = RRDInterval NominalDiffTime
+
+class RRDSpec s
+instance ( Occurs RRDPath s
+ , OccursOpt KeepOldRRD s
+ , OccursOpt RRDStartTime s
+ , OccursOpt RRDInterval s
+ , Occurs RRDDataSources s
+ )
+ => RRDSpec s
+
+class NonEmptyDSList l
+instance ( DSList l
+ , DataSource d
+ )
+ => NonEmptyDSList (Cons d l)
+
+class DSList l
+instance DSList Nil
+instance ( DSList l
+ , DataSource d
+ )
+ => DSList (Cons d l)
+
+data RRDDataSources
+ = forall l.
+ ( NonEmptyDSList l
+ , Graph l -- FIXME: this constraint is too weak
+ )
+ => RRDDataSources l
+
+-- RRDDataSources is a graph.
+instance ( DSList g
+ , NodeSet g
+ , NoDuplicates (Map NodeIDA g)
+ )
+ => Graph g
+ where
+ type Empty g = Nil
+ type Nodes g = g
+
+type instance IsEmpty Nil = True
+type instance IsEmpty (Cons e l) = False
+
+instance ( NodeIDSet (MentionedVars d)
+ , DataSource d
+ )
+ => Node d
+ where
+ type NodeID d = DSName d
+ type LinksFrom d = MentionedVars d
-- |The 'createRRD' function lets you set up new Round Robin Database
-- (RRD) files. The file is created at its final, full size and filled
-- with @*UNKNOWN*@ data.
-createRRD
- :: FilePath -- ^The name of the RRD you want to create. RRD files
- -- should end with the extension @.rrd@. However,
- -- RRDtool will accept any filename.
- -> Bool -- ^Do not clobber an existing file of the same name.
- -> Maybe POSIXTime -- ^Specifies the time in seconds since
- -- @1970-01-01 UTC@ when the first value should
- -- be added to the RRD. RRDtool will not accept
- -- any data timed before or at the time
- -- specified. (default: @now - 10s@)
- -> Maybe NominalDiffTime -- ^Specifies the base interval in
- -- seconds with which data will be fed
- -- into the RRD. (default: 300 sec)
- -> [DataSource] -- ^Data sources to accept input from.
- -> IO ()
+createRRD :: ( RRDSpec s
+ )
+ => s -> IO ()
createRRD = error "FIXME"
+
+testMain :: IO ()
+testMain = let s = RRDPath "test.rrd" .&.
+ KeepOldRRD .&.
+ RRDDataSources testDSList .&.
+ Nil
+ in
+ createRRD s
+
+testDSList = let a = ComputedDataSource {
+ cdsName = [$hString|foo|]
+ , cdsExpr = Var [$hString|bar|]
+ }
+ b = ComputedDataSource {
+ cdsName = [$hString|bar|]
+ , cdsExpr = Var [$hString|foo|] -- shouldn't typecheck!
+ }
+ c = ComputedDataSource {
+ cdsName = [$hString|baz|]
+ , cdsExpr = Var [$hString|foo|] -- should typecheck!
+ }
+ in a .&. b .&. Nil
\ No newline at end of file
projects / hs-rrdtool.git / blobdiff