7 module Database.RRDtool.Create
10 , ExternalDataSource(..)
11 , ComputedDataSource(..)
18 -- Database.RRDtool.Expression
27 , VariableShiftPredictOp(..)
28 , FixedShiftPredictOp(..)
34 import Data.Time.Clock
35 import Data.Time.Clock.POSIX
36 import Database.RRDtool.Expression
37 import Types.Data.Bool
40 -- |A single RRD can accept input from several data sources (DS), for
41 -- example incoming and outgoing traffic on a specific communication
42 -- line. With the DS configuration option you must define some basic
43 -- properties of each data source you want to store in the RRD.
45 -- /NOTE on COUNTER vs DERIVE/
47 -- by Don Baarda <don.baarda@baesystems.com>
49 -- If you cannot tolerate ever mistaking the occasional counter reset
50 -- for a legitimate counter wrap, and would prefer \"Unknowns\" for
51 -- all legitimate counter wraps and resets, always use DERIVE with
52 -- @'dsMin' = 0@. Otherwise, using COUNTER with a suitable max will
53 -- return correct values for all legitimate counter wraps, mark some
54 -- counter resets as \"Unknown\", but can mistake some counter resets
55 -- for a legitimate counter wrap.
57 -- For a 5 minute step and 32-bit counter, the probability of
58 -- mistaking a counter reset for a legitimate wrap is arguably about
59 -- 0.8% per 1Mbps of maximum bandwidth. Note that this equates to 80%
60 -- for 100Mbps interfaces, so for high bandwidth interfaces and a
61 -- 32bit counter, DERIVE with @'dsMin' = 0@ is probably preferable. If
62 -- you are using a 64bit counter, just about any max setting will
63 -- eliminate the possibility of mistaking a reset for a counter wrap.
67 = GAUGE -- ^GAUGE is for things like temperatures or number of
68 -- people in a room or the value of a RedHat share.
69 | COUNTER -- ^COUNTER is for continuous incrementing counters
70 -- like the ifInOctets counter in a router. The COUNTER
71 -- data source assumes that the counter never
72 -- decreases, except when a counter overflows. The
73 -- update function takes the overflow into account. The
74 -- counter is stored as a per-second rate. When the
75 -- counter overflows, RRDtool checks if the overflow
76 -- happened at the 32bit or 64bit border and acts
77 -- accordingly by adding an appropriate value to the
79 | DERIVE -- ^DERIVE will store the derivative of the line going
80 -- from the last to the current value of the data
81 -- source. This can be useful for gauges, for example,
82 -- to measure the rate of people entering or leaving a
83 -- room. Internally, derive works exactly like COUNTER
84 -- but without overflow checks. So if your counter does
85 -- not reset at 32 or 64 bit you might want to use
86 -- DERIVE and combine it with a 'dsMin' value of 0.
87 | ABSOLUTE -- ^ABSOLUTE is for counters which get reset upon
88 -- reading. This is used for fast counters which tend
89 -- to overflow. So instead of reading them normally you
90 -- reset them after every read to make sure you have a
91 -- maximum time available before the next
92 -- overflow. Another usage is for things you count like
93 -- number of messages since the last update.
94 deriving (Show, Eq, Ord)
96 data ExternalDataSource vn
97 = ExternalDataSource {
98 -- |The name you will use to reference this particular data
99 -- source from an RRD. A ds name must be 1 to 19 characters
100 -- long in the characters @[a-zA-Z0-9_]@.
102 -- |The type of this data source.
103 , edsType :: !ExternalDSType
104 -- |Defines the maximum number of seconds that may pass
105 -- between two updates of this data source before the value of
106 -- the data source is assumed to be @*UNKNOWN*@.
107 , edsHeartbeat :: !NominalDiffTime
108 -- |'edsMin' and 'edsMax' Define the expected range values for
109 -- data supplied by a data source. If 'edsMin' and\/or 'edsMax'
110 -- any value outside the defined range will be regarded as
111 -- @*UNKNOWN*@. If you do not know or care about 'edsMin' and
112 -- 'edsMax', set them to 'Nothing' for unknown. Note that
113 -- 'edsMin' and 'edsMax' always refer to the processed values of
114 -- the DS. For a traffic-'COUNTER' type DS this would be the
115 -- maximum and minimum data-rate expected from the device.
117 -- If information on minimal\/maximal expected values is
118 -- available, always set the min and\/or max properties. This
119 -- will help RRDtool in doing a simple sanity check on the
120 -- data supplied when running update.
121 , edsMin :: !(Maybe Double)
123 , edsMax :: !(Maybe Double)
125 deriving (Show, Eq, Ord)
127 instance ( IsVarName vn ~ True
129 => DataSource (ExternalDataSource vn)
132 -- |ComputedDataSource is for storing the result of a formula applied
133 -- to other data sources in the RRD. This data source is not supplied
134 -- a value on update, but rather its Primary Data Points (PDPs) are
135 -- computed from the PDPs of the data sources according to the
136 -- rpn-expression that defines the formula. Consolidation functions
137 -- are then applied normally to the PDPs of the COMPUTE data source
138 -- (that is the rpn-expression is only applied to generate PDPs). In
139 -- database software, such data sets are referred to as \"virtual\" or
140 -- \"computed\" columns.
143 data ComputedDataSource vn e
144 = ComputedDataSource {
147 -- |rpn-expression defines the formula used to compute the
148 -- PDPs of a COMPUTE data source from other data sources in
149 -- the same \<RRD\>. It is similar to defining a CDEF argument
150 -- for the graph command. For COMPUTE data sources, the
151 -- following RPN operations are not supported: COUNT, PREV,
152 -- TIME, and LTIME. In addition, in defining the RPN
153 -- expression, the COMPUTE data source may only refer to the
154 -- names of data source listed previously in the create
155 -- command. This is similar to the restriction that CDEFs must
156 -- refer only to DEFs and CDEFs previously defined in the same
162 deriving (Show, Eq, Ord)
164 instance ( IsVarName vn ~ True
165 , IsCommonExpr e ~ True
167 => DataSource (ComputedDataSource vn e)
170 dsTest = ComputedDataSource {
172 -- , cdsExpr = Previous :<: Const 100
173 -- , cdsExpr = Var "foo" :<: Const 100
174 , cdsExpr = AverageOf (Const 100 .*. Const 200 .*. HNil)
178 -- |The name of the RRD you want to create. RRD files should end with
179 -- the extension @.rrd@. However, RRDtool will accept any filename.
180 newtype RRDPath = RRDPath FilePath
182 -- |Do not clobber an existing file of the same name.
183 data KeepOldRRD = KeepOldRRD
185 -- |Specifies the time in seconds since @1970-01-01 UTC@ when the
186 -- first value should be added to the RRD. RRDtool will not accept any
187 -- data timed before or at the time specified. (default: @now - 10s@)
188 newtype RRDStartTime = RRDStartTime POSIXTime
190 -- |Specifies the base interval in seconds with which data will be fed
191 -- into the RRD. (default: 300 sec)
192 newtype RRDInterval = RRDInterval NominalDiffTime
195 instance ( HOccurs RRDPath s
196 , HOccursOpt KeepOldRRD s
197 , HOccursOpt RRDStartTime s
198 , HOccursOpt RRDInterval s
202 -- |The 'createRRD' function lets you set up new Round Robin Database
203 -- (RRD) files. The file is created at its final, full size and filled
204 -- with @*UNKNOWN*@ data.
205 createRRD :: RRDSpec s => s -> IO ()
206 createRRD = error "FIXME"
209 testMain = let s = RRDPath "test.rrd" .&.