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