| Safe Haskell | None |
|---|
Ganeti.Query.Filter
Description
Implementation of the Ganeti Query2 filterning.
The filtering of results should be done in two phases.
In the first phase, before contacting any remote nodes for runtime
data, the filtering should be executed with Nothing for the runtime
context. This will make all non-runtime filters filter correctly,
whereas all runtime filters will respond successfully. As described in
the Python version too, this makes for example Or filters very
inefficient if they contain runtime fields.
Once this first filtering phase has been done, we hopefully eliminated
some remote nodes out of the list of candidates, we run the remote
data gathering, and we evaluate the filter again, this time with a
Just runtime context. This will make all filters work correctly.
Note that the second run will re-evaluate the config/simple fields, without caching; this is not perfect, but we consider config accesses very cheap (and the configuration snapshot we have won't change between the two runs, hence we will not get inconsistent results).
Synopsis
- compileFilter :: FieldMap a b -> Filter FilterField -> ErrorResult (Filter (FieldGetter a b, QffMode))
- qffField :: QffMode -> JSValue -> ErrorResult JSValue
- wrapGetter :: ConfigData -> Maybe b -> a -> (FieldGetter a b, QffMode) -> (JSValue -> ErrorResult Bool) -> MaybeT ErrorResult Bool
- trueFilter :: JSValue -> ErrorResult Bool
- type Comparator = forall a. (Eq a, Ord a) => a -> a -> Bool
- eqFilter :: QffMode -> FilterValue -> JSValue -> ErrorResult Bool
- binOpFilter :: Comparator -> FilterValue -> JSValue -> ErrorResult Bool
- regexpFilter :: FilterRegex -> JSValue -> ErrorResult Bool
- containsFilter :: FilterValue -> JSValue -> ErrorResult Bool
- data Comparison
- toCompFun :: Comparison -> Comparator
- data FilterOp field val where
- Truth :: FilterOp field ()
- Comp :: Comparison -> FilterOp field FilterValue
- Regex :: FilterOp field FilterRegex
- Contains :: FilterOp field FilterValue
- evaluateFilterM :: (Monad m, Applicative m) => (forall val. FilterOp field val -> field -> val -> m Bool) -> Filter field -> m Bool
- evaluateQueryFilter :: ConfigData -> Maybe b -> a -> Filter (FieldGetter a b, QffMode) -> ErrorResult Bool
- evaluateFilterJSON :: Filter JSValue -> ErrorResult Bool
- tryGetter :: ConfigData -> Maybe b -> a -> FieldGetter a b -> Maybe ResultEntry
- requestedNames :: FilterField -> Filter FilterField -> Maybe [FilterValue]
- makeSimpleFilter :: String -> [Either String Integer] -> Filter FilterField
Documentation
compileFilter :: FieldMap a b -> Filter FilterField -> ErrorResult (Filter (FieldGetter a b, QffMode)) Source #
Compiles a filter based on field names to one based on getters.
qffField :: QffMode -> JSValue -> ErrorResult JSValue Source #
Processes a field value given a QffMode.
wrapGetter :: ConfigData -> Maybe b -> a -> (FieldGetter a b, QffMode) -> (JSValue -> ErrorResult Bool) -> MaybeT ErrorResult Bool Source #
Wraps a getter, filter pair. If the getter is FieldRuntime but
we don't have a runtime context, we skip the filtering, returning
Nothing in the MaybeT. Otherwise, we pass the actual value to the filter.
trueFilter :: JSValue -> ErrorResult Bool Source #
Helper to evaluate a filter getter (and the value it generates) in a boolean context.
type Comparator = forall a. (Eq a, Ord a) => a -> a -> Bool Source #
A type synonim for a rank-2 comparator function. This is used so
that we can pass the usual <=, >, == functions to binOpFilter
and for them to be used in multiple contexts.
eqFilter :: QffMode -> FilterValue -> JSValue -> ErrorResult Bool Source #
Equality checker.
This will handle hostnames correctly, if the mode is set to
QffHostname.
binOpFilter :: Comparator -> FilterValue -> JSValue -> ErrorResult Bool Source #
Helper to evaluate a filder getter (and the value it generates) in a boolean context. Note the order of arguments is reversed from the filter definitions (due to the call chain), make sure to compare in the reverse order too!.
regexpFilter :: FilterRegex -> JSValue -> ErrorResult Bool Source #
Implements the RegexpFilter matching.
containsFilter :: FilterValue -> JSValue -> ErrorResult Bool Source #
Implements the ContainsFilter matching.
data Comparison Source #
Ways we can compare things in the filter language.
Instances
| Eq Comparison # | |
Defined in Ganeti.Query.Filter | |
| Ord Comparison # | |
Defined in Ganeti.Query.Filter Methods compare :: Comparison -> Comparison -> Ordering (<) :: Comparison -> Comparison -> Bool (<=) :: Comparison -> Comparison -> Bool (>) :: Comparison -> Comparison -> Bool (>=) :: Comparison -> Comparison -> Bool max :: Comparison -> Comparison -> Comparison min :: Comparison -> Comparison -> Comparison | |
| Show Comparison # | |
Defined in Ganeti.Query.Filter Methods showsPrec :: Int -> Comparison -> ShowS show :: Comparison -> String showList :: [Comparison] -> ShowS | |
toCompFun :: Comparison -> Comparator Source #
Turns a comparison into the corresponding Haskell function.
data FilterOp field val where Source #
Operations in the leaves of the Ganeti filter language.
Constructors
| Truth :: FilterOp field () | |
| Comp :: Comparison -> FilterOp field FilterValue | |
| Regex :: FilterOp field FilterRegex | |
| Contains :: FilterOp field FilterValue |
evaluateFilterM :: (Monad m, Applicative m) => (forall val. FilterOp field val -> field -> val -> m Bool) -> Filter field -> m Bool Source #
Checks if a filter matches.
The leaves of the filter are evaluated against an object using the passed
opFun; that is why the object need not be passed in.
The field type describes the "accessors" that are used to query
values from the object; those values are to be matched against the
val type in the filter leaves.
Useful monads m for this are ErrorResult and Maybe.
evaluateQueryFilter :: ConfigData -> Maybe b -> a -> Filter (FieldGetter a b, QffMode) -> ErrorResult Bool Source #
Verifies if a given item passes a filter. The runtime context might be missing, in which case most of the filters will consider this as passing the filter.
evaluateFilterJSON :: Filter JSValue -> ErrorResult Bool Source #
Evaluates a Filter on a JSON object.
tryGetter :: ConfigData -> Maybe b -> a -> FieldGetter a b -> Maybe ResultEntry Source #
Runs a getter with potentially missing runtime context.
requestedNames :: FilterField -> Filter FilterField -> Maybe [FilterValue] Source #
Computes the requested names, if only names were requested (and
with equality). Otherwise returns Nothing.
makeSimpleFilter :: String -> [Either String Integer] -> Filter FilterField Source #
Builds a simple filter from a list of names.