prometheus/rules/rules.go
Julius Volz 01f652cb4c Separate storage implementation from interfaces.
This was initially motivated by wanting to distribute the rule checker
tool under `tools/rule_checker`. However, this was not possible without
also distributing the LevelDB dynamic libraries because the tool
transitively depended on Levigo:

rule checker -> query layer -> tiered storage layer -> leveldb

This change separates external storage interfaces from the
implementation (tiered storage, leveldb storage, memory storage) by
putting them into separate packages:

- storage/metric: public, implementation-agnostic interfaces
- storage/metric/tiered: tiered storage implementation, including memory
                         and LevelDB storage.

I initially also considered splitting up the implementation into
separate packages for tiered storage, memory storage, and LevelDB
storage, but these are currently so intertwined that it would be another
major project in itself.

The query layers and most other parts of Prometheus now have notion of
the storage implementation anymore and just use whatever implementation
they get passed in via interfaces.

The rule_checker is now a static binary :)

Change-Id: I793bbf631a8648ca31790e7e772ecf9c2b92f7a0
2014-04-16 13:30:19 +02:00

43 lines
1.7 KiB
Go

// Copyright 2013 Prometheus Team
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package rules
import (
"html/template"
clientmodel "github.com/prometheus/client_golang/model"
"github.com/prometheus/prometheus/rules/ast"
"github.com/prometheus/prometheus/storage/metric"
)
// A Rule encapsulates a vector expression which is evaluated at a specified
// interval and acted upon (currently either recorded or used for alerting).
type Rule interface {
// Name returns the name of the rule.
Name() string
// EvalRaw evaluates the rule's vector expression without triggering any
// other actions, like recording or alerting.
EvalRaw(timestamp clientmodel.Timestamp, storage metric.PreloadingPersistence) (ast.Vector, error)
// Eval evaluates the rule, including any associated recording or alerting actions.
Eval(timestamp clientmodel.Timestamp, storage metric.PreloadingPersistence) (ast.Vector, error)
// ToDotGraph returns a Graphviz dot graph of the rule.
ToDotGraph() string
// String returns a human-readable string representation of the rule.
String() string
// HTMLSnippet returns a human-readable string representation of the rule,
// decorated with HTML elements for use the web frontend.
HTMLSnippet() template.HTML
}