prometheus/storage/local/interface.go

97 lines
4.5 KiB
Go

// Copyright 2014 The Prometheus Authors
// 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 local
import (
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/storage/metric"
)
// Storage ingests and manages samples, along with various indexes. All methods
// are goroutine-safe. Storage implements storage.SampleAppender.
type Storage interface {
prometheus.Collector
// Append stores a sample in the Storage. Multiple samples for the same
// fingerprint need to be submitted in chronological order, from oldest
// to newest. When Append has returned, the appended sample might not be
// queryable immediately. (Use WaitForIndexing to wait for complete
// processing.) The implementation might remove labels with empty value
// from the provided Sample as those labels are considered equivalent to
// a label not present at all.
Append(*model.Sample) error
// NeedsThrottling returns true if the Storage has too many chunks in memory
// already or has too many chunks waiting for persistence.
NeedsThrottling() bool
// NewPreloader returns a new Preloader which allows preloading and pinning
// series data into memory for use within a query.
NewPreloader() Preloader
// MetricsForLabelMatchers returns the metrics from storage that satisfy the given
// label matchers. At least one label matcher must be specified that does not
// match the empty string.
MetricsForLabelMatchers(...*metric.LabelMatcher) map[model.Fingerprint]metric.Metric
// LastSamplePairForFingerprint returns the last sample pair for the
// provided fingerprint. If the respective time series does not exist or
// has an evicted head chunk, nil is returned.
LastSamplePairForFingerprint(model.Fingerprint) *model.SamplePair
// Get all of the label values that are associated with a given label name.
LabelValuesForLabelName(model.LabelName) model.LabelValues
// Get the metric associated with the provided fingerprint.
MetricForFingerprint(model.Fingerprint) metric.Metric
// Drop all time series associated with the given fingerprints.
DropMetricsForFingerprints(...model.Fingerprint)
// Run the various maintenance loops in goroutines. Returns when the
// storage is ready to use. Keeps everything running in the background
// until Stop is called.
Start() error
// Stop shuts down the Storage gracefully, flushes all pending
// operations, stops all maintenance loops,and frees all resources.
Stop() error
// WaitForIndexing returns once all samples in the storage are
// indexed. Indexing is needed for FingerprintsForLabelMatchers and
// LabelValuesForLabelName and may lag behind.
WaitForIndexing()
}
// SeriesIterator enables efficient access of sample values in a series. Its
// methods are not goroutine-safe. A SeriesIterator iterates over a snapshot of
// a series, i.e. it is safe to continue using a SeriesIterator after or during
// modifying the corresponding series, but the iterator will represent the state
// of the series prior the modification.
type SeriesIterator interface {
// Gets the value that is closest before the given time. In case a value
// exists at precisely the given time, that value is returned. If no
// applicable value exists, a SamplePair with timestamp model.Earliest
// and value 0.0 is returned.
ValueAtOrBeforeTime(model.Time) model.SamplePair
// Gets the boundary values of an interval: the first and last value
// within a given interval.
BoundaryValues(metric.Interval) []model.SamplePair
// Gets all values contained within a given interval.
RangeValues(metric.Interval) []model.SamplePair
}
// A Preloader preloads series data necessary for a query into memory, pins it
// until released via Close(), and returns an iterator for the pinned data. Its
// methods are generally not goroutine-safe.
type Preloader interface {
PreloadRange(
fp model.Fingerprint,
from model.Time, through model.Time,
) (SeriesIterator, error)
// Close unpins any previously requested series data from memory.
Close()
}