prometheus/storage/interface.go

217 lines
7.5 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 storage
import (
"context"
"errors"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/tsdb/chunkenc"
"github.com/prometheus/prometheus/tsdb/chunks"
"github.com/prometheus/prometheus/tsdb/tombstones"
)
// The errors exposed.
var (
ErrNotFound = errors.New("not found")
ErrOutOfOrderSample = errors.New("out of order sample")
ErrDuplicateSampleForTimestamp = errors.New("duplicate sample for timestamp")
ErrOutOfBounds = errors.New("out of bounds")
)
// Appendable allows creating appenders.
type Appendable interface {
// Appender returns a new appender for the storage.
Appender() Appender
}
// Storage ingests and manages samples, along with various indexes. All methods
// are goroutine-safe. Storage implements storage.SampleAppender.
// TODO(bwplotka): Add ChunkQueryable to Storage in next PR.
type Storage interface {
Queryable
Appendable
// StartTime returns the oldest timestamp stored in the storage.
StartTime() (int64, error)
// Close closes the storage and all its underlying resources.
Close() error
}
// A Queryable handles queries against a storage.
// Use it when you need to have access to all samples without chunk encoding abstraction e.g promQL.
type Queryable interface {
// Querier returns a new Querier on the storage.
Querier(ctx context.Context, mint, maxt int64) (Querier, error)
}
// Querier provides querying access over time series data of a fixed time range.
type Querier interface {
baseQuerier
// Select returns a set of series that matches the given label matchers.
// Caller can specify if it requires returned series to be sorted. Prefer not requiring sorting for better performance.
// It allows passing hints that can help in optimising select, but it's up to implementation how this is used if used at all.
Select(sortSeries bool, hints *SelectHints, matchers ...*labels.Matcher) (SeriesSet, Warnings, error)
}
// A ChunkQueryable handles queries against a storage.
// Use it when you need to have access to samples in encoded format.
type ChunkQueryable interface {
// ChunkQuerier returns a new ChunkQuerier on the storage.
ChunkQuerier(ctx context.Context, mint, maxt int64) (ChunkQuerier, Warnings, error)
}
// ChunkQuerier provides querying access over time series data of a fixed time range.
type ChunkQuerier interface {
baseQuerier
// Select returns a set of series that matches the given label matchers.
// Caller can specify if it requires returned series to be sorted. Prefer not requiring sorting for better performance.
// It allows passing hints that can help in optimising select, but it's up to implementation how this is used if used at all.
Select(sortSeries bool, hints *SelectHints, matchers ...*labels.Matcher) (ChunkSeriesSet, Warnings, error)
}
type baseQuerier interface {
// LabelValues returns all potential values for a label name.
// It is not safe to use the strings beyond the lifefime of the querier.
LabelValues(name string) ([]string, Warnings, error)
// LabelNames returns all the unique label names present in the block in sorted order.
LabelNames() ([]string, Warnings, error)
// Close releases the resources of the Querier.
Close() error
}
// SelectHints specifies hints passed for data selections.
// This is used only as an option for implementation to use.
type SelectHints struct {
Start int64 // Start time in milliseconds for this select.
End int64 // End time in milliseconds for this select.
Step int64 // Query step size in milliseconds.
Func string // String representation of surrounding function or aggregation.
Grouping []string // List of label names used in aggregation.
By bool // Indicate whether it is without or by.
Range int64 // Range vector selector range in milliseconds.
}
// QueryableFunc is an adapter to allow the use of ordinary functions as
// Queryables. It follows the idea of http.HandlerFunc.
type QueryableFunc func(ctx context.Context, mint, maxt int64) (Querier, error)
// Querier calls f() with the given parameters.
func (f QueryableFunc) Querier(ctx context.Context, mint, maxt int64) (Querier, error) {
return f(ctx, mint, maxt)
}
// Appender provides batched appends against a storage.
// It must be completed with a call to Commit or Rollback and must not be reused afterwards.
//
// Operations on the Appender interface are not goroutine-safe.
type Appender interface {
// Add adds a sample pair for the given series. A reference number is
// returned which can be used to add further samples in the same or later
// transactions.
// Returned reference numbers are ephemeral and may be rejected in calls
// to AddFast() at any point. Adding the sample via Add() returns a new
// reference number.
// If the reference is 0 it must not be used for caching.
Add(l labels.Labels, t int64, v float64) (uint64, error)
// AddFast adds a sample pair for the referenced series. It is generally
// faster than adding a sample by providing its full label set.
AddFast(ref uint64, t int64, v float64) error
// Commit submits the collected samples and purges the batch. If Commit
// returns a non-nil error, it also rolls back all modifications made in
// the appender so far, as Rollback would do. In any case, an Appender
// must not be used anymore after Commit has been called.
Commit() error
// Rollback rolls back all modifications made in the appender so far.
// Appender has to be discarded after rollback.
Rollback() error
}
// SeriesSet contains a set of series.
type SeriesSet interface {
Next() bool
At() Series
Err() error
}
var emptySeriesSet = errSeriesSet{}
// EmptySeriesSet returns a series set that's always empty.
func EmptySeriesSet() SeriesSet {
return emptySeriesSet
}
type errSeriesSet struct {
err error
}
func (s errSeriesSet) Next() bool { return false }
func (s errSeriesSet) At() Series { return nil }
func (s errSeriesSet) Err() error { return s.err }
// Series exposes a single time series and allows iterating over samples.
type Series interface {
Labels
SampleIteratable
}
// ChunkSeriesSet contains a set of chunked series.
type ChunkSeriesSet interface {
Next() bool
At() ChunkSeries
Err() error
}
// ChunkSeries exposes a single time series and allows iterating over chunks.
type ChunkSeries interface {
Labels
ChunkIteratable
}
// Labels represents an item that has labels e.g. time series.
type Labels interface {
// Labels returns the complete set of labels. For series it means all labels identifying the series.
Labels() labels.Labels
}
type SampleIteratable interface {
// Iterator returns a new iterator of the data of the series.
Iterator() chunkenc.Iterator
}
type ChunkIteratable interface {
// ChunkIterator returns a new iterator that iterates over non-overlapping chunks of the series.
Iterator() chunks.Iterator
}
// TODO(bwplotka): Remove in next Pr.
type DeprecatedChunkSeriesSet interface {
Next() bool
At() (labels.Labels, []chunks.Meta, tombstones.Intervals)
Err() error
}
type Warnings []error