prometheus/storage/interface.go
Łukasz Mierzwa a4317bf0ec
Run gofumpt on all files (#10392)
* Run gofumpt on all files

Getting golangci-lint errors when building on my laptop, possibly because I have newer version of gofumpt then what it was formatted with.
Run gofumpt -w -extra on all files as it will be needed in the future anyway.

* Update golangci-lint to v1.44.2

v1.44.0 upgraded gofumpt so bumping version in CI will help keep formatting correct for everyone

* Address golangci-lint error

Getting 'error-strings: error strings should not be capitalized or end with punctuation or a newline' from revive here.
Drop new line.

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-03-03 17:21:05 +01:00

321 lines
12 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"
"fmt"
"github.com/prometheus/prometheus/model/exemplar"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/tsdb/chunkenc"
"github.com/prometheus/prometheus/tsdb/chunks"
)
// 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")
ErrOutOfOrderExemplar = errors.New("out of order exemplar")
ErrDuplicateExemplar = errors.New("duplicate exemplar")
ErrExemplarLabelLength = fmt.Errorf("label length for exemplar exceeds maximum of %d UTF-8 characters", exemplar.ExemplarMaxLabelSetLength)
ErrExemplarsDisabled = fmt.Errorf("exemplar storage is disabled or max exemplars is less than or equal to 0")
)
// SeriesRef is a generic series reference. In prometheus it is either a
// HeadSeriesRef or BlockSeriesRef, though other implementations may have
// their own reference types.
type SeriesRef uint64
// Appendable allows creating appenders.
type Appendable interface {
// Appender returns a new appender for the storage. The implementation
// can choose whether or not to use the context, for deadlines or to check
// for errors.
Appender(ctx context.Context) Appender
}
// SampleAndChunkQueryable allows retrieving samples as well as encoded samples in form of chunks.
type SampleAndChunkQueryable interface {
Queryable
ChunkQueryable
}
// Storage ingests and manages samples, along with various indexes. All methods
// are goroutine-safe. Storage implements storage.Appender.
type Storage interface {
SampleAndChunkQueryable
Appendable
// StartTime returns the oldest timestamp stored in the storage.
StartTime() (int64, error)
// Close closes the storage and all its underlying resources.
Close() error
}
// ExemplarStorage ingests and manages exemplars, along with various indexes. All methods are
// goroutine-safe. ExemplarStorage implements storage.ExemplarAppender and storage.ExemplarQuerier.
type ExemplarStorage interface {
ExemplarQueryable
ExemplarAppender
}
// 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 {
LabelQuerier
// 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
}
// 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, error)
}
// ChunkQuerier provides querying access over time series data of a fixed time range.
type ChunkQuerier interface {
LabelQuerier
// 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
}
// LabelQuerier provides querying access over labels.
type LabelQuerier interface {
// LabelValues returns all potential values for a label name.
// It is not safe to use the strings beyond the lifetime of the querier.
// If matchers are specified the returned result set is reduced
// to label values of metrics matching the matchers.
LabelValues(name string, matchers ...*labels.Matcher) ([]string, Warnings, error)
// LabelNames returns all the unique label names present in the block in sorted order.
// If matchers are specified the returned result set is reduced
// to label names of metrics matching the matchers.
LabelNames(matchers ...*labels.Matcher) ([]string, Warnings, error)
// Close releases the resources of the Querier.
Close() error
}
type ExemplarQueryable interface {
// ExemplarQuerier returns a new ExemplarQuerier on the storage.
ExemplarQuerier(ctx context.Context) (ExemplarQuerier, error)
}
// ExemplarQuerier provides reading access to time series data.
type ExemplarQuerier interface {
// Select all the exemplars that match the matchers.
// Within a single slice of matchers, it is an intersection. Between the slices, it is a union.
Select(start, end int64, matchers ...[]*labels.Matcher) ([]exemplar.QueryResult, 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.
// DisableTrimming allows to disable trimming of matching series chunks based on query Start and End time.
// When disabled, the result may contain samples outside the queried time range but Select() performances
// may be improved.
DisableTrimming bool
}
// TODO(bwplotka): Move to promql/engine_test.go?
// 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 {
// Append adds a sample pair for the given series.
// An optional series reference can be provided to accelerate calls.
// A series reference number is returned which can be used to add further
// samples to the given series in the same or later transactions.
// Returned reference numbers are ephemeral and may be rejected in calls
// to Append() at any point. Adding the sample via Append() returns a new
// reference number.
// If the reference is 0 it must not be used for caching.
Append(ref SeriesRef, l labels.Labels, t int64, v float64) (SeriesRef, 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
ExemplarAppender
}
// GetRef is an extra interface on Appenders used by downstream projects
// (e.g. Cortex) to avoid maintaining a parallel set of references.
type GetRef interface {
// Returns reference number that can be used to pass to Appender.Append(),
// and a set of labels that will not cause another copy when passed to Appender.Append().
// 0 means the appender does not have a reference to this series.
GetRef(lset labels.Labels) (SeriesRef, labels.Labels)
}
// ExemplarAppender provides an interface for adding samples to exemplar storage, which
// within Prometheus is in-memory only.
type ExemplarAppender interface {
// AppendExemplar adds an exemplar for the given series labels.
// An optional reference number can be provided to accelerate calls.
// A reference number is returned which can be used to add further
// exemplars in the same or later transactions.
// Returned reference numbers are ephemeral and may be rejected in calls
// to Append() at any point. Adding the sample via Append() returns a new
// reference number.
// If the reference is 0 it must not be used for caching.
// Note that in our current implementation of Prometheus' exemplar storage
// calls to Append should generate the reference numbers, AppendExemplar
// generating a new reference number should be considered possible erroneous behaviour and be logged.
AppendExemplar(ref SeriesRef, l labels.Labels, e exemplar.Exemplar) (SeriesRef, error)
}
// SeriesSet contains a set of series.
type SeriesSet interface {
Next() bool
// At returns full series. Returned series should be iterable even after Next is called.
At() Series
// The error that iteration as failed with.
// When an error occurs, set cannot continue to iterate.
Err() error
// A collection of warnings for the whole set.
// Warnings could be return even iteration has not failed with error.
Warnings() Warnings
}
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 }
func (s errSeriesSet) Warnings() Warnings { return nil }
// ErrSeriesSet returns a series set that wraps an error.
func ErrSeriesSet(err error) SeriesSet {
return errSeriesSet{err: err}
}
var emptyChunkSeriesSet = errChunkSeriesSet{}
// EmptyChunkSeriesSet returns a chunk series set that's always empty.
func EmptyChunkSeriesSet() ChunkSeriesSet {
return emptyChunkSeriesSet
}
type errChunkSeriesSet struct {
err error
}
func (s errChunkSeriesSet) Next() bool { return false }
func (s errChunkSeriesSet) At() ChunkSeries { return nil }
func (s errChunkSeriesSet) Err() error { return s.err }
func (s errChunkSeriesSet) Warnings() Warnings { return nil }
// ErrChunkSeriesSet returns a chunk series set that wraps an error.
func ErrChunkSeriesSet(err error) ChunkSeriesSet {
return errChunkSeriesSet{err: err}
}
// Series exposes a single time series and allows iterating over samples.
type Series interface {
Labels
SampleIterable
}
// ChunkSeriesSet contains a set of chunked series.
type ChunkSeriesSet interface {
Next() bool
// At returns full chunk series. Returned series should be iterable even after Next is called.
At() ChunkSeries
// The error that iteration has failed with.
// When an error occurs, set cannot continue to iterate.
Err() error
// A collection of warnings for the whole set.
// Warnings could be return even iteration has not failed with error.
Warnings() Warnings
}
// ChunkSeries exposes a single time series and allows iterating over chunks.
type ChunkSeries interface {
Labels
ChunkIterable
}
// 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 SampleIterable interface {
// Iterator returns a new, independent iterator of the data of the series.
Iterator() chunkenc.Iterator
}
type ChunkIterable interface {
// Iterator returns a new, independent iterator that iterates over potentially overlapping
// chunks of the series, sorted by min time.
Iterator() chunks.Iterator
}
type Warnings []error