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2e30f1231b
The docs suggest the Next method returns a bool, but that's not the case (`Entry` is an int). ``` // Next advances the parser to the next sample. It returns false if no // more samples were read or an error occurred. Next() (Entry, error) ``` The docs were first added ind80a3de235in 2017. Back then the signature was indeed `func (p *Parser) Next() bool`. But then it got refactored in76a4a46cb0and the signature changed with it, yet docs stayed the same - and eventually made their way into the `Parser` interface. However, the Protobuf parser does have the right wording:5de2df752f``` // Next advances the parser to the next "sample" (emulating the behavior of a // text format parser). It returns (EntryInvalid, io.EOF) if no samples were // read. ``` Changing all other implementations (and the interface itself) to match this doc. Signed-off-by: Ondrej Kokes <ondrej.kokes@gmail.com>
114 lines
4.3 KiB
Go
114 lines
4.3 KiB
Go
// Copyright 2018 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package textparse
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import (
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"mime"
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"github.com/prometheus/common/model"
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"github.com/prometheus/prometheus/model/exemplar"
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"github.com/prometheus/prometheus/model/histogram"
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"github.com/prometheus/prometheus/model/labels"
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)
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// Parser parses samples from a byte slice of samples in the official
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// Prometheus and OpenMetrics text exposition formats.
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type Parser interface {
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// Series returns the bytes of a series with a simple float64 as a
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// value, the timestamp if set, and the value of the current sample.
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Series() ([]byte, *int64, float64)
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// Histogram returns the bytes of a series with a sparse histogram as a
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// value, the timestamp if set, and the histogram in the current sample.
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// Depending on the parsed input, the function returns an (integer) Histogram
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// or a FloatHistogram, with the respective other return value being nil.
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Histogram() ([]byte, *int64, *histogram.Histogram, *histogram.FloatHistogram)
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// Help returns the metric name and help text in the current entry.
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// Must only be called after Next returned a help entry.
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// The returned byte slices become invalid after the next call to Next.
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Help() ([]byte, []byte)
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// Type returns the metric name and type in the current entry.
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// Must only be called after Next returned a type entry.
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// The returned byte slices become invalid after the next call to Next.
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Type() ([]byte, model.MetricType)
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// Unit returns the metric name and unit in the current entry.
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// Must only be called after Next returned a unit entry.
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// The returned byte slices become invalid after the next call to Next.
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Unit() ([]byte, []byte)
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// Comment returns the text of the current comment.
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// Must only be called after Next returned a comment entry.
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// The returned byte slice becomes invalid after the next call to Next.
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Comment() []byte
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// Metric writes the labels of the current sample into the passed labels.
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// It returns the string from which the metric was parsed.
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Metric(l *labels.Labels) string
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// Exemplar writes the exemplar of the current sample into the passed
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// exemplar. It can be called repeatedly to retrieve multiple exemplars
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// for the same sample. It returns false once all exemplars are
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// retrieved (including the case where no exemplars exist at all).
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Exemplar(l *exemplar.Exemplar) bool
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// CreatedTimestamp returns the created timestamp (in milliseconds) for the
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// current sample. It returns nil if it is unknown e.g. if it wasn't set,
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// if the scrape protocol or metric type does not support created timestamps.
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CreatedTimestamp() *int64
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// Next advances the parser to the next sample.
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// It returns (EntryInvalid, io.EOF) if no samples were read.
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Next() (Entry, error)
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}
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// New returns a new parser of the byte slice.
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//
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// This function always returns a valid parser, but might additionally
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// return an error if the content type cannot be parsed.
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func New(b []byte, contentType string, parseClassicHistograms bool, st *labels.SymbolTable) (Parser, error) {
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if contentType == "" {
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return NewPromParser(b, st), nil
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}
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mediaType, _, err := mime.ParseMediaType(contentType)
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if err != nil {
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return NewPromParser(b, st), err
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}
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switch mediaType {
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case "application/openmetrics-text":
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return NewOpenMetricsParser(b, st), nil
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case "application/vnd.google.protobuf":
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return NewProtobufParser(b, parseClassicHistograms, st), nil
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default:
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return NewPromParser(b, st), nil
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}
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}
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// Entry represents the type of a parsed entry.
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type Entry int
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const (
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EntryInvalid Entry = -1
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EntryType Entry = 0
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EntryHelp Entry = 1
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EntrySeries Entry = 2 // A series with a simple float64 as value.
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EntryComment Entry = 3
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EntryUnit Entry = 4
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EntryHistogram Entry = 5 // A series with a native histogram as a value.
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)
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