124 lines
3.4 KiB
Go
124 lines
3.4 KiB
Go
// Copyright 2020 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 promlint provides a linter for Prometheus metrics.
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package promlint
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import (
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"errors"
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"io"
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"sort"
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dto "github.com/prometheus/client_model/go"
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"github.com/prometheus/common/expfmt"
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)
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// A Linter is a Prometheus metrics linter. It identifies issues with metric
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// names, types, and metadata, and reports them to the caller.
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type Linter struct {
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// The linter will read metrics in the Prometheus text format from r and
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// then lint it, _and_ it will lint the metrics provided directly as
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// MetricFamily proto messages in mfs. Note, however, that the current
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// constructor functions New and NewWithMetricFamilies only ever set one
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// of them.
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r io.Reader
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mfs []*dto.MetricFamily
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customValidations []Validation
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}
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// New creates a new Linter that reads an input stream of Prometheus metrics in
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// the Prometheus text exposition format.
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func New(r io.Reader) *Linter {
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return &Linter{
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r: r,
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}
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}
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// NewWithMetricFamilies creates a new Linter that reads from a slice of
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// MetricFamily protobuf messages.
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func NewWithMetricFamilies(mfs []*dto.MetricFamily) *Linter {
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return &Linter{
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mfs: mfs,
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}
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}
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// AddCustomValidations adds custom validations to the linter.
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func (l *Linter) AddCustomValidations(vs ...Validation) {
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if l.customValidations == nil {
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l.customValidations = make([]Validation, 0, len(vs))
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}
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l.customValidations = append(l.customValidations, vs...)
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}
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// Lint performs a linting pass, returning a slice of Problems indicating any
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// issues found in the metrics stream. The slice is sorted by metric name
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// and issue description.
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func (l *Linter) Lint() ([]Problem, error) {
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var problems []Problem
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if l.r != nil {
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d := expfmt.NewDecoder(l.r, expfmt.NewFormat(expfmt.TypeTextPlain))
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mf := &dto.MetricFamily{}
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for {
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if err := d.Decode(mf); err != nil {
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if errors.Is(err, io.EOF) {
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break
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}
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return nil, err
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}
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problems = append(problems, l.lint(mf)...)
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}
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}
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for _, mf := range l.mfs {
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problems = append(problems, l.lint(mf)...)
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}
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// Ensure deterministic output.
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sort.SliceStable(problems, func(i, j int) bool {
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if problems[i].Metric == problems[j].Metric {
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return problems[i].Text < problems[j].Text
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}
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return problems[i].Metric < problems[j].Metric
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})
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return problems, nil
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}
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// lint is the entry point for linting a single metric.
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func (l *Linter) lint(mf *dto.MetricFamily) []Problem {
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var problems []Problem
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for _, fn := range defaultValidations {
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errs := fn(mf)
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for _, err := range errs {
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problems = append(problems, newProblem(mf, err.Error()))
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}
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}
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if l.customValidations != nil {
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for _, fn := range l.customValidations {
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errs := fn(mf)
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for _, err := range errs {
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problems = append(problems, newProblem(mf, err.Error()))
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}
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}
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}
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// TODO(mdlayher): lint rules for specific metrics types.
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return problems
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}
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