Merge pull request #743 from prometheus/beorn7/test

Add linter helpers to testutil
This commit is contained in:
Björn Rabenstein 2020-04-27 14:49:40 +02:00 committed by GitHub
commit 00d5f9eb03
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4 changed files with 166 additions and 27 deletions

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@ -0,0 +1,46 @@
// Copyright 2020 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 testutil
import (
"fmt"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/testutil/promlint"
)
// CollectAndLint registers the provided Collector with a newly created pedantic
// Registry. It then calls GatherAndLint with that Registry and with the
// provided metricNames.
func CollectAndLint(c prometheus.Collector, metricNames ...string) ([]promlint.Problem, error) {
reg := prometheus.NewPedanticRegistry()
if err := reg.Register(c); err != nil {
return nil, fmt.Errorf("registering collector failed: %s", err)
}
return GatherAndLint(reg, metricNames...)
}
// GatherAndLint gathers all metrics from the provided Gatherer and checks them
// with the linter in the promlint package. If any metricNames are provided,
// only metrics with those names are checked.
func GatherAndLint(g prometheus.Gatherer, metricNames ...string) ([]promlint.Problem, error) {
got, err := g.Gather()
if err != nil {
return nil, fmt.Errorf("gathering metrics failed: %s", err)
}
if metricNames != nil {
got = filterMetrics(got, metricNames)
}
return promlint.NewWithMetricFamilies(got).Lint()
}

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@ -0,0 +1,71 @@
// Copyright 2020 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 testutil
import (
"testing"
"github.com/prometheus/client_golang/prometheus"
)
func TestCollectAndLintGood(t *testing.T) {
cnt := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "some_total",
Help: "A value that represents a counter.",
ConstLabels: prometheus.Labels{
"label1": "value1",
},
},
[]string{"foo"},
)
cnt.WithLabelValues("bar")
cnt.WithLabelValues("baz")
problems, err := CollectAndLint(cnt)
if err != nil {
t.Error("Unexpected error:", err)
}
if len(problems) > 0 {
t.Error("Unexpected lint problems:", problems)
}
}
func TestCollectAndLintBad(t *testing.T) {
cnt := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "someThing_ms",
Help: "A value that represents a counter.",
ConstLabels: prometheus.Labels{
"label1": "value1",
},
},
[]string{"fooBar"},
)
cnt.WithLabelValues("bar")
cnt.WithLabelValues("baz")
problems, err := CollectAndLint(cnt)
if err != nil {
t.Error("Unexpected error:", err)
}
if len(problems) < 5 {
// The exact nature of the lint problems found is tested within
// the promlint package itself. Here we only want to make sure
// that the collector successfully hits the linter and that at
// least the five problems that the linter could recognize at
// the time of writing this test are flagged.
t.Error("Not enough lint problems found.")
}
}

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@ -29,7 +29,13 @@ import (
// A Linter is a Prometheus metrics linter. It identifies issues with metric
// names, types, and metadata, and reports them to the caller.
type Linter struct {
r io.Reader
// The linter will read metrics in the Prometheus text format from r and
// then lint it, _and_ it will lint the metrics provided directly as
// MetricFamily proto messages in mfs. Note, however, that the current
// constructor functions New and NewWithMetricFamilies only ever set one
// of them.
r io.Reader
mfs []*dto.MetricFamily
}
// A Problem is an issue detected by a Linter.
@ -42,40 +48,52 @@ type Problem struct {
}
// newProblem is helper function to create a Problem.
func newProblem(mf dto.MetricFamily, text string) Problem {
func newProblem(mf *dto.MetricFamily, text string) Problem {
return Problem{
Metric: mf.GetName(),
Text: text,
}
}
// New creates a new Linter that reads an input stream of Prometheus metrics.
// Only the Prometheus text exposition format is supported.
// New creates a new Linter that reads an input stream of Prometheus metrics in
// the Prometheus text exposition format.
func New(r io.Reader) *Linter {
return &Linter{
r: r,
}
}
// NewWithMetricFamilies creates a new Linter that reads from a slice of
// MetricFamily protobuf messages.
func NewWithMetricFamilies(mfs []*dto.MetricFamily) *Linter {
return &Linter{
mfs: mfs,
}
}
// Lint performs a linting pass, returning a slice of Problems indicating any
// issues found in the metrics stream. The slice is sorted by metric name
// issues found in the metrics stream. The slice is sorted by metric name
// and issue description.
func (l *Linter) Lint() ([]Problem, error) {
// TODO(mdlayher): support for protobuf exposition format?
d := expfmt.NewDecoder(l.r, expfmt.FmtText)
var problems []Problem
var mf dto.MetricFamily
for {
if err := d.Decode(&mf); err != nil {
if err == io.EOF {
break
if l.r != nil {
d := expfmt.NewDecoder(l.r, expfmt.FmtText)
mf := &dto.MetricFamily{}
for {
if err := d.Decode(mf); err != nil {
if err == io.EOF {
break
}
return nil, err
}
return nil, err
problems = append(problems, lint(mf)...)
}
}
for _, mf := range l.mfs {
problems = append(problems, lint(mf)...)
}
@ -91,8 +109,8 @@ func (l *Linter) Lint() ([]Problem, error) {
}
// lint is the entry point for linting a single metric.
func lint(mf dto.MetricFamily) []Problem {
fns := []func(mf dto.MetricFamily) []Problem{
func lint(mf *dto.MetricFamily) []Problem {
fns := []func(mf *dto.MetricFamily) []Problem{
lintHelp,
lintMetricUnits,
lintCounter,
@ -113,7 +131,7 @@ func lint(mf dto.MetricFamily) []Problem {
}
// lintHelp detects issues related to the help text for a metric.
func lintHelp(mf dto.MetricFamily) []Problem {
func lintHelp(mf *dto.MetricFamily) []Problem {
var problems []Problem
// Expect all metrics to have help text available.
@ -125,7 +143,7 @@ func lintHelp(mf dto.MetricFamily) []Problem {
}
// lintMetricUnits detects issues with metric unit names.
func lintMetricUnits(mf dto.MetricFamily) []Problem {
func lintMetricUnits(mf *dto.MetricFamily) []Problem {
var problems []Problem
unit, base, ok := metricUnits(*mf.Name)
@ -146,7 +164,7 @@ func lintMetricUnits(mf dto.MetricFamily) []Problem {
// lintCounter detects issues specific to counters, as well as patterns that should
// only be used with counters.
func lintCounter(mf dto.MetricFamily) []Problem {
func lintCounter(mf *dto.MetricFamily) []Problem {
var problems []Problem
isCounter := mf.GetType() == dto.MetricType_COUNTER
@ -165,7 +183,7 @@ func lintCounter(mf dto.MetricFamily) []Problem {
// lintHistogramSummaryReserved detects when other types of metrics use names or labels
// reserved for use by histograms and/or summaries.
func lintHistogramSummaryReserved(mf dto.MetricFamily) []Problem {
func lintHistogramSummaryReserved(mf *dto.MetricFamily) []Problem {
// These rules do not apply to untyped metrics.
t := mf.GetType()
if t == dto.MetricType_UNTYPED {
@ -206,7 +224,7 @@ func lintHistogramSummaryReserved(mf dto.MetricFamily) []Problem {
}
// lintMetricTypeInName detects when metric types are included in the metric name.
func lintMetricTypeInName(mf dto.MetricFamily) []Problem {
func lintMetricTypeInName(mf *dto.MetricFamily) []Problem {
var problems []Problem
n := strings.ToLower(mf.GetName())
@ -224,7 +242,7 @@ func lintMetricTypeInName(mf dto.MetricFamily) []Problem {
}
// lintReservedChars detects colons in metric names.
func lintReservedChars(mf dto.MetricFamily) []Problem {
func lintReservedChars(mf *dto.MetricFamily) []Problem {
var problems []Problem
if strings.Contains(mf.GetName(), ":") {
problems = append(problems, newProblem(mf, "metric names should not contain ':'"))
@ -235,7 +253,7 @@ func lintReservedChars(mf dto.MetricFamily) []Problem {
var camelCase = regexp.MustCompile(`[a-z][A-Z]`)
// lintCamelCase detects metric names and label names written in camelCase.
func lintCamelCase(mf dto.MetricFamily) []Problem {
func lintCamelCase(mf *dto.MetricFamily) []Problem {
var problems []Problem
if camelCase.FindString(mf.GetName()) != "" {
problems = append(problems, newProblem(mf, "metric names should be written in 'snake_case' not 'camelCase'"))
@ -252,7 +270,7 @@ func lintCamelCase(mf dto.MetricFamily) []Problem {
}
// lintUnitAbbreviations detects abbreviated units in the metric name.
func lintUnitAbbreviations(mf dto.MetricFamily) []Problem {
func lintUnitAbbreviations(mf *dto.MetricFamily) []Problem {
var problems []Problem
n := strings.ToLower(mf.GetName())
for _, s := range unitAbbreviations {

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@ -31,6 +31,10 @@
// testing custom prometheus.Collector implementations and in particular whole
// exporters, i.e. programs that retrieve telemetry data from a 3rd party source
// and convert it into Prometheus metrics.
//
// In a similar pattern, CollectAndLint and GatherAndLint can be used to detect
// metrics that have issues with their name, type, or metadata without being
// necessarily invalid, e.g. a counter with a name missing the “_total” suffix.
package testutil
import (
@ -136,8 +140,8 @@ func CollectAndCount(c prometheus.Collector) int {
}
// CollectAndCompare registers the provided Collector with a newly created
// pedantic Registry. It then does the same as GatherAndCompare, gathering the
// metrics from the pedantic Registry.
// pedantic Registry. It then calls GatherAndCompare with that Registry and with
// the provided metricNames.
func CollectAndCompare(c prometheus.Collector, expected io.Reader, metricNames ...string) error {
reg := prometheus.NewPedanticRegistry()
if err := reg.Register(c); err != nil {