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4d654ee22b
While implementing a different feature, I found that Labels.Get() was performing a linear search. I wondered whether it would perform any better with a binary search approach, and wrote a benchmark: the answer is that it's probably doesn't worth it, so I just decided to leave the benchmark and the results for the next reader. Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
738 lines
15 KiB
Go
738 lines
15 KiB
Go
// Copyright 2019 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 labels
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import (
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"fmt"
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"strings"
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"testing"
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"github.com/stretchr/testify/require"
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)
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func TestLabels_String(t *testing.T) {
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cases := []struct {
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lables Labels
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expected string
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}{
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{
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lables: Labels{
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{
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Name: "t1",
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Value: "t1",
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},
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{
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Name: "t2",
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Value: "t2",
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},
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},
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expected: "{t1=\"t1\", t2=\"t2\"}",
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},
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{
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lables: Labels{},
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expected: "{}",
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},
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{
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lables: nil,
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expected: "{}",
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},
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}
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for _, c := range cases {
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str := c.lables.String()
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require.Equal(t, c.expected, str)
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}
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}
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func TestLabels_MatchLabels(t *testing.T) {
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labels := Labels{
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{
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Name: "__name__",
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Value: "ALERTS",
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},
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{
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Name: "alertname",
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Value: "HTTPRequestRateLow",
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},
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{
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Name: "alertstate",
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Value: "pending",
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},
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{
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Name: "instance",
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Value: "0",
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},
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{
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Name: "job",
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Value: "app-server",
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},
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{
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Name: "severity",
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Value: "critical",
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},
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}
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tests := []struct {
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providedNames []string
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on bool
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expected Labels
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}{
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// on = true, explicitly including metric name in matching.
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{
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providedNames: []string{
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"__name__",
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"alertname",
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"alertstate",
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"instance",
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},
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on: true,
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expected: Labels{
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{
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Name: "__name__",
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Value: "ALERTS",
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},
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{
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Name: "alertname",
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Value: "HTTPRequestRateLow",
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},
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{
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Name: "alertstate",
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Value: "pending",
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},
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{
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Name: "instance",
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Value: "0",
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},
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},
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},
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// on = false, explicitly excluding metric name from matching.
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{
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providedNames: []string{
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"__name__",
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"alertname",
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"alertstate",
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"instance",
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},
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on: false,
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expected: Labels{
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{
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Name: "job",
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Value: "app-server",
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},
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{
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Name: "severity",
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Value: "critical",
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},
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},
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},
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// on = true, explicitly excluding metric name from matching.
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{
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providedNames: []string{
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"alertname",
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"alertstate",
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"instance",
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},
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on: true,
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expected: Labels{
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{
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Name: "alertname",
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Value: "HTTPRequestRateLow",
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},
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{
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Name: "alertstate",
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Value: "pending",
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},
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{
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Name: "instance",
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Value: "0",
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},
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},
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},
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// on = false, implicitly excluding metric name from matching.
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{
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providedNames: []string{
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"alertname",
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"alertstate",
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"instance",
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},
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on: false,
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expected: Labels{
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{
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Name: "job",
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Value: "app-server",
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},
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{
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Name: "severity",
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Value: "critical",
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},
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},
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},
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}
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for i, test := range tests {
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got := labels.MatchLabels(test.on, test.providedNames...)
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require.Equal(t, test.expected, got, "unexpected labelset for test case %d", i)
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}
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}
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func TestLabels_HasDuplicateLabelNames(t *testing.T) {
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cases := []struct {
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Input Labels
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Duplicate bool
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LabelName string
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}{
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{
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Input: FromMap(map[string]string{"__name__": "up", "hostname": "localhost"}),
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Duplicate: false,
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}, {
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Input: append(
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FromMap(map[string]string{"__name__": "up", "hostname": "localhost"}),
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FromMap(map[string]string{"hostname": "127.0.0.1"})...,
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),
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Duplicate: true,
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LabelName: "hostname",
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},
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}
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for i, c := range cases {
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l, d := c.Input.HasDuplicateLabelNames()
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require.Equal(t, c.Duplicate, d, "test %d: incorrect duplicate bool", i)
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require.Equal(t, c.LabelName, l, "test %d: incorrect label name", i)
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}
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}
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func TestLabels_WithoutEmpty(t *testing.T) {
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for _, test := range []struct {
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input Labels
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expected Labels
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}{
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{
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input: Labels{
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{Name: "foo"},
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{Name: "bar"},
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},
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expected: Labels{},
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},
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{
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input: Labels{
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{Name: "foo"},
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{Name: "bar"},
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{Name: "baz"},
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},
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expected: Labels{},
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},
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{
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input: Labels{
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{Name: "__name__", Value: "test"},
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{Name: "hostname", Value: "localhost"},
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{Name: "job", Value: "check"},
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},
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expected: Labels{
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{Name: "__name__", Value: "test"},
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{Name: "hostname", Value: "localhost"},
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{Name: "job", Value: "check"},
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},
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},
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{
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input: Labels{
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{Name: "__name__", Value: "test"},
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{Name: "hostname", Value: "localhost"},
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{Name: "bar"},
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{Name: "job", Value: "check"},
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},
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expected: Labels{
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{Name: "__name__", Value: "test"},
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{Name: "hostname", Value: "localhost"},
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{Name: "job", Value: "check"},
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},
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},
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{
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input: Labels{
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{Name: "__name__", Value: "test"},
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{Name: "foo"},
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{Name: "hostname", Value: "localhost"},
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{Name: "bar"},
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{Name: "job", Value: "check"},
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},
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expected: Labels{
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{Name: "__name__", Value: "test"},
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{Name: "hostname", Value: "localhost"},
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{Name: "job", Value: "check"},
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},
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},
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{
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input: Labels{
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{Name: "__name__", Value: "test"},
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{Name: "foo"},
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{Name: "baz"},
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{Name: "hostname", Value: "localhost"},
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{Name: "bar"},
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{Name: "job", Value: "check"},
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},
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expected: Labels{
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{Name: "__name__", Value: "test"},
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{Name: "hostname", Value: "localhost"},
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{Name: "job", Value: "check"},
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},
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},
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} {
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t.Run("", func(t *testing.T) {
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require.Equal(t, test.expected, test.input.WithoutEmpty())
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})
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}
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}
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func TestLabels_Equal(t *testing.T) {
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labels := Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "222",
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},
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}
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tests := []struct {
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compared Labels
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expected bool
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}{
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "222",
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},
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{
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Name: "ccc",
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Value: "333",
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},
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},
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expected: false,
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},
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bar",
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Value: "222",
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},
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},
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expected: false,
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},
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "233",
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},
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},
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expected: false,
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},
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "222",
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},
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},
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expected: true,
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},
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}
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for i, test := range tests {
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got := Equal(labels, test.compared)
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require.Equal(t, test.expected, got, "unexpected comparison result for test case %d", i)
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}
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}
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func TestLabels_FromStrings(t *testing.T) {
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labels := FromStrings("aaa", "111", "bbb", "222")
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expected := Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "222",
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},
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}
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require.Equal(t, expected, labels, "unexpected labelset")
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require.Panics(t, func() { FromStrings("aaa", "111", "bbb") }) //nolint:staticcheck // Ignore SA5012, error is intentional test.
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}
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func TestLabels_Compare(t *testing.T) {
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labels := Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "222",
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},
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}
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tests := []struct {
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compared Labels
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expected int
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}{
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "110",
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},
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{
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Name: "bbb",
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Value: "222",
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},
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},
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expected: 1,
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},
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "233",
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},
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},
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expected: -1,
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},
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bar",
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Value: "222",
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},
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},
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expected: 1,
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},
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbc",
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Value: "222",
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},
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},
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expected: -1,
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},
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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},
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expected: 1,
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},
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "222",
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},
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{
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Name: "ccc",
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Value: "333",
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},
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{
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Name: "ddd",
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Value: "444",
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},
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},
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expected: -2,
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},
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{
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compared: Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "222",
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},
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},
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expected: 0,
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},
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}
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for i, test := range tests {
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got := Compare(labels, test.compared)
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require.Equal(t, test.expected, got, "unexpected comparison result for test case %d", i)
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}
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}
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func TestLabels_Has(t *testing.T) {
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tests := []struct {
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input string
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expected bool
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}{
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{
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input: "foo",
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expected: false,
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},
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{
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input: "aaa",
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expected: true,
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},
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}
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labelsSet := Labels{
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{
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Name: "aaa",
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Value: "111",
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},
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{
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Name: "bbb",
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Value: "222",
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},
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}
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for i, test := range tests {
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got := labelsSet.Has(test.input)
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require.Equal(t, test.expected, got, "unexpected comparison result for test case %d", i)
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}
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}
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func TestLabels_Get(t *testing.T) {
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require.Equal(t, "", Labels{{"aaa", "111"}, {"bbb", "222"}}.Get("foo"))
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require.Equal(t, "111", Labels{{"aaa", "111"}, {"bbb", "222"}}.Get("aaa"))
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}
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// BenchmarkLabels_Get was written to check whether a binary search can improve the performance vs the linear search implementation
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// The results have shown that binary search would only be better when searching last labels in scenarios with more than 10 labels.
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// In the following list, `old` is the linear search while `new` is the binary search implementaiton (without calling sort.Search, which performs even worse here)
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// name old time/op new time/op delta
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// Labels_Get/with_5_labels/get_first_label 5.12ns ± 0% 14.24ns ± 0% ~ (p=1.000 n=1+1)
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// Labels_Get/with_5_labels/get_middle_label 13.5ns ± 0% 18.5ns ± 0% ~ (p=1.000 n=1+1)
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// Labels_Get/with_5_labels/get_last_label 21.9ns ± 0% 18.9ns ± 0% ~ (p=1.000 n=1+1)
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// Labels_Get/with_10_labels/get_first_label 5.11ns ± 0% 19.47ns ± 0% ~ (p=1.000 n=1+1)
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// Labels_Get/with_10_labels/get_middle_label 26.2ns ± 0% 19.3ns ± 0% ~ (p=1.000 n=1+1)
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// Labels_Get/with_10_labels/get_last_label 42.8ns ± 0% 23.4ns ± 0% ~ (p=1.000 n=1+1)
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// Labels_Get/with_30_labels/get_first_label 5.10ns ± 0% 24.63ns ± 0% ~ (p=1.000 n=1+1)
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// Labels_Get/with_30_labels/get_middle_label 75.8ns ± 0% 29.7ns ± 0% ~ (p=1.000 n=1+1)
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// Labels_Get/with_30_labels/get_last_label 169ns ± 0% 29ns ± 0% ~ (p=1.000 n=1+1)
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func BenchmarkLabels_Get(b *testing.B) {
|
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maxLabels := 30
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allLabels := make(Labels, maxLabels)
|
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for i := 0; i < maxLabels; i++ {
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allLabels[i] = Label{Name: strings.Repeat(string('a'+byte(i)), 5)}
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}
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for _, size := range []int{5, 10, maxLabels} {
|
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b.Run(fmt.Sprintf("with %d labels", size), func(b *testing.B) {
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labels := allLabels[:size]
|
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for _, scenario := range []struct {
|
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desc, label string
|
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}{
|
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{"get first label", labels[0].Name},
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{"get middle label", labels[size/2].Name},
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{"get last label", labels[size-1].Name},
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} {
|
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b.Run(scenario.desc, func(b *testing.B) {
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b.ResetTimer()
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for i := 0; i < b.N; i++ {
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_ = labels.Get(scenario.label)
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}
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})
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}
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})
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}
|
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}
|
|
|
|
func TestLabels_Copy(t *testing.T) {
|
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require.Equal(t, Labels{{"aaa", "111"}, {"bbb", "222"}}, Labels{{"aaa", "111"}, {"bbb", "222"}}.Copy())
|
|
}
|
|
|
|
func TestLabels_Map(t *testing.T) {
|
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require.Equal(t, map[string]string{"aaa": "111", "bbb": "222"}, Labels{{"aaa", "111"}, {"bbb", "222"}}.Map())
|
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}
|
|
|
|
func TestLabels_WithLabels(t *testing.T) {
|
|
require.Equal(t, Labels{{"aaa", "111"}, {"bbb", "222"}}, Labels{{"aaa", "111"}, {"bbb", "222"}, {"ccc", "333"}}.WithLabels("aaa", "bbb"))
|
|
}
|
|
|
|
func TestLabels_WithoutLabels(t *testing.T) {
|
|
require.Equal(t, Labels{{"aaa", "111"}}, Labels{{"aaa", "111"}, {"bbb", "222"}, {"ccc", "333"}}.WithoutLabels("bbb", "ccc"))
|
|
require.Equal(t, Labels{{"aaa", "111"}}, Labels{{"aaa", "111"}, {"bbb", "222"}, {MetricName, "333"}}.WithoutLabels("bbb"))
|
|
}
|
|
|
|
func TestBulider_NewBulider(t *testing.T) {
|
|
require.Equal(
|
|
t,
|
|
&Builder{
|
|
base: Labels{{"aaa", "111"}},
|
|
del: []string{},
|
|
add: []Label{},
|
|
},
|
|
NewBuilder(Labels{{"aaa", "111"}}),
|
|
)
|
|
}
|
|
|
|
func TestBuilder_Del(t *testing.T) {
|
|
require.Equal(
|
|
t,
|
|
&Builder{
|
|
del: []string{"bbb"},
|
|
add: []Label{{"aaa", "111"}, {"ccc", "333"}},
|
|
},
|
|
(&Builder{
|
|
del: []string{},
|
|
add: []Label{{"aaa", "111"}, {"bbb", "222"}, {"ccc", "333"}},
|
|
}).Del("bbb"),
|
|
)
|
|
}
|
|
|
|
func TestBuilder_Set(t *testing.T) {
|
|
require.Equal(
|
|
t,
|
|
&Builder{
|
|
base: Labels{{"aaa", "111"}},
|
|
del: []string{},
|
|
add: []Label{{"bbb", "222"}},
|
|
},
|
|
(&Builder{
|
|
base: Labels{{"aaa", "111"}},
|
|
del: []string{},
|
|
add: []Label{},
|
|
}).Set("bbb", "222"),
|
|
)
|
|
|
|
require.Equal(
|
|
t,
|
|
&Builder{
|
|
base: Labels{{"aaa", "111"}},
|
|
del: []string{},
|
|
add: []Label{{"bbb", "333"}},
|
|
},
|
|
(&Builder{
|
|
base: Labels{{"aaa", "111"}},
|
|
del: []string{},
|
|
add: []Label{{"bbb", "222"}},
|
|
}).Set("bbb", "333"),
|
|
)
|
|
}
|
|
|
|
func TestBuilder_Labels(t *testing.T) {
|
|
require.Equal(
|
|
t,
|
|
Labels{{"aaa", "111"}, {"ccc", "333"}, {"ddd", "444"}},
|
|
(&Builder{
|
|
base: Labels{{"aaa", "111"}, {"bbb", "222"}, {"ccc", "333"}},
|
|
del: []string{"bbb"},
|
|
add: []Label{{"ddd", "444"}},
|
|
}).Labels(),
|
|
)
|
|
}
|
|
|
|
func TestLabels_Hash(t *testing.T) {
|
|
lbls := Labels{
|
|
{Name: "foo", Value: "bar"},
|
|
{Name: "baz", Value: "qux"},
|
|
}
|
|
require.Equal(t, lbls.Hash(), lbls.Hash())
|
|
require.NotEqual(t, lbls.Hash(), Labels{lbls[1], lbls[0]}.Hash(), "unordered labels match.")
|
|
require.NotEqual(t, lbls.Hash(), Labels{lbls[0]}.Hash(), "different labels match.")
|
|
}
|
|
|
|
var benchmarkLabelsResult uint64
|
|
|
|
func BenchmarkLabels_Hash(b *testing.B) {
|
|
for _, tcase := range []struct {
|
|
name string
|
|
lbls Labels
|
|
}{
|
|
{
|
|
name: "typical labels under 1KB",
|
|
lbls: func() Labels {
|
|
lbls := make(Labels, 10)
|
|
for i := 0; i < len(lbls); i++ {
|
|
// Label ~20B name, 50B value.
|
|
lbls[i] = Label{Name: fmt.Sprintf("abcdefghijabcdefghijabcdefghij%d", i), Value: fmt.Sprintf("abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij%d", i)}
|
|
}
|
|
return lbls
|
|
}(),
|
|
},
|
|
{
|
|
name: "bigger labels over 1KB",
|
|
lbls: func() Labels {
|
|
lbls := make(Labels, 10)
|
|
for i := 0; i < len(lbls); i++ {
|
|
//Label ~50B name, 50B value.
|
|
lbls[i] = Label{Name: fmt.Sprintf("abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij%d", i), Value: fmt.Sprintf("abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij%d", i)}
|
|
}
|
|
return lbls
|
|
}(),
|
|
},
|
|
{
|
|
name: "extremely large label value 10MB",
|
|
lbls: func() Labels {
|
|
lbl := &strings.Builder{}
|
|
lbl.Grow(1024 * 1024 * 10) // 10MB.
|
|
word := "abcdefghij"
|
|
for i := 0; i < lbl.Cap()/len(word); i++ {
|
|
_, _ = lbl.WriteString(word)
|
|
}
|
|
return Labels{{Name: "__name__", Value: lbl.String()}}
|
|
}(),
|
|
},
|
|
} {
|
|
b.Run(tcase.name, func(b *testing.B) {
|
|
var h uint64
|
|
|
|
b.ReportAllocs()
|
|
b.ResetTimer()
|
|
for i := 0; i < b.N; i++ {
|
|
h = tcase.lbls.Hash()
|
|
}
|
|
benchmarkLabelsResult = h
|
|
})
|
|
}
|
|
}
|