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Resolve conflicts between multiple exported label prefixes (#9479)

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Resolve conflicts between multiple exported label prefixes

Signed-off-by: Shirley Leu <shirley.w.leu@gmail.com>
This commit is contained in:
Shirley Leu 2021-10-15 20:31:03 +02:00 committed by GitHub
parent 4e1dacf2d1
commit c890ea407f
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 114 additions and 2 deletions
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41
scrape/scrape.go
View file

@ -24,6 +24,7 @@ import (
"math"
"net/http"
"reflect"
"sort"
"strconv"
"sync"
"time"
@ -648,15 +649,19 @@ func mutateSampleLabels(lset labels.Labels, target *Target, honor bool, rc []*re
}
}
} else {
var conflictingExposedLabels labels.Labels
for _, l := range target.Labels() {
// existingValue will be empty if l.Name doesn't exist.
existingValue := lset.Get(l.Name)
if existingValue != "" {
lb.Set(model.ExportedLabelPrefix+l.Name, existingValue)
conflictingExposedLabels = append(conflictingExposedLabels, labels.Label{Name: l.Name, Value: existingValue})
}
// It is now safe to set the target label.
lb.Set(l.Name, l.Value)
}
if len(conflictingExposedLabels) > 0 {
resolveConflictingExposedLabels(lb, conflictingExposedLabels)
}
}
res := lb.Labels()
@ -668,6 +673,38 @@ func mutateSampleLabels(lset labels.Labels, target *Target, honor bool, rc []*re
return res
}
func resolveConflictingExposedLabels(lb *labels.Builder, conflictingExposedLabels labels.Labels) {
sort.SliceStable(conflictingExposedLabels, func(i, j int) bool {
return len(conflictingExposedLabels[i].Name) < len(conflictingExposedLabels[j].Name)
})
allLabelNames := map[string]struct{}{}
for _, v := range lb.Labels() {
allLabelNames[v.Name] = struct{}{}
}
resolved := createNewLabels(allLabelNames, conflictingExposedLabels, nil)
for _, l := range resolved {
lb.Set(l.Name, l.Value)
}
}
func createNewLabels(existingNames map[string]struct{}, conflictingLabels, resolvedLabels labels.Labels) labels.Labels {
for i := 0; i < len(conflictingLabels); i++ {
newName := model.ExportedLabelPrefix + conflictingLabels[i].Name
if _, ok := existingNames[newName]; !ok {
resolvedLabels = append(resolvedLabels, labels.Label{Name: newName, Value: conflictingLabels[i].Value})
conflictingLabels = append(conflictingLabels[:i], conflictingLabels[i+1:]...)
i--
existingNames[newName] = struct{}{}
} else {
conflictingLabels[i] = labels.Label{Name: newName, Value: conflictingLabels[i].Value}
return createNewLabels(existingNames, conflictingLabels, resolvedLabels)
}
}
return resolvedLabels
}
func mutateReportSampleLabels(lset labels.Labels, target *Target) labels.Labels {
lb := labels.NewBuilder(lset)

75
scrape/scrape_test.go
View file

@ -1379,6 +1379,81 @@ func TestScrapeLoopAppend(t *testing.T) {
}
}
func TestScrapeLoopAppendForConflictingPrefixedLabels(t *testing.T) {
testcases := map[string]struct {
targetLabels []string
exposedLabels string
expected []string
}{
"One target label collides with existing label": {
targetLabels: []string{"foo", "2"},
exposedLabels: `metric{foo="1"} 0`,
expected: []string{"__name__", "metric", "exported_foo", "1", "foo", "2"},
},
"One target label collides with existing label, plus target label already with prefix 'exported'": {
targetLabels: []string{"foo", "2", "exported_foo", "3"},
exposedLabels: `metric{foo="1"} 0`,
expected: []string{"__name__", "metric", "exported_exported_foo", "1", "exported_foo", "3", "foo", "2"},
},
"One target label collides with existing label, plus existing label already with prefix 'exported": {
targetLabels: []string{"foo", "3"},
exposedLabels: `metric{foo="1" exported_foo="2"} 0`,
expected: []string{"__name__", "metric", "exported_exported_foo", "1", "exported_foo", "2", "foo", "3"},
},
"One target label collides with existing label, both already with prefix 'exported'": {
targetLabels: []string{"exported_foo", "2"},
exposedLabels: `metric{exported_foo="1"} 0`,
expected: []string{"__name__", "metric", "exported_exported_foo", "1", "exported_foo", "2"},
},
"Two target labels collide with existing labels, both with and without prefix 'exported'": {
targetLabels: []string{"foo", "3", "exported_foo", "4"},
exposedLabels: `metric{foo="1" exported_foo="2"} 0`,
expected: []string{"__name__", "metric", "exported_exported_foo", "1", "exported_exported_exported_foo",
"2", "exported_foo", "4", "foo", "3"},
},
"Extreme example": {
targetLabels: []string{"foo", "0", "exported_exported_foo", "1", "exported_exported_exported_foo", "2"},
exposedLabels: `metric{foo="3" exported_foo="4" exported_exported_exported_foo="5"} 0`,
expected: []string{
"__name__", "metric",
"exported_exported_exported_exported_exported_foo", "5",
"exported_exported_exported_exported_foo", "3",
"exported_exported_exported_foo", "2",
"exported_exported_foo", "1",
"exported_foo", "4",
"foo", "0",
},
},
}
for name, tc := range testcases {
t.Run(name, func(t *testing.T) {
app := &collectResultAppender{}
sl := newScrapeLoop(context.Background(), nil, nil, nil,
func(l labels.Labels) labels.Labels {
return mutateSampleLabels(l, &Target{labels: labels.FromStrings(tc.targetLabels...)}, false, nil)
},
nil,
func(ctx context.Context) storage.Appender { return app }, nil, 0, true, 0, nil, 0, 0, false,
)
slApp := sl.appender(context.Background())
_, _, _, err := sl.append(slApp, []byte(tc.exposedLabels), "", time.Date(2000, 1, 1, 1, 0, 0, 0, time.UTC))
require.NoError(t, err)
require.NoError(t, slApp.Commit())
require.Equal(t, []sample{
{
metric: labels.FromStrings(tc.expected...),
t: timestamp.FromTime(time.Date(2000, 1, 1, 1, 0, 0, 0, time.UTC)),
v: 0,
},
}, app.result)
})
}
}
func TestScrapeLoopAppendCacheEntryButErrNotFound(t *testing.T) {
// collectResultAppender's AddFast always returns ErrNotFound if we don't give it a next.
app := &collectResultAppender{}