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- // Copyright 2018 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 prometheus
-
- import (
- "errors"
- "fmt"
- "strings"
- "unicode/utf8"
-
- "github.com/prometheus/common/model"
- )
-
- // Labels represents a collection of label name -> value mappings. This type is
- // commonly used with the With(Labels) and GetMetricWith(Labels) methods of
- // metric vector Collectors, e.g.:
- // myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
- //
- // The other use-case is the specification of constant label pairs in Opts or to
- // create a Desc.
- type Labels map[string]string
-
- // reservedLabelPrefix is a prefix which is not legal in user-supplied
- // label names.
- const reservedLabelPrefix = "__"
-
- var errInconsistentCardinality = errors.New("inconsistent label cardinality")
-
- func makeInconsistentCardinalityError(fqName string, labels, labelValues []string) error {
- return fmt.Errorf(
- "%w: %q has %d variable labels named %q but %d values %q were provided",
- errInconsistentCardinality, fqName,
- len(labels), labels,
- len(labelValues), labelValues,
- )
- }
-
- func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
- if len(labels) != expectedNumberOfValues {
- return fmt.Errorf(
- "%w: expected %d label values but got %d in %#v",
- errInconsistentCardinality, expectedNumberOfValues,
- len(labels), labels,
- )
- }
-
- for name, val := range labels {
- if !utf8.ValidString(val) {
- return fmt.Errorf("label %s: value %q is not valid UTF-8", name, val)
- }
- }
-
- return nil
- }
-
- func validateLabelValues(vals []string, expectedNumberOfValues int) error {
- if len(vals) != expectedNumberOfValues {
- return fmt.Errorf(
- "%w: expected %d label values but got %d in %#v",
- errInconsistentCardinality, expectedNumberOfValues,
- len(vals), vals,
- )
- }
-
- for _, val := range vals {
- if !utf8.ValidString(val) {
- return fmt.Errorf("label value %q is not valid UTF-8", val)
- }
- }
-
- return nil
- }
-
- func checkLabelName(l string) bool {
- return model.LabelName(l).IsValid() && !strings.HasPrefix(l, reservedLabelPrefix)
- }
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