| // 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( |
| "%s: %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( |
| "%s: 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( |
| "%s: 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) |
| } |