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329 lines
11 KiB
329 lines
11 KiB
// Copyright 2015 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 relabel
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import (
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"crypto/md5"
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"encoding/binary"
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"fmt"
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"strconv"
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"strings"
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"github.com/grafana/regexp"
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"github.com/prometheus/common/model"
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"github.com/prometheus/prometheus/model/labels"
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)
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var (
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relabelTarget = regexp.MustCompile(`^(?:(?:[a-zA-Z_]|\$(?:\{\w+\}|\w+))+\w*)+$`)
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DefaultRelabelConfig = Config{
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Action: Replace,
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Separator: ";",
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Regex: MustNewRegexp("(.*)"),
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Replacement: "$1",
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}
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)
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// Action is the action to be performed on relabeling.
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type Action string
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const (
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// Replace performs a regex replacement.
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Replace Action = "replace"
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// Keep drops targets for which the input does not match the regex.
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Keep Action = "keep"
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// Drop drops targets for which the input does match the regex.
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Drop Action = "drop"
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// KeepEqual drops targets for which the input does not match the target.
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KeepEqual Action = "keepequal"
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// DropEqual drops targets for which the input does match the target.
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DropEqual Action = "dropequal"
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// HashMod sets a label to the modulus of a hash of labels.
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HashMod Action = "hashmod"
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// LabelMap copies labels to other labelnames based on a regex.
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LabelMap Action = "labelmap"
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// LabelDrop drops any label matching the regex.
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LabelDrop Action = "labeldrop"
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// LabelKeep drops any label not matching the regex.
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LabelKeep Action = "labelkeep"
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// Lowercase maps input letters to their lower case.
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Lowercase Action = "lowercase"
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// Uppercase maps input letters to their upper case.
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Uppercase Action = "uppercase"
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)
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// UnmarshalYAML implements the yaml.Unmarshaler interface.
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func (a *Action) UnmarshalYAML(unmarshal func(interface{}) error) error {
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var s string
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if err := unmarshal(&s); err != nil {
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return err
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}
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switch act := Action(strings.ToLower(s)); act {
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case Replace, Keep, Drop, HashMod, LabelMap, LabelDrop, LabelKeep, Lowercase, Uppercase, KeepEqual, DropEqual:
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*a = act
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return nil
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}
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return fmt.Errorf("unknown relabel action %q", s)
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}
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// Config is the configuration for relabeling of target label sets.
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type Config struct {
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// A list of labels from which values are taken and concatenated
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// with the configured separator in order.
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SourceLabels model.LabelNames `yaml:"source_labels,flow,omitempty"`
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// Separator is the string between concatenated values from the source labels.
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Separator string `yaml:"separator,omitempty"`
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// Regex against which the concatenation is matched.
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Regex Regexp `yaml:"regex,omitempty"`
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// Modulus to take of the hash of concatenated values from the source labels.
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Modulus uint64 `yaml:"modulus,omitempty"`
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// TargetLabel is the label to which the resulting string is written in a replacement.
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// Regexp interpolation is allowed for the replace action.
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TargetLabel string `yaml:"target_label,omitempty"`
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// Replacement is the regex replacement pattern to be used.
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Replacement string `yaml:"replacement,omitempty"`
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// Action is the action to be performed for the relabeling.
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Action Action `yaml:"action,omitempty"`
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}
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// UnmarshalYAML implements the yaml.Unmarshaler interface.
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func (c *Config) UnmarshalYAML(unmarshal func(interface{}) error) error {
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*c = DefaultRelabelConfig
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type plain Config
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if err := unmarshal((*plain)(c)); err != nil {
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return err
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}
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if c.Regex.Regexp == nil {
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c.Regex = MustNewRegexp("")
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}
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return c.Validate()
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}
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func (c *Config) Validate() error {
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if c.Action == "" {
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return fmt.Errorf("relabel action cannot be empty")
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}
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if c.Modulus == 0 && c.Action == HashMod {
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return fmt.Errorf("relabel configuration for hashmod requires non-zero modulus")
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}
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if (c.Action == Replace || c.Action == HashMod || c.Action == Lowercase || c.Action == Uppercase || c.Action == KeepEqual || c.Action == DropEqual) && c.TargetLabel == "" {
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return fmt.Errorf("relabel configuration for %s action requires 'target_label' value", c.Action)
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}
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if c.Action == Replace && !strings.Contains(c.TargetLabel, "$") && !model.LabelName(c.TargetLabel).IsValid() {
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return fmt.Errorf("%q is invalid 'target_label' for %s action", c.TargetLabel, c.Action)
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}
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if c.Action == Replace && strings.Contains(c.TargetLabel, "$") && !relabelTarget.MatchString(c.TargetLabel) {
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return fmt.Errorf("%q is invalid 'target_label' for %s action", c.TargetLabel, c.Action)
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}
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if (c.Action == Lowercase || c.Action == Uppercase || c.Action == KeepEqual || c.Action == DropEqual) && !model.LabelName(c.TargetLabel).IsValid() {
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return fmt.Errorf("%q is invalid 'target_label' for %s action", c.TargetLabel, c.Action)
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}
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if (c.Action == Lowercase || c.Action == Uppercase || c.Action == KeepEqual || c.Action == DropEqual) && c.Replacement != DefaultRelabelConfig.Replacement {
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return fmt.Errorf("'replacement' can not be set for %s action", c.Action)
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}
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if c.Action == LabelMap && !relabelTarget.MatchString(c.Replacement) {
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return fmt.Errorf("%q is invalid 'replacement' for %s action", c.Replacement, c.Action)
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}
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if c.Action == HashMod && !model.LabelName(c.TargetLabel).IsValid() {
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return fmt.Errorf("%q is invalid 'target_label' for %s action", c.TargetLabel, c.Action)
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}
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if c.Action == DropEqual || c.Action == KeepEqual {
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if c.Regex != DefaultRelabelConfig.Regex ||
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c.Modulus != DefaultRelabelConfig.Modulus ||
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c.Separator != DefaultRelabelConfig.Separator ||
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c.Replacement != DefaultRelabelConfig.Replacement {
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return fmt.Errorf("%s action requires only 'source_labels' and `target_label`, and no other fields", c.Action)
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}
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}
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if c.Action == LabelDrop || c.Action == LabelKeep {
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if c.SourceLabels != nil ||
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c.TargetLabel != DefaultRelabelConfig.TargetLabel ||
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c.Modulus != DefaultRelabelConfig.Modulus ||
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c.Separator != DefaultRelabelConfig.Separator ||
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c.Replacement != DefaultRelabelConfig.Replacement {
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return fmt.Errorf("%s action requires only 'regex', and no other fields", c.Action)
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}
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}
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return nil
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}
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// Regexp encapsulates a regexp.Regexp and makes it YAML marshalable.
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type Regexp struct {
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*regexp.Regexp
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}
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// NewRegexp creates a new anchored Regexp and returns an error if the
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// passed-in regular expression does not compile.
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func NewRegexp(s string) (Regexp, error) {
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regex, err := regexp.Compile("^(?:" + s + ")$")
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return Regexp{Regexp: regex}, err
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}
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// MustNewRegexp works like NewRegexp, but panics if the regular expression does not compile.
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func MustNewRegexp(s string) Regexp {
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re, err := NewRegexp(s)
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if err != nil {
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panic(err)
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}
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return re
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}
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// UnmarshalYAML implements the yaml.Unmarshaler interface.
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func (re *Regexp) UnmarshalYAML(unmarshal func(interface{}) error) error {
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var s string
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if err := unmarshal(&s); err != nil {
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return err
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}
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r, err := NewRegexp(s)
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if err != nil {
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return err
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}
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*re = r
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return nil
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}
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// MarshalYAML implements the yaml.Marshaler interface.
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func (re Regexp) MarshalYAML() (interface{}, error) {
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if re.String() != "" {
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return re.String(), nil
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}
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return nil, nil
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}
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// IsZero implements the yaml.IsZeroer interface.
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func (re Regexp) IsZero() bool {
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return re.Regexp == DefaultRelabelConfig.Regex.Regexp
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}
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// String returns the original string used to compile the regular expression.
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func (re Regexp) String() string {
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if re.Regexp == nil {
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return ""
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}
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str := re.Regexp.String()
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// Trim the anchor `^(?:` prefix and `)$` suffix.
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return str[4 : len(str)-2]
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}
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// Process returns a relabeled version of the given label set. The relabel configurations
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// are applied in order of input.
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// There are circumstances where Process will modify the input label.
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// If you want to avoid issues with the input label set being modified, at the cost of
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// higher memory usage, you can use lbls.Copy().
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// If a label set is dropped, EmptyLabels and false is returned.
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func Process(lbls labels.Labels, cfgs ...*Config) (ret labels.Labels, keep bool) {
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lb := labels.NewBuilder(lbls)
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if !ProcessBuilder(lb, cfgs...) {
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return labels.EmptyLabels(), false
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}
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return lb.Labels(), true
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}
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// ProcessBuilder is like Process, but the caller passes a labels.Builder
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// containing the initial set of labels, which is mutated by the rules.
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func ProcessBuilder(lb *labels.Builder, cfgs ...*Config) (keep bool) {
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for _, cfg := range cfgs {
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keep = relabel(cfg, lb)
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if !keep {
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return false
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}
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}
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return true
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}
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func relabel(cfg *Config, lb *labels.Builder) (keep bool) {
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var va [16]string
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values := va[:0]
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if len(cfg.SourceLabels) > cap(values) {
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values = make([]string, 0, len(cfg.SourceLabels))
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}
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for _, ln := range cfg.SourceLabels {
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values = append(values, lb.Get(string(ln)))
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}
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val := strings.Join(values, cfg.Separator)
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switch cfg.Action {
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case Drop:
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if cfg.Regex.MatchString(val) {
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return false
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}
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case Keep:
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if !cfg.Regex.MatchString(val) {
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return false
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}
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case DropEqual:
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if lb.Get(cfg.TargetLabel) == val {
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return false
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}
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case KeepEqual:
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if lb.Get(cfg.TargetLabel) != val {
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return false
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}
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case Replace:
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indexes := cfg.Regex.FindStringSubmatchIndex(val)
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// If there is no match no replacement must take place.
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if indexes == nil {
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break
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}
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target := model.LabelName(cfg.Regex.ExpandString([]byte{}, cfg.TargetLabel, val, indexes))
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if !target.IsValid() {
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break
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}
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res := cfg.Regex.ExpandString([]byte{}, cfg.Replacement, val, indexes)
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if len(res) == 0 {
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lb.Del(string(target))
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break
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}
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lb.Set(string(target), string(res))
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case Lowercase:
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lb.Set(cfg.TargetLabel, strings.ToLower(val))
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case Uppercase:
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lb.Set(cfg.TargetLabel, strings.ToUpper(val))
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case HashMod:
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hash := md5.Sum([]byte(val))
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// Use only the last 8 bytes of the hash to give the same result as earlier versions of this code.
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mod := binary.BigEndian.Uint64(hash[8:]) % cfg.Modulus
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lb.Set(cfg.TargetLabel, strconv.FormatUint(mod, 10))
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case LabelMap:
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lb.Range(func(l labels.Label) {
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if cfg.Regex.MatchString(l.Name) {
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res := cfg.Regex.ReplaceAllString(l.Name, cfg.Replacement)
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lb.Set(res, l.Value)
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}
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})
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case LabelDrop:
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lb.Range(func(l labels.Label) {
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if cfg.Regex.MatchString(l.Name) {
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lb.Del(l.Name)
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}
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})
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case LabelKeep:
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lb.Range(func(l labels.Label) {
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if !cfg.Regex.MatchString(l.Name) {
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lb.Del(l.Name)
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}
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})
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default:
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panic(fmt.Errorf("relabel: unknown relabel action type %q", cfg.Action))
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}
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return true
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}
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