martin-helmich/prometheus-nginxlog-exporter

package config

import (
    "fmt"
    "regexp"
)

// RelabelConfig is a struct describing a single re-labeling configuration for taking
// over label values from an access log line into a Prometheus metric
type RelabelConfig struct {
    TargetLabel string              `hcl:",key" yaml:"target_label"`
    SourceValue string              `hcl:"from" yaml:"from"`
    Whitelist   []string            `hcl:"whitelist"`
    Matches     []RelabelValueMatch `hcl:"match"`
    Split       int                 `hcl:"split"`
    Separator   string              `hcl:"separator"`
    OnlyCounter bool                `hcl:"only_counter" yaml:"only_counter"`

    WhitelistExists bool
    WhitelistMap    map[string]interface{}
}

// RelabelValueMatch describes a single label match statement
type RelabelValueMatch struct {
    RegexpString string `hcl:",key" yaml:"regexp"`
    Replacement  string `hcl:"replacement"`

    CompiledRegexp *regexp.Regexp
}

// Compile compiles expressions and lookup tables for efficient later use
func (c *RelabelConfig) Compile() error {
    c.WhitelistMap = make(map[string]interface{})
    c.WhitelistExists = len(c.Whitelist) > 0

    for i := range c.Whitelist {
        c.WhitelistMap[c.Whitelist[i]] = nil
    }

    for i := range c.Matches {
        if c.Matches[i].RegexpString != "" {
            r, err := regexp.Compile(c.Matches[i].RegexpString)
            if err != nil {
                return fmt.Errorf("could not compile regexp '%s': %s", c.Matches[i].RegexpString, err.Error())
            }

            c.Matches[i].CompiledRegexp = r
        }
    }

    return nil
}