windows_exporter/config/config.go

85 lines
2.1 KiB
Go

// Copyright 2018 Prometheus Team
// 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 config
import (
"io/ioutil"
"os"
"github.com/alecthomas/kingpin/v2"
"github.com/prometheus-community/windows_exporter/log"
"gopkg.in/yaml.v3"
)
type getFlagger interface {
GetFlag(name string) *kingpin.FlagClause
}
// Resolver represents a configuration file resolver for kingpin.
type Resolver struct {
flags map[string]string
}
// NewResolver returns a Resolver structure.
func NewResolver(file string) (*Resolver, error) {
flags := map[string]string{}
log.Infof("Loading configuration file: %v", file)
if _, err := os.Stat(file); err != nil {
return nil, err
}
b, err := ioutil.ReadFile(file)
if err != nil {
return nil, err
}
var rawValues map[string]interface{}
err = yaml.Unmarshal(b, &rawValues)
if err != nil {
return nil, err
}
// Flatten nested YAML values
flattenedValues := flatten(rawValues)
for k, v := range flattenedValues {
if _, ok := flags[k]; !ok {
flags[k] = v
}
}
return &Resolver{flags: flags}, nil
}
func (c *Resolver) setDefault(v getFlagger) {
for name, value := range c.flags {
f := v.GetFlag(name)
if f != nil {
f.Default(value)
}
}
}
// Bind sets active flags with their default values from the configuration file(s).
func (c *Resolver) Bind(app *kingpin.Application, args []string) error {
// Parse the command line arguments to get the selected command.
pc, err := app.ParseContext(args)
if err != nil {
return err
}
c.setDefault(app)
if pc.SelectedCommand != nil {
c.setDefault(pc.SelectedCommand)
}
return nil
}