sys-exporter/config/config.go

package config

import (
	"fmt"
	"os"

	"github.com/goccy/go-yaml"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

const DefaultConfigFileLocation = "/etc/sys-exporter/config.yml"

type logConfigJson struct {
	Level string `yaml:"level"`
}

func (c logConfigJson) logConfig() (LogConfig, error) {
	lvl, err := zap.ParseAtomicLevel(c.Level)
	if err != nil {
		return LogConfig{}, err
	}
	return LogConfig{
		Level: lvl,
	}, nil
}

type appConfigJson struct {
	LogConfig  logConfigJson `yaml:"logging"`
	Collectors []string      `yaml:"collectors"`
}

func (c appConfigJson) appConfig() (AppConfig, error) {
	lc, err := c.LogConfig.logConfig()
	if err != nil {
		return AppConfig{}, err
	}

	return AppConfig{
		LogConfig:  lc,
		Collectors: c.Collectors,
	}, nil
}

type LogConfig struct {
	Level zap.AtomicLevel `yaml:"level"`
}

func (c *LogConfig) ZapConfig() zap.Config {
	zapC := zap.Config{
		Level:            c.Level,
		Development:      true, // TODO: remove later
		Encoding:         "console",
		EncoderConfig:    zap.NewDevelopmentEncoderConfig(),
		OutputPaths:      []string{"stdout"},
		ErrorOutputPaths: []string{"stderr"},
	}

	zapC.EncoderConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder

	return zapC
}

type AppConfig struct {
	LogConfig
	Collectors []string
}

func New(filepath string) (*AppConfig, error) {
	fileContent, err := os.ReadFile(filepath)
	if err != nil {
		return nil, fmt.Errorf("failed to open config file: %w", err)
	}

	var v appConfigJson
	if err := yaml.Unmarshal(fileContent, &v); err != nil {
		return nil, fmt.Errorf("failed to parse config file: %w", err)
	}
	trueConf, err := v.appConfig()
	if err != nil {
		return nil, fmt.Errorf("failed to validate config: %w", err)
	}
	return &trueConf, nil
}