config.go

package rmhttp

import (
	"fmt"

	"dario.cat/mergo"
	env "github.com/caarlos0/env/v11"
)

// ------------------------------------------------------------------------------------------------
// TIMEOUT CONFIG
// ------------------------------------------------------------------------------------------------

// The TimeoutConfig contains settings (with defaults) for configuring timeouts in the system.
// These settings mostly correlate to those used by the underlying http.Server
type TimeoutConfig struct {
	TCPReadTimeout         int    `env:"TCP_READ_TIMEOUT"         envDefault:"2"`
	TCPReadHeaderTimeout   int    `env:"TCP_READ_HEADER_TIMEOUT"  envDefault:"1"`
	TCPIdleTimeout         int    `env:"TCP_IDLE_TIMEOUT"         envDefault:"120"`
	TCPWriteTimeout        int    `env:"TCP_WRITE_TIMEOUT"        envDefault:"5"`
	TCPWriteTimeoutPadding int    `env:"TCP_WRITE_TIMEOUT_BUFFER" envDefault:"1"`
	RequestTimeout         int    `env:"HTTP_REQUEST_TIMEOUT"     envDefault:"7"`
	TimeoutMessage         string `env:"HTTP_TIMEOUT_MESSAGE"     envDefault:"Request Timeout"`
}

// ------------------------------------------------------------------------------------------------
// SSL CONFIG
// ------------------------------------------------------------------------------------------------

// The SSLConfig contains settings (with defaults) for configuring SSL in the server.
type SSLConfig struct {
	Enable bool   `env:"ENABLE_SSL"`
	Cert   string `env:"SSL_CERT"`
	Key    string `env:"SSL_KEY"`
}

// ------------------------------------------------------------------------------------------------
// CONFIG
// ------------------------------------------------------------------------------------------------

// The Config contains settings (with defaults) for configuring the app, server and router.
type Config struct {
	Host                         string `env:"HOST"`
	Port                         int    `env:"PORT"  envDefault:"8080"`
	Debug                        bool   `env:"DEBUG"`
	DisableGeneralOptionsHandler bool
	Logger                       Logger
	SSL                          SSLConfig
	Timeout                      TimeoutConfig
}

// loadConfig parses the environment variables defined in the Config objects (with defaults), then merges those
// with the config that the user may have supplied. This function only gets called during app initialisation.
//
// This function will return a completed config, or error if the environment variables cannot be parsed.
func LoadConfig(cfg Config) (Config, error) {
	config := Config{}
	if err := env.Parse(&config); err != nil {
		return config, fmt.Errorf("failed to load environment variables: %v", err)
	}

	// Merge the main config
	err := mergo.Merge(&config, cfg, mergo.WithOverride)
	if err != nil {
		return config, fmt.Errorf("failed to merge user supplied and default configs: %v", err)
	}

	// Merge the SSL config
	err = mergo.Merge(&config.SSL, cfg.SSL, mergo.WithOverride)
	if err != nil {
		return config, fmt.Errorf("failed to merge user supplied and default SSL configs: %v", err)
	}

	// Merge the Timeout config
	err = mergo.Merge(&config.Timeout, cfg.Timeout, mergo.WithOverride)
	if err != nil {
		return config, fmt.Errorf(
			"failed to merge user supplied and default Timeout configs: %v",
			err,
		)
	}

	return config, nil
}