config.go

package config

import (
	"context"
	"fmt"
	"io/ioutil"
	"time"

	"github.com/anz-bank/sysl-go/common"
	"github.com/anz-bank/sysl-go/validator"

	"github.com/mitchellh/mapstructure"
	"gopkg.in/yaml.v2"
)

type DefaultConfig struct {
	Library LibraryConfig `yaml:"library"`
	GenCode GenCodeConfig `yaml:"genCode"`

	// development config can be used to set some config options only appropriate for dev/test environments.
	Development *DevelopmentConfig `yaml:"development"`
}

// LoadConfig reads and validates a configuration loaded from file.
// file: the path to the yaml-encoded config file
// defaultConfig: a pointer to the default config struct to populate
// customConfig: a pointer to the custom config struct to populate.
func LoadConfig(file string, defaultConfig *DefaultConfig, customConfig interface{}) error {
	b, err := ioutil.ReadFile(file)
	if err != nil {
		return fmt.Errorf("read config file error: %s", err)
	}

	if err = yaml.Unmarshal(b, customConfig); err != nil {
		return fmt.Errorf("unmarshal config file error: %s", err)
	}

	c := make(map[string]interface{})
	if err = yaml.Unmarshal(b, &c); err != nil {
		return fmt.Errorf("unmarshal config file error: %s", err)
	}

	decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
		Metadata:   nil,
		DecodeHook: mapstructure.StringToTimeDurationHookFunc(),
		Result:     defaultConfig,
	})
	if err != nil {
		return err
	}

	err = decoder.Decode(c)
	if err != nil {
		return err
	}

	err = validator.Validate(defaultConfig)
	if err != nil {
		return err
	}

	err = validator.Validate(customConfig)
	if err != nil {
		return err
	}

	return err
}

func NewCallback(
	config *GenCodeConfig,
	downstreamTimeOut time.Duration,
	mapError func(ctx context.Context, err error) *common.HTTPError,
) common.Callback {
	// construct the rest configuration (aka. gen callback)
	return common.Callback{
		UpstreamTimeout:   config.Upstream.ContextTimeout,
		DownstreamTimeout: downstreamTimeOut,
		RouterBasePath:    config.Upstream.HTTP.BasePath,
		UpstreamConfig:    &config.Upstream,
		MapErrorFunc:      mapError,
	}
}