bootstrap.go

package main

import (
	"fmt"
	"os"

	"github.com/elwinar/rambler/log"
	"github.com/kelseyhightower/envconfig"
	"github.com/urfave/cli"
)

// Bootstrap do the initialization job, and finish by setting the
// `service` global var that will be used by other commands.
func Bootstrap(ctx *cli.Context) error {
	return bootstrap(ctx.GlobalString("configuration"), ctx.GlobalString("environment"), ctx.GlobalBool("debug"), ctx.GlobalBool("dry-run"))
}

func bootstrap(configuration, environment string, debug, dryRun bool) (err error) {
	logger = log.NewLogger(func(l *log.Logger) {
		l.PrintDebug = debug
	})

	var cfg Configuration

	if configuration != DefaultConfiguration || exists(configuration) {
		logger.Debug("loading configuration from %s", configuration)
		cfg, err = Load(configuration)
		if err != nil {
			return fmt.Errorf("unable to load configuration from file: %s", err)
		}
	}

	err = envconfig.Process("rambler", &cfg)
	if err != nil {
		return fmt.Errorf("unable to load configuration from env: %s", err)
	}

	logger.Debug("loading environment %s", environment)
	env, err := cfg.Env(environment)
	if err != nil {
		return fmt.Errorf("unable to load requested environment: %s", err)
	}

	logger.Debug("initializing service")
	service, err = NewService(env, dryRun)
	if err != nil {
		return fmt.Errorf("unable to initialize the migration service: %s", err)
	}

	return nil
}

func exists(file string) bool {
	if _, err := os.Stat(file); err == nil {
		return true
	}
	return false
}