program.go

package cmd

import (
	"fmt"
	"net/http"
	"os"
	"strings"

	"github.com/golang-migrate/migrate/v4/source"
	"github.com/jessevdk/go-flags"
	"github.com/jmoiron/sqlx"
	"github.com/rs/zerolog"

	"orus.io/orus-io/go-orusapi"
	"orus.io/orus-io/go-orusapi/database"
)

type ConfigFile struct {
	ConfigFile string `long:"config" short:"c" env:"CONFIG" no-ini:"t" description:"A configuration file"`
}

type InfoOptions struct {
	Environment string `long:"environment" env:"ENVIRONMENT" ini-name:"environment" default:"default" description:"A environment name, used in sentry and prometheus"`
}

type Program struct {
	BootstrapParser *flags.Parser
	Parser          *flags.Parser

	Logger zerolog.Logger

	ConfigFileOption ConfigFile
	InfoOptions      InfoOptions
	LoggingOptions   *orusapi.LoggingOptions
	DatabaseOptions  database.Options

	DB *sqlx.DB

	ServeCmd   *ServeCmd
	MigrateCmd *MigrateCmd

	hasDB           bool
	dbMigrateSource source.Driver

	setupHandler func(*Program) http.Handler
}

type Option func(program *Program)

func WithHandler(factory func(*Program) http.Handler) Option {
	return func(program *Program) {
		program.setupHandler = factory
	}
}

func WithDatabase(migrateSource source.Driver) Option {
	return func(program *Program) {
		program.hasDB = true
		program.dbMigrateSource = migrateSource
	}
}

func NewProgram(name string, options ...Option) *Program {
	bootstrapParser := flags.NewNamedParser(name, flags.IgnoreUnknown)
	parser := flags.NewNamedParser(name, flags.HelpFlag|flags.PassDoubleDash)

	program := Program{
		BootstrapParser: bootstrapParser,
		Parser:          parser,
		Logger:          orusapi.DefaultLogger(os.Stdout),
	}

	for _, opt := range options {
		opt(&program)
	}

	program.LoggingOptions = orusapi.MustLoggingOptions(
		orusapi.NewLoggingOptions(&program.Logger, os.Stdout))

	bootstrapParser.NamespaceDelimiter = "-"
	bootstrapParser.EnvNamespaceDelimiter = "_"
	bootstrapParser.EnvNamespace = strings.ToUpper(name)

	if _, err := bootstrapParser.AddGroup(
		"Configuration", "Configuration file", &program.ConfigFileOption,
	); err != nil {
		panic(err)
	}

	if _, err := parser.AddGroup("Configuration", "Configuration file", &program.ConfigFileOption); err != nil {
		panic(err)
	}
	if _, err := parser.AddGroup("Info", "Info options", &program.InfoOptions); err != nil {
		panic(err)
	}

	{
		g, err := parser.AddGroup("Logging", "Logging options", program.LoggingOptions)
		if err != nil {
			panic(err)
		}
		g.Namespace = "log"
		g.EnvNamespace = "LOG"
	}

	program.ServeCmd = SetupServeCmd(&program)

	if program.hasDB {
		g, err := parser.AddGroup("Database", "Database options", &program.DatabaseOptions)
		if err != nil {
			panic(err)
		}
		g.Namespace = "db"
		g.EnvNamespace = "DB"

		program.MigrateCmd = SetupMigrateCmd(&program)
	}

	return &program
}

func (program *Program) ParseArgs(args []string) int {
	if _, err := program.BootstrapParser.ParseArgs(args); err != nil {
		program.Logger.Err(err).Msg("could not parse command line")

		return 1
	}
	if program.ConfigFileOption.ConfigFile != "" {
		program.Logger.Debug().Str("configfile", program.ConfigFileOption.ConfigFile).Msg("parsing configuration file")
		iniParser := flags.NewIniParser(program.Parser)
		if err := iniParser.ParseFile(program.ConfigFileOption.ConfigFile); err != nil {
			program.Logger.Err(err).Msg("")

			return 1
		}
	}

	if _, err := program.Parser.Parse(); err != nil {
		code := 1
		if fe, ok := err.(*flags.Error); ok {
			if fe.Type == flags.ErrHelp {
				code = 0
				// this error actually contains a help message for the user
				// so we print it on the console
				fmt.Println(err)
			} else {
				program.Logger.Error().Msg(err.Error())
			}
		} else {
			program.Logger.Err(err).Msg("")
		}

		return code
	}

	return 0
}

func (program *Program) EnsureDB() error {
	if !program.hasDB {
		return nil
	}

	program.Logger.Debug().Msg("Connecting to the database...")

	if err := database.IsUptodate(
		program.DatabaseOptions.DSN, program.dbMigrateSource,
	); err != nil {
		return err
	}

	db, err := program.DatabaseOptions.Open()
	if err != nil {
		return err
	}

	if err := db.Ping(); err != nil {
		return err
	}

	program.DB = db

	program.Logger.Info().Msg("Connected to the database")

	return nil
}

func (program *Program) CloseDB() {
	if !program.hasDB || program.DB == nil {
		return
	}
	if err := program.DB.Close(); err != nil {
		program.Logger.Err(err).Msg("could not close database connection properly")
	}
}