gitivity/config.go

package main

import (
	"errors"
	"fmt"

	"github.com/yuin/gopher-lua"
)

// Server holds information about a Gitea server.
type Server struct {
	servername string
	url        string
	username   string
	token      string
	primary    bool
}

// Servers holds all of the server structures.
type Servers map[string]*Server

// getPrimary gets the primary server contained in this map. Returns an error if no primary server is defined.
func (servers *Servers) getPrimary() (*Server, error) {
	for _, s := range *servers {
		if s.primary {
			return s, nil
		}
	}
	return &Server{}, errors.New("No primary server found.")
}

// Configuration holds data retrieved from a Lua script.
type Configuration struct {
	servers Servers
}

// getStringFromTable parses a text value from the configuration file.
func getStringFromTable(L *lua.LState, lobj lua.LValue, key string, out *string) error {
	lv := L.GetTable(lobj, lua.LString(key))
	if text, ok := lv.(lua.LString); ok {
		*out = string(text)
	} else {
		return errors.New("Text is not a string!")
	}
	return nil
}

// getBoolFromTable parses a boolean value from the configuration file.
func getBoolFromTable(L *lua.LState, lobj lua.LValue, key string, out *bool) error {
	lv := L.GetTable(lobj, lua.LString(key))
	if val, ok := lv.(lua.LBool); ok {
		*out = bool(val)
	} else {
		return errors.New(fmt.Sprintf("Failed to get configuration value '%s'", key))
	}
	return nil
}

// parseServerFromTable parses a Lua table into a Server structure.
func parseServerFromTable(L *lua.LState, table lua.LValue) (Server, error) {
	server := Server{}
	if err := getStringFromTable(L, table, "servername", &server.servername); err != nil {
		return server, err
	}
	if err := getStringFromTable(L, table, "username", &server.username); err != nil {
		return server, err
	}
	if err := getStringFromTable(L, table, "token", &server.token); err != nil {
		return server, err
	}
	if err := getStringFromTable(L, table, "url", &server.url); err != nil {
		return server, err
	}

	lv := L.GetTable(table, lua.LString("primary"))
	if val, ok := lv.(lua.LBool); ok {
		server.primary = bool(val)
	} else if _, ok := lv.(*lua.LNilType); !ok {
		panic("Config error : " + server.servername + " : Primary is neither nil nor boolean")
	}

	return server, nil
}

// Configuration.Parse parses a Lua configuration file into a Configuration struct.
func (config *Configuration) Parse(fname string) error {
	config.servers = make(map[string]*Server)
	L := lua.NewState()
	defer L.Close()

	L.DoFile(fname)
	table := L.Get(-1)

	found_primary := false
	for i := 1; i <= L.ObjLen(table); i++ {
		lserver := L.GetTable(table, lua.LNumber(i))
		if server, err := parseServerFromTable(L, lserver); err == nil {
			if !found_primary && server.primary {
				found_primary = true
			} else if server.primary {
				panic("Config error : " + server.servername + " : Cannot have multiple primary servers!")
			}
			config.servers[server.servername] = &server
		} else {
			return err
		}
	}
	return nil
}