server/backend/generation.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path"
	"runtime"
	"sync"

	"srs.epita.fr/fic-server/libfic"
)

type GenerateType int

const (
	GenPublic GenerateType = iota
	GenEvents
	GenTeams
	GenThemes
)

type genStruct struct {
	Id   string
	Type GenerateType
}

var parallelJobs = runtime.NumCPU()
var genTeamQueue chan *fic.Team
var genQueue chan genStruct
var inQueueMutex sync.RWMutex
var inGenQueue map[GenerateType]bool

func init() {
	genTeamQueue = make(chan *fic.Team)
	genQueue = make(chan genStruct)
	inGenQueue = map[GenerateType]bool{}
}

func launchWorkers() {
	log.Println("Running with", parallelJobs, "worker(s)")
	for i := parallelJobs; i > 0; i-- {
		go consumer()
	}
}

func appendGenQueue(gs genStruct) {
	inQueueMutex.RLock()
	if v, ok := inGenQueue[gs.Type]; !ok || !v {
		inQueueMutex.RUnlock()

		inQueueMutex.Lock()
		inGenQueue[gs.Type] = true
		inQueueMutex.Unlock()

		genQueue <- gs
	} else {
		inQueueMutex.RUnlock()
	}
}

func consumer() {
	for {
		var id string
		var err error

		select {
		case gt := <-genTeamQueue:
			err = genTeamMyFile(gt)

		case gs := <-genQueue:
			id = gs.Id

			inQueueMutex.Lock()
			inGenQueue[gs.Type] = false
			inQueueMutex.Unlock()

			switch gs.Type {
			case GenPublic:
				err = genMyPublicFile()
			case GenEvents:
				err = genEventsFile()
			case GenTeams:
				err = genTeamsFile()
			case GenThemes:
				err = genThemesFile()
			}
		}

		if err != nil {
			log.Println(id, "[ERR] Unable to generate:", err)
		}
	}
}

// Generate issues.json for a given team
func genTeamIssuesFile(team *fic.Team) error {
	dirPath := path.Join(TeamsDir, fmt.Sprintf("%d", team.Id))

	if s, err := os.Stat(dirPath); os.IsNotExist(err) {
		os.MkdirAll(dirPath, 0777)
	} else if !s.IsDir() {
		return fmt.Errorf("%s is not a directory", dirPath)
	}

	if my, err := team.MyIssueFile(); err != nil {
		return err
	} else if j, err := json.Marshal(my); err != nil {
		return err
	} else if err = ioutil.WriteFile(path.Join(dirPath, "issues.json"), j, 0644); err != nil {
		return err
	}

	return nil
}

// Generate my.json and wait.json for a given team
func genTeamMyFile(team *fic.Team) error {
	dirPath := path.Join(TeamsDir, fmt.Sprintf("%d", team.Id))

	if s, err := os.Stat(dirPath); os.IsNotExist(err) {
		os.MkdirAll(dirPath, 0777)
	} else if !s.IsDir() {
		return fmt.Errorf("%s is not a directory", dirPath)
	}

	if my, err := fic.MyJSONTeam(team, true); err != nil {
		return err
	} else if j, err := json.Marshal(my); err != nil {
		return err
	} else if err = ioutil.WriteFile(path.Join(dirPath, "my.json"), j, 0666); err != nil {
		return err
	}

	// Speed up generation when challenge is started
	if !ChStarted {
		if my, err := fic.MyJSONTeam(team, false); err != nil {
			return err
		} else if j, err := json.Marshal(my); err != nil {
			return err
		} else if err = ioutil.WriteFile(path.Join(dirPath, "wait.json"), j, 0666); err != nil {
			return err
		}
	}

	return nil
}

// Generate public my.json file
func genMyPublicFile() error {
	dirPath := path.Join(TeamsDir, "public")

	if s, err := os.Stat(dirPath); os.IsNotExist(err) {
		os.MkdirAll(dirPath, 0777)
	} else if !s.IsDir() {
		return fmt.Errorf("%s is not a directory", dirPath)
	}

	if my, err := fic.MyJSONTeam(nil, true); err != nil {
		return err
	} else if j, err := json.Marshal(my); err != nil {
		return err
	} else if err = ioutil.WriteFile(path.Join(dirPath, "my.json"), j, 0666); err != nil {
		return err
	}

	os.Symlink("my.json", path.Join(dirPath, "wait.json"))

	if teams, err := fic.ExportTeams(true); err != nil {
		return err
	} else if j, err := json.Marshal(teams); err != nil {
		return err
	} else if err = ioutil.WriteFile(path.Join(dirPath, "teams.json"), j, 0666); err != nil {
		return err
	}

	return nil
}

// Generate general evemts.json file
func genEventsFile() error {
	if evts, err := fic.GetLastEvents(); err != nil {
		return err
	} else if j, err := json.Marshal(evts); err != nil {
		return err
	} else if err = ioutil.WriteFile(path.Join(TeamsDir, "events.json"), j, 0666); err != nil {
		return err
	}

	return nil
}

// Generate general teams.json file
func genTeamsFile() error {
	if teams, err := fic.ExportTeams(false); err != nil {
		return err
	} else if j, err := json.Marshal(teams); err != nil {
		return err
	} else if err = ioutil.WriteFile(path.Join(TeamsDir, "teams.json"), j, 0666); err != nil {
		return err
	}

	if teams, err := fic.ExportTeams(true); err != nil {
		return err
	} else if j, err := json.Marshal(teams); err != nil {
		return err
	} else if err = ioutil.WriteFile(path.Join(TeamsDir, "public", "teams.json"), j, 0666); err != nil {
		return err
	}

	return nil
}

// Generate general themes.json file
func genThemesFile() error {
	if themes, err := fic.ExportThemes(); err != nil {
		return err
	} else if j, err := json.Marshal(themes); err != nil {
		return err
	} else if err = ioutil.WriteFile(path.Join(TeamsDir, "themes.json"), j, 0666); err != nil {
		return err
	}

	return nil
}

func genAll() {
	appendGenQueue(genStruct{Type: GenThemes})
	appendGenQueue(genStruct{Type: GenTeams})
	appendGenQueue(genStruct{Type: GenEvents})
	appendGenQueue(genStruct{Type: GenPublic})

	if teams, err := fic.GetActiveTeams(); err != nil {
		log.Println("Team retrieval error: ", err)
	} else {
		for _, team := range teams {
			myteam := team // team is reused, we need to create a new variable here to store the value
			genTeamQueue <- myteam
		}
	}
}