add server shutdown log

.gitignore

@@ -1 +1,4 @@
 .idea/
+cache/
+
+/config.toml

AGENTS.md

@@ -0,0 +1,9 @@
+## Role
+
+Write code like a Go Senior Developer. 
+Use the best practices, write modern idiomatic code, and handle all errors. 
+Keep an eye on security.
+
+## Context
+
+- go 1.25.5

README.md

@@ -0,0 +1,32 @@
+# Trackers
+
+Опрашивает ссылки со списками torrent-трекеров, 
+соединяет их в один список. Поддерживает кеширование,
+http, file источники.
+
+Учебный проект.
+
+## Запуск
+
+```shell
+trackers --config config.toml
+```
+
+Получение списка трекеров:
+
+```shell
+curl http://127.0.0.1:8080/list
+```
+
+## Конфигурация
+
+Источники для трекеров описываются в toml-конфиге:
+
+```toml
+port = 8080
+
+sources = [
+    "https://example.com",
+    "file:///home/user/local-file.txt",
+]
+```

go.mod

@@ -1,3 +1,5 @@
 module git.vakhrushev.me/av/trackers
 
 go 1.25.5
+
+require github.com/pelletier/go-toml/v2 v2.2.4

go.sum

@@ -0,0 +1,2 @@
+github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
+github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=

main.go

@@ -0,0 +1,318 @@
+package main
+
+import (
+	"context"
+	"crypto/sha1"
+	"encoding/hex"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"sort"
+	"strings"
+	"sync"
+	"syscall"
+	"time"
+
+	toml "github.com/pelletier/go-toml/v2"
+)
+
+type Config struct {
+	Port         int      `toml:"port"`
+	PollInterval string   `toml:"poll_interval"`
+	CacheDir     string   `toml:"cache_dir"`
+	Sources      []string `toml:"sources"`
+}
+
+func loadConfig(path string) (Config, time.Duration, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return Config{}, 0, fmt.Errorf("read config: %w", err)
+	}
+
+	var cfg Config
+	if err := toml.Unmarshal(data, &cfg); err != nil {
+		return Config{}, 0, fmt.Errorf("parse config: %w", err)
+	}
+
+	if cfg.Port == 0 {
+		cfg.Port = 8080
+	}
+	if cfg.CacheDir == "" {
+		cfg.CacheDir = "cache"
+	}
+	intervalText := cfg.PollInterval
+	if intervalText == "" {
+		intervalText = "60m"
+	}
+
+	interval, err := time.ParseDuration(intervalText)
+	if err != nil {
+		return Config{}, 0, fmt.Errorf("parse poll_interval: %w", err)
+	}
+	if interval <= 0 {
+		return Config{}, 0, errors.New("poll_interval must be positive")
+	}
+
+	if len(cfg.Sources) == 0 {
+		return Config{}, 0, errors.New("no sources configured")
+	}
+
+	return cfg, interval, nil
+}
+
+type Aggregator struct {
+	mu        sync.RWMutex
+	perSource map[string]map[string]struct{}
+}
+
+func NewAggregator() *Aggregator {
+	return &Aggregator{perSource: make(map[string]map[string]struct{})}
+}
+
+func (a *Aggregator) Update(source string, links []string) {
+	set := make(map[string]struct{}, len(links))
+	for _, link := range links {
+		set[link] = struct{}{}
+	}
+
+	a.mu.Lock()
+	a.perSource[source] = set
+	a.mu.Unlock()
+}
+
+func (a *Aggregator) List() []string {
+	a.mu.RLock()
+	defer a.mu.RUnlock()
+
+	combined := make(map[string]struct{})
+	for _, set := range a.perSource {
+		for link := range set {
+			combined[link] = struct{}{}
+		}
+	}
+
+	list := make([]string, 0, len(combined))
+	for link := range combined {
+		list = append(list, link)
+	}
+
+	sort.Strings(list)
+	return list
+}
+
+func main() {
+	configPath := flag.String("config", "config.toml", "path to config file")
+	flag.Parse()
+
+	cfg, interval, err := loadConfig(*configPath)
+	if err != nil {
+		log.Fatalf("config error: %v", err)
+	}
+
+	if err := os.MkdirAll(cfg.CacheDir, 0o755); err != nil {
+		log.Fatalf("cache dir: %v", err)
+	}
+
+	agg := NewAggregator()
+
+	client := &http.Client{Timeout: 15 * time.Second}
+
+	for _, source := range cfg.Sources {
+		cached, err := loadCachedLinks(cfg.CacheDir, source)
+		if err != nil {
+			log.Printf("load cache for %s: %v", source, err)
+		}
+		if len(cached) > 0 {
+			agg.Update(source, cached)
+		}
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	for _, source := range cfg.Sources {
+		go pollSource(ctx, source, interval, cfg.CacheDir, agg, client)
+	}
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/list", func(w http.ResponseWriter, r *http.Request) {
+		links := agg.List()
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		for i, link := range links {
+			if i > 0 {
+				_, _ = w.Write([]byte("\n\n"))
+			}
+			_, _ = w.Write([]byte(link))
+		}
+	})
+
+	server := &http.Server{
+		Addr:              fmt.Sprintf(":%d", cfg.Port),
+		Handler:           mux,
+		ReadHeaderTimeout: 5 * time.Second,
+		ReadTimeout:       10 * time.Second,
+		WriteTimeout:      10 * time.Second,
+	}
+
+	go func() {
+		<-ctx.Done()
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		log.Printf("server shutdown")
+		if err := server.Shutdown(shutdownCtx); err != nil {
+			log.Printf("server shutdown error: %v", err)
+		}
+	}()
+
+	log.Printf("listening on :%d", cfg.Port)
+	if err := server.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+		log.Fatalf("server error: %v", err)
+	}
+}
+
+func pollSource(ctx context.Context, source string, interval time.Duration, cacheDir string, agg *Aggregator, client *http.Client) {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	runOnce(ctx, source, cacheDir, agg, client)
+
+	for {
+		select {
+		case <-ctx.Done():
+			log.Printf("poller shutdown")
+			return
+		case <-ticker.C:
+			runOnce(ctx, source, cacheDir, agg, client)
+		}
+	}
+}
+
+func runOnce(ctx context.Context, source string, cacheDir string, agg *Aggregator, client *http.Client) {
+	links, err := fetchSource(ctx, source, client)
+	if err != nil {
+		log.Printf("poll %s: %v", source, err)
+		return
+	}
+	if len(links) == 0 {
+		agg.Update(source, nil)
+		if err := writeCache(cacheDir, source, nil); err != nil {
+			log.Printf("write cache %s: %v", source, err)
+		}
+		return
+	}
+
+	agg.Update(source, links)
+	if err := writeCache(cacheDir, source, links); err != nil {
+		log.Printf("write cache %s: %v", source, err)
+	}
+}
+
+func fetchSource(ctx context.Context, source string, client *http.Client) ([]string, error) {
+	u, err := url.Parse(source)
+	if err != nil {
+		return nil, fmt.Errorf("invalid source url: %w", err)
+	}
+
+	switch u.Scheme {
+	case "http", "https":
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, source, nil)
+		if err != nil {
+			return nil, fmt.Errorf("build request: %w", err)
+		}
+		resp, err := client.Do(req)
+		if err != nil {
+			return nil, fmt.Errorf("request failed: %w", err)
+		}
+		defer resp.Body.Close()
+		if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+			return nil, fmt.Errorf("unexpected status: %s", resp.Status)
+		}
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return nil, fmt.Errorf("read body: %w", err)
+		}
+		return normalizeLinks(string(body)), nil
+	case "file":
+		path := u.Path
+		if path == "" {
+			return nil, errors.New("file source path is empty")
+		}
+		data, err := os.ReadFile(path)
+		if err != nil {
+			return nil, fmt.Errorf("read file: %w", err)
+		}
+		return normalizeLinks(string(data)), nil
+	default:
+		return nil, fmt.Errorf("unsupported source scheme: %s", u.Scheme)
+	}
+}
+
+func normalizeLinks(content string) []string {
+	rawLines := strings.Split(content, "\n")
+	set := make(map[string]struct{})
+
+	for _, line := range rawLines {
+		link := strings.TrimSpace(line)
+		if link == "" {
+			continue
+		}
+		if !isValidTrackerLink(link) {
+			continue
+		}
+		set[link] = struct{}{}
+	}
+
+	result := make([]string, 0, len(set))
+	for link := range set {
+		result = append(result, link)
+	}
+	sort.Strings(result)
+	return result
+}
+
+func isValidTrackerLink(link string) bool {
+	u, err := url.Parse(link)
+	if err != nil {
+		return false
+	}
+
+	switch u.Scheme {
+	case "http", "https", "udp", "ws", "wss":
+	default:
+		return false
+	}
+
+	if u.Hostname() == "" {
+		return false
+	}
+
+	return true
+}
+
+func cacheFilePath(cacheDir, source string) string {
+	sum := sha1.Sum([]byte(source))
+	filename := hex.EncodeToString(sum[:]) + ".txt"
+	return filepath.Join(cacheDir, filename)
+}
+
+func writeCache(cacheDir, source string, links []string) error {
+	path := cacheFilePath(cacheDir, source)
+	data := strings.Join(links, "\n")
+	return os.WriteFile(path, []byte(data), 0o644)
+}
+
+func loadCachedLinks(cacheDir, source string) ([]string, error) {
+	path := cacheFilePath(cacheDir, source)
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	return normalizeLinks(string(data)), nil
+}