feat: only fetch big list of all events every ten minutes instead of on every request

main.go

@@ -9,6 +9,7 @@ import (
 	"io"
 	"net/http"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -16,7 +17,11 @@ const (
 	API_URL = "https://api.events.ccc.de/congress/2024"
 )
 
-var ROOMS []Room
+var (
+	SCHEDULE_MUTEX sync.Mutex
+	SCHEDULE       []Event
+	ROOMS          []Room
+)
 
 type Token struct {
 	Token string `json:"token"`
@@ -91,6 +96,24 @@ func scrape_hub() ([]Event, error) {
 	return events, nil
 }
 
+func cron_fetch() {
+	for {
+		fmt.Println("starting cron...")
+		schedule, err := scrape_hub()
+		if err != nil {
+			fmt.Println("Cron failed; retrying in a minute")
+			time.Sleep(1 * time.Minute)
+			continue
+		}
+
+		SCHEDULE_MUTEX.Lock()
+		SCHEDULE = schedule
+		SCHEDULE_MUTEX.Unlock()
+
+		time.Sleep(10 * time.Minute)
+	}
+}
+
 func get_rooms() ([]Room, error) {
 	println("get rooms")
 	resp, err := http.Get(fmt.Sprintf("%s/rooms", API_URL))
@@ -215,14 +238,12 @@ func get_schedule(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "Unauthorized", http.StatusUnauthorized)
 		return
 	}
-	schedule, err := scrape_hub()
-	if err != nil {
-		http.Error(w, "Unauthorized", http.StatusUnauthorized)
-		return
-	}
+
+	SCHEDULE_MUTEX.Lock()
+	defer SCHEDULE_MUTEX.Unlock()
 
 	var my_events []Event
-	for _, event := range schedule {
+	for _, event := range SCHEDULE {
 		for _, id := range ids {
 			if event.ID == id {
 				my_events = append(my_events, event)
@@ -263,6 +284,13 @@ func main() {
 		return
 	}
 	ROOMS = rooms
+	schedule, err := scrape_hub()
+	if err != nil {
+		return
+	}
+	SCHEDULE = schedule
+
+	go cron_fetch()
 
 	println("Stating Server")
 	// Start a web server to serve the iCal file