avoid calendar cache on cold starts (#8311)

Co-authored-by: Keith Williams <keithwillcode@gmail.com>
Co-authored-by: Omar López <zomars@me.com>

packages/core/CalendarManager.ts

@@ -19,6 +19,7 @@ import type { CredentialPayload, CredentialWithAppName } from "@calcom/types/Cre
 import type { EventResult } from "@calcom/types/EventManager";
 
 const log = logger.getChildLogger({ prefix: ["CalendarManager"] });
+let coldStart = true;
 
 export const getCalendarCredentials = (credentials: Array<CredentialPayload>) => {
   const calendarCredentials = getApps(credentials)
@@ -183,48 +184,71 @@ export const getCachedResults = async (
  */
 const getNextCache = async (username: string, month: string): Promise<EventBusyDate[][]> => {
   let localCache: EventBusyDate[][] = [];
+  const { NODE_ENV } = process.env;
+  const cacheDir = `${NODE_ENV === "development" ? NODE_ENV : process.env.BUILD_ID}`;
+  const baseUrl = `${WEBAPP_URL}/_next/data/${cacheDir}/en`;
+  const url = `${baseUrl}/${username}/calendar-cache/${month}.json?user=${username}&month=${month}`;
   try {
-    const { NODE_ENV } = process.env;
-    const cacheDir = `${NODE_ENV === "development" ? NODE_ENV : process.env.BUILD_ID}`;
-    const baseUrl = `${WEBAPP_URL}/_next/data/${cacheDir}/en`;
-    console.log(`${baseUrl}/${username}/calendar-cache/${month}.json?user=${username}&month=${month}`);
-    localCache = await fetch(
-      `${baseUrl}/${username}/calendar-cache/${month}.json?user=${username}&month=${month}`
-    )
+    localCache = await fetch(url)
       .then((r) => r.json())
       .then((json) => json?.pageProps?.results);
-    // No need to wait for this, the purpose is to force re-validation every second as indicated
-    // in page getStaticProps.
-    fetch(`${baseUrl}/${username}/calendar-cache/${month}`).catch(console.log);
   } catch (e) {
-    log.warn(e);
+    log.warn(url, e);
   }
   return localCache;
 };
+/**
+ * Get months between given dates
+ * @returns ["2023-04", "2024-05"]
+ */
+const getMonths = (dateFrom: string, dateTo: string): string[] => {
+  const months: string[] = [dayjs(dateFrom).format("YYYY-MM")];
+  for (
+    let i = 1;
+    dayjs(dateFrom).add(i, "month").isBefore(dateTo) ||
+    dayjs(dateFrom).add(i, "month").isSame(dateTo, "month");
+    i++
+  ) {
+    months.push(dayjs(dateFrom).add(i, "month").format("YYYY-MM"));
+  }
+  return months;
+};
 
+const createCalendarCachePage = (username: string, month: string): void => {
+  // No need to wait for this, the purpose is to force re-validation every second as indicated
+  // in page getStaticProps.
+  fetch(`${WEBAPP_URL}/${username}/calendar-cache/${month}`).catch(console.log);
+};
 export const getBusyCalendarTimes = async (
   username: string,
   withCredentials: CredentialPayload[],
   dateFrom: string,
-  dateTo: string
+  dateTo: string,
+  selectedCalendars: SelectedCalendar[]
 ) => {
   let results: EventBusyDate[][] = [];
-  if (dayjs(dateFrom).isSame(dayjs(dateTo), "month")) {
-    results = await getNextCache(username, dayjs(dateFrom).format("YYYY-MM"));
-  } else {
-    // if dateFrom and dateTo is from different months get cache by each month
-    const months: string[] = [dayjs(dateFrom).format("YYYY-MM")];
-    for (
-      let i = 1;
-      dayjs(dateFrom).add(i, "month").isBefore(dateTo) ||
-      dayjs(dateFrom).add(i, "month").isSame(dateTo, "month");
-      i++
-    ) {
-      months.push(dayjs(dateFrom).add(i, "month").format("YYYY-MM"));
+  const months = getMonths(dateFrom, dateTo);
+  try {
+    if (coldStart) {
+      results = await getCachedResults(withCredentials, dateFrom, dateTo, selectedCalendars);
+      logger.info("Generating calendar cache in background");
+      // on cold start the calendar cache page generated in the background
+      Promise.all(months.map((month) => createCalendarCachePage(username, month)));
+    } else {
+      if (months.length === 1) {
+        results = await getNextCache(username, dayjs(dateFrom).format("YYYY-MM"));
+      } else {
+        // if dateFrom and dateTo is from different months get cache by each month
+        const data: EventBusyDate[][][] = await Promise.all(
+          months.map((month) => getNextCache(username, month))
+        );
+        results = data.flat(1);
+      }
     }
-    const data: EventBusyDate[][][] = await Promise.all(months.map((month) => getNextCache(username, month)));
-    results = data.flat(1);
+  } catch (e) {
+    logger.warn(e);
   }
+  coldStart = false;
   return results.reduce((acc, availability) => acc.concat(availability), []);
 };
 

packages/core/getBusyTimes.ts

@@ -6,6 +6,7 @@ import dayjs from "@calcom/dayjs";
 import logger from "@calcom/lib/logger";
 import { performance } from "@calcom/lib/server/perfObserver";
 import prisma from "@calcom/prisma";
+import type { SelectedCalendar } from "@calcom/prisma/client";
 import type { EventBusyDetails } from "@calcom/types/Calendar";
 
 export async function getBusyTimes(params: {
@@ -17,6 +18,7 @@ export async function getBusyTimes(params: {
   beforeEventBuffer?: number;
   afterEventBuffer?: number;
   endTime: string;
+  selectedCalendars: SelectedCalendar[];
 }) {
   const {
     credentials,
@@ -27,6 +29,7 @@ export async function getBusyTimes(params: {
     endTime,
     beforeEventBuffer,
     afterEventBuffer,
+    selectedCalendars,
   } = params;
   logger.silly(
     `Checking Busy time from Cal Bookings in range ${startTime} to ${endTime} for input ${JSON.stringify({
@@ -119,7 +122,20 @@ export async function getBusyTimes(params: {
   performance.mark("prismaBookingGetEnd");
   performance.measure(`prisma booking get took $1'`, "prismaBookingGetStart", "prismaBookingGetEnd");
   if (credentials?.length > 0) {
-    const calendarBusyTimes = await getBusyCalendarTimes(username, credentials, startTime, endTime);
+    const startConnectedCalendarsGet = performance.now();
+    const calendarBusyTimes = await getBusyCalendarTimes(
+      username,
+      credentials,
+      startTime,
+      endTime,
+      selectedCalendars
+    );
+    const endConnectedCalendarsGet = performance.now();
+    logger.debug(
+      `Connected Calendars get took ${
+        endConnectedCalendarsGet - startConnectedCalendarsGet
+      } ms for user ${username}`
+    );
     busyTimes.push(
       ...calendarBusyTimes.map((value) => ({
         ...value,

packages/core/getUserAvailability.ts

@@ -149,6 +149,7 @@ export async function getUserAvailability(
     username: `${user.username}`,
     beforeEventBuffer,
     afterEventBuffer,
+    selectedCalendars: user.selectedCalendars,
   });
 
   let bufferedBusyTimes: EventBusyDetails[] = busyTimes.map((a) => ({