feat: support auto-pause live updates (#2947)

Co-authored-by: Vinh <vinh@vinh.tech>

src/core/server/config.ts

@@ -217,6 +217,13 @@ const config = convict({
     default: false,
     env: "DISABLE_LIVE_UPDATES",
   },
+  disable_live_updates_timeout: {
+    doc:
+      "Disables subscriptions for the comment stream for all stories across all tenants where a comment has not been left within the timeout",
+    format: "ms",
+    default: "2 weeks",
+    env: "DISABLE_LIVE_UPDATES_TIMEOUT",
+  },
   disable_client_routes: {
     doc:
       "Disables mounting of client routes for developing with Webpack Dev Server",

src/core/server/graph/resolvers/LiveConfiguration.ts

@@ -1,9 +1,14 @@
 import { isUndefined } from "lodash";
+import { DateTime } from "luxon";
 
-import { GQLLiveConfigurationTypeResolver } from "coral-server/graph/schema/__generated__/types";
 import * as settings from "coral-server/models/settings";
 
-export type LiveConfigurationInput = settings.LiveConfiguration;
+import { GQLLiveConfigurationTypeResolver } from "coral-server/graph/schema/__generated__/types";
+
+export interface LiveConfigurationInput extends settings.LiveConfiguration {
+  lastCommentedAt?: Date;
+  createdAt?: Date;
+}
 
 export const LiveConfiguration: GQLLiveConfigurationTypeResolver<LiveConfigurationInput> = {
   configurable: (source, args, ctx) =>
@@ -13,6 +18,32 @@ export const LiveConfiguration: GQLLiveConfigurationTypeResolver<LiveConfigurati
       return false;
     }
 
+    // This typecast is needed because the custom `ms` format does not return the
+    // desired `number` type even though that's the only type it can output.
+    const disableLiveUpdatesTimeout = (ctx.config.get(
+      "disable_live_updates_timeout"
+    ) as unknown) as number;
+    if (disableLiveUpdatesTimeout > 0) {
+      // If one of these is available, use it to determine the time since the
+      // last comment.
+      const lastCommentedAt = source.lastCommentedAt || source.createdAt;
+      if (
+        // If a date is found...
+        lastCommentedAt &&
+        // And the date (when we add the timeout duration) is before the current
+        // date...
+        DateTime.fromJSDate(lastCommentedAt)
+          .plus({
+            milliseconds: disableLiveUpdatesTimeout,
+          })
+          .toJSDate() <= ctx.now
+      ) {
+        // Then we know that the last comment (or lack there of) was left more
+        // than the timeout specified in configuration.
+        return false;
+      }
+    }
+
     if (isUndefined(source.enabled)) {
       return ctx.tenant.live.enabled;
     }

src/core/server/graph/resolvers/Story.ts

@@ -11,6 +11,7 @@ import {
 
 import { CommentCountsInput } from "./CommentCounts";
 import { storyModerationInputResolver } from "./ModerationQueues";
+import { StorySettingsInput } from "./StorySettings";
 
 export const Story: GQLStoryTypeResolver<story.Story> = {
   comments: (s, input, ctx) => ctx.loaders.Comments.forStory(s.id, input),
@@ -26,7 +27,16 @@ export const Story: GQLStoryTypeResolver<story.Story> = {
   commentCounts: (s): CommentCountsInput => s,
   // Merge tenant settings into the story settings so we can easily inherit the
   // options if they exist.
-  settings: (s, input, ctx) => defaultsDeep({}, s.settings, ctx.tenant),
+  settings: (s, input, ctx): StorySettingsInput =>
+    defaultsDeep(
+      {
+        // Pass these options as required by StorySettingsInput.
+        lastCommentedAt: s.lastCommentedAt,
+        createdAt: s.createdAt,
+      },
+      s.settings,
+      ctx.tenant
+    ),
   moderationQueues: storyModerationInputResolver,
   site: (s, input, ctx) => ctx.loaders.Sites.site.load(s.siteID),
 };

src/core/server/graph/resolvers/StorySettings.ts

@@ -7,8 +7,21 @@ import {
   GQLStorySettingsTypeResolver,
 } from "../schema/__generated__/types";
 
-export const StorySettings: GQLStorySettingsTypeResolver<story.StorySettings> = {
-  live: (s) => s.live || {},
+import { LiveConfigurationInput } from "./LiveConfiguration";
+
+export interface StorySettingsInput extends story.StorySettings {
+  lastCommentedAt?: Date;
+  createdAt?: Date;
+}
+
+export const StorySettings: GQLStorySettingsTypeResolver<StorySettingsInput> = {
+  live: (s): LiveConfigurationInput => ({
+    // Live may not be available sometimes, fix it here with the inline ||.
+    ...(s.live || { enabled: false }),
+    // Pass these options as required by LiveConfigurationInput.
+    lastCommentedAt: s.lastCommentedAt,
+    createdAt: s.createdAt,
+  }),
   moderation: (s, input, ctx) => s.moderation || ctx.tenant.moderation,
   premodLinksEnable: (s, input, ctx) =>
     s.premodLinksEnable || ctx.tenant.premodLinksEnable,

src/core/server/models/story/index.ts

@@ -48,11 +48,9 @@ export interface StreamModeSettings {
   expertIDs?: string[];
 }
 
-export type StorySettings = DeepPartial<
-  StreamModeSettings &
-    GlobalModerationSettings &
-    Pick<GQLStorySettings, "messageBox" | "mode" | "experts">
->;
+export type StorySettings = StreamModeSettings &
+  GlobalModerationSettings &
+  Pick<GQLStorySettings, "messageBox" | "mode" | "experts">;
 
 export type StoryMetadata = GQLStoryMetadata;
 
@@ -83,7 +81,7 @@ export interface Story extends TenantResource {
    * settings provides a point where the settings can be overridden for a
    * specific Story.
    */
-  settings: StorySettings;
+  settings: DeepPartial<StorySettings>;
 
   /**
    * closedAt is the date that the Story was forced closed at, or false to
@@ -378,7 +376,7 @@ export async function updateStory(
     throw err;
   }
 }
-export type UpdateStorySettingsInput = StorySettings;
+export type UpdateStorySettingsInput = DeepPartial<StorySettings>;
 
 export async function updateStorySettings(
   mongo: Db,