From be3ec61a6669cd96cc797c7a7a53105179213f69 Mon Sep 17 00:00:00 2001
From: Chocobozzz <me@florianbigard.com>
Date: Mon, 15 May 2023 11:09:16 +0200
Subject: Atomic live segment file write

---
 server/lib/live/live-segment-sha-store.ts | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/server/lib/live/live-segment-sha-store.ts b/server/lib/live/live-segment-sha-store.ts
index 251301141..17e0c6a82 100644
--- a/server/lib/live/live-segment-sha-store.ts
+++ b/server/lib/live/live-segment-sha-store.ts
@@ -1,11 +1,11 @@
-import { writeJson } from 'fs-extra'
+import { move, writeJson } from 'fs-extra'
+import PQueue from 'p-queue'
 import { basename } from 'path'
 import { mapToJSON } from '@server/helpers/core-utils'
 import { logger, loggerTagsFactory } from '@server/helpers/logger'
 import { MStreamingPlaylistVideo } from '@server/types/models'
 import { buildSha256Segment } from '../hls'
 import { storeHLSFileFromPath } from '../object-storage'
-import PQueue from 'p-queue'
 
 const lTags = loggerTagsFactory('live')
 
@@ -14,7 +14,10 @@ class LiveSegmentShaStore {
   private readonly segmentsSha256 = new Map<string, string>()
 
   private readonly videoUUID: string
+
   private readonly sha256Path: string
+  private readonly sha256PathTMP: string
+
   private readonly streamingPlaylist: MStreamingPlaylistVideo
   private readonly sendToObjectStorage: boolean
   private readonly writeQueue = new PQueue({ concurrency: 1 })
@@ -26,7 +29,10 @@ class LiveSegmentShaStore {
     sendToObjectStorage: boolean
   }) {
     this.videoUUID = options.videoUUID
+
     this.sha256Path = options.sha256Path
+    this.sha256PathTMP = options.sha256Path + '.tmp'
+
     this.streamingPlaylist = options.streamingPlaylist
     this.sendToObjectStorage = options.sendToObjectStorage
   }
@@ -66,7 +72,9 @@ class LiveSegmentShaStore {
 
   private writeToDisk () {
     return this.writeQueue.add(async () => {
-      await writeJson(this.sha256Path, mapToJSON(this.segmentsSha256))
+      // Atomic write
+      await writeJson(this.sha256PathTMP, mapToJSON(this.segmentsSha256))
+      await move(this.sha256PathTMP, this.sha256Path, { overwrite: true })
 
       if (this.sendToObjectStorage) {
         const url = await storeHLSFileFromPath(this.streamingPlaylist, this.sha256Path)
-- 
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