From 832a0facba2f60cead6be23fbe59707e44db7e64 Mon Sep 17 00:00:00 2001
From: Miguel Serrano <mserranom@users.noreply.github.com>
Date: Tue, 7 Feb 2023 10:14:50 +0100
Subject: [PATCH] Merge pull request #11658 from
 overleaf/bg-add-concurrency-to-migration

add concurrency to the history migration script

GitOrigin-RevId: 059a1a8b402627b03cb6dab79b5da22189f32704
---
 .../web/scripts/history/migrate_history.js    | 47 ++++++++++++++++---
 1 file changed, 40 insertions(+), 7 deletions(-)

diff --git a/services/web/scripts/history/migrate_history.js b/services/web/scripts/history/migrate_history.js
index 50aa9c91a3..9e35912165 100644
--- a/services/web/scripts/history/migrate_history.js
+++ b/services/web/scripts/history/migrate_history.js
@@ -11,6 +11,7 @@ const { waitForDb } = require('../../app/src/infrastructure/mongodb')
 const minimist = require('minimist')
 const fs = require('fs')
 const util = require('util')
+const pLimit = require('p-limit')
 const logger = require('@overleaf/logger')
 logger.initialize('history-migration')
 // disable logging to stdout from internal modules
@@ -31,14 +32,16 @@ const argv = minimist(process.argv.slice(2), {
   string: ['output'],
   alias: {
     verbose: 'v',
+    output: 'o',
     'dry-run': 'd',
+    concurrency: 'j',
     'use-query-hint': 'q',
     'retry-failed': 'r',
     'archive-on-failure': 'a',
   },
   default: {
     output: DEFAULT_OUTPUT_FILE,
-    'write-concurrency': 10,
+    concurrency: 1,
     'batch-size': 100,
     'max-upgrades-to-attempt': false,
     'max-failures': 50,
@@ -122,6 +125,9 @@ async function migrateProjects(projectsToMigrate) {
   let projectsFailed = 0
 
   console.log('Starting migration...')
+  if (argv.concurrency > 1) {
+    console.log(`Using ${argv.concurrency} concurrent migrations`)
+  }
   // send log output for each migration to a file
   const output = fs.createWriteStream(argv.output, { flags: 'a' })
   console.log(`Writing log output to ${argv.output}`)
@@ -129,25 +135,43 @@ async function migrateProjects(projectsToMigrate) {
   function logJson(obj) {
     logger.log(JSON.stringify(obj))
   }
+  // limit the number of concurrent migrations
+  const limit = pLimit(argv.concurrency)
+  const jobs = []
   // throttle progress reporting to 2x per second
   const progressBar = createProgressBar()
   let i = 0
   const N = projectsToMigrate.length
   const progressBarTimer = setInterval(() => {
+    if (INTERRUPT) {
+      return // don't update the progress bar if we're shutting down
+    }
     progressBar(
       i,
       N,
       `Migrated: ${projectsMigrated}, Failed: ${projectsFailed}`
     )
   }, 500)
-  for (const project of projectsToMigrate) {
+
+  async function _migrateProject(project) {
+    if (INTERRUPT) {
+      return // don't start any new jobs if we're shutting down
+    }
     const startTime = new Date()
     try {
-      if (INTERRUPT) {
-        break
-      }
       const result = await upgradeProject(project._id)
+      i++
+      if (INTERRUPT && limit.activeCount > 1) {
+        // an interrupt was requested while this job was running
+        // report that we're waiting for the remaining jobs to finish
+        console.log(
+          `Waiting for remaining ${
+            limit.activeCount - 1
+          } active jobs to finish\r`
+        )
+      }
       if (result.error) {
+        // failed to migrate this project
         logJson({
           project_id: project._id,
           result,
@@ -157,6 +181,7 @@ async function migrateProjects(projectsToMigrate) {
         })
         projectsFailed++
       } else {
+        // successfully migrated this project
         logJson({
           project_id: project._id,
           result,
@@ -166,6 +191,7 @@ async function migrateProjects(projectsToMigrate) {
         projectsMigrated++
       }
     } catch (err) {
+      // unexpected error from the migration
       projectsFailed++
       logJson({
         project_id: project._id,
@@ -174,8 +200,13 @@ async function migrateProjects(projectsToMigrate) {
         endTime: new Date(),
       })
     }
-    i++
   }
+
+  for (const project of projectsToMigrate) {
+    jobs.push(limit(_migrateProject, project))
+  }
+  // wait for all the queued jobs to complete
+  await Promise.all(jobs)
   clearInterval(progressBarTimer)
   progressBar(i, N, `Migrated: ${projectsMigrated}, Failed: ${projectsFailed}`)
   process.stdout.write('\n')
@@ -210,7 +241,9 @@ async function main() {
 // then history could get into a broken state
 // Instead, skip any unprocessed projects and exit() at end of the batch.
 process.on('SIGINT', function () {
-  console.log('\nCaught SIGINT, waiting for in process upgrades to complete')
+  console.log(
+    '\nCaught SIGINT, waiting for all in-progess upgrades to complete'
+  )
   INTERRUPT = true
 })