Migrer un forum NodeBB avec MongoDB vers Discourse

As you properly know, NodeBB supports two DB backends, Redis and MongoDB. Discourse importer script supports them both. In this tutorial, we will learn how to migrate NodeBB with MongoDB as DB backend. We will be using NodeBB Importer with mongo adapter. If your NodeBB forum uses Redis as backend then please follow this tutorial which demonstrate the redis adapter.

The plan

  • Preparing the development environment.

  • Export database from production environment.

  • Import the production DB to a Discourse instance.

  • Run the importer script.

What can be migrated

  • Groups
  • Attachments
  • Categories
    • Root Category => Root Category
    • Sub Category & Sub-Sub-Category => Sub-Category
  • Topics & Posts
    • pinned topic => pinned topic
    • locked topic => closed topic
    • topic views
    • upvoted_by
    • styles, mentions, emoji, and attachments.
  • Users (with the following attributes)
    • profile background
    • avatars
    • banned status
    • username
    • name
    • email
    • admin
    • bio
    • group
    • website
    • location
    • joining at

Preparing Local Development Environment

As mentioned in our plan we first need to prepare our development environment. Follow one of these guides to install Discourse itself:

:bulb: Please, consult this guide if you have any problems setting up Discourse server.

Then install MongoDB database server.

Ubuntu-18-04:

$ wget -qO - https://www.mongodb.org/static/pgp/server-4.0.asc | sudo apt-key add -
$ echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-4.0.list
$ sudo apt-get update
$ sudo apt-get install -y mongodb-org
$ sudo service mongod status

For more details, refer to the official guide

Mac OS:

$ brew tap mongodb/brew
$ brew install mongodb-community@4.0
$ brew services start mongodb-community@4.0
$ brew services status mongodb-community@4.0

For more details, refer to the official guide

Windows 10:

Download the installer and install MongoDB as a Windows service:

https://fastdl.mongodb.org/win32/mongodb-win32-x86_64-2008plus-ssl-4.0.12-signed.msi

Run the cmd with Administrative privileges to check if the mongo server is working properly:

"C:\Program Files\MongoDB\Server\4.0\bin\mongo.exe"

For more details, refer to the official guide.

This environment will be our Discourse server.

Exporting Production Database Dump:

Shut down your NodeBB forum (production server).

$ cd /path_to_nodebb
$ ./nodebb stop

Shut down your database:

$ sudo service mongodb stop

Backup your DB:

$ mongodump --out ~/my_backup_path/

The output of the previous command will be something like this:

2019-08-16T15:17:09.845+0300 done dumping admin.system.users (1 document)
2019-08-16T15:17:09.846+0300 done dumping admin.system.version (2 documents)
2019-08-16T15:17:09.849+0300 done dumping nodebb.sessions (10 documents)
2019-08-16T15:17:09.850+0300 done dumping nodebb.socket.io (215 documents)
2019-08-16T15:17:09.854+0300 done dumping nodebb.objects (1488 documents)

Note that the backup is actually a directory, not just a file.

:bulb: You can check the size of your DB by running use myDatabase then db.stats().dataSize; inside mongo CLI. The returned value will be in bytes.

Backup your forum assets:

$ cd /path_to_nodebb_root_directory/
$ tar -czf ./uploads.tar.gz ./public/uploads

After you have your DB and assets forum you should copy them to Discourse server.

Importing The Database

Now that we have our database we can import it in our local MongoDB instance:

$ mongorestore ~/path_of_my_backup_directory/

For more options, refer to official guide.

Next, you need to extract the uploads.tar.gz so the importer can import the assets:

$ tar xvzf uploads.tar.gz

Running The Importer Script

Now that our database and assets in place we are ready to run our importer script. Before that, we need to edit the NodeBB importer script to fit our needs.

This is the path of your NodeBB uploads folder:

ATTACHMENT_DIR = '/absolute_path/uploads'

Next, we need to tell the importer to use the mongo adapter instead of redis adapter:

adapter = NodeBB::Mongo
@client = adapter.new('mongodb://127.0.0.1:27017/nodebb')

# adapter = NodeBB::Redis
# @client = adapter.new(
# host: "localhost",
# port: "6379",
# db: 14
# )

Run the importer with clean Discourse and mongo gem support:

$ cd ~/discourse
$ echo "gem 'mongo'" >> Gemfile
$ bundle install
$ bundle exec rake db:drop db:create db:migrate
$ bundle exec ruby script/import_scripts/nodebb/nodebb.rb

The importer will connect to the MongoDB instance and migrates everything to Discourse.

After the importer finishes, start Discourse:

$ bundle exec rails server

Start Sidekiq to process the migrated data:

$ bundle exec sidekiq

You can monitor the progress at http://localhost:3000/sidekiq/queues.

Perform a Discourse backup and upload it to your Discourse production server by following this tutorial.

:tada:

If you have any questions about the process I am happy to help.

Happy migration :grinning:

10 « J'aime »

Great work really. While I was trying, I am getting below error. Any idea what I might be doing wrong here?

importing groups
   10 / 10 (100.0%)  [474765 items/min]    
importing top level categories...
    8 / 8 (100.0%)  [437896 items/min]    
importing child categories...
   68 / 68 (100.0%)  [774048 items/min]  
importing users
 5534 / 5534 (100.0%)  [355520 items/min]    
adding users to groups...

importing topics...
Traceback (most recent call last):
	12: from script/import_scripts/nodebb/nodebb.rb:532:in `<main>'
	11: from /home/fsuzer/discourse/script/import_scripts/base.rb:47:in `perform'
	10: from script/import_scripts/nodebb/nodebb.rb:52:in `execute'
	 9: from script/import_scripts/nodebb/nodebb.rb:336:in `import_topics'
	 8: from /home/fsuzer/discourse/script/import_scripts/base.rb:877:in `batches'
	 7: from /home/fsuzer/discourse/script/import_scripts/base.rb:877:in `loop'
	 6: from /home/fsuzer/discourse/script/import_scripts/base.rb:878:in `block in batches'
	 5: from script/import_scripts/nodebb/nodebb.rb:337:in `block in import_topics'
	 4: from /home/fsuzer/discourse/script/import_scripts/nodebb/mongo.rb:71:in `topics'
	 3: from /home/fsuzer/discourse/script/import_scripts/nodebb/mongo.rb:71:in `map'
	 2: from /home/fsuzer/discourse/script/import_scripts/nodebb/mongo.rb:71:in `block in topics'
	 1: from /home/fsuzer/discourse/script/import_scripts/nodebb/mongo.rb:79:in `topic'
/home/fsuzer/discourse/script/import_scripts/nodebb/mongo.rb:100:in `post': undefined method `[]' for nil:NilClass (NoMethodError)

Some field from the topic is empty. Or perhaps the topic query returned nothing.

1 « J'aime »

Can someone help me?

Error: Could not find gem ‘mongo’ in any of the gem sources listed in your Gemfile.

After $ bundle install

This will happen if you skipped this:

Make sure you Gemfile has this line:

gem 'mongo'

Then run:

$ bundle install
1 « J'aime »

Gem

Thanks for your help. But this line already exists in my file. I also did the previous steps informed.

I don’t know if that helps, but when I run gem list mongo it’s not listed.

Your Gemfile sounds weird to me. Please, can you share the whole content?

Your Gemfile is just wrong. It should have another content, just like this:

In addition to:

gem 'mongo'

Hey,

Thanks for the guide! When I run the migration script, this is what I get when the script reaches the point where it imports users:

Traceback (most recent call last):
        21: from script/import_scripts/nodebb/nodebb.rb:532:in `<main>'
        20: from /home/odyslam/forum/discourse/script/import_scripts/base.rb:47:in `perform'
        19: from script/import_scripts/nodebb/nodebb.rb:50:in `execute'
        18: from script/import_scripts/nodebb/nodebb.rb:130:in `import_users'
        17: from /home/odyslam/forum/discourse/script/import_scripts/base.rb:262:in `create_users'
        16: from /home/odyslam/forum/discourse/script/import_scripts/base.rb:262:in `each'
        15: from /home/odyslam/forum/discourse/script/import_scripts/base.rb:274:in `block in create_users'
        14: from /home/odyslam/forum/discourse/script/import_scripts/base.rb:391:in `create_user'
        13: from /home/odyslam/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activesupport-6.0.3.3/lib/active_support/core_ext/object/try.rb:15:in `try'
        12: from /home/odyslam/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activesupport-6.0.3.3/lib/active_support/core_ext/object/try.rb:15:in `public_send'
        11: from script/import_scripts/nodebb/nodebb.rb:164:in `block (2 levels) in import_users'
        10: from script/import_scripts/nodebb/nodebb.rb:211:in `import_profile_picture'
         9: from /home/odyslam/forum/discourse/lib/upload_creator.rb:45:in `create_for'
         8: from /home/odyslam/forum/discourse/lib/distributed_mutex.rb:14:in `synchronize'
         7: from /home/odyslam/forum/discourse/lib/distributed_mutex.rb:29:in `synchronize'
         6: from /home/odyslam/forum/discourse/lib/distributed_mutex.rb:29:in `synchronize'
         5: from /home/odyslam/forum/discourse/lib/distributed_mutex.rb:33:in `block in synchronize'
         4: from /home/odyslam/forum/discourse/lib/upload_creator.rb:66:in `block in create_for'
         3: from /home/odyslam/forum/discourse/lib/upload_creator.rb:381:in `optimize!'
         2: from /home/odyslam/forum/discourse/app/models/optimized_image.rb:178:in `ensure_safe_paths!'
         1: from /home/odyslam/forum/discourse/app/models/optimized_image.rb:178:in `each'
/home/odyslam/forum/discourse/app/models/optimized_image.rb:179:in `block in ensure_safe_paths!': Discourse::InvalidAccess (Discourse::InvalidAccess)

I managed to bypass this by commenting out the part that uploads profile pictures, that’s not a problem.

Now I get the nil error when importing topics. :frowning:

Traceback (most recent call last):
        12: from script/import_scripts/nodebb/nodebb.rb:532:in `<main>'
        11: from /home/odyslam/forum/discourse/script/import_scripts/base.rb:47:in `perform'
        10: from script/import_scripts/nodebb/nodebb.rb:52:in `execute'
         9: from script/import_scripts/nodebb/nodebb.rb:336:in `import_topics'
         8: from /home/odyslam/forum/discourse/script/import_scripts/base.rb:862:in `batches'
         7: from /home/odyslam/forum/discourse/script/import_scripts/base.rb:862:in `loop'
         6: from /home/odyslam/forum/discourse/script/import_scripts/base.rb:863:in `block in batches'
         5: from script/import_scripts/nodebb/nodebb.rb:337:in `block in import_topics'
         4: from /home/odyslam/forum/discourse/script/import_scripts/nodebb/mongo.rb:71:in `topics'
         3: from /home/odyslam/forum/discourse/script/import_scripts/nodebb/mongo.rb:71:in `map'
         2: from /home/odyslam/forum/discourse/script/import_scripts/nodebb/mongo.rb:71:in `block in topics'
         1: from /home/odyslam/forum/discourse/script/import_scripts/nodebb/mongo.rb:79:in `topic'
/home/odyslam/forum/discourse/script/import_scripts/nodebb/mongo.rb:100:in `post': undefined method `[]' for nil:NilClass (NoMethodError)

In case anyone is interested in the future, I managed to perform the migration. Here are some comments regarding my experience; there are a couple of gotchas in the process.

2 « J'aime »
21: from script/import_scripts/nodebb/nodebb.rb:532:in `main`
        20: from /home/nodebb/discourse/script/import_scripts/base.rb:47:in `perform`
        19: from script/import_scripts/nodebb/nodebb.rb:50:in `execute`
        18: from script/import_scripts/nodebb/nodebb.rb:130:in `import_users`
        17: from /home/nodebb/discourse/script/import_scripts/base.rb:264:in `create_users`
        16: from /home/nodebb/discourse/script/import_scripts/base.rb:264:in `each`
        15: from /home/nodebb/discourse/script/import_scripts/base.rb:276:in `block in create_users`
        14: from /home/nodebb/discourse/script/import_scripts/base.rb:393:in `create_user`
        13: from /home/nodebb/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activesupport-6.1.4.1/lib/active_support/core_ext/object/try.rb:15:in `try`
        12: from /home/nodebb/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/activesupport-6.1.4.1/lib/active_support/core_ext/object/try.rb:15:in `public_send`
        11: from script/import_scripts/nodebb/nodebb.rb:164:in `block (2 levels) in import_users`
        10: from script/import_scripts/nodebb/nodebb.rb:211:in `import_profile_picture`
         9: from /home/nodebb/discourse/lib/upload_creator.rb:64:in `create_for`
         8: from /home/nodebb/discourse/lib/distributed_mutex.rb:14:in `synchronize`
         7: from /home/nodebb/discourse/lib/distributed_mutex.rb:29:in `synchronize`
         6: from /home/nodebb/discourse/lib/distributed_mutex.rb:29:in `synchronize`
         5: from /home/nodebb/discourse/lib/distributed_mutex.rb:33:in `block in synchronize`
         4: from /home/nodebb/discourse/lib/upload_creator.rb:83:in `block in create_for`
         3: from /home/nodebb/discourse/lib/upload_creator.rb:501:in `optimize!`
         2: from /home/nodebb/discourse/app/models/optimized_image.rb:181:in `ensure_safe_paths!`
         1: from /home/nodebb/discourse/app/models/optimized_image.rb:181:in `each`
/home/nodebb/discourse/app/models/optimized_image.rb:182:in `block in ensure_safe_paths!': Discourse::InvalidAccess (Discourse::InvalidAccess)

@enigmaty Je rencontre la même erreur que @OdysLam @FreeWorLD.

Bonjour !
Quelqu’un a-t-il déjà essayé de migrer de la dernière version de NodeBB 4.9.x vers la version de développement actuelle de Discourse ?

/home/dev/discourse/script/import_scripts/nodebb/mongo.rb:100:in 'NodeBB::Mongo#post': undefined method '[]' for nil (NoMethodError)

      post["timestamp"] = timestamp_to_date(post["timestamp"])
                                                ^^^^^^^^^^^^^
        from /home/dev/discourse/script/import_scripts/nodebb/mongo.rb:95:in 'block in NodeBB::Mongo#posts'
        from /home/dev/discourse/script/import_scripts/nodebb/mongo.rb:95:in 'Array#map'
        from /home/dev/discourse/script/import_scripts/nodebb/mongo.rb:95:in 'NodeBB::Mongo#posts'
        from script/import_scripts/nodebb/nodebb.rb:413:in 'block in ImportScripts::NodeBB#import_posts'
        from /home/dev/discourse/script/import_scripts/base.rb:943:in 'block in ImportScripts::Base#batches'
        from 内部:kernel:168:in 'Kernel#loop'
        from /home/dev/discourse/script/import_scripts/base.rb:942:in 'ImportScripts::Base#batches'
        from script/import_scripts/nodebb/nodebb.rb:412:in 'ImportScripts::NodeBB#import_posts'
        from script/import_scripts/nodebb/nodebb.rb:52:in 'ImportScripts::NodeBB#execute'
        from /home/dev/discourse/script/import_scripts/base.rb:47:in 'ImportScripts::Base#perform'
        from script/import_scripts/nodebb/nodebb.rb:568:in '<main>'

J’ai cette erreur lors de la migration dans l’environnement de développement.
Des idées ?

Les scripts de migration sont-ils toujours supportés par la Communauté en 2026 ?
Le champ timestamp existe et contient des données valides.

Merci.

Le problème est que post est nil. Vous n’avez donc pas configuré les choses correctement. Avez-vous importé les utilisateurs ?

Nous pouvons essayer, mais c’est assez limité. Vous devrez probablement comprendre comment fonctionnent beaucoup de choses qui peuvent dépasser ce qui est facilement supportable dans un forum.

3 « J'aime »
importing users
      182 / 182 (100.0%)  [437953 items/min]
adding users to groups...

importing topics...
      132 / 132 (100.0%)  [3567036 items/min]
importing posts...
/home/dev/discourse/script/import_scripts/nodebb/mongo.rb:100:in 'NodeBB::Mongo#post': undefined method '[]' for nil (NoMethodError)

      post["timestamp"] = timestamp_to_date(post["timestamp"])
                                                ^^^^^^^^^^^^^
        from /home/dev/discourse/script/import_scripts/nodebb/mongo.rb:95:in 'block in NodeBB::Mongo#posts'
        from /home/dev/discourse/script/import_scripts/nodebb/mongo.rb:95:in 'Array#map'
        from /home/dev/discourse/script/import_scripts/nodebb/mongo.rb:95:in 'NodeBB::Mongo#posts'
        from script/import_scripts/nodebb/nodebb.rb:413:in 'block in ImportScripts::NodeBB#import_posts'
        from /home/dev/discourse/script/import_scripts/base.rb:943:in 'block in ImportScripts::Base#batches'
        from 内部:kernel:168:in 'Kernel#loop'
        from /home/dev/discourse/script/import_scripts/base.rb:942:in 'ImportScripts::Base#batches'
        from script/import_scripts/nodebb/nodebb.rb:412:in 'ImportScripts::NodeBB#import_posts'
        from script/import_scripts/nodebb/nodebb.rb:52:in 'ImportScripts::NodeBB#execute'
        from /home/dev/discourse/script/import_scripts/base.rb:47:in 'ImportScripts::Base#perform'
        from script/import_scripts/nodebb/nodebb.rb:568:in '<main>'


Les utilisateurs semblent avoir été importés correctement selon la sortie du script, voir ci-dessus.

Désolé, êtes-vous une personne vivante ou juste une IA-assistante suffisamment intelligente ?

Alors le problème vient du fait qu’il ne lit pas les données des publications.

Mon hypothèse est que cela se situe ici et que pour une raison quelconque, il ne trouve pas les publications.

    def posts(offset = 0, page_size = 2000)
      post_keys = mongo.find(_key: "posts:pid").skip(offset).limit(page_size).pluck(:value)

      post_keys.map { |post_key| post(post_key) }
    end

Je suis une personne réelle qui gagne sa vie en soutenant Discourse depuis une décennie et qui a écrit un tas d’importateurs et a importé plus d’une centaine de forums à partir de diverses autres plateformes.

Si vous voulez l’aide d’un assistant IA, consultez https://ask.discourse.com/

6 « J'aime »

J’ai réussi d’une manière ou d’une autre à faire fonctionner la fonction du script correctement.

Voici mes changements (avec un petit coup de main de Claude Code :slight_smile:)

 =>mongo.rb
   
   def posts(offset = 0, page_size = 1000)
      post_keys = mongo.find(_key: "posts:pid").skip(offset).limit(page_size).pluck(:value)
      post_keys
          .map { |pid| post(pid) }
          .compact  # <-- supprime tous les résultats nuls (pids orphelins)
      post_keys.map { |post_key| post(post_key) }
    end

    def post(id)
    post = mongo.find(_key: "post:#{id}").first
    return nil if post.nil? # <-- vérification nulle
    post["timestamp"] = timestamp_to_date(post["timestamp"])
    if post["upvoted_by"] = mongo.find(_key: "pid:#{id}:upvote").first
        post["upvoted_by"] = mongo.find(_key: "pid:#{id}:upvote").first[:members]
      else
        post["upvoted_by"] = []
      end

      post["pid"] = post["pid"].to_s
      post["deleted"] = post["deleted"].to_s

      post
    end
	
=>nodebb.rb

 create_posts(posts, total: post_count, offset: offset) do |post|
        # sauter si le post est nul
		# sauter si c'est un merged_post
        next if post.nil?
        next if @merged_posts_map[post["pid"]]

        # sauter s'il est supprimé
        next if post["deleted"] == "1"

        raw = post["content"]
        post_id = "p#{post["pid"]}"

        next if raw.blank?
        topic = topic_lookup_from_imported_post_id("t#{post["tid"]}")

        unless topic
          puts "Topic with id #{post["tid"]} not found, skipping"
          next
        end	

Il semble fonctionner correctement maintenant.

Bien que je ne sache pas à quel point c’est correct du point de vue de l’architecture interne de Discourse, à première vue, cela semble fonctionner.

Toutes suggestions d’amélioration et d’optimisation sont les bienvenues.

1 « J'aime »

Astuce : ne faites pas en sorte que cela échoue complètement en silence - changez ceci en

if post.nil?
  puts "!!! Impossible de trouver le message #{id}"
  return nil
end

Sinon, vous vous demanderez pourquoi la moitié de vos messages manque et après des heures de frustration, vous découvrirez que c’est à cause de cela.

même chose pour ces deux-là

        next if post.nil?
        next if post["deleted"] == "1"
5 « J'aime »

Méthode posts réécrite dans le fichier mongo.rb

def posts(offset = 0, page_size = 1000)
post_keys = mongo.find(_key: “posts:pid”).sort(score: 1).skip(offset).limit(page_size).pluck(:value)
post_keys.map { |pid| post(pid)}.compact
end

Insérez le texte de la citation ici

Cette approche garantit que les publications au sein d’un sujet sont triées dans le bon ordre chronologique. Ascendant.
Notez l’appel sort(score: 1).