Fediversity/matrix/draupnir

Table of Contents

• Draupnir
• Configuration
• Rate limiting

Draupnir

Draupnir is the way to do moderation. It can exchange banlists with other servers, and drop reports that people send into its moderation room so that moderators can act upon them.

Start by creating a room where moderators can give Draupnir commands. This room should not be encrypted. Then create a user for Draupnir, this user should ideally be an admin user.

Once you've created the user, log in as this user, maybe set an avatar, join the room you've created and then copy the access token. This token is used by the Draupnir software to login.

After that, close the window or client, but do not logout. If you logout, the token will be invalidated.

Make sure you have the right npm, Node.js, yarn and what-have-you (see Draupnir's documentation) and prepare the software:

mkdir /opt
cd /opt
git clone https://github.com/the-draupnir-project/Draupnir.git
cd Draupnir
git fetch --tags
mkdir datastorage
yarn global add corepack
useradd -m draupnir
chown -R draupnir:draupnir

Now, "compile" the stuff as user draupnir:

sudo -u draupnir bash -c "install yarn"
sudo -u draupnir bash -c "yarn build"

When this is completed successfully, it's time to configure Draupnir.

Configuration

Under config you'll find the default configuration file, default.yaml. Copy it to production.yaml and change what you must.

Option	Value	Meaning
homeserverUrl	http://localhost:8008	Where to communicate with Synapse when using network port
homeserverUrl	http://unix:/run/matrix-synapse/incoming_main.sock	Where to communicate with Synapse when using UNIX sockets (see Workers)
rawHomeserverUrl	https://matrix.example.com	Same as server_name
accessToken	access token	Copy from login session or create in Synapse Admin)
password	password	Password for the account
dataPath	/opt/Draupnir/datastorage	Storage
managementRoom	room ID	Room where moderators command Draupnir

This should give a working bot.

There are a few other bits that you probably want to change. Draupnir can direct reports to the management room, this is what you should change to activate that:

web:
  enabled: true
  port: 8082
  address: ::1
  abuseReporting:
    enabled: true

pollReports: true
displayReports: true

For this to work (for reports to reach Draupnir) you'll need to configure nginx to forward requests for reports to Draupnir:

location ~ ^/_matrix/client/(r0|v3)/rooms/([^/]*)/report/(.*)$ {
    # The r0 endpoint is deprecated but still used by many clients.
    # As of this writing, the v3 endpoint is the up-to-date version.
    
    # Alias the regexps, to ensure that they're not rewritten.
    set $room_id $2;
    set $event_id $3;
    proxy_pass http://[::1]:8082/api/1/report/$room_id/$event_id;
}

# Reports that need to reach Synapse (not sure if this is used)
location /_synapse/admin/v1/event_reports {
    proxy_pass http://localhost:8008;
    proxy_set_header X-Forwarded-For $remote_addr;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header Host $host;
    client_max_body_size 50M;
    proxy_http_version 1.1;
    
location ~ ^/_synapse/admin/v1/rooms/([^/]*)/context/(.*)$ {
    set $room_id $2;
    set $event_id $3;
    proxy_pass http://localhost:8008/_synapse/admin/v1/rooms/$room_id/context/$event_id;
    proxy_set_header X-Forwarded-For $remote_addr;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header Host $host;
    client_max_body_size 50M;
    proxy_http_version 1.1;
}

Rate limiting

Normal users are rate limited, to prevent them from flooding the server. Draupnir is meant to stop those events, but if it it itself rate limited, it won't work all that well.

How rate limiting is configured server-wide is documented in Synapse's documentation. Overriding is, unfortunately, not something you can easily configure in the configuration files. You'll have to do that in the database itself:

INSERT INTO ratelimit_override VALUES ('@draupnir:example.com', 0, 0);