# Setting up Matrix Corporal (optional, advanced)

> [!WARNING]
> This is an advanced feature! It requires prior experience with Matrix and a specific need for using [Matrix Corporal](https://github.com/devture/matrix-corporal). If you're unsure whether you have such a need, you most likely don't.

The playbook can install and configure [matrix-corporal](https://github.com/devture/matrix-corporal) for you.

In short, it's a sort of automation and firewalling service, which is helpful if you're instaling Matrix services in a controlled corporate environment.

See the project's [documentation](https://github.com/devture/matrix-corporal/blob/main/README.md) to learn what it does and why it might be useful to you.

If you decide that you'd like to let this playbook install it for you, you'd need to also:
- (required) [set up the Shared Secret Auth password provider module](configuring-playbook-shared-secret-auth.md)
- (optional, but encouraged) [set up the REST authentication password provider module](configuring-playbook-rest-auth.md)

## Adjusting the playbook configuration

Add the following configuration to your `inventory/host_vars/matrix.example.com/vars.yml` file (adapt to your needs):

```yaml
# The Shared Secret Auth password provider module is required for Corporal to work.
# See configuring-playbook-shared-secret-auth.md
matrix_synapse_ext_password_provider_shared_secret_auth_enabled: true
matrix_synapse_ext_password_provider_shared_secret_auth_shared_secret: YOUR_SHARED_SECRET_GOES_HERE

# When matrix-corporal is acting as the primary authentication provider,
# you need to set up the REST authentication password provider module
# to make Interactive User Authentication work.
# This is necessary for certain user actions (like E2EE, device management, etc).
#
# See configuring-playbook-rest-auth.md
matrix_synapse_ext_password_provider_rest_auth_enabled: true
matrix_synapse_ext_password_provider_rest_auth_endpoint: "http://matrix-corporal:41080/_matrix/corporal"

matrix_corporal_enabled: true

# See below for an example of how to use a locally-stored static policy
matrix_corporal_policy_provider_config: |
  {
    "Type": "http",
    "Uri": "https://intranet.example.com/matrix/policy",
    "AuthorizationBearerToken": "SOME_SECRET",
    "CachePath": "/var/cache/matrix-corporal/last-policy.json",
    "ReloadIntervalSeconds": 1800,
    "TimeoutMilliseconds": 300
  }

# If you also want to enable Matrix Corporal's HTTP API…
matrix_corporal_http_api_enabled: true
matrix_corporal_http_api_auth_token: "AUTH_TOKEN_HERE"

# If you need to change matrix-corporal's user ID from the default (matrix-corporal).
# In any case, you need to make sure this Matrix user is created on your server.
matrix_corporal_corporal_user_id_local_part: "matrix-corporal"

# Because Corporal peridoically performs lots of user logins from the same IP,
# you may need raise Synapse's ratelimits.
# The values below are just an example. Tweak to your use-case (number of users, etc.)
matrix_synapse_rc_login:
  address:
    per_second: 50
    burst_count: 300
  account:
    per_second: 0.17
    burst_count: 3
  failed_attempts:
    per_second: 0.17
    burst_count: 3
```

Matrix Corporal operates with a specific Matrix user on your server. By default, it's `matrix-corporal` (controllable by the `matrix_corporal_reconciliation_user_id_local_part` setting, see above).

No matter what Matrix user ID you configure to run it with, make sure that:

- the Matrix Corporal user is created by [registering it](registering-users.md) **with administrator privileges**. Use a password you remember, as you'll need to log in from time to time to create or join rooms

- the Matrix Corporal user is joined and has Admin/Moderator-level access to any rooms you want it to manage

### Using a locally-stored static policy

If you'd like to use a [static policy file](https://github.com/devture/matrix-corporal/blob/master/docs/policy-providers.md#static-file-pull-style-policy-provider), you can use a configuration like this:

```yaml
matrix_corporal_policy_provider_config: |
  {
    "Type": "static_file",
    "Path": "/etc/matrix-corporal/policy.json"
  }

# Modify the policy below as you see fit
aux_file_definitions:
  - dest: "{{ matrix_corporal_config_dir_path }}/policy.json"
    content: |
      {
        "schemaVersion": 1,
        "identificationStamp": "stamp-1",
        "flags": {
          "allowCustomUserDisplayNames": false,
          "allowCustomUserAvatars": false,
          "forbidRoomCreation": false,
          "forbidEncryptedRoomCreation": true,
          "forbidUnencryptedRoomCreation": false,
          "allowCustomPassthroughUserPasswords": true,
          "allowUnauthenticatedPasswordResets": false,
          "allow3pidLogin": false
        },
        "managedCommunityIds": [],
        "managedRoomIds": [],
        "users": []
      }
```

To learn more about what the policy configuration, see the matrix-corporal documentation on [policy](https://github.com/devture/matrix-corporal/blob/master/docs/policy.md).

### Extending the configuration

There are some additional things you may wish to configure about the component.

Take a look at:

- `roles/custom/matrix-corporal/defaults/main.yml` for some variables that you can customize via your `vars.yml` file
- `roles/custom/matrix-corporal/templates/config.json.j2` for the bridge's default configuration. You can override settings (even those that don't have dedicated playbook variables) using the `matrix_corporal_configuration_extension_json` variable

## Installing

After configuring the playbook, run it with [playbook tags](playbook-tags.md) as below:

<!-- NOTE: let this conservative command run (instead of install-all) to make it clear that failure of the command means something is clearly broken. -->
```sh
ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start
```

The shortcut commands with the [`just` program](just.md) are also available: `just run-tags setup-aux-files,setup-corporal,start` or `just setup-all`

`just run-tags setup-aux-files,setup-corporal,start` is useful for maintaining your setup quickly when its components remain unchanged. If you adjust your `vars.yml` to remove other components, you'd need to run `just setup-all`, or these components will still remain installed. Note `just setup-all` runs the `ensure-matrix-users-created` tag too.

## Matrix Corporal files

The following local filesystem paths are mounted in the `matrix-corporal` container and can be used in your configuration (or policy):

- `/matrix/corporal/config` is mounted at `/etc/matrix-corporal` (read-only)

- `/matrix/corporal/var` is mounted at `/var/matrix-corporal` (read and write)

- `/matrix/corporal/cache` is mounted at `/var/cache/matrix-corporal` (read and write)

As an example: you can create your own configuration files in `/matrix/corporal/config` and they will appear in `/etc/matrix-corporal` in the Docker container. Your configuration (stuff in `matrix_corporal_policy_provider_config`) needs to refer to these files via the local container paths — `/etc/matrix-corporal` (read-only), `/var/matrix-corporal` (read and write), `/var/cache/matrix-corporal` (read and write).

## Troubleshooting

As with all other services, you can find the logs in [systemd-journald](https://www.freedesktop.org/software/systemd/man/systemd-journald.service.html) by logging in to the server with SSH and running `journalctl -fu matrix-corporal`.

### Increase logging verbosity

If you want to increase the verbosity, add the following configuration to your `vars.yml` file and re-run the playbook:

```yaml
matrix_corporal_debug: true
```
