remote-dconf

Allows access to a remote server's dconf database. That way, a service can query a central configuration server for its configuration, for example in a microservices architecture.

Access is only allowed with authentication. Only HTTP basic authentication is supported.

Using the defaults, you can acquire a dump of the entire dconf database as such:

curl http://test@0.0.0.0:8000/

You should also consult the dconf manpage.

Requirements

• PHP >= 8.0
• bash
• dconf-cli

Installation

remote-dconf is expected to be installed in /opt/remote-dconf.

For ease of use, build.sh will generate a deb, which you can then install and manage with dpkg.

Running

start.sh will initialise some environment variables, then run index.php with the PHP built-in web server. (php -S)

For ease of use, you will find a systemd service in etc/remote-dconf.service, so you can manage the server with systemd.

Configuration

There are three things to configure: the dconf database to read, the port, and the authorisation token.

• database: the dconf database of the user the process is running as will be used. All the magic is handled by dconf. You can find the dconf database at ~/.config/dconf/user.
• port: configured in the dconf entry /org/vas/remote-dconf/port. If not found, defaults to 8000.
• token: configured in the dconf entry /org/vas/remote-dconf/token. If not found, defaults to test.

Architecture

Code is kept intentionally minimal and avoids external dependencies. remote-dconf is written in barebones PHP; composer is not used.

You will find some utility classes in lib:

• request.php provides a nicer API to PHP request data, which is normally stored in globals.
• response.php provides a nicer API for serving responses. Responses serve themselves through the serve() method.

index.php performs the business logic, which should be self-explanatory.

There is no PHP dconf library. Instead, we use the dconf binary and pipe its output to our response. To reduce unnecessary forking, our authentication token is loaded into an environment variable.

We use the PHP built-in server, which doesn't have the best performance, but it can manage a few hundred requests per second. For the purposes of this project, this should suffice.

If you want encryption, you should use a reverse proxy.