Telodendria

Telodendria: The terminal branches of an axon.

Telodendria is a Matrix homeserver implementation written from scratch in ANSI C. It is designed to be lightweight and simple, yet functional. Telodendria differentiates itself from other Matrix homeserver implementations because it:

• Is written in C, a stable, low-level programming language with a long history, low build and runtime overhead, and wide compatibility.
• Is written with minimalism as a primary design goal. Whenever possible and practical, no third-party libraries are pulled in to the source code. Everything Telodendria needs is custom written. As a result, Telodendria depends only on a standard C compiler and POSIX C library to be built, both of which are built in to a good Unix-style operating system already, which means you shouldn't have to install anything extra.
• Uses a flat-file directory structure to store data instead of a database. This has a number of advantages:
  • It makes setup and maintenance much easier.
  • It allows Telodendria to run on systems with fewer resources.
• Is packaged as a single small, statically-linked and highly-optimized binary that can be run just about anywhere. It is designed to be extremely easy to set up and consume as few resources as possible.
• Is permissively licensed. Telodendria is licensed under a modified MIT license, which imposes few restrictions on what you can do with it.

Telodendria is on Matrix! Check out the official Matrix rooms:

Download

Telodendria is distributed as source tarballs, in true Unix fashion. If you want, you can verify the checksum of your download, and check the signature. To check the signature, you'll need signify, and the signify public key: telodendria-signify.pub.

If your operating system has an official package or port of Telodendria, you should prefer to use that instead of manually downloading the source and building it. If your operating system's package or port is too out of date for your tastes, please contact the package's maintainers to notify them, or offer to update the package yourself.

You can check out the change log here.

Documentation

Telodendria's documentation is distributed with the source code as man pages, which contain all of the information on how to build the source, configure it, as well as contribute to the project. The man pages are also available online for convenience:

• telodendria(7) - Introduction
• telodendria(8) - Command line
• telodendria.conf(5) - Configuration
• td(8) - Build script and patch instructions

Project Status

Telodendria is a very ambitious project. There's a lot that needs to happen yet before it is usable. At the moment, there's nothing that even remotely ressembles a Matrix homeserver here; I'm still getting off the ground and building a foundation.

But just because there's nothing here yet doesn't mean you should go away! I could always use help, so you are more than welcome to help out if you want things to go quicker. Please see the Contributing section for details on how you can get involved.

The Telodendria roadmap is organized into phases, with each phase representing a new milestone in the project's lifetime.

Phase 1: Getting Off The Ground

A new open-source project needs a few basic things before development can begin. This phase covers the pre-development stage of Telodendria.

• Name this project
• Set up a CVS repository
• Make CVS repository public
• Write a coding style guide
• Write a build script
• Add a license
• Add support and issue reporting guide
• Add table of contents to this document

Phase 2: Building A Foundation

Matrix homeservers require a few prerequisites. In this phase, we build up all the tools required to properly implement a Matrix homeserver. This includes basic data structures, exchange format parsers, and more. We also build up a command line application, multi-threaded HTTP server, and architect a flat-file database framework.

• Implement an array
• Implement a logging facility
• Implement argument parsing (-c file -Vh)
• Implement a hash map
• Combine library code files
• Implement configuration file parsing using the hash map
• Base64 encoding/decoding with padded/unpadded support
• Write a release script
• UTF-8 encoder
• Implement a JSON library using the hash map and array
  • Basic encoding from HashMap/Array/strings, etc.
  • Basic decoding to HashMap/Array/strings, etc.
  • Proper string encoding
  • Proper string decoding
  • Canonical JSON
    • Keys are sorted lexicographically
    • Floats are not allowed (ignore any float values)
    • Encode as UTF-8 instead of using \u escapes
    • Decode encoded strings to UTF-8
• Write a function that gets the current Unix timestamp in milliseconds.
• Figure out how to wWrite unit tests for array/hashmap/etc
• Parse the Telodendria config file
• Add license/documentation comments to all source files
• Implement a simple HTTP server
  • Implement param parser
  • URL encoder/decoder
• Design the server architecture
  • Route requests
  • Handle requests
  • Data abstraction layer
  • Error generation

Phase 3: Welcome To Matrix

When the foundations are laid, we can start implementing a real Matrix homeserver. This phase tracks our current progress in implementing the Matrix specification.

• Client-Server API
  • Error responses
  • /_matrix/client/versions
  • CORS Headers
  • Well-known URIs
  • Client Authentication
  • Capabilities negotiation
• Server-Server API
• Application Service API
• Identity Service API
• Push Gateway API
• Room Versions

Phase 4: A Real Homeserver

The Matrix specification is only a part of what it takes to be a production-ready Matrix homeserver. While the spec details how clients and homeservers interact with each other, we still need a way to administer our homeserver. This phase tracks our progress on getting Telodendria packaged, as well as writing some useful administrative tools. Only when these things are completed can we call Telodendria "production-ready."

• Create an OpenBSD package and get it submitted to ports
• Create a command line tool to manage Telodendria
  • Configuration file generation
  • User management
  • Room management
• Migrate from Synapse. I run a Synapse homeserver right now, so somehow I have to get all my data into the Telodendria format.

Documentation Status

This documentation needs just a little work. Here's the things on my list for that:

• Update Rationale section
• Update Project description (no longer a CGI binary)
• Update project code requirements (ANSI C, POSIX.1c)
• Clean up dark mode colors (tables, background, code snippets)
• Add logo (possibly center title?)
• Update Code Style to not include indent or line rules, but to use indent(1) instead.
• Fix typo "Subitting Patches" in Table of Contents
• Make a note in Getting The Code that the password for the anoncvs account is just anoncvs.
• Add Contributors list
• Add list of make.sh recipes, and what they do
• Improve Google Lighthouse score
  • Image elements do not have explicit width and height
  • Background and foreground colors do not have a sufficient contrast ratio. (msg-error div)
  • Lists do not contain only li elements.
• Add other message divs for notes and warnings.

Rationale

I want a lightweight Matrix homeserver designed specifically for OpenBSD and other Unix-like operating systems. I want a homeserver that can be developed and compiled with built-in tools. I want it to function entirely on a base OS install without having to install any extra packages whatsoever. I've found that as far as these goals are concerned, the existing homeserver implementations fall short. This project aims to prove that Matrix homeservers can be lightweight and written in such a way that very few, if any, third-party libraries need to be pulled in.

I also want to learn how Matrix works, and I want to understand the code I'm running on my server, which is why I'm writing every component from scratch, even the HTTP server.

Telodendria doesn't use a database like all the other homeservers. Instead, it operates more like email: it uses a flat-file data structure similar to Maildir to store data. The advantage of this is that it saves server maintainers from also having to maintain a database. It greatly simplifies the process of getting a Matrix homeserver up and running, and it makes it highly portable. It also is extremely easy to back up and restore with base tools; just tar(1) up the directory, and you're good to go.

Telodendria is developed and tested on OpenBSD, but you'll find that it should just run on any POSIX operating system without modification.

Project Goals

The goals of this project are generally divided into user goals, and developer goals, depending on who they impact the most. This isn't an exhaustive list, but it is a list of things that I want to prioritize, because other server implementations lack them.

The user goals are as follows:

• To implement the latest Matrix specification as fully and completely as possible. All features should eventually be present in Telodendria.
• To be a production-ready Matrix server capable of handling a lot of users. Telodendria should have good performance in many diverse environments. It should scale up well for large instances, and yet also be able to scale down to a peer-to-peer device.
• To be easier to configure than any of the other Matrix homeserver implementations. The configuration file should be flexible, well-documented, and easy to understand and modify. An intuitive command-line tool for administrative tasks should also be available.

The developer goals are as follows:

• To have as few external build and run dependencies as possible. It should be possible to compile Telodendria on any POSIX operating system right out of the box, and have it be totally statically linked, ready to run under a chroot(8). You'll even notice that the documentation is written in HTML directly, not Markdown, to remove the dependency on a Markdown parser and renderer.
• To have a simple yet elegant workflow, and not depend on any large or complex development tools, such as code forges. The entire development workflow should be able to be successfully and efficiently completed on a base OpenBSD install. Of course you don't have to use OpenBSD for development by any means, but the point is, the workflow should not require a lot of tools.
• To be written in clean, elegant, well-tested, and well-documented code. The goal is to build a Matrix homeserver from the ground up, not just because I don't like the way existing homeservers are implemented, but also so I can learn how Matrix really works, and maybe even teach others along the way.
• To foster a welcoming community environment. Many of the big communities such as Linux and OpenBSD have fairly hostile leaders. Telodendria shouldn't have a hostile leader. I want to be as understanding as I can, and talk through issues politely and in a civil manner. If I'm failing in this way, don't be afraid to call me out!

Getting Support

Telodendria is designed to be fairly straightforward, but that doesn't mean there won't be hiccups along the way. If you are struggling to get Telodendria up and running, you're more than welcome to reach out for support. Just join the #telodendria-general:bancino.net Matrix channel. Before you do though, make sure you're running the latest version of Telodendria and you've thoroughly read through all the relevant documentation.

Contributing

Telodendria is an open source project. As such, it welcomes contributions. There are many ways you can contribute, and any way you can is greatly appreciated.

Reporting Issues

If—after you've reached out to #telodendria-general:bancino.net—it has been determined that there is a problem with Telodendria, it should be reported to #telodendria-issues:bancino.net. There it can be discussed further. The issues room serves as the official issue tracker of Telodendria; although severe issues may be copied into a TODO file in the CVS repository just so they don't get lost.

Developing

The primary language used to write Telodendria code is ANSI C. Other languages you'll find in the Telodendria repository are shell scripts and HTML. If you have any experience at all with any of these languages, your contributions are valuable. Please follow the guidelines in this section to ensure the contribution workflow goes as smoothly as possible.

Getting The Code

If you'd like to hack on Telodendria, you'll need the following tools in addition to the tools required to build the source:

• cvs for checking out and updating a local copy of the source code.
• indent for formatting your code before generating patches
• patch for applying patches to your local copy of the source code.

Note that all of these tools are built into OpenBSD. While you of course don't have to use OpenBSD to develop Telodendria, it may make the process a little easier. In fact, these tools were chosen precisely because they were built into OpenBSD, the operating system I use.

You can download an official release tarball if you would really like, but the preferred way is to check out the source code from CVS. This makes generating patches a lot easier.

If you already checkout out the code previously, make sure you update your local copy before you start developing:

You should now have the latest Telodendria source code. Follow the Code Style as you make your changes. If the cvs command fails with a Connection refused error message, then try setting the CVS_RSH environment variable to ssh, like this:

Then run the checkout again. Some versions of CVS don't use SSH to checkout by default, so if yours doesn't, you might want to put that line in your .bashrc or other shell init script.

Code Style

In general, these are the conventions used by the code base. This guide may be slightly outdated or subject to change, however. The source code itself is the absolute source of truth, so as long as you make your code look like the code surrounding it, you should be fine.

• All function, enumeration, structure, and header names are CamelCase. This is preferred to snake_case because it is more compact.
• All variable names are lowerCamelCase. This is preferred to snake_case because it is more compact.
• enums and structs are always typedef-ed to their same name. The typedef occurs in the public API header, and the actual declaration occurs in the implementation file.
• A feature of the code base lives in a single .c file that has a matching header file. The header file should only export public symbols, everything else in the .c file should be static.
• Anywhere curly braces are optional, there must still be curly braces. This makes it easy to add on to the code later, and just makes things less ambiguous.

As far as actually formatting the code goes, such as where to put brackets and whether you use tabs or spaces, use indent(1) to take care of all of that. The root of the repository has a .indent.pro file that should automatically be loaded by indent(1) to set the correct rules. If you don't have access to a working indent(1), just indicate in your patch that I should run indent(1) on the code after applying it. I'll likely run my indent(1) on the code anyway though, just to make sure the spacing is consistent, if nothing else.

Submitting Patches

Telodendria aims at remaining as minimal as possible. This doesn't just mean minimal code, it also means a minimal development process, which is why Telodendria doesn't use GitHub, GitLab, or even SourceHut. Instead, the contribution workflow operates on submitting patch files to a public Matrix room, sort of like the OpenBSD project operates on patch files sent to a public mailing list.

If you're not used to manually creating and submitting patches instead of opening a "pull request," you should be pleased to hear that submitting patches is fairly easy to do if you've got the CVS sources checked out. In fact, I find it easier than having to make a GitHub account, forking a project repository, and then making a pull request for it. Once you have made your changes in your local copy of the code, and you've configured your environment using the instructions in The Build Script, just run the patch recipe:

This will automatically generate a patch file for all your changes, and then open it in your preferred editor. You can also generate a patch for only certain files and directories. To do that, set PATCHSET, like this:

As you'll notice, the top of the patch file should have some email-style headers that look like this:

As much information as possible should be filled out for you, such as the date. An attempt to fill out the From header was also made, but the information there can be made more accurate by setting MXID to your Matrix ID, and DISPLAY_NAME to your real name in your environment, or the .env file. The Subject should very briefly describe what the patch is about.

You'll also notice these lines:

This is a checkbox that tells me whether or not you actually have the rights to submit your patch, and that once you submit the patch, your code is bound by the Telodendria license. The full text of the developer certificate of origin is as follows:

1. The contribution was created in whole or in part by me, and I have the right to submit it under the open source license of the Telodendria project; or
2. The contribution is based upon a previous work that, to the best of my knowledge, is covered under an appropriate open-source license and I have the right under that license to submit that work with modifications, whether created in whole or in part by me, under the Telodendria project license; or
3. The contribution was provided directly to me by some other person who certified (1), (2), or (3), and I have not modified it.
4. I understand and agree that this project and the contribution are public and that a record of the contribution—including all personal information I submit with it—is maintained indefinitely and may be redistributed consistent with this project or the open-source licenses involved.

After the headers, but before the checkbox, write a more thorough description of the patch and why it was created. Then, send the resulting patch file to #telodendria-patches:bancino.net, so it can be discussed and reviewed by the community.

Try to keep your patches on topic—make one patch file per feature or bug fix being implemented. It is okay if your patches depend on previous patches, just indicate that in the patch. Note that it may take a while for patches to be committed, and some patches may not be committed at all. In either case, all sent patches are queued from the Matrix room into the public patch directory, so they can be referenced easier in the future. If you want to reference a submitted patch in a Matrix message or email, it might be a good idea to link to it in the public patch directory.

The public patch directory works as follows: when you send your patch to the Matrix room, it is downloaded by the Telodendria Bot and placed in the ingress/ directory, named as the message ID. Then, it is assigned a Telodendria patch ID and copied to the p/ directory as just ${id}.patch. This is a permanent link that will always reference your patch. Then, your patch is symlinked to the queue/ directory. I have a script that automatically ingresses patches and queues them for me, and I'll use this to review patches. If your patch is accepted, the queue symlink will be moved to the accepted/ directory and the patch is committed to the official CVS repository. If you patch is rejected for some reason, its symlink will be moved to the rejected/ directory. Regardless of the state of your patch, it will always remain permalinked in the p/ directory, and when it is accepted or rejected, Telodendria Bot will send a message.

You're always welcome to inquire about rejected patches, and request they be reviewed again, or you can use them as a starting point for future patches.

Resources

• Old Telodendria Versions
• Matrix Spec Mirror (Download matrix-spec-v1.3.tar.gz)
• Public Patch Directory