Trillian Tessera

Trillian Tessera is a Go library for building tile-based transparency logs (tlogs). It is the logical successor to the approach Trillian v1 takes in building and operating logs.

The implementation and its APIs bake-in current best-practices based on the lessons learned over the past decade of building and operating transparency logs in production environments and at scale.

Tessera was introduced at the Transparency.Dev summit in October 2024. Watch Introducing Trillian Tessera for all the details, but here's a summary of the high level goals:

• tlog-tiles API and storage
• Support for both cloud and on-premises infrastructure
  • GCP
  • AWS (#24)
  • MySQL
  • POSIX
• Make it easy to build and deploy new transparency logs on supported infrastructure
  • Library instead of microservice architecture
  • No additional services to manage
  • Lower TCO for operators compared with Trillian v1
• Fast sequencing and integration of entries
• Optional functionality which can be enabled for those ecosystems/logs which need it (only pay the cost for what you need):
  • "Best-effort" de-duplication of entries
  • Synchronous integration
• Broadly similar write-throughput and write-availability, and potentially far higher read-throughput and read-availability compared to Trillian v1 (dependent on underlying infrastructure)
• Enable building of arbitrary log personalities, including support for the peculiarities of a Static CT API compliant log.

The main non-goal is to support transparency logs using anything other than the tlog-tiles API. While it is possible to deploy a custom personality in front of Tessera that adapts the tlog-tiles API into any other API, this strategy will lose a lot of the read scaling that Tessera is designed for.

Status

Tessera is under active development, with the alpha milestone coming soon. Users of GCP, MySQL, and POSIX are welcome to try the relevant Getting Started guide.

Roadmap

Alpha expected by Q4 2024, and production ready in the first half of 2025.

What’s happening to Trillian v1?

Trillian v1 is still in use in production environments by multiple organisations in multiple ecosystems, and is likely to remain so for the mid-term.

New ecosystems, or existing ecosystems looking to evolve, should strongly consider planning a migration to Tessera and adopting the patterns it encourages. Note that to achieve the full benefits of Tessera, logs must use the tlog-tiles API.

Getting started

The best place to start is the codelab provided in the conformance directory. This will walk you through setting up your first log, writing some entries to it via HTTP, and inspecting the contents.

Take a look at the example personalities in the /cmd/ directory:

• posix: example of operating a log backed by a local filesystem
  • This example runs an HTTP web server that takes arbitrary data and adds it to a file-based log.
• mysql: example of operating a log that uses MySQL
  • This example is easiest deployed via docker compose, which allows for easy setup and teardown.
• gcp: example of operating a log running in GCP
  • This example can be deployed via terraform (see the deployment directory).
• posix-oneshot: exmaple of a command line tool to add entries to a log stored on the local filesystem
  • This example is not a long-lived process; running the command integrates entries into the log which lives only as files.

The main.go files for each of these example personalities try to strike a balance when demonstrating features of Tessera between simplicity, and demonstrating best practices. Please raise issues against the repo, or chat to us in Slack if you have ideas for making the examples more accessible!

Contributing

See CONTRIBUTING.md for details.

License

This repo is licensed under the Apache 2.0 license, see LICENSE for details

Contact

• Slack: https://transparency-dev.slack.com/ (invitation)
• Mailing list: https://groups.google.com/forum/#!forum/trillian-transparency

Acknowledgements

Tessera builds upon the hard work, experience, and lessons from many many folks involved in transparency ecosystems over the years.