tlaplus / awesome-tlaplus

A curated list of TLA+ resources.

Awesome TLA+

TLA+ is a formal specification and verification language to help engineers design, specify, reason about, and verify complex software and hardware systems. It is widely used to verify the algorithms in distributed systems.

Contents

• WebSites
• Discussions
• Users
• Tools
• Books
• TLA+ blog posts and articles
• Real-world specs
• TLA+ Video Resources
• Scientific papers
• (University) courses teaching (with) TLA+

WebSites

• Homepage: http://www.tlapl.us (https://lamport.azurewebsites.net/tla/tla.html)
• TLA+ Project: https://project.tlapl.us (https://github.com/tlaplus)
• TLA+ Community Modules: https://modules.tlapl.us/ (https://github.com/tlaplus/CommunityModules)
• TLA+ Examples: https://examples.tlapl.us (https://github.com/tlaplus/Examples)
• Learn TLA+ (PlusCal): https://learntla.com/

Discussions

• google groups: https://groups.google.com/forum/#!forum/tlaplus
• reddit: https://www.reddit.com/r/tlaplus/
• twitter: https://twitter.com/tlaplus
• stackoverflow: https://stackoverflow.com/questions/tagged/tla%2b

Users

• Microsoft
• Atomix
• Informal Systems: TLA+ for protocol specification, model checking, model-based testing, and security audits of blockchains
• Open Networking Foundation
• Zilliqa Research

Tools

Verification

• TLC: https://tools.tlapl.us (https://github.com/tlaplus/tlaplus)
• TLAPM: https://proofs.tlapl.us (https://github.com/tlaplus/tlapm)
• Apalache: https://apalache.informal.systems/

IDEs

• VSCode-extension: https://github.com/tlaplus/vscode-tlaplus
• Toolbox (Eclipse based IDE): https://tools.tlapl.us (https://github.com/tlaplus/tlaplus)
• Jupyter notebook: https://github.com/kelvich/tlaplus_jupyter
• Emacs mode: https://github.com/ratish-punnoose/tla-mode
• Another Emacs mode: https://git.sdf.org/bch/tlamode/
• Intellij IDEA plugin: https://github.com/ocadaruma/tlaplus-intellij-plugin

Misc

• Better-comments (VSCode): https://github.com/alygin/better-comments
• TLC command-line wrapper: https://github.com/pmer/tla-bin

Parsers

• SANY (Syntactic Analyzer): A parser and syntax checker for TLA+ specifications
• TLAPS: A system for mechanically checking proofs written in TLA+
• tree-sitter-tlaplus: A tree-sitter grammar for TLA⁺ and PlusCal
• tlapy: A collection of Python tools for working with TLA+ specifications

Books

• Specifying Systems (freely available)
• Hyperbook (freely available)
• Practical TLA+
• TLA+ in Practice and Theory (freely available)

TLA+ blog posts and articles

name	description
AWS and TLA+	Use of Formal Methods at Amazon Web Services
Batch Installer	Sending async batches of commands.
Redux	Redux reducers with verifying a temporal property.
Zero Downtime Deployments	A simple model of a deploying new code to servers where at least one server is always available to clients, and all available servers show the same code version.
Trading Algorithm	Trading boths executing trades in a simulated market, showing how it’s susceptible to flash crashes.
Detecting Linked-List Cycles	Finding cycles in linked lists.
Replicated Storage	Replicated storage system with a quorum.
Rate Limiter	Independent workers hitting a rate-limited API.
Thread Pool	Multiple reader and writer threads sharing a bounded queue, discovering deadlocks.
Bank Transfer	Specifying a bank transfer with overdraft protection.
Finding bugs in systems through formalization	Ensuring distributed jobs go from “pending” to “completed”.
Building A "Simple" Distributed System	Rebalanser - distributed resource allocation library.
Train Sidings – A TLA+ Example	Railroad line where two trains can pass each other.
Azure Cosmos TLA+ specifications	The consistency levels offered by Azure Cosmos DB (also see Murat Demirbas' talk).
Modeling Streamlet in TLA+	A PlusCal spec of a crash fault-tolerant variant of the Streamlet blockchain protocol.
Using TLA+ in the Real World to Understand a Glibc Bug	Lifting code to the specification level to study a complex concurrency bug.
tla-specs	Collection of documented TLA+ explorations.

Real-world specs (not part of TLA+ Examples)

name	description
Distributed Lock	TLA+ specification of a replicated state machine for distributed locking
Generating All Combinations and Partitions	Spec of an algorithm in Knuth's TAOCP. It's Java implemenation is used by TLC.
Just-in-Time Paxos	TLA+ specification of an experimental consensus protocol that relies on high-precision clock synchronization to order proposals
Multi-primary Replication Protocol	TLA+ specification of a multi-primary replication protocol created for ONOS
P4Runtime Protocol Specification	TLA+ specification of the P4Runtime API that was used to demonstrate and fix safety violations in the protocol
Raft Consensus Algorithm	TLA+ specification of the Raft consensus algorithm
Raft Consensus Algorithm w/ Client	TLA+ specification of the Raft consensus algorithm and linearizable client
Sequentially Consistent Raft Streams	TLA+ specification of an algorithm for sequentially consistent streaming responses from a Raft cluster
SWIM Membership Protocol	TLA+ specification of the Scalable Weakly-consistent Infection-style Membership (SWIM) protocol
TendermintAcc	TLA+ specification of Tendermint consensus tuned for safety and fork accountability properties, including an inductive invariant
Tendermint Light Client	TLA+ specification of the Tendermint light client
TLA+ in TIDB	verify the distributed consensus algorithm : Raft & the implementation of distributed transaction.

TLA+ Video Resources

• The TLA+ Video Course
• Dr TLA+
• TLA+ Community Meeting 2018
• TLA+ conf 2019
• Debugging software designs using testable pseudo-code (TLA+)
• The practice and Theory of TLA+
• Tackling Concurrency Bugs with TLA+
• Formal verification applied
• Thinking Above the Code
• Building confidence in concurrent code with a model checker (aka TLA+ for programmers)

Scientific papers

• Search Arxiv, DBLP, ...

Theory

• Lamport's TLA+ publications
• Stephan Merz's publications

Tools

• Model Checking TLA+ Specifications
• Verifying Safety Properties with the TLA+ Proof System
• TLA+ model checking made symbolic
• The TLA+ Toolbox

Application

• eXtreme Modelling in Practice
• Specifying and Model Checking Workflows of Single Page Applications with TLA+

(University) courses teaching (with) TLA+

• EECS4315 Mission-Critical Systems (Winter 2023 - Section Z)
• SUNY Buffalo: CSE 4/586 Distributed Systems (Notes)
• Portland State: CS410/510 Practical Specification and Verification
• University of Wellington: SWEN421 - Formal Software Engineering
• Bordeaux INP: IF311 Formal Software Design
• TU Kaiserslautern: Programming Distributed Systems
• University of Iowa: CS5620f15 Distributed Systems and Algorithms
• University of Tartu: Systems Modelling
• University of Colorado: Distributed Systems Verification
• University of California, San Diego: CSE 128 Spring 2005 Concurrency

awesome-tlaplus's Issues

Add section about existing TLA+ parsers

There are many TLA+ parsers out there. Those interested in parsing might want to add a section (or subsection of the "Tools" section) here.

/cc @johnyf @ahelwer

Should this list be added to the list of awesome lists?

The Awesome movement is pretty strong and active, see https://github.com/sindresorhus/awesome.
Adding awesome-tlaplus to that list should increase TLA+'s visibility. However, this requires a bit of refactoring according to their style guides: https://github.com/sindresorhus/awesome/blob/main/pull_request_template.md.

Earlier this year I helped with getting awesome-coq into the list of awesome list and can give a hand with this refactoring if it's considered worthwhile for the TLA+ community.