This document discusses Redis Fault Injection (RedFI), a tool for introducing faults during testing to simulate error conditions that may not otherwise occur. It provides fault injection as a proxy to Redis in a transparent way. Example use cases include testing race conditions, latency, dropped connections, and slow consumers. The document demonstrates RedFI and outlines future plans to integrate similar fault injection into Envoy and build replay and regression detection systems.

1. Redis Fault Injection
@LafiKL

2. $ whoami
■ Lead Systems Research Engineer at Misk Innovation
■ Experienced in building distributed systems and high
scalability
■ Twitter: @LafiKL
■ Github: @LafiKL

3. Story Time
Based on true events

5. Idempotent functions
f(f(x)) = f(x)

6. Why Redis In particular?
Redis is a swiss-army knife, used in many scenarios such as:
■ K/V Cache
■ Rate Limiting
■ Queue
■ Geo DB
■ Session Storage
■ External Shared State
■ Notifications
■ ...and the list goes on

7. Fault Injection Testing
In software testing, fault injection is a technique for improving the coverage of a
test by introducing faults to test code paths, in particular error handling code
paths, that might otherwise rarely be followed.
From Wikipedia

9. Features:
• Provides command level rule selection
• Acts as a proxy, so it's transparent to users, and clients
don't need to change anything
• It ships as a single binary. No dependencies.
• CLI & HTTP API to control the attack plan.

10. Client
SET key value
Client connects to RedFI
transparently
SET key value
Checks the rules against the
command sequentially
RedFI
Redis is oblivious to what RedFI is
doing
Redis

11. Example Use Cases:
• Race conditions testing
• Handling network Latency
• Handling dropped/flaky connections
• Slow consumers (When used a jobs store)

12. Demo Time!

13. Future Plans:
• Integrate similar fault injection knobs into Envoy
• Shift focus on building the replay and regression detection
systems

14. Thank You