Catch blocking Postgres migrations before they hit production

[ayarotsky]

I built a tool to detect dangerous Postgres migrations in projects that use Diesel or SQLx. Operations like CREATE INDEX idx_users_email ON users(email) seem harmless, but block all writes for the entire duration of the index build.

diesel-guard analyzes your migration SQL and shows exactly what's unsafe and how to fix it:

❌ ADD INDEX non-concurrently

Problem:
  Creating an index without CONCURRENTLY acquires a SHARE lock,
  blocking all writes (INSERT, UPDATE, DELETE) during the build.

Safe alternative:
  CREATE INDEX CONCURRENTLY idx_users_email ON users(email);

Installation:
  cargo install diesel-guard
  diesel-guard check migrations/

Currently supported checks: https://github.com/ayarotsky/diesel-guard?tab=readme-ov-file#checks

Feedback and contributions welcome!