Email newsletter project based on Zero to Production in Rust.

1. User subscribes to newsletter (user status is set to "pending confirmation")
2. User receives a confirmation email with generated token
3. User confirms email (user status is set to "confirmed")
4. User gets sent an email every time new issue drops

Backend Development

User authorization

• OWASP guidelines
• Password hashing + salt (argon2id hasher with work parameters)
• Protection against preimage attacks, dictionary attacks, timing attacks

Databases

• Postgres with sqlx and support for offline mode (for docker building)
  • Compile-time correctness checks of queries
  • SQL for queries
  • Async support
• Database migrations
• Database transactions

Deployment

• Fly.io Docker app deploy with Postgres cluster
• Zero-downtime deployments (incremental migrations and code updates)

Docker

• Image size optimization (minimal runtimes, multi-stage builds)
• Image build run time optimization (caching dependencies binary with cargo-chef)

Testing

• Unit testing (reqwest)
• Integration testing
• Property-based testing (quickcheck and fake)
• Continuous Integration (GitHub actions)
• Continuous Deployment (fly.io)

Observability

• log logging,
• tracing spans
• bunyan formatting layer

Type-driven development

• Parse, don't validate -> maintaining invariants with newtype pattern

SMTP protocol for sending emails

• lettre

Error handling

• Custom error generation with thiserror and anyhow
• Enum error types for control flow

Actix-web

• Multithreaded execution
• Actix extractors with serde
• Actix middleware
• Actix cookies

Configuration file parsing

• config
• Hierarchical configuration files
• Environment variables parsing

Protection of sensitive data

• secrecy