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Daily Workflow

4 min read

Prerequisites: Testing
Next: PyO3 Overview

This article describes the recommended day-to-day development loop for Rust, compared to Python, and lists the one-off tools that make it faster and more productive.

Python vs Rust Workflow Comparison

Python workflow              Rust workflow
─────────────────────────    ─────────────────────────────
activate venv                (nothing to activate)
write code                   write code
python script.py             cargo run
pytest                       cargo test
black . && flake8 .          cargo fmt && cargo clippy
push to CI                   push to CI (cargo test + clippy)

The biggest shift: in Rust you get compile errors as you type (via rust-analyzer), so many bugs are caught before you ever run cargo build.

The Recommended Inner Loop

Step 1: Keep `cargo check` Running in the Background

# Install cargo-watch (do this once)
cargo install cargo-watch

# In one terminal — re-run `cargo check` on every file save
cargo watch -x check

# Alternatively, re-run tests on every save (slower but more thorough)
cargo watch -x test

cargo check does a full type-check in under 2 seconds on most projects. You see compiler errors immediately as you write code — similar to rust-analyzer in the IDE, but in the terminal.

Step 2: Use `cargo check` — not `cargo build` — for Fast Feedback

cargo check    # type-check only, no binary; fastest feedback
cargo test     # run tests (also does a type-check)
cargo run      # build + run (only when you need to see actual output)

Step 3: For PyO3 Extensions, Use `maturin develop`

# After editing src/lib.rs:
maturin develop --release   # recompile and reinstall (~5–30s)
python scripts/python_demo.py        # test the changes from Python

Before Committing

Run all four commands before every commit:

cargo fmt                    # format code (non-negotiable)
cargo clippy -- -D warnings  # lint; -D warnings fails on any warning
cargo test                   # all tests must pass
cargo build --release        # verify the optimised build works too

These are idiomatic gate checks. Many projects run them in CI as well.

One-Liner Pre-Commit Check

cargo fmt && cargo clippy -- -D warnings && cargo test && cargo build --release

Useful One-Off Tools

Install with cargo install — these persist across projects:

cargo install cargo-watch     # re-run commands on file changes
cargo install cargo-expand    # show what macros expand to (debugging macros)
cargo install cargo-audit     # check dependencies for known vulnerabilities
cargo install cargo-outdated  # show which deps have newer versions
cargo install cargo-flamegraph # generate flame graphs for profiling
cargo install cargo-nextest   # faster test runner with better output

Handling Slow Compile Times

Rust's incremental compiler caches intermediate results, so after the first build only changed files are recompiled. Two settings further reduce compile times for development:

# .cargo/config.toml (in your project root)
[build]
# Use the faster mold linker (Linux)
# Install: sudo apt-get install mold
# rustflags = ["-C", "link-arg=-fuse-ld=mold"]

[profile.dev]
opt-level = 0   # disable optimisation in dev builds
debug = 1       # less debug info = faster link

The `logferry` Development Loop

# Edit src/lib.rs in your IDE (rust-analyzer gives real-time errors)

# Quick type-check (fastest)
cargo check

# Run pure-Rust tests (no Python needed)
cargo test

# Rebuild and test from Python
maturin develop --release
python scripts/python_demo.py

# Lint before committing
cargo fmt && cargo clippy -- -D warnings

CI Configuration (GitHub Actions Example)

# .github/workflows/ci.yml
name: CI
on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: dtolnay/rust-toolchain@stable
        with:
          components: rustfmt, clippy

      - name: Format check
        run: cargo fmt --check

      - name: Clippy
        run: cargo clippy -- -D warnings

      - name: Test
        run: cargo test

      - name: Release build
        run: cargo build --release

Python vs Rust Workflow Comparison

The Recommended Inner Loop

Step 1: Keep cargo check Running in the Background

Step 2: Use cargo check — not cargo build — for Fast Feedback

Step 3: For PyO3 Extensions, Use maturin develop