Outro for concurrency (#14)

Author: LukeMathWalker

Cargo.lock

@@ -0,0 +1,26 @@
+# Wrapping up
+
+You should now have a strong theoretical foundation to reason about your options whenever
+you have a Python problem that could benefit from a concurrent solution.
+
+That's only the beginning, though. To truly master conccurent programming, you need to practice it!\
+This wasn't the right venue to cover all the possible concurrency patterns you can express with Rust.
+Luckily enough, there's plenty of resources available to help you on that side! We recommend, in particular,
+the ["Threads" chapter](https://rust-exercises.com/100-exercises/07_threads/00_intro.html) of our own
+Rust course. It follows the same hands-on approach we've been using in this book, and it's a great way to
+get more practice with Rust's concurrency primitives.
+
+Take the final exercise as a capstone project: you'll have to design a non-trivial algorithm and piece together
+various concurrenty primitives to implement a solution that's both correct and efficient. Don't shy
+away from the challenge: embrace it, it's the best way to learn!
+
+## Beyond performance
+
+A note, in closing: writing **correct** concurrent code is tricky.\
+We highlighted Rust, in this chapter, as a way to circumvent the limitations of Python's GIL and ultimately
+improve the performance of your code. But that's only half of the story.\
+Rust's type system and ownership model make it much easier to write concurrent code that's correct, too.
+As you delve deeper into the world of concurrent programming, you'll come to appreciate the real value of Rust's
+`Send` and `Sync` traits, which we've only briefly touched upon when discussing data races.
+
+As the saying goes: people come to Rust for the performance, but they stay for its safety and correctness guarantees.

book/src/03_concurrency/06_outro.md

@@ -23,3 +23,4 @@
   - [Releasing the GIL](03_concurrency/03_releasing_the_gil.md)
   - [Minimize GIL locking](03_concurrency/04_minimize_gil_locking.md)
   - [Immutable types](03_concurrency/05_immutable_types.md)
+  - [Outro](03_concurrency/06_outro.md)

book/src/SUMMARY.md

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+[package]
+name = "outro3"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+crossbeam = "0.8"
+pyo3 = { workspace = true }
+scraper = "0.22"
+ureq = "2"
+url = "2"

exercises/03_concurrency/06_outro/Cargo.toml

@@ -0,0 +1,25 @@
+[build-system]
+requires = ["maturin>=1.8,<2.0"]
+build-backend = "maturin"
+
+[project]
+name = "outro3"
+requires-python = ">=3.13"
+classifiers = [
+  "Programming Language :: Rust",
+  "Programming Language :: Python :: Implementation :: CPython",
+  "Programming Language :: Python :: Implementation :: PyPy",
+]
+version = "0.1.0"
+
+[tool.maturin]
+features = ["pyo3/extension-module"]
+
+[tool.uv]
+cache-keys = ["pyproject.toml", "Cargo.toml", "src/*.rs"]
+
+[tool.uv.sources]
+outro3 = { workspace = true }
+
+[tool.uv.workspace]
+members = ["sample"]

exercises/03_concurrency/06_outro/pyproject.toml

@@ -0,0 +1,10 @@
+# python generated files
+__pycache__/
+*.py[oc]
+build/
+dist/
+wheels/
+*.egg-info
+
+# venv
+.venv

exercises/03_concurrency/06_outro/sample/.gitignore

@@ -0,0 +1,19 @@
+[project]
+name = "outro3_sample"
+version = "0.1.0"
+dependencies = ["outro3"]
+readme = "README.md"
+requires-python = ">=3.13"
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[dependency-groups]
+dev = ["pytest>=8.2.2"]
+
+[tool.hatch.metadata]
+allow-direct-references = true
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/sample"]

exercises/03_concurrency/06_outro/sample/README.md

@@ -0,0 +1 @@
+

exercises/03_concurrency/06_outro/sample/pyproject.toml

@@ -0,0 +1,10 @@
+# Modify the Rust extension to get the test below to pass
+# Do NOT modify the test itself!
+import pytest
+
+from outro3 import site_map
+
+def test_site_map():
+    discovered_urls = set()
+    site_map("https://rust-exercises.com", discovered_urls)
+    assert len(discovered_urls) >= 200