Second Edition

Changes in the code for the second edition of the book.

Author: rmariano

LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2016-2019 Mariano Anaya
+Copyright (c) 2016-2020 Mariano Anaya
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -1,5 +1,11 @@
 # Clean code in Python
 
+## Book
+
+The source code for the examples listed in the
+[book](https://www.amazon.com/Clean-Code-Python-Refactor-codebase-ebook/dp/B07G19CHRM/ref=sr_1_1?s=books&ie=UTF8&qid=1535483811&sr=1-1)
+is under ``book/src``.
+
 ## EuroPython 2016 Talk
 
 Sources of the talk, as presented at EuroPython 2016.
@@ -9,9 +15,3 @@ The source code of the talk is under ``talk/src``.
 [Slides](https://speakerdeck.com/rmariano/clean-code-in-python)
 [EuroPython Page](https://ep2016.europython.eu/conference/talks/clean-code-in-python)
 [Video](https://www.youtube.com/watch?v=7ADbOHW1dTA)
-
-## Book
-
-The source code for the examples listed in the
-[book](https://www.amazon.com/Clean-Code-Python-Refactor-codebase-ebook/dp/B07G19CHRM/ref=sr_1_1?s=books&ie=UTF8&qid=1535483811&sr=1-1)
-is under ``book/src``.

book/src/.gitignore

@@ -0,0 +1,7 @@
+__pycache__
+*.sw[op]
+.mypy_cache/
+*.tar.gz
+.pytest_cache/
+.pytype
+env/

book/src/Makefile

@@ -1,8 +1,17 @@
+PYTHON=python3.9
+ENV_NAME=.env
+DOCKER_VERSION:=latest
+
+.PHONY: clean
 clean:
-	find . -name "*.swp" -o -name "__pycache__" | xargs rm -fr
-	find . -type d -name "*_cache*" | xargs rm -fr
+	find . -name "*.swp" -o -name "__pycache__" -o -name ".mypy_cache" | xargs rm -fr
+	rm -fr $(ENV_NAME)
 
+.PHONY: setup
 setup:
-	pip install -r requirements.txt
+	$(PYTHON) -m venv $(ENV_NAME)
+	$(ENV_NAME)/bin/python -m pip install -r requirements.txt
 
-.PHONY: clean setup
+.PHONY: shell
+shell:
+	docker run -it rmariano/ccip:$(DOCKER_VERSION)

book/src/README.rst

@@ -1,16 +1,38 @@
 Clean Code in Python
 --------------------
+Code for the book 'Clean code in Python', second edition.
+
+Requirements
+============
+The code in this repository can be run directly in a local machine, provided some dependencies are met (explained in the
+next section).  Alternatively, a Docker image is provided, which can be used to interact directly with.
+
+Running it locally
+^^^^^^^^^^^^^^^^^^
+The code in this repository assumes Python 3.9+ is installed in the system, and that ``python3.9`` is available in the
+current path.
+
+    - Python 3.9+
+    - GNU make and building tools for the dependencies (gcc, python3 dev files, etc.)
+
+Docker
+^^^^^^
+A docker image is provided to make it simpler for readers to try out the code examples.
+You can obtain the image, and interact with it by running::
+
+    docker pull rmariano/ccip:latest
+    docker run -it rmariano/ccip:latest
 
 Setup
 =====
-
-Create a virtual environment, and once activated run::
+To install the dependencies, run::
 
     make setup
 
-This will install the common dependencies. Besides this, each chapter might
-have additional ones, for which another ``make setup`` will have to be run
-inside that particular directory.
+This will create a new virtual environment, called ``.env`` and install the dependencies on it. From this point, you
+need to activate the virtual environment to run the rest of the code examples. The environment is activated by running::
+
+    source .env/bin/activate
 
 Each chapter has its corresponding directory given by its number.
 
@@ -35,7 +57,7 @@ Chapters Index
 * Chapter 04: The SOLID Principles
 * Chapter 05: Decorators
 * Chapter 06: Getting More out of our Objects with Descriptors
-* Chapter 07: Using Generators
+* Chapter 07: Generators, Iterators, and Asynchronous Programming
 * Chapter 08: Unit Testing and Refactoring
 * Chapter 09: Common Design Patterns
 * Chapter 10: Clean Architecture

book/src/ch01/Makefile

@@ -1,18 +1,23 @@
+.PHONY: typehint
 typehint:
 	mypy --ignore-missing-imports src/
 
+.PHONY: test
 test:
 	pytest tests/
 
+.PHONY: lint
 lint:
 	pylint src/
 
+.PHONY: checklist
 checklist: lint typehint test
 
+.PHONY: black
 black:
 	black -l 79 *.py
 
-setup:
-	$(VIRTUAL_ENV)/bin/pip install -r requirements.txt
-
-.PHONY: typehint test lint checklist black
+.PHONY: clean
+clean:
+	find . -type f -name "*.pyc" | xargs rm -fr
+	find . -type d -name __pycache__ | xargs rm -fr

book/src/ch01/README.rst

@@ -1,10 +1,6 @@
 Chapter 01 - Introduction, Tools, and Formatting
 ================================================
 
-Install dependencies::
-
-   make setup
-
 Run the  tests::
 
    make test

book/src/ch01/requirements.txt

@@ -2,21 +2,22 @@
 
 > Annotations
 """
+from dataclasses import dataclass
+from typing import Tuple
 
+Client = Tuple[int, str]
 
-class Point:  # pylint: disable=R0903
-    """Example to be used as return type of locate"""
-    def __init__(self, lat, long):
-        self.lat = lat
-        self.long = long
 
+def process_clients(clients: list[Client]):  # type: ignore
+    ...
 
-def locate(latitude: float, longitude: float) -> Point:
-    """Find an object in the map by its coordinates"""
-    return Point(latitude, longitude)
 
-
-class NewPoint:  # pylint: disable=R0903
-    """Example to display its __annotations__ attribute."""
+@dataclass
+class Point:
     lat: float
     long: float
+
+
+def locate(latitude: float, longitude: float) -> Point:
+    """Find an object in the map by its coordinates"""
+    return Point(latitude, longitude)

book/src/ch01/src/annotations.py

@@ -0,0 +1,23 @@
+"""Clean Code in Python - Chapter 1: Introduction, Tools, and Formatting
+
+> Extra code for isolated examples
+"""
+
+
+def data_from_response(response: dict) -> dict:
+    """If the response is OK, return its payload.
+    - response: A dict like::
+    {
+        "status": 200, # <int>
+        "timestamp": "....", # ISO format string of the current date time
+        "payload": { ... } # dict with the returned data
+    }
+    - Returns a dictionary like::
+    {"data": { .. } }
+
+    - Raises:
+    - ValueError if the HTTP status is != 200
+    """
+    if response["status"] != 200:
+        raise ValueError
+    return {"data": response["payload"]}

book/src/ch01/src/other.py

@@ -1,20 +1,20 @@
-"""Clean Code in Python - Chapter 01: Introcution, Tools, and Formatting
+"""Clean Code in Python - Chapter 01: Introduction, Tools, and Formatting
 
 Tests for annotations examples
 
 """
 import pytest
 
-from src.annotations import NewPoint, Point, locate
+from src.annotations import Point, locate
 
 
 @pytest.mark.parametrize(
-    "element,expected",
+    "defined_object,expected",
     (
         (locate, {"latitude": float, "longitude": float, "return": Point}),
-        (NewPoint, {"lat": float, "long": float}),
+        (Point, {"lat": float, "long": float}),
     ),
 )
-def test_annotations(element, expected):
-    """test the class/functions againts its expected annotations"""
-    assert getattr(element, "__annotations__") == expected
+def test_annotations(defined_object, expected):
+    """test the class/functions against its expected annotations"""
+    assert getattr(defined_object, "__annotations__") == expected

book/src/ch01/src/test_annotations.py

@@ -0,0 +1,22 @@
+"""Clean Code in Python - Chapter 1: Introduction, Tools, and Formatting
+
+> Tools for type hinting: examples
+"""
+from __future__ import annotations
+
+import logging
+from typing import List, Union, Tuple
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+
+def broadcast_notification(
+    message: str, relevant_user_emails: Union[List[str], Tuple[str]]
+):
+    for email in relevant_user_emails:
+        logger.info("Sending %r to %r", message, email)
+
+
+broadcast_notification("welcome", ["user1@domain.com", "user2@domain.com"])
+broadcast_notification("welcome", "user1@domain.com")  # type: ignore

book/src/ch01/src/type_hinting_example.py

@@ -0,0 +1,20 @@
+"""Clean Code in Python - Chapter 1: Introduction, Tools, and Formatting
+
+> Tools for type hinting: examples
+"""
+from __future__ import annotations
+
+import logging
+from typing import Iterable
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+
+def broadcast_notification(message: str, relevant_user_emails: Iterable[str]):
+    for email in relevant_user_emails:
+        logger.info("Sending %r to %r", message, email)
+
+
+broadcast_notification("welcome", ["user1@domain.com", "user2@domain.com"])
+broadcast_notification("welcome", "user1@domain.com")

book/src/ch01/src/type_hinting_example_2.py

@@ -1,7 +1,23 @@
 PYTHON:=$(VIRTUAL_ENV)/bin/python
+export PYTHONPATH=src
 
+.PHONY: test
 test:
-	@$(PYTHON) -m doctest *.py
-	@$(PYTHON) -m unittest *.py
+	@$(PYTHON) -m doctest tests/*.py
+	@$(PYTHON) -m unittest tests/*.py
 
-.PHONY: test
+.PHONY: typehint
+typehint:
+	mypy src tests
+
+.PHONY: lint
+lint:
+	black --check --line-length=79 src tests
+
+.PHONY: format
+format:
+	black --line-length=79 src tests
+
+.PHONY: clean
+clean:
+	find . -type d -name __pycache__ | xargs rm -fr {}

book/src/ch02/Makefile

@@ -0,0 +1,37 @@
+"""Clean Code in Python - Second edition
+Chapter 02: Assignment expressions
+"""
+
+import re
+from typing import Iterable, Set
+
+ARN_REGEX = re.compile(r"arn:aws:[a-z0-9\-]*:[a-z0-9\-]*:(?P<account_id>\d+):.*")
+
+
+def collect_account_ids_from_arns(arns: Iterable[str]) -> Set[str]:
+    """Given several ARNs in the form
+
+        arn:partition:service:region:account-id:resource-id
+
+    Collect the unique account IDs found on those strings, and return them.
+    """
+    collected_account_ids = set()
+    for arn in arns:
+        matched = re.match(ARN_REGEX, arn)
+        if matched is not None:
+            account_id = matched.groupdict()["account_id"]
+            collected_account_ids.add(account_id)
+    return collected_account_ids
+
+
+def collect_account_ids_from_arns2(arns: Iterable[str]) -> Set[str]:
+    matched_arns = filter(None, (re.match(ARN_REGEX, arn) for arn in arns))
+    return {m.groupdict()["account_id"] for m in matched_arns}
+
+
+def collect_account_ids_from_arns3(arns: Iterable[str]) -> Set[str]:
+    return {
+        matched.groupdict()["account_id"]
+        for arn in arns
+        if (matched := re.match(ARN_REGEX, arn)) is not None
+    }

book/src/ch02/properties.py

@@ -12,7 +12,7 @@ def mark_coordinate(grid, coord):
 class Boundaries:
     def __init__(self, width, height):
         self.width = width
-        self.height = height
+        self.height = heigh
 
     def __contains__(self, coord):
         x, y = coord