fix: use ruff check and format (#44)

* ci: add ruff (check & format), remove black

- ruff check is fantastic
- ruff format is a drop-in replacement for black (in particular the upcoming preview)
  the only places where ruff disagrees with black I agree with the former

* ci: configure ruff

- select all rules
- disable the 4 rules globally that conflict with ruff format
- disable certain rules on a per-file basis
  - assert is allowed in tests
  - we are using print in the unit tests to track execution

* fix: ruff errors

fix all errors detected by ruff after we turned on nearly all the rules

* ci: configure vscode to use ruff

helps find and fix ruff errors

Author: abid-mujtaba

.vscode/settings.json

@@ -1,17 +1,13 @@
 {
-    "python.formatting.provider": "black",
-    "python.linting.pylintEnabled": true,
-    "python.linting.mypyEnabled": true,
-    "python.linting.mypyArgs": [
-        "--show-column-numbers",
-        "--no-pretty",
-        "--strict"
-    ],
     "python.testing.pytestArgs": [
         "-sqx",
         "tests"
     ],
     "python.testing.unittestEnabled": false,
     "python.testing.pytestEnabled": true,
-    "python.envFile": "${workspaceFolder}/.env"
+    "python.envFile": "${workspaceFolder}/.env",
+    "[python]": {
+        "editor.formatOnSave": true,
+        "editor.defaultFormatter": "charliermarsh.ruff"
+    }
 }

example/src/example/server/__main__.py

@@ -4,10 +4,9 @@
 
 from .processor import app
 
-
 if __name__ == "__main__":
     logging.basicConfig(
         format="%(asctime)s %(name)s %(filename)s:%(lineno)d - %(message)s",
         level=logging.INFO,
     )
-    app.run(host="0.0.0.0", port=80)
+    app.run(host="0.0.0.0", port=80)  # noqa: S104

example/src/example/server/dba.py

@@ -1,12 +1,13 @@
 """DB (Postgres) Accessor."""
 
-from contextlib import contextmanager
+from __future__ import annotations
+
 import os
-from typing import Any, cast, Iterator, Optional
+from contextlib import contextmanager
+from typing import Any, Iterator, cast
 
 import psycopg
 
-
 DB_USER = "postgres"
 DB_PASSWORD = os.environ["POSTGRES_PASSWORD"]
 DB_HOST = "db-host"
@@ -16,7 +17,7 @@
 
 
 @contextmanager
-def get_cursor(autocommit: bool = False) -> Iterator[psycopg.Cursor[Optional[Record]]]:
+def get_cursor(autocommit: bool = False) -> Iterator[psycopg.Cursor[Record | None]]:
     """Create cursor to postgres DB."""
     conn = psycopg.connect(
         autocommit=autocommit, user=DB_USER, password=DB_PASSWORD, host=DB_HOST
@@ -27,7 +28,7 @@ def get_cursor(autocommit: bool = False) -> Iterator[psycopg.Cursor[Optional[Rec
         yield cursor
 
 
-def get_operation(uuid: int) -> Optional[str]:
+def get_operation(uuid: int) -> str | None:
     """Get operation for given uuid from operations table."""
     with get_cursor() as cursor:
         query = """

example/src/example/server/processor.py

@@ -2,11 +2,10 @@
 
 import logging
 
-from flask import Flask, jsonify, Response, request
+from flask import Flask, Response, jsonify, request
 
 from . import dba
 
-
 logger = logging.getLogger(__name__)
 app = Flask(__name__)
 
@@ -20,12 +19,10 @@ def process_test() -> Response:
 
 @app.route("/compute", methods=["POST"])
 def process_compute() -> Response:
-    """The /compute end-point fetches operation corresponding to uuid and applies it."""
+    """Fetch operation corresponding to uuid and apply it."""
     payload = request.json
     logger.info("Request to /compute: %s", payload)
 
-    assert payload
-
     uuid = payload["uuid"]
     value = payload["input"]
 

example/tests/integration/conftest.py

@@ -1,49 +1,11 @@
 """Fixtures for integration tests."""
 
 from typing import Iterator
-import pytest
 
-# import dba
+import pytest
 
 
-@pytest.fixture
+@pytest.fixture()
 def base_url() -> Iterator[str]:
     """URL to flask server in composable environment."""
-    yield "http://server"
-
-
-# @pytest.fixture(name="uuid")
-# def uuid_fixture() -> Iterator[int]:
-#     """Yield the uuid used for testing."""
-#     yield 1234
-
-# @pytest.fixture(name="operation")
-# def operation_fixture(uuid: int) -> Iterator[str]:
-#     """Bind uuid to operation string in DB."""
-#     with dba.get_cursor(autocommit=True) as cursor:
-#         operation = "identity"
-#         query = """
-#             INSERT
-#                 INTO operations
-#                 (
-#                     uuid,
-#                     operation
-#                 )
-#             VALUES
-#                 (
-#                     %(uuid)s,
-#                     %(operation)s
-#                 )
-#         """
-#         cursor.execute(query, {"uuid": uuid, "operation": operation})
-
-#     yield operation
-
-# with dba.get_cursor(autocommit=True) as cursor:
-#     query = """
-#         DELETE
-#             FROM operations
-#         WHERE
-#             uuid=%(uuid)s
-#     """
-#     cursor.execute(query, {"uuid": uuid})
+    return "http://server"

example/tests/integration/test_compute.py

@@ -1,9 +1,12 @@
 """Test the compute end-point."""
 
 import json
+
 import requests
 
-from .utils import base_url, operation, Uuid
+from .utils import Uuid, base_url, operation
+
+HTTP_OK = 200
 
 
 @operation.set("identity")
@@ -16,42 +19,44 @@ def test_compute_identity(uuid: Uuid) -> None:
     response = requests.post(f"{base_url}/compute", json=payload, timeout=5)
 
     # THEN
-    assert response.status_code == 200
+    assert response.status_code == HTTP_OK
 
     output = json.loads(response.text)
-    assert output["result"] == 9  # Identity operation
+    assert output["result"] == payload["input"]  # Identity operation
 
 
 @operation.set("square")
 def test_compute_square(uuid: Uuid) -> None:
     """Test the /compute end-point for a user with square operation."""
     # GIVEN
     payload = {"uuid": uuid, "input": 9}
+    expected_result = 9 * 9  # square operation
 
     # WHEN
     response = requests.post(f"{base_url}/compute", json=payload, timeout=5)
 
     # THEN
-    assert response.status_code == 200
+    assert response.status_code == HTTP_OK
 
     output = json.loads(response.text)
-    assert output["result"] == 81  # square operation
+    assert output["result"] == expected_result
 
 
 @operation.set("cube")
 def test_compute_cube(uuid: Uuid) -> None:
     """Test the /compute end-point for a user with cube operation."""
     # GIVEN
     payload = {"uuid": uuid, "input": 9}
+    expected_result = 9 * 9 * 9  # cube operation
 
     # WHEN
     response = requests.post(f"{base_url}/compute", json=payload, timeout=5)
 
     # THEN
-    assert response.status_code == 200
+    assert response.status_code == HTTP_OK
 
     output = json.loads(response.text)
-    assert output["result"] == 729  # cube operation
+    assert output["result"] == expected_result
 
 
 # Note: No operation record in the DB
@@ -65,7 +70,7 @@ def test_compute_no_operation() -> None:
     response = requests.post(f"{base_url}/compute", json=payload, timeout=5)
 
     # THEN
-    assert response.status_code == 200
+    assert response.status_code == HTTP_OK
 
     output = json.loads(response.text)
     assert "error" in output

example/tests/integration/test_test_endpoint.py

@@ -1,10 +1,13 @@
 """Test the /test end-point in the server."""
 
 import json
+
 import requests
 
 from .utils import base_url
 
+HTTP_OK = 200
+
 
 def test_test_endpoint() -> None:
     """Test the /test end-point in the server."""
@@ -15,7 +18,7 @@ def test_test_endpoint() -> None:
     response = requests.get(url, timeout=5)
 
     # THEN
-    assert response.status_code == 200
+    assert response.status_code == HTTP_OK
     payload = json.loads(response.text)
 
     assert payload["test"]["success"] is True

example/tests/integration/utils.py

@@ -1,9 +1,10 @@
 """Utilities for testing such as shared constants and fixtures."""
 
 from typing import NewType, ParamSpec
-from example.server import dba
 
-from testing.fixtures import fixture, FixtureDefinition
+from testing.fixtures import FixtureDefinition, fixture
+
+from example.server import dba
 
 P = ParamSpec("P")
 Uuid = NewType("Uuid", int)

pyproject.toml

@@ -49,7 +49,27 @@ version_toml = [
 branch = "main"
 upload_to_release = true    # auto create Github Release
 
+[tool.ruff]
+select = ["ALL"]
+ignore = [
+    "D203",  # First 4 rules are mutually incompatible and incompatible with ruff format
+    "D212",
+    "COM812",
+    "ISC001",
+    "FBT",  # Boolean values in function signatures
+    "ANN101",  # Annotate `self` parameter of class methods
+]
+
+[tool.ruff.per-file-ignores]
+"**/tests/**/*.py" = [
+    "S101"  # assert is allowed in tests
+]
+"tests/unit/*.py" = [
+    "T201"  # we are using print to track execution path
+]
+
 [tool.pylint.'MESSAGE CONTROL']
 disable = [
-    "invalid-name"
+    "invalid-name",
+    "no-else-raise",  # conflicts with ruff
 ]