add replay middleware and testing with nox (#12)

* add replay middleware

* add editorconfig

* add nox

* remove os matrix

Author: joshuadavidthomas

.editorconfig

@@ -0,0 +1,27 @@
+# http://editorconfig.org
+
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[{{Justfile,.justfile},*.{py,rst,ini,md}}]
+indent_size = 4
+indent_style = space
+
+[*.py]
+line_length = 120
+multi_line_output = 3
+
+[*.{css,html,js,json,sass,scss,yml,yaml}]
+indent_size = 2
+indent_style = space
+
+[*.md]
+trim_trailing_whitespace = false
+
+[{Makefile,*.bat}]
+indent_style = tab

.github/workflows/test.yml

@@ -15,13 +15,14 @@ env:
 
 jobs:
   test:
-    name: Python ${{ matrix.python-version }} on ${{ startsWith(matrix.os, 'macos-') && 'macOS' || startsWith(matrix.os, 'windows-') && 'Windows' || 'Linux' }}
-    runs-on: ${{ matrix.os }}
+    name: Python ${{ matrix.python-version }}, Django ${{ matrix.django-version }}, psycopg ${{ matrix.psycopg-version }}
+    runs-on: 'ubuntu-latest'
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, windows-latest, macos-latest]
         python-version: ['3.8', '3.9', '3.10', '3.11', '3.12-dev']
+        django-version: ['3.2', '4.0', '4.1', '4.2', 'main']
+        psycopg-version: ['2', "3"]
     steps:
     - uses: actions/checkout@v3
 
@@ -32,12 +33,11 @@ jobs:
 
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
-        python -m pip install '.[test]'
+        python -m pip install --upgrade pip nox
 
     - name: Run tests
       run: |
-        pytest
+          nox --session "tests-${{ matrix.python-version }}(psycopg='${{ matrix.psycopg-version }}', django='${{ matrix.django-version }}')"
 
   tests:
     runs-on: ubuntu-latest

noxfile.py

@@ -0,0 +1,67 @@
+from __future__ import annotations
+
+import nox
+
+PY38 = "3.8"
+PY39 = "3.9"
+PY310 = "3.10"
+PY311 = "3.11"
+PY312 = "3.12"
+PY_VERSIONS = [PY38, PY39, PY310, PY311, PY312]
+PY_DEFAULT = PY38
+
+DJ32 = "3.2"
+DJ40 = "4.0"
+DJ41 = "4.1"
+DJ42 = "4.2"
+DJMAIN = "main"
+DJMAIN_MIN_PY = PY310
+DJ_VERSIONS = [DJ32, DJ40, DJ41, DJ42, DJMAIN]
+DJ_DEFAULT = DJ32
+
+PSYCOPG2 = "2"
+PSYCOPG3 = "3"
+PSYCOPG_VERSIONS = [PSYCOPG2, PSYCOPG3]
+PSYCOPG_DEFAULT = PSYCOPG3
+
+
+def version(ver: str) -> tuple[int, ...]:
+    """Convert a string version to a tuple of ints, e.g. "3.10" -> (3, 10)"""
+    return tuple(map(int, ver.split(".")))
+
+
+def should_skip(python: str, django: str, psycopg: str) -> tuple(bool, str | None):
+    """Return True if the test should be skipped"""
+    if django == DJMAIN and version(python) < version(DJMAIN_MIN_PY):
+        return True, f"Django {DJMAIN} requires Python {DJMAIN_MIN_PY}+"
+
+    if django == DJ32 and version(python) >= version(PY312):
+        return True, f"Django {DJ32} requires Python < {PY312}"
+
+    if psycopg == PSYCOPG3 and version(python) >= version(PY312):
+        return True, f"psycopg3 requires Python < {PY312}"
+
+    return False, None
+
+
+@nox.session(python=PY_VERSIONS)
+@nox.parametrize("django", DJ_VERSIONS)
+@nox.parametrize("psycopg", PSYCOPG_VERSIONS)
+def tests(session, django, psycopg):
+    skip = should_skip(session.python, django, psycopg)
+    if skip[0]:
+        session.skip(skip[1])
+
+    session.install(".[test]")
+
+    if django == DJMAIN:
+        session.install("https://github.com/django/django/archive/refs/heads/main.zip")
+    else:
+        session.install(f"django=={django}")
+
+    if psycopg == PSYCOPG2:
+        session.install("psycopg2-binary")
+    elif psycopg == PSYCOPG3:
+        session.install("psycopg[binary]")
+
+    session.run("pytest")

pyproject.toml

@@ -1,15 +1,9 @@
 [build-system]
-requires = ["hatchling"]
 build-backend = "hatchling.build"
+requires = ["hatchling"]
 
 [project]
-name = "django-flyio"
-description = 'A set of simple utilities for Django apps running on Fly.io'
-readme = "README.md"
-requires-python = ">=3.8"
-license = "MIT"
-keywords = []
-authors = [{ name = "Josh", email = "[email protected]" }]
+authors = [{name = "Josh", email = "[email protected]"}]
 classifiers = [
   "Development Status :: 4 - Beta",
   "License :: OSI Approved :: MIT License",
@@ -24,11 +18,19 @@ classifiers = [
   "Programming Language :: Python :: Implementation :: CPython",
 ]
 dependencies = ["django>=3.2", "dj_database_url"]
+description = 'A set of simple utilities for Django apps running on Fly.io'
 dynamic = ["version"]
+keywords = []
+license = "MIT"
+name = "django-flyio"
+readme = "README.md"
+requires-python = ">=3.8"
 
 [project.optional-dependencies]
 dev = ["black", "hatch", "ruff"]
-test = ["coverage[toml]", "pytest", "pytest-asyncio", "pytest-django"]
+psycopg = ["psycopg[binary]"]
+psycopg2 = ["psycopg2-binary"]
+test = ["coverage[toml]", "nox", "pytest", "pytest-asyncio", "pytest-django"]
 types = ["django-stubs", "mypy"]
 
 [project.urls]
@@ -40,32 +42,44 @@ Source = "https://github.com/joshuadavidthomas/django-flyio"
 path = "src/django_flyio/__init__.py"
 
 [tool.black]
-target-version = ["py38"]
 line-length = 120
 skip-string-normalization = true
+target-version = ["py38"]
 
 [tool.coverage.report]
 exclude_lines = ["no cov", "if __name__ == .__main__.:", "if TYPE_CHECKING:"]
 
 [tool.mypy]
+ignore_missing_imports = true
 mypy_path = "src/"
 namespace_packages = false
 show_error_codes = true
 strict = true
 warn_unreachable = true
-ignore_missing_imports = true
 
 [[tool.mypy.overrides]]
-module = "tests.*"
 allow_untyped_defs = true
+module = "tests.*"
 
 [tool.pytest.ini_options]
-django_find_project = false
 DJANGO_SETTINGS_MODULE = "tests.settings"
+django_find_project = false
 pythonpath = ". src"
 
 [tool.ruff]
-target-version = "py38"
+ignore = [
+  # Allow non-abstract empty methods in abstract base classes
+  "B027", # Allow boolean positional values in function calls, like `dict.get(... True)`
+  "FBT003", # Ignore checks for possible passwords
+  "S105",
+  "S106",
+  "S107", # Ignore complexity
+  "C901",
+  "PLR0911",
+  "PLR0912",
+  "PLR0913",
+  "PLR0915",
+]
 line-length = 120
 select = [
   "A",
@@ -94,30 +108,15 @@ select = [
   "W",
   "YTT",
 ]
-ignore = [
-  # Allow non-abstract empty methods in abstract base classes
-  "B027",
-  # Allow boolean positional values in function calls, like `dict.get(... True)`
-  "FBT003",
-  # Ignore checks for possible passwords
-  "S105",
-  "S106",
-  "S107",
-  # Ignore complexity
-  "C901",
-  "PLR0911",
-  "PLR0912",
-  "PLR0913",
-  "PLR0915",
-]
+target-version = "py38"
 unfixable = [
   # Don't touch unused imports
   "F401",
 ]
 
 [tool.ruff.isort]
-known-first-party = ["django_flyio"]
 force-single-line = true
+known-first-party = ["django_flyio"]
 required-imports = ["from __future__ import annotations"]
 
 [tool.ruff.flake8-tidy-imports]

src/django_flyio/middleware.py

@@ -8,13 +8,21 @@
 
 import asyncio
 import os
+from http import HTTPStatus
 from typing import Awaitable
 from typing import Callable
 
 from django.http import HttpRequest
+from django.http.response import HttpResponse
 from django.http.response import HttpResponseBase
 
+try:
+    from psycopg.errors import ReadOnlySqlTransaction
+except ImportError:
+    from psycopg2.errors import ReadOnlySqlTransaction
+
 FLY_SERVER = "fly-server"
+FLY_REPLAY = "fly-replay"
 
 
 class FlyResponseMiddleware:
@@ -58,3 +66,39 @@ def add_response_headers(self, response: HttpResponseBase) -> None:
                 response[FLY_SERVER] = f"{machine_id}-{region}"
             else:
                 response[FLY_SERVER] = "unknown"
+
+
+class FlyReplayMiddleware:
+    sync_capable = True
+    async_capable = True
+
+    def __init__(
+        self,
+        get_response: (
+            Callable[[HttpRequest], HttpResponseBase] | Callable[[HttpRequest], Awaitable[HttpResponseBase]]
+        ),
+    ) -> None:
+        self.get_response = get_response
+        if asyncio.iscoroutinefunction(self.get_response):
+            # Mark the class as async-capable, but do the actual switch
+            # inside __call__ to avoid swapping out dunder methods
+            self._is_coroutine = asyncio.coroutines._is_coroutine  # type: ignore [attr-defined]
+        else:
+            self._is_coroutine = None
+
+    def __call__(self, request: HttpRequest) -> HttpResponseBase | Awaitable[HttpResponseBase]:
+        return self.__acall__(request) if self._is_coroutine else self.get_response(request)
+
+    async def __acall__(self, request: HttpRequest) -> HttpResponseBase:
+        aresponse = self.get_response(request)
+        assert not isinstance(aresponse, HttpResponseBase)  # noqa: S101
+        return await aresponse
+
+    def process_exception(self, request: HttpRequest, exception: Exception) -> HttpResponseBase:  # noqa: ARG002
+        if isinstance(exception, ReadOnlySqlTransaction):
+            primary_region = os.getenv("PRIMARY_REGION", None)
+            response = HttpResponse()
+            response.content = response.make_bytes(f"retry in region {primary_region}")
+            response.status_code = HTTPStatus.CONFLICT
+            response[FLY_REPLAY] = f"region={primary_region}"
+            return response