Add support for spatialite database backend (#439)

.github/workflows/ci.yml

@@ -15,8 +15,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
-        os: [ubuntu-22.04]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+        os: [ubuntu-24.04]
     runs-on: ${{ matrix.os }}
     name: "${{ matrix.os }} Python: ${{ matrix.python-version }}"
     services:
@@ -44,7 +44,7 @@ jobs:
     - name: Install OS Packages
       run: |
         sudo apt-get update
-        sudo apt-get install binutils libproj-dev gdal-bin libmemcached-dev
+        sudo apt-get install binutils libproj-dev gdal-bin libmemcached-dev libsqlite3-mod-spatialite
     - uses: actions/checkout@v3
       with:
         fetch-depth: 0

django_prometheus/db/backends/spatialite/base.py

@@ -0,0 +1,14 @@
+from django.contrib.gis.db.backends.spatialite import base, features
+from django.db.backends.sqlite3 import base as sqlite_base
+
+from django_prometheus.db.common import DatabaseWrapperMixin
+
+
+class DatabaseFeatures(features.DatabaseFeatures):
+    """Our database has the exact same features as the base one."""
+
+    pass
+
+
+class DatabaseWrapper(DatabaseWrapperMixin, base.DatabaseWrapper):
+    CURSOR_CLASS = sqlite_base.SQLiteCursorWrapper

django_prometheus/tests/end2end/testapp/settings.py

@@ -81,6 +81,10 @@
         "HOST": "127.0.0.1",
         "PORT": "3306",
     },
+    "spatialite": {
+        "ENGINE": "django_prometheus.db.backends.spatialite",
+        "NAME": "db_spatialite.sqlite3",
+    },
     # The following databases are used by test_db.py only
     "test_db_1": {
         "ENGINE": "django_prometheus.db.backends.sqlite3",

django_prometheus/tests/end2end/testapp/test_db.py

@@ -178,3 +178,35 @@ def test_counters(self):
             alias="postgis",
             vendor="postgresql",
         )
+
+
+@pytest.mark.skipif("spatialite" not in connections, reason="Skipped unless spatialite database is enabled")
+class TestSpatialiteDbMetrics(BaseDBTest):
+    """Test django_prometheus.db metrics for spatialite backend.
+
+    Note regarding the values of metrics: many tests interact with the
+    database, and the test runner itself does. As such, tests that
+    require that a metric has a specific value are at best very
+    fragile. Consider asserting that the value exceeds a certain
+    threshold, or check by how much it increased during the test.
+    """
+
+    def test_counters(self):
+        r = save_registry()
+        connection = connections["spatialite"]
+
+        # Make sure the extension is loaded and geospatial tables are created
+        connection.prepare_database()
+
+        cursor = connection.cursor()
+
+        for _ in range(20):
+            cursor.execute("SELECT 1")
+
+        assert_metric_compare(
+            r,
+            lambda a, b: a + 20 <= b < a + 25,
+            "django_db_execute_total",
+            alias="spatialite",
+            vendor="sqlite",
+        )

pyproject.toml

@@ -23,14 +23,13 @@ legacy_tox_ini = """
 [tox]
 min_version = 4.4
 envlist =
-    {py37,py38,py39,py310,py311}-django{320}-{end2end,unittests}
+    {py38,py39,py310,py311}-django{320}-{end2end,unittests}
     {py38,py39,py310,py311,py312}-django{400,410,420}-{end2end,unittests}
     {py310,py311,py312}-django{500,510}-{end2end,unittests}
     py39-lint
 
 [gh-actions]
 python =
-    3.7: py37
     3.8: py38
     3.9: py39, py39-lint
     3.10: py310