fix: add schematize service name for django caching [backport 2.19] (#11854)

Backport 6613185 from #11843 to 2.19.

Currently, we treat django caching as a separate service.
This is a quick fix so that behavior aligns with our public docs;
inferred services connected to django should be directly connected to
the third-party service not django.
The service name should adhere to the name rule from
`schematize_service_name` rather than `django`.

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Co-authored-by: Quinna Halim <[email protected]>

Author: github-actions[bot]

ddtrace/contrib/internal/django/patch.py

@@ -215,7 +215,7 @@ def traced_cache(django, pin, func, instance, args, kwargs):
         "django.cache",
         span_name="django.cache",
         span_type=SpanTypes.CACHE,
-        service=config.django.cache_service_name,
+        service=schematize_service_name(config.django.cache_service_name),
         resource=utils.resource_from_cache_prefix(func_name(func), instance),
         tags=tags,
         pin=pin,

releasenotes/notes/django-cache-service-name-schematization-bef19b44b7414016.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    tracing(django): Fixes issue where django cache is represented as a django service rather than the third party service.

tests/contrib/django/test_django.py

@@ -30,6 +30,7 @@
 from ddtrace.ext import http
 from ddtrace.ext import user
 from ddtrace.internal.compat import ensure_text
+from ddtrace.internal.schema import schematize_service_name
 from ddtrace.propagation._utils import get_wsgi_header
 from ddtrace.propagation.http import HTTP_HEADER_PARENT_ID
 from ddtrace.propagation.http import HTTP_HEADER_SAMPLING_PRIORITY
@@ -769,6 +770,18 @@ def test_cache_get(test_spans):
     assert_dict_issuperset(span.get_tags(), expected_meta)
 
 
+def test_cache_service_schematization(test_spans):
+    cache = django.core.cache.caches["default"]
+
+    with override_config("django", dict(cache_service_name="test-cache-service")):
+        cache.get("missing_key")
+        spans = test_spans.get_spans()
+        assert spans
+        span = spans[0]
+        expected_service_name = schematize_service_name(config.django.cache_service_name)
+        assert span.service == expected_service_name
+
+
 def test_cache_get_rowcount_existing_key(test_spans):
     # get the default cache
     cache = django.core.cache.caches["default"]