Bug 1851253 - adjust cache code to support two backends in the future…

…. r=aryx (#7837)

tests/test_setup.py

@@ -1,7 +1,7 @@
 import pytest
 import responses
 from celery import current_app
-from django.core.cache import cache
+from django.core.cache import caches
 from django.core.management import call_command
 
 from treeherder.utils.http import fetch_text
@@ -28,6 +28,8 @@ def test_no_missing_migrations():
 
 def test_django_cache():
     """Test the Django cache backend & associated server are properly set up."""
+    cache = caches['default']
+
     k, v = 'my_key', 'my_value'
     cache.set(k, v, 10)
     assert cache.get(k) == v

treeherder/model/error_summary.py

@@ -3,7 +3,7 @@
 import re
 import newrelic.agent
 
-from django.core.cache import cache
+from django.core.cache import caches
 
 from treeherder.model.models import Bugscache, TextLogError
 
@@ -32,6 +32,8 @@ def get_error_summary(job, queryset=None):
 
     Caches the results if there are any.
     """
+    db_cache = caches['default']
+    cache = caches['default']
     cache_key = 'error-summary-{}'.format(job.id)
     cached_error_summary = cache.get(cache_key)
     if cached_error_summary is not None:
@@ -41,7 +43,7 @@ def get_error_summary(job, queryset=None):
     line_cache_key = 'mc_error_lines'
     if job.repository == "comm-central":
         line_cache_key = 'cc_error_lines'
-    line_cache = cache.get(line_cache_key)
+    line_cache = db_cache.get(line_cache_key)
     if line_cache is None:
         line_cache = {str(job.submit_time.date()): {}}
     else:
@@ -83,7 +85,7 @@ def get_error_summary(job, queryset=None):
         logger.error('error caching error_summary for job %s: %s', job.id, e, exc_info=True)
 
     try:
-        cache.set(line_cache_key, line_cache, LINE_CACHE_TIMEOUT)
+        db_cache.set(line_cache_key, line_cache, LINE_CACHE_TIMEOUT)
     except Exception as e:
         newrelic.agent.record_custom_event('error caching error_lines for job', job.id)
         logger.error('error caching error_lines for job %s: %s', job.id, e, exc_info=True)

treeherder/webapp/api/note.py

@@ -1,4 +1,4 @@
-from django.core.cache import cache
+from django.core.cache import caches
 
 from rest_framework import viewsets
 from rest_framework.decorators import action
@@ -93,7 +93,8 @@ def create(self, request, project):
         if fc_id == 2:  # this is for fixed_by_commit (backout | follow_up_commit)
             # remove cached failure line counts
             line_cache_key = 'error_lines'
-            line_cache = cache.get(line_cache_key)
+            db_cache = caches['default']
+            line_cache = db_cache.get(line_cache_key)
             date = current_job.submit_time.date().isoformat()
             if line_cache and date in line_cache.keys():
                 for err in TextLogError.objects.filter(job=current_job):
@@ -107,7 +108,7 @@ def create(self, request, project):
                         ):
                             del line_cache[date]["new_lines"][cache_clean_line]
                         try:
-                            cache.set(line_cache_key, line_cache, LINE_CACHE_TIMEOUT)
+                            db_cache.set(line_cache_key, line_cache, LINE_CACHE_TIMEOUT)
                         except Exception as e:
                             logger.error(
                                 'error caching error_lines for job %s: %s',