Playing around with the Redis caching

src/documents/caching.py

@@ -0,0 +1,11 @@
+from typing import Final
+
+CLASSIFIER_VERSION_KEY: Final[str] = "classifier_version"
+CLASSIFIER_HASH_KEY: Final[str] = "classifier_hash"
+CLASSIFIER_MODIFIED_KEY: Final[str] = "classifier_modified"
+
+CACHE_1_MINUTE: Final[int] = 60
+CACHE_5_MINUTES: Final[int] = 5 * CACHE_1_MINUTE
+
+DOC_SUGGESTIONS_BASE: Final[str] = "doc_{}_suggest"
+DOC_METADATA_BASE: Final[str] = "doc_{}_metadata"

src/documents/classifier.py

@@ -10,8 +10,13 @@ from pathlib import Path
 from typing import Optional
 
 from django.conf import settings
+from django.core.cache import cache
 from sklearn.exceptions import InconsistentVersionWarning
 
+from documents.caching import CACHE_5_MINUTES
+from documents.caching import CLASSIFIER_HASH_KEY
+from documents.caching import CLASSIFIER_MODIFIED_KEY
+from documents.caching import CLASSIFIER_VERSION_KEY
 from documents.models import Document
 from documents.models import MatchingModel
 
@@ -322,6 +327,10 @@ class DocumentClassifier:
         self.last_doc_change_time = latest_doc_change
         self.last_auto_type_hash = hasher.digest()
 
+        cache.set(CLASSIFIER_MODIFIED_KEY, self.last_doc_change_time, CACHE_5_MINUTES)
+        cache.set(CLASSIFIER_HASH_KEY, hasher.hexdigest(), CACHE_5_MINUTES)
+        cache.set(CLASSIFIER_VERSION_KEY, self.FORMAT_VERSION, CACHE_5_MINUTES)
+
         return True
 
     def preprocess_content(self, content: str) -> str:  # pragma: no cover

src/documents/conditionals.py

@@ -1,9 +1,13 @@
-import pickle
 from datetime import datetime
 from typing import Optional
 
 from django.conf import settings
+from django.core.cache import cache
 
+from documents.caching import CACHE_5_MINUTES
+from documents.caching import CLASSIFIER_HASH_KEY
+from documents.caching import CLASSIFIER_MODIFIED_KEY
+from documents.caching import CLASSIFIER_VERSION_KEY
 from documents.classifier import DocumentClassifier
 from documents.models import Document
 
@@ -19,13 +23,18 @@ def suggestions_etag(request, pk: int) -> Optional[str]:
     """
     if not settings.MODEL_FILE.exists():
         return None
-    with open(settings.MODEL_FILE, "rb") as f:
-        schema_version = pickle.load(f)
-        if schema_version != DocumentClassifier.FORMAT_VERSION:
+    cache_hits = cache.get_many(
+        [CLASSIFIER_VERSION_KEY, CLASSIFIER_HASH_KEY],
+    )
+    if (
+        CLASSIFIER_VERSION_KEY in cache_hits
+        and cache_hits[CLASSIFIER_VERSION_KEY] != DocumentClassifier.FORMAT_VERSION
+    ):
+        return None
+    elif CLASSIFIER_HASH_KEY in cache_hits:
+        cache.touch(CLASSIFIER_HASH_KEY, CACHE_5_MINUTES)
+        return f"{cache_hits[CLASSIFIER_HASH_KEY]}:{settings.NUMBER_OF_SUGGESTED_DATES}"
     return None
-        _ = pickle.load(f)
-        last_auto_type_hash: bytes = pickle.load(f)
-        return f"{last_auto_type_hash}:{settings.NUMBER_OF_SUGGESTED_DATES}"
 
 
 def suggestions_last_modified(request, pk: int) -> Optional[datetime]:
@@ -36,12 +45,18 @@ def suggestions_last_modified(request, pk: int) -> Optional[datetime]:
     """
     if not settings.MODEL_FILE.exists():
         return None
-    with open(settings.MODEL_FILE, "rb") as f:
-        schema_version = pickle.load(f)
-        if schema_version != DocumentClassifier.FORMAT_VERSION:
+    cache_hits = cache.get_many(
+        [CLASSIFIER_VERSION_KEY, CLASSIFIER_MODIFIED_KEY],
+    )
+    if (
+        CLASSIFIER_VERSION_KEY in cache_hits
+        and cache_hits[CLASSIFIER_VERSION_KEY] != DocumentClassifier.FORMAT_VERSION
+    ):
+        return None
+    elif CLASSIFIER_MODIFIED_KEY in cache_hits:
+        cache.touch(CLASSIFIER_MODIFIED_KEY, CACHE_5_MINUTES)
+        return cache_hits[CLASSIFIER_MODIFIED_KEY]
     return None
-        last_doc_change_time = pickle.load(f)
-        return last_doc_change_time
 
 
 def metadata_etag(request, pk: int) -> Optional[str]:

src/documents/views.py

@@ -15,6 +15,7 @@ from urllib.parse import quote
 import pathvalidate
 from django.conf import settings
 from django.contrib.auth.models import User
+from django.core.cache import cache
 from django.db.models import Case
 from django.db.models import Count
 from django.db.models import IntegerField
@@ -62,6 +63,9 @@ from documents import bulk_edit
 from documents.bulk_download import ArchiveOnlyStrategy
 from documents.bulk_download import OriginalAndArchiveStrategy
 from documents.bulk_download import OriginalsOnlyStrategy
+from documents.caching import CACHE_5_MINUTES
+from documents.caching import DOC_METADATA_BASE
+from documents.caching import DOC_SUGGESTIONS_BASE
 from documents.classifier import load_classifier
 from documents.conditionals import metadata_etag
 from documents.conditionals import metadata_last_modified
@@ -407,6 +411,14 @@ class DocumentViewSet(
         except Document.DoesNotExist:
             raise Http404
 
+        doc_key = DOC_METADATA_BASE.format(doc.pk)
+
+        cache_hit = cache.get(doc_key)
+
+        if cache_hit is not None:
+            cache.touch(doc_key, CACHE_5_MINUTES)
+            return Response(cache_hit)
+
         meta = {
             "original_checksum": doc.checksum,
             "original_size": self.get_filesize(doc.source_path),
@@ -436,6 +448,8 @@ class DocumentViewSet(
             meta["archive_size"] = None
             meta["archive_metadata"] = None
 
+        cache.set(doc_key, meta, CACHE_5_MINUTES)
+
         return Response(meta)
 
     @action(methods=["get"], detail=True)
@@ -454,6 +468,14 @@ class DocumentViewSet(
         ):
             return HttpResponseForbidden("Insufficient permissions")
 
+        doc_key = DOC_SUGGESTIONS_BASE.format(doc.pk)
+
+        cache_hit = cache.get(doc_key)
+
+        if cache_hit is not None:
+            cache.touch(doc_key, CACHE_5_MINUTES)
+            return Response(cache_hit)
+
         classifier = load_classifier()
 
         dates = []
@@ -463,8 +485,7 @@ class DocumentViewSet(
                 {i for i in itertools.islice(gen, settings.NUMBER_OF_SUGGESTED_DATES)},
             )
 
-        return Response(
-            {
+        resp_data = {
             "correspondents": [
                 c.id for c in match_correspondents(doc, classifier, request.user)
             ],
@@ -475,11 +496,12 @@ class DocumentViewSet(
             "storage_paths": [
                 dt.id for dt in match_storage_paths(doc, classifier, request.user)
             ],
-                "dates": [
-                    date.strftime("%Y-%m-%d") for date in dates if date is not None
-                ],
-            },
-        )
+            "dates": [date.strftime("%Y-%m-%d") for date in dates if date is not None],
+        }
+
+        cache.set(doc_key, resp_data, CACHE_5_MINUTES)
+
+        return Response(resp_data)
 
     @action(methods=["get"], detail=True)
     @method_decorator(cache_control(public=False, max_age=5 * 60))

src/paperless/settings.py

@@ -762,7 +762,10 @@ CELERY_BEAT_SCHEDULE_FILENAME = os.path.join(DATA_DIR, "celerybeat-schedule.db")
 # django setting.
 CACHES = {
     "default": {
-        "BACKEND": "django.core.cache.backends.redis.RedisCache",
+        "BACKEND": os.environ.get(
+            "PAPERLESS_CACHE_BACKEND",
+            "django.core.cache.backends.redis.RedisCache",
+        ),
         "LOCATION": _CHANNELS_REDIS_URL,
     },
 }

src/setup.cfg

@@ -3,6 +3,7 @@ DJANGO_SETTINGS_MODULE = paperless.settings
 addopts = --pythonwarnings=all --cov --cov-report=html --cov-report=xml --numprocesses auto --maxprocesses=16 --quiet --durations=50
 env =
     PAPERLESS_DISABLE_DBHANDLER=true
+    PAPERLESS_CACHE_BACKEND=django.core.cache.backends.dummy.DummyCache
 
 [coverage:run]
 source =