Fixed now: googleapis/python-storage/issues/372

.travis.yml

@@ -2,22 +2,17 @@ os: linux
 dist: bionic
 sudo: false
 language: python
-env:
-  - STORAGE_EMULATOR_HOST="http://localhost:8080"
 python:
  - "3.5"
  - "3.6"
  - "3.7"
  - "3.8"
  - "3.9"
  - "pypy3"
-services:
-  - docker
 install:
  - pip install -r requirements.txt
  - pip install coveralls
  - pip install --editable .
- - mkdir -p examples/emulated_storage/test-bucket && docker run -d --name fake-gcs-server -p 8080:8080 -v ${PWD}/examples/emulated_storage:/data fsouza/fake-gcs-server -scheme http -port 8080
 script: py.test
 after_success:
   - coveralls

flask_caching/backends/googlecloudstoragecache.py

@@ -3,8 +3,6 @@
 import json
 import logging
 
-from google.auth.credentials import AnonymousCredentials
-from google.cloud import storage, exceptions
 from flask_caching.backends.base import BaseCache
 
 
@@ -47,6 +45,11 @@ def __init__(
         super(GoogleCloudStorageCache, self).__init__(default_timeout)
         if not isinstance(bucket, str):
             raise ValueError("GCSCache bucket parameter must be a string")
+        try:
+            from google.auth.credentials import AnonymousCredentials
+            from google.cloud import storage, exceptions
+        except ImportError:
+            raise RuntimeError("no google.cloud module found")
         if anonymous:
             self._client = storage.Client(
                 credentials=AnonymousCredentials(), project="test", **kwargs
@@ -87,15 +90,13 @@ def set(self, key, value, timeout=None):
         except (UnicodeDecodeError, TypeError):
             content_type = "application/octet-stream"
         blob = self.bucket.blob(full_key)
-        blob.upload_from_string(value, content_type=content_type)
         if timeout is None:
             timeout = self.default_timeout
         if timeout != 0:
             # Use 'Custom-Time' for expiry
             # https://cloud.google.com/storage/docs/metadata#custom-time
-            blob.reload()
             blob.custom_time = self._now(delta=timeout)
-            blob.patch()
+        blob.upload_from_string(value, content_type=content_type)
         logger.debug("set key %r", full_key)
         return True
 

requirements.txt

@@ -7,3 +7,4 @@ pytest-xprocess
 redis
 pylibmc
 google-cloud-storage
+gcp-storage-emulator

setup.py

@@ -84,7 +84,15 @@ def run_tests(self):
     platforms="any",
     python_requires=">=3.5",
     install_requires=["Flask"],
-    tests_require=["pytest", "pytest-cov", "pytest-xprocess", "pylibmc", "redis"],
+    tests_require=[
+        "pytest",
+        "pytest-cov",
+        "pytest-xprocess",
+        "pylibmc",
+        "redis",
+        "google-cloud-storage",
+        "gcp-storage-emulator",
+    ],
     cmdclass={"test": PyTest},
     classifiers=[
         "Development Status :: 5 - Production/Stable",

tests/conftest.py

@@ -121,6 +121,10 @@ class Starter(ProcessStarter):
 
 @pytest.fixture(scope="class")
 def gcs_bucket(request):
+    try:
+        from google.cloud import storage
+    except ImportError:
+        pytest.skip("Python package 'google-cloud-storage' is not installed.")
     bucket = os.environ.get("CACHE_GCS_BUCKET")
     if not bucket:
         pytest.skip("'CACHE_GCS_BUCKET' environment variable is not set.")
@@ -133,9 +137,10 @@ def gcs_bucket(request):
 
 @pytest.fixture(scope="class")
 def gcs_emulator(request):
-    emulator = os.environ.get("STORAGE_EMULATOR_HOST")
-    if not emulator:
-        pytest.skip("'STORAGE_EMULATOR_HOST' not set.")
+    try:
+        from gcp_storage_emulator.server import create_server
+    except ImportError:
+        pytest.skip("Python package 'gcp-storage-emulator' is not installed.")
     if sys.version_info.major == 3 and sys.version_info.minor < 6:
         pytest.skip("Obsolete Python version.")
-    return emulator
+    return create_server

tests/test_backend_cache.py

@@ -9,6 +9,7 @@
     :license: BSD, see LICENSE for more details.
 """
 import errno
+import os
 import time
 
 import pytest
@@ -31,6 +32,17 @@
         except ImportError:
             memcache = None
 
+try:
+    from google.cloud import storage, exceptions
+except ImportError:
+    storage = None
+    exceptions = None
+
+try:
+    from gcp_storage_emulator.server import create_server
+except ImportError:
+    create_server = None
+
 
 class CacheTestsBase(object):
     _can_use_fast_sleep = True
@@ -357,18 +369,26 @@ def _delete_many(self, keys):
         return True
 
 
-# _guaranteed_deletes disabled, because emulator doesn't handle blob.custom_time correctly.
 class TestFakeGoogleCloudStorageCache(GenericCacheTests):
-    _guaranteed_deletes = False
-
     @pytest.fixture(scope="class", autouse=True)
     def requirements(self, gcs_emulator):
         pass
 
     @pytest.fixture
-    def make_cache(self):
+    def make_cache(self, gcs_emulator):
+        orig_env = os.environ.get("STORAGE_EMULATOR_HOST")
+        os.environ["STORAGE_EMULATOR_HOST"] = "http://localhost:9023"
+        server = gcs_emulator(
+            "localhost", 9023, in_memory=True, default_bucket="test-bucket"
+        )
+        server.start()
         c = FakeGoogleCloudStorageCache(
             bucket="test-bucket", delete_expired_objects_on_read=True, anonymous=True
         )
         yield lambda: c
         c.clear()
+        server.stop()
+        if orig_env is None:
+            del os.environ["STORAGE_EMULATOR_HOST"]
+        else:
+            os.environ["STORAGE_EMULATOR_HOST"] = orig_env