Add NullFastlyCache service, use it in development (pypi#14317)

dev/environment

@@ -39,7 +39,7 @@ ARCHIVE_FILES_BACKEND=warehouse.packaging.services.LocalArchiveFileStorage path=
 SIMPLE_BACKEND=warehouse.packaging.services.LocalSimpleStorage path=/var/opt/warehouse/simple/ url=http://localhost:9001/simple/{path}
 DOCS_BACKEND=warehouse.packaging.services.LocalDocsStorage path=/var/opt/warehouse/docs/
 SPONSORLOGOS_BACKEND=warehouse.admin.services.LocalSponsorLogoStorage path=/var/opt/warehouse/sponsorlogos/
-
+ORIGIN_CACHE=warehouse.cache.origin.fastly.NullFastlyCache api_key=some_api_key service_id=some_service_id
 MAIL_BACKEND=warehouse.email.services.ConsoleAndSMTPEmailSender host=maildev port=1025 ssl=false [email protected]
 
 BREACHED_EMAILS=warehouse.accounts.NullEmailBreachedService

tests/unit/cache/origin/test_fastly.py

@@ -610,3 +610,28 @@ def test_purge_key_no_fallback(
 
         assert cacher._purge_key.calls == _purge_key_calls
         assert metrics.increment.calls == []
+
+
+class TestNullFastlyCache:
+    def test_purge_key_prints(self, capsys, metrics):
+        purge_key = pretend.stub(delay=pretend.stub())
+        request = pretend.stub(
+            registry=pretend.stub(
+                settings={
+                    "origin_cache.api_endpoint": "https://api.example.com",
+                    "origin_cache.api_key": "the api key",
+                    "origin_cache.service_id": "the service id",
+                }
+            ),
+            task=lambda f: purge_key,
+        )
+        cacher = fastly.NullFastlyCache.create_service(None, request)
+        cacher.purge_key("one", metrics=metrics)
+
+        captured = capsys.readouterr()
+        expected = """
+Origin cache purge issued:
+* URL: 'https://api.example.com/service/the service id/purge/one'
+* Headers: {'Accept': 'application/json', 'Fastly-Key': 'the api key', 'Fastly-Soft-Purge': '1'}
+"""  # noqa
+        assert captured.out.strip() == expected.strip()

warehouse/cache/origin/fastly.py

@@ -143,3 +143,23 @@ def purge_key(self, key, metrics=None):
                     tags=[f"ip_address:{self.api_connect_via}"],
                 )
                 self._double_purge_key(key)  # Do not connect via on fallback
+
+
+@implementer(IOriginCache)
+class NullFastlyCache(FastlyCache):
+    """Same as FastlyCache, but it doesn't issue any requests"""
+
+    def _purge_key(self, key, connect_via=None):
+        path = "/service/{service_id}/purge/{key}".format(
+            service_id=self.service_id, key=key
+        )
+        url = urllib.parse.urljoin(self.api_endpoint, path)
+        headers = {
+            "Accept": "application/json",
+            "Fastly-Key": self.api_key,
+            "Fastly-Soft-Purge": "1",
+        }
+
+        print("Origin cache purge issued:")
+        print(f"* URL: {url!r}")
+        print(f"* Headers: {headers!r}")