Run integration tests both with and without HTTP storage protocol.

.github/workflows/ci.yml

@@ -229,7 +229,11 @@ jobs:
           # aren't too long. On Windows tox won't pass it through so it has no
           # effect. On Linux it doesn't make a difference one way or another.
           TMPDIR: "/tmp"
-        run: tox -e integration
+        run: |
+          # Run with Foolscap forced:
+          __TAHOE_INTEGRATION_FORCE_FOOLSCAP=1 tox -e integration
+          # Run with Foolscap not forced, which should result in HTTP being used.
+          __TAHOE_INTEGRATION_FORCE_FOOLSCAP=0 tox -e integration
 
       - name: Upload eliot.log in case of failure
         uses: actions/upload-artifact@v1

integration/util.py

@@ -1,14 +1,6 @@
 """
 Ported to Python 3.
 """
-from __future__ import unicode_literals
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
-from future.utils import PY2
-if PY2:
-    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 import sys
 import time
@@ -38,6 +30,7 @@ from allmydata.util.configutil import (
     write_config,
 )
 from allmydata import client
+from allmydata.testing import foolscap_only_for_integration_testing
 
 import pytest_twisted
 
@@ -300,6 +293,14 @@ def _create_node(reactor, request, temp_dir, introducer_furl, flog_gatherer, nam
                 u'log_gatherer.furl',
                 flog_gatherer,
             )
+            force_foolscap = foolscap_only_for_integration_testing()
+            if force_foolscap is not None:
+                set_config(
+                    config,
+                    'storage',
+                    'force_foolscap',
+                    str(force_foolscap),
+                )
             write_config(FilePath(config_path), config)
         created_d.addCallback(created)
 

src/allmydata/protocol_switch.py

@@ -30,6 +30,7 @@ from foolscap.api import Tub
 
 from .storage.http_server import HTTPServer, build_nurl
 from .storage.server import StorageServer
+from .testing import foolscap_only_for_integration_testing
 
 
 class _PretendToBeNegotiation(type):
@@ -170,6 +171,21 @@ class _FoolscapOrHttps(Protocol, metaclass=_PretendToBeNegotiation):
         # and later data, otherwise assume HTTPS.
         self._timeout.cancel()
         if self._buffer.startswith(b"GET /id/"):
+            if foolscap_only_for_integration_testing() == False:
+                # Tahoe will prefer HTTP storage protocol over Foolscap when possible.
+                #
+                # If this is branch is taken, we are running a test that should
+                # be using HTTP for the storage protocol. As such, we
+                # aggressively disable Foolscap to ensure that HTTP is in fact
+                # going to be used. If we hit this branch that means our
+                # expectation that HTTP will be used was wrong, suggesting a
+                # bug in either the code of the integration testing setup.
+                #
+                # This branch should never be hit in production!
+                self.transport.loseConnection()
+                print("FOOLSCAP IS DISABLED, I PITY THE FOOLS WHO SEE THIS MESSAGE")
+                return
+
             # We're a Foolscap Negotiation server protocol instance:
             transport = self.transport
             buf = self._buffer

src/allmydata/testing/__init__.py

@@ -0,0 +1,18 @@
+import os
+from typing import Optional
+
+
+def foolscap_only_for_integration_testing() -> Optional[bool]:
+    """
+    Return whether HTTP storage protocol has been disabled / Foolscap
+    forced, for purposes of integration testing.
+
+    This is determined by the __TAHOE_INTEGRATION_FORCE_FOOLSCAP environment
+    variable, which can be 1, 0, or not set, corresponding to results of
+    ``True``, ``False`` and ``None`` (i.e. default).
+    """
+    force_foolscap = os.environ.get("__TAHOE_INTEGRATION_FORCE_FOOLSCAP")
+    if force_foolscap is None:
+        return None
+
+    return bool(int(force_foolscap))