Fix HTTPServer.serve_forever blocking whole processtest

Original report: https://github.com/eventlet/eventlet/issues/249

Explanation is in the comments in the code.

4 files changed, 59 insertions, 1 deletions

diff --git a/eventlet/green/selectors.py b/eventlet/green/selectors.py
index 26427ec..9d482fe 100644
--- a/eventlet/green/selectors.py
+++ b/eventlet/green/selectors.py
@@ -3,9 +3,29 @@ import sys
 from eventlet import patcher
 from eventlet.green import select
 
+__patched__ = [
+    'SelectSelector',
+    'PollSelector',
+    'EpollSelector',
+    'DevpollSelector',
+    'KqueueSelector',
+]
+
 patcher.inject('selectors', globals(), ('select', select))
 
 del patcher
 
 if sys.platform != 'win32':
     SelectSelector._select = staticmethod(select.select)
+
+
+# We only have green select so the options are:
+# * leave it be and have selectors that block
+# * try to pretend the "bad" selectors don't exist
+# * replace all with SelectSelector for the price of possibly different
+#   performance characteristic and missing fileno() method (if someone
+#   uses it it'll result in a crash, we may want to implement it in the future)
+PollSelector = SelectSelector
+EpollSelector = SelectSelector
+DevpollSelector = SelectSelector
+KqueueSelector = SelectSelector
diff --git a/eventlet/patcher.py b/eventlet/patcher.py
index eb09f9a..40207f9 100644
--- a/eventlet/patcher.py
+++ b/eventlet/patcher.py
@@ -331,7 +331,13 @@ def _green_os_modules():
 
 def _green_select_modules():
     from eventlet.green import select
-    return [('select', select)]
+    modules = [('select', select)]
+
+    if sys.version_info >= (3, 4):
+        from eventlet.green import selectors
+        modules.append(('selectors', selectors))
+
+    return modules
 
 
 def _green_socket_modules():
diff --git a/tests/isolated/patcher_socketserver_selectors.py b/tests/isolated/patcher_socketserver_selectors.py
new file mode 100644
index 0000000..97df6e2
--- /dev/null
+++ b/tests/isolated/patcher_socketserver_selectors.py
@@ -0,0 +1,28 @@
+if __name__ == '__main__':
+    import eventlet
+    eventlet.monkey_patch()
+
+    from eventlet.support.six.moves.BaseHTTPServer import (
+        HTTPServer,
+        BaseHTTPRequestHandler,
+    )
+    import threading
+
+    server = HTTPServer(('localhost', 0), BaseHTTPRequestHandler)
+    thread = threading.Thread(target=server.serve_forever)
+
+    # Before fixing it the code would never go pass this line because:
+    # * socketserver.BaseServer that's used behind the scenes here uses
+    #   selectors.PollSelector if it's available and we don't have green poll
+    #   implementation so this just couldn't work
+    # * making socketserver use selectors.SelectSelector wasn't enough as
+    #   until now we just failed to monkey patch selectors module
+    #
+    # Due to the issues above this thread.start() call effectively behaved
+    # like calling server.serve_forever() directly in the current thread
+    #
+    # Original report: https://github.com/eventlet/eventlet/issues/249
+    thread.start()
+
+    server.shutdown()
+    print('pass')
diff --git a/tests/patcher_test.py b/tests/patcher_test.py
index 2e458c5..deae8ef 100644
--- a/tests/patcher_test.py
+++ b/tests/patcher_test.py
@@ -506,3 +506,7 @@ def test_threading_condition():
 
 def test_threading_join():
     tests.run_isolated('patcher_threading_join.py')
+
+
+def test_socketserver_selectors():
+    tests.run_isolated('patcher_socketserver_selectors.py')