Switch over to a generator

pull/19465/head
Richard Belleville 6 years ago
parent 7dccc07c2a
commit b31431aea3
  1. 6
      examples/python/cancellation/client.py
  2. 4
      examples/python/cancellation/hash_name.proto
  3. 61
      examples/python/cancellation/server.py

@ -40,12 +40,12 @@ def main():
while True:
print("Sending request")
future = stub.Find.future(hash_name_pb2.HashNameRequest(desired_name="doctor",
maximum_hamming_distance=0))
ideal_hamming_distance=1))
# TODO(rbellevi): Do not leave in a cancellation based on timeout.
# That's best handled by, well.. timeout.
try:
result = future.result(timeout=2.0)
print("Got response: \n{}".format(response))
result = future.result(timeout=20.0)
print("Got response: \n{}".format(result))
except grpc.FutureTimeoutError:
print("Cancelling request")
future.cancel()

@ -18,7 +18,8 @@ package hash_name;
message HashNameRequest {
string desired_name = 1;
int32 maximum_hamming_distance = 2;
int32 ideal_hamming_distance = 2;
int32 interesting_hamming_distance = 3;
}
message HashNameResponse {
@ -29,4 +30,5 @@ message HashNameResponse {
service HashFinder {
rpc Find (HashNameRequest) returns (HashNameResponse) {}
rpc FindRange (HashNameRequest) returns (stream HashNameResponse) {}
}

@ -79,25 +79,39 @@ def _get_hash(secret):
return base64.b64encode(hasher.digest())
def _find_secret_of_length(target, maximum_distance, length, stop_event):
def _find_secret_of_length(target, ideal_distance, length, stop_event, interesting_hamming_distance=None):
digits = [0] * length
while True:
if stop_event.is_set():
return hash_name_pb2.HashNameResponse()
# Yield a sentinel and stop the generator if the RPC has been
# cancelled.
yield None
raise StopIteration()
secret = b''.join(struct.pack('B', i) for i in digits)
hash = _get_hash(secret)
distance = _get_substring_hamming_distance(hash, target)
if distance <= maximum_distance:
return hash_name_pb2.HashNameResponse(secret=base64.b64encode(secret),
if interesting_hamming_distance is not None and distance <= interesting_hamming_distance:
# Surface interesting candidates, but don't stop.
yield hash_name_pb2.HashNameResponse(secret=base64.b64encode(secret),
hashed_name=hash,
hamming_distance=distance)
elif distance <= ideal_distance:
# Yield the ideal candidate followed by a sentinel to signal the end
# of the stream.
yield hash_name_pb2.HashNameResponse(secret=base64.b64encode(secret),
hashed_name=hash,
hamming_distance=distance)
yield None
raise StopIteration()
digits[-1] += 1
i = length - 1
while digits[i] == _BYTE_MAX + 1:
digits[i] = 0
i -= 1
if i == -1:
return None
# Terminate the generator since we've run out of strings of
# `length` bytes.
raise StopIteration()
else:
digits[i] += 1
@ -106,11 +120,15 @@ def _find_secret(target, maximum_distance, stop_event):
length = 1
while True:
print("Checking strings of length {}.".format(length))
match = _find_secret_of_length(target, maximum_distance, length, stop_event)
if match is not None:
return match
if stop_event.is_set():
return hash_name_pb2.HashNameResponse()
for candidate in _find_secret_of_length(target, maximum_distance, length, stop_event):
if candidate is not None:
yield candidate
else:
raise StopIteration()
if stop_event.is_set():
# Terminate the generator if the RPC has been cancelled.
raise StopIteration()
print("Incrementing length")
length += 1
@ -121,12 +139,28 @@ class HashFinder(hash_name_pb2_grpc.HashFinderServicer):
def on_rpc_done():
stop_event.set()
context.add_callback(on_rpc_done)
result = _find_secret(request.desired_name, request.maximum_hamming_distance, stop_event)
return result
candidates = list(_find_secret(request.desired_name, request.ideal_hamming_distance, stop_event))
if not candidates:
return hash_name_pb2.HashNameResponse()
return candidates[-1]
def FindRange(self, request, context):
stop_event = threading.Event()
def on_rpc_done():
stop_event.set()
context.add_callback(on_rpc_done)
secret_generator = _find_secret(request.desired_name,
request.ideal_hamming_distance,
stop_event,
interesting_hamming_distance=request.interesting_hamming_distance)
for candidate in secret_generator:
yield candidate
def _run_server(port):
server = grpc.server(futures.ThreadPoolExecutor(max_workers=1))
server = grpc.server(futures.ThreadPoolExecutor(max_workers=1),
maximum_concurrent_rpcs=1)
hash_name_pb2_grpc.add_HashFinderServicer_to_server(
HashFinder(), server)
address = '{}:{}'.format(_SERVER_HOST, port)
@ -151,6 +185,7 @@ def main():
args = parser.parse_args()
_run_server(args.port)
if __name__ == "__main__":
logging.basicConfig()
main()

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