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shm.py
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shm.py
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import sentry_sdk
sentry_sdk.init("https://d88678349f5d4e20b707882f78f2f78e@o490365.ingest.sentry.io/5554165")
import numpy as np
import SharedArray # pip install SharedArray
import sys
import time
import struct
import server
import json
import traceback
CLIENT_SLEEP_S = 1/10000 #0.1ms
SERVER_SLEEP_S = 1/10000 #0.1ms
MESSAGE_TYPE_POST = 1
MESSAGE_TYPE_RESPONSE = 2
# Buffer layout:
# 1 byte: status
# 2 bytes: json length
# N bytes: json
# 4 bytes: data length
# N bytes: data
MAX_JSON_LENGTH = 10000
MAX_DATA_LENGTH = 199998
BUFFER_SIZE = 1 + 2 + MAX_JSON_LENGTH + 4 + MAX_DATA_LENGTH
def attach_or_create(name):
name = "shm://" + name
try:
return SharedArray.attach(name)
except Exception:
pass
return SharedArray.create(name, BUFFER_SIZE, dtype=np.uint8)
def server_turn(buf):
return buf[0] == MESSAGE_TYPE_POST
def encode_json_and_data(buf, json_raw, data, throw_exceptions):
data = data.view(dtype=np.uint8)
index = 1
json_raw_bytes = json_raw.encode("utf-8")
errormsg = None
if len(json_raw_bytes) > MAX_JSON_LENGTH:
errormsg = "json too long: %s" % len(json_raw_bytes)
elif len(data) > MAX_DATA_LENGTH:
errormsg = "data too long: %s" % len(data)
if errormsg:
if throw_exceptions:
raise Exception(errormsg)
else:
json_raw_bytes = json.dumps({"error": errormsg}).encode("utf-8")
data = np.zeros(0, dtype=np.uint8)
buf[index : index + 2] = memoryview(struct.pack("H", len(json_raw_bytes)))
index += 2
buf[index : index + len(json_raw_bytes)] = memoryview(json_raw_bytes)
index += len(json_raw_bytes)
buf[index : index + 4] = memoryview(struct.pack("I", len(data)))
index += 4
buf[index : index + len(data)] = data
def decode_json_and_data(buf):
index = 1
json_length, = buf[index : index + 2].view(dtype=np.uint16)
index += 2
if json_length > MAX_JSON_LENGTH:
raise Exception("bad json length %s" % json_length)
json_raw = buf[index : index + json_length].tobytes()
index += json_length
data_length, = buf[index : index + 4].view(dtype=np.uint32)
index += 4
if data_length > MAX_DATA_LENGTH:
raise Exception("bad data length %s" % data_length)
data = buf[index : index + data_length].view(np.uint8)
return json_raw, data
class ShmServer:
@staticmethod
def post(buf):
try:
in_json_raw, in_data = decode_json_and_data(buf)
out_json_raw, out_data = server.handle_json_post(in_json_raw, in_data)
encode_json_and_data(buf, out_json_raw, out_data,
throw_exceptions=False)
except Exception as e:
encode_json_and_data(buf, json.dumps(
{"error": str(e), "inner_bt": traceback.format_exc()}
), np.zeros(0, dtype=np.uint8), throw_exceptions=False)
@staticmethod
def run(buffer_names):
buffers = [attach_or_create(buffer_name) for buffer_name in buffer_names]
while True:
didAction = False
for buf in buffers:
if server_turn(buf):
ShmServer.post(buf)
buf[0] = MESSAGE_TYPE_RESPONSE
didAction = True
if not didAction:
time.sleep(SERVER_SLEEP_S)
class ShmClient:
def __init__(self, shm_name):
self.buf = attach_or_create(shm_name)
def handle_post(self, in_json_raw, in_data):
encode_json_and_data(self.buf, in_json_raw, in_data, throw_exceptions=True)
self.buf[0] = MESSAGE_TYPE_POST
self.wait_resp_()
return decode_json_and_data(self.buf)
def wait_resp_(self):
while server_turn(self.buf):
time.sleep(CLIENT_SLEEP_S)
class FakeClient:
def handle_post(self, in_json_raw, in_data):
out_json_raw, out_data = server.handle_json_post(in_json_raw, in_data)
return out_json_raw.encode("utf-8"), out_data
if __name__ == "__main__":
ShmServer.run(sys.argv[1:])