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196 lines
6.7 KiB

import socket
import select
import sys
import logging
from .wire import decode_varint, encode
from .reader import BytesBuffer
from .msg import RequestDecoder, message_types
# hold the asyncronous state of a connection
# ie. we may not get enough bytes on one read to decode the message
logger = logging.getLogger(__name__)
class Connection():
def __init__(self, fd, app):
self.fd = fd
self.app = app
self.recBuf = BytesBuffer(bytearray())
self.resBuf = BytesBuffer(bytearray())
self.msgLength = 0
self.decoder = RequestDecoder(self.recBuf)
self.inProgress = False # are we in the middle of a message
def recv(this):
data = this.fd.recv(1024)
if not data: # what about len(data) == 0
raise IOError("dead connection")
this.recBuf.write(data)
# ABCI server responds to messges by calling methods on the app
class ABCIServer():
def __init__(self, app, port=5410):
self.app = app
# map conn file descriptors to (app, reqBuf, resBuf, msgDecoder)
self.appMap = {}
self.port = port
self.listen_backlog = 10
self.listener = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.listener.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.listener.setblocking(0)
self.listener.bind(('', port))
self.listener.listen(self.listen_backlog)
self.shutdown = False
self.read_list = [self.listener]
self.write_list = []
def handle_new_connection(self, r):
new_fd, new_addr = r.accept()
new_fd.setblocking(0) # non-blocking
self.read_list.append(new_fd)
self.write_list.append(new_fd)
print('new connection to', new_addr)
self.appMap[new_fd] = Connection(new_fd, self.app)
def handle_conn_closed(self, r):
self.read_list.remove(r)
self.write_list.remove(r)
r.close()
print("connection closed")
def handle_recv(self, r):
# app, recBuf, resBuf, conn
conn = self.appMap[r]
while True:
try:
print("recv loop")
# check if we need more data first
if conn.inProgress:
if (conn.msgLength == 0 or conn.recBuf.size() < conn.msgLength):
conn.recv()
else:
if conn.recBuf.size() == 0:
conn.recv()
conn.inProgress = True
# see if we have enough to get the message length
if conn.msgLength == 0:
ll = conn.recBuf.peek()
if conn.recBuf.size() < 1 + ll:
# we don't have enough bytes to read the length yet
return
print("decoding msg length")
conn.msgLength = decode_varint(conn.recBuf)
# see if we have enough to decode the message
if conn.recBuf.size() < conn.msgLength:
return
# now we can decode the message
# first read the request type and get the particular msg
# decoder
typeByte = conn.recBuf.read(1)
typeByte = int(typeByte[0])
resTypeByte = typeByte + 0x10
req_type = message_types[typeByte]
if req_type == "flush":
# messages are length prefixed
conn.resBuf.write(encode(1))
conn.resBuf.write([resTypeByte])
conn.fd.send(conn.resBuf.buf)
conn.msgLength = 0
conn.inProgress = False
conn.resBuf = BytesBuffer(bytearray())
return
decoder = getattr(conn.decoder, req_type)
print("decoding args")
req_args = decoder()
print("got args", req_args)
# done decoding message
conn.msgLength = 0
conn.inProgress = False
req_f = getattr(conn.app, req_type)
if req_args is None:
res = req_f()
elif isinstance(req_args, tuple):
res = req_f(*req_args)
else:
res = req_f(req_args)
if isinstance(res, tuple):
res, ret_code = res
else:
ret_code = res
res = None
print("called", req_type, "ret code:", ret_code, 'res:', res)
if ret_code != 0:
print("non-zero retcode:", ret_code)
if req_type in ("echo", "info"): # these dont return a ret code
enc = encode(res)
# messages are length prefixed
conn.resBuf.write(encode(len(enc) + 1))
conn.resBuf.write([resTypeByte])
conn.resBuf.write(enc)
else:
enc, encRet = encode(res), encode(ret_code)
# messages are length prefixed
conn.resBuf.write(encode(len(enc) + len(encRet) + 1))
conn.resBuf.write([resTypeByte])
conn.resBuf.write(encRet)
conn.resBuf.write(enc)
except IOError as e:
print("IOError on reading from connection:", e)
self.handle_conn_closed(r)
return
except Exception as e:
logger.exception("error reading from connection")
self.handle_conn_closed(r)
return
def main_loop(self):
while not self.shutdown:
r_list, w_list, _ = select.select(
self.read_list, self.write_list, [], 2.5)
for r in r_list:
if (r == self.listener):
try:
self.handle_new_connection(r)
# undo adding to read list ...
except NameError as e:
print("Could not connect due to NameError:", e)
except TypeError as e:
print("Could not connect due to TypeError:", e)
except:
print("Could not connect due to unexpected error:", sys.exc_info()[0])
else:
self.handle_recv(r)
def handle_shutdown(self):
for r in self.read_list:
r.close()
for w in self.write_list:
try:
w.close()
except Exception as e:
print(e) # TODO: add logging
self.shutdown = True