#!/usr/bin/env python3
import json
import os
import signal
import sys
import base64
import types
[docs]def b2s(b):
return base64.b85encode(b).decode('ascii')
[docs]def s2b(s):
return base64.b85decode(s.encode('ascii'))
[docs]class Agent:
[docs] def __init__(self):
self.methods = {}
self.register('load', self.load)
self.register('list', self.list)
# use real stdin/stdout
self.stdin = sys.stdin
self.stdout = sys.stdout
# use stderr for normal prints
sys.stdout = sys.stderr
[docs] def send(self, data):
self.stdout.write(json.dumps(data)+'\n')
self.stdout.flush()
[docs] def register(self, name, func):
assert name not in self.methods
self.methods[name] = func
[docs] def load(self, name, source):
module = types.ModuleType(name)
exec(compile(source, '<loaded {}>'.format(name), 'exec'), module.__dict__)
for k, v in module.methods.items():
self.register('{}.{}'.format(name, k), v)
[docs] def list(self):
return list(self.methods.keys())
[docs] def run(self):
for line in self.stdin:
if not line:
continue
try:
request = json.loads(line)
except json.JSONDecodeError:
self.send({'error': 'request parsing failed for {}'.format(repr(line))})
break
if request.get('close', False):
break
name = request['method']
args = request['args']
kwargs = request['kwargs']
try:
response = self.methods[name](*args, **kwargs)
self.send({'result': response})
except Exception as e: # pylint: disable=broad-except
import traceback
try:
tb = [list(x) for x in traceback.extract_tb(sys.exc_info()[2])]
except:
tb = None
self.send({'exception': repr(e), 'tb': tb})
[docs]def handle_test(*args, **kwargs): # pylint: disable=unused-argument
return args[::-1]
[docs]def handle_error(message):
raise ValueError(message)
[docs]def handle_usbtmc(index, cmd, read=False):
assert isinstance(index, int)
cmd = s2b(cmd)
fd = os.open('/dev/usbtmc{}'.format(index), os.O_RDWR)
os.write(fd, cmd)
if not read:
os.close(fd)
return None
data = []
while True:
data.append(os.read(fd, 4096))
if len(data[-1]) < 4096:
break
os.close(fd)
return b2s(b''.join(data))
[docs]def main():
signal.signal(signal.SIGINT, signal.SIG_IGN)
a = Agent()
a.register('test', handle_test)
a.register('error', handle_error)
a.register('usbtmc', handle_usbtmc)
a.run()
if __name__ == "__main__":
main()