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# See the file "LICENSE" for information about the copyright
# and warranty status of this software.
'''Classes for handling asynchronous connections to a blockchain
daemon.'''
import asyncio
import json
import aiohttp
from lib.util import LoggedClass
class DaemonError(Exception):
'''Raised when the daemon returns an error in its results that
cannot be remedied by retrying.'''
class Daemon(LoggedClass):
'''Handles connections to a daemon at the given URL.'''
def __init__(self, url):
super().__init__()
self.url = url
self.logger.info('connecting to daemon at URL {}'.format(url))
async def send_single(self, method, params=None):
payload = {'method': method}
if params:
payload['params'] = params
result, = await self.send((payload, ))
return result
async def send_many(self, mp_pairs):
payload = [{'method': method, 'params': params}
for method, params in mp_pairs]
return await self.send(payload)
async def send_vector(self, method, params_list):
payload = [{'method': method, 'params': params}
for params in params_list]
return await self.send(payload)
async def send(self, payload):
assert isinstance(payload, (tuple, list))
data = json.dumps(payload)
while True:
try:
async with aiohttp.post(self.url, data=data) as resp:
result = await resp.json()
except asyncio.CancelledError:
raise
except Exception as e:
msg = 'aiohttp error: {}'.format(e)
secs = 3
else:
errs = tuple(item['error'] for item in result)
if not any(errs):
return tuple(item['result'] for item in result)
if any(err.get('code') == -28 for err in errs):
msg = 'daemon still warming up.'
secs = 30
else:
msg = '{}'.format(errs)
raise DaemonError(msg)
self.logger.error('{}. Sleeping {:d}s and trying again...'
.format(msg, secs))
await asyncio.sleep(secs)