async def _establish_connection(self):
"""Establishing SSH connection to the network device"""
logger.info(
"Host {}: Establishing connection to port {}".format(self._host, self._port)
)
output = ""
# initiate SSH connection
fut = asyncssh.connect(**self._connect_params_dict)
try:
self._conn = await asyncio.wait_for(fut, self._timeout)
except asyncssh.DisconnectError as e:
raise DisconnectError(self._host, e.code, e.reason)
except asyncio.TimeoutError:
raise TimeoutError(self._host)
self._stdin, self._stdout, self._stderr = await self._conn.open_session(
term_type="Dumb", term_size=(200, 24)
)
logger.info("Host {}: Connection is established".format(self._host))
# Flush unnecessary data
delimiters = map(re.escape, type(self)._delimiter_list)
delimiters = r"|".join(delimiters)
output = await self._read_until_pattern(delimiters)
logger.debug(
"Host {}: Establish Connection Output: {}".format(self._host, repr(output))
)
return output
async def _read_until_pattern(self, pattern='', re_flags=0):
"""Read channel until pattern detected. Return ALL data available"""
output = ''
logger.info("Host {}: Reading until pattern".format(self._host))
if not pattern:
pattern = self._base_pattern
logger.debug("Host {}: Reading pattern: {}".format(self._host, pattern))
while True:
fut = self._stdout.read(self._MAX_BUFFER)
try:
output += await asyncio.wait_for(fut, self._timeout)
except asyncio.TimeoutError:
raise TimeoutError(self._host)
if re.search(pattern, output, flags=re_flags):
logger.debug("Host {}: Reading pattern '{}' was found: {}".format(self._host, pattern, repr(output)))
return output
async def _read_until_prompt_or_pattern(self, pattern="", re_flags=0):
"""Read until either self.base_pattern or pattern is detected. Return ALL data available"""
output = ""
logger.info("Host {}: Reading until prompt or pattern".format(
self._host))
if not pattern:
pattern = self._base_pattern
base_prompt_pattern = self._base_pattern
while True:
fut = self._stdout.read(self._MAX_BUFFER)
try:
output += await asyncio.wait_for(fut, self._timeout)
except asyncio.TimeoutError:
raise TimeoutError(self._host)
if re.search(pattern, output, flags=re_flags) or re.search(
base_prompt_pattern, output, flags=re_flags):
logger.debug(
"Host {}: Reading pattern '{}' or '{}' was found: {}".
format(self._host, pattern, base_prompt_pattern,
repr(output)))
return output
