Method read_until_pattern

netmiko/base_connection.py:660–750

Read channel until pattern is detected. Will return string up to and including pattern. Returns ReadTimeout if pattern not detected in read_timeout seconds. :param pattern: Regular expression pattern used to identify that reading is done. :param read_timeout: maxi

(
        self,
        pattern: str = "",
        read_timeout: float = 10.0,
        re_flags: int = 0,
        max_loops: Optional[int] = None,
    )

        return output

    def read_until_pattern(
        self,
        pattern: str = "",
        read_timeout: float = 10.0,
        re_flags: int = 0,
        max_loops: Optional[int] = None,
    ) -> str:
        """Read channel until pattern is detected.

        Will return string up to and including pattern.

        Returns ReadTimeout if pattern not detected in read_timeout seconds.

        :param pattern: Regular expression pattern used to identify that reading is done.

        :param read_timeout: maximum time to wait looking for pattern. Will raise ReadTimeout.
            A read_timeout value of 0 will cause the loop to never timeout (i.e. it will keep
            reading indefinitely until pattern is detected.

        :param re_flags: regex flags used in conjunction with pattern (defaults to no flags).

        :param max_loops: Deprecated in Netmiko 4.x. Will be eliminated in Netmiko 5.
        """
        if max_loops is not None:
            msg = """\n
Netmiko 4.x has deprecated the use of max_loops with read_until_pattern.
You should convert all uses of max_loops over to read_timeout=x
where x is the total number of seconds to wait before timing out.\n"""
            warnings.warn(msg, DeprecationWarning)

        if self.read_timeout_override:
            read_timeout = self.read_timeout_override

        output = ""
        loop_delay = 0.01
        start_time = time.time()
        # if read_timeout == 0 or 0.0 keep reading indefinitely
        while (time.time() - start_time < read_timeout) or (not read_timeout):
            output += self.read_channel()

            if re.search(pattern, output, flags=re_flags):
                if "(" in pattern and "(?:" not in pattern:
                    msg = f"""
Parenthesis found in pattern.

pattern: {pattern}\n

This can be problemtic when used in read_until_pattern().

You should ensure that you use either non-capture groups i.e. '(?:' or that the
parenthesis completely wrap the pattern '(pattern)'"""
                    log.debug(msg)
                results = re.split(pattern, output, maxsplit=1, flags=re_flags)

                # The string matched by pattern must be retained in the output string.
                # re.split will do this if capturing parenthesis are used.
                if len(results) == 2:
                    # no capturing parenthesis, convert and try again.