Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=25b5413f895bc6135... Commit: 25b5413f895bc61357ef4afab255e3125335d4ec Parent: b0bda090054db75995ea350f55b59ae8444690da Author: Tony Asleson tasleson@redhat.com AuthorDate: Tue Nov 29 11:07:21 2016 -0600 Committer: Tony Asleson tasleson@redhat.com CommitterDate: Tue Nov 29 16:50:30 2016 -0600
lvmdbusd: Make lvm shell read more robust
Make sure JSON is correct before we stop trying to read. --- daemons/lvmdbusd/lvm_shell_proxy.py | 98 ++++++++++++++++++----------------- 1 files changed, 50 insertions(+), 48 deletions(-)
diff --git a/daemons/lvmdbusd/lvm_shell_proxy.py b/daemons/lvmdbusd/lvm_shell_proxy.py index 50f2201..464da79 100755 --- a/daemons/lvmdbusd/lvm_shell_proxy.py +++ b/daemons/lvmdbusd/lvm_shell_proxy.py @@ -42,18 +42,22 @@ def _quote_arg(arg):
class LVMShellProxy(object): + + # Read until we get prompt back and a result + # @param: no_output Caller expects no output to report FD + # Returns stdout, report, stderr (report is JSON!) def _read_until_prompt(self, no_output=False): stdout = "" report = "" stderr = "" keep_reading = True - extra_passes = 2 + extra_passes = 3 + report_json = {} + prev_report_len = 0
# Try reading from all FDs to prevent one from filling up and causing - # a hang. We were assuming that we won't get the lvm prompt back - # until we have already received all the output from stderr and the - # report descriptor too, this is an incorrect assumption. Lvm will - # return the prompt before we get the report! + # a hang. Keep reading until we get the prompt back and the report + # FD does not contain valid JSON while keep_reading: try: rd_fd = [ @@ -87,26 +91,39 @@ class LVMShellProxy(object): raise Exception(self.lvm_shell.returncode, "%s" % stderr)
if stdout.endswith(SHELL_PROMPT): - # It appears that lvm doesn't write the report and flush - # that before it writes the shell prompt as occasionally - # we get the prompt with no report. if no_output: keep_reading = False else: - # Most of the time we have data, if we have none lets - # take another spin and hope we get it. - if len(report) != 0: - keep_reading = False + cur_report_len = len(report) + if cur_report_len != 0: + # Only bother to parse if we have more data + if prev_report_len != cur_report_len: + prev_report_len = cur_report_len + # Parse the JSON if it's good we are done, + # if not we will try to read some more. + try: + report_json = json.loads(report) + keep_reading = False + except ValueError: + pass else: + log_error("RACE!", 'bg_black', 'fg_light_red') + + if keep_reading: extra_passes -= 1 if extra_passes <= 0: - keep_reading = False + if len(report): + raise ValueError("Invalid json: %s" % + report) + else: + raise ValueError( + "lvm returned no JSON output!")
except IOError as ioe: log_debug(str(ioe)) pass
- return stdout, report, stderr + return stdout, report_json, stderr
def _write_cmd(self, cmd): cmd_bytes = bytes(cmd, "utf-8") @@ -169,33 +186,24 @@ class LVMShellProxy(object): self._write_cmd('lastlog\n')
# read everything from the STDOUT to the next prompt - stdout, report, stderr = self._read_until_prompt() - - try: - log = json.loads(report) - - if 'log' in log: - error_msg = "" - # Walk the entire log array and build an error string - for log_entry in log['log']: - if log_entry['log_type'] == "error": - if error_msg: - error_msg += ', ' + log_entry['log_message'] - else: - error_msg = log_entry['log_message'] + stdout, report_json, stderr = self._read_until_prompt() + if 'log' in report_json: + error_msg = "" + # Walk the entire log array and build an error string + for log_entry in report_json['log']: + if log_entry['log_type'] == "error": + if error_msg: + error_msg += ', ' + log_entry['log_message'] + else: + error_msg = log_entry['log_message']
- return error_msg + return error_msg
- return 'No error reason provided! (missing "log" section)' - except ValueError: - log_error("Invalid JSON returned from LVM") - log_error("BEGIN>>\n%s\n<<END" % report) - return "Invalid JSON returned from LVM when retrieving exit code" + return 'No error reason provided! (missing "log" section)'
def call_lvm(self, argv, debug=False): rc = 1 error_msg = "" - json_result = ""
if self.lvm_shell.poll(): raise Exception( @@ -210,27 +218,21 @@ class LVMShellProxy(object): self._write_cmd(cmd)
# read everything from the STDOUT to the next prompt - stdout, report, stderr = self._read_until_prompt() + stdout, report_json, stderr = self._read_until_prompt()
# Parse the report to see what happened - if report and len(report): - try: - json_result = json.loads(report) - if 'log' in json_result: - if json_result['log'][-1:][0]['log_ret_code'] == '1': - rc = 0 - else: - error_msg = self.get_error_msg() - except ValueError: - # Bubble up the invalid json. - error_msg = "Invalid json %s" % report + if 'log' in report_json: + if report_json['log'][-1:][0]['log_ret_code'] == '1': + rc = 0 + else: + error_msg = self.get_error_msg()
if debug or rc != 0: log_error(('CMD: %s' % cmd)) log_error(("EC = %d" % rc)) log_error(("ERROR_MSG=\n %s\n" % error_msg))
- return rc, json_result, error_msg + return rc, report_json, error_msg
def exit_shell(self): try: