[checkmk-commits] Check_MK Git: check_mk: Simplify implementation of notify --keepalive

Module: check_mk Branch: master Commit: 3335179923e78ad11a6b6f3d9e6e28e72bfdc6dd URL: http://git.mathias-kettner.de/git/?p=check_mk.git;a=commit;h=3335179923e78a… Author: Mathias Kettner <mk(a)mathias-kettner.de> Date: Mon Jul 22 17:51:47 2013 +0200 Simplify implementation of notify --keepalive --- modules/notify.py | 131 +++++++++++++++++++++++++++++------------------------ 1 file changed, 72 insertions(+), 59 deletions(-) diff --git a/modules/notify.py b/modules/notify.py index 9102a46..39dd198 100644 --- a/modules/notify.py +++ b/modules/notify.py @@ -311,7 +311,7 @@ def do_notify(args): notify_keepalive() else: - notify_notify() + notify_notify(notification_context_from_env()) except Exception, e: if g_interactive: @@ -345,81 +345,91 @@ def notify_config_timestamp(): def notify_keepalive(): - global g_notify_readahead_buffer - g_notify_readahead_buffer = "" config_timestamp = notify_config_timestamp() - # Send signal that we are ready to receive the next notification - sys.stdout.write("*") - sys.stdout.flush() + # Send signal that we are ready to receive the next notification, but + # not after a config-reload-restart (see below) + if os.getenv("CMK_NOTIFY_RESTART") != "1": + notify_log("Starting in keepalive mode with PID %d" % os.getpid()) + sys.stdout.write("*") + sys.stdout.flush() + else: + notify_log("We are back after a restart.") while True: try: # If the configuration has changed, we do a restart. But we do # this check just before the next notification arrives. We must - # *not* read data from stdin, just peek! On the other hand we - # must *not* restart when there is danger that the buffered - # sys.stdin has already read data from the next notification. That - # would get lost! So we do restart if: - # - The last time we look *no* data was available on stdin. - # - Now there *is* data available - # - The buffer of stdin is empty - # - The timestamp of the youngest configuration file has changed. + # *not* read data from stdin, just peek! There is still one + # problem: when restarting we must *not* send the initial '*' + # byte, because that must be not no sooner then the notification + # has been sent. We do this by setting the environment variable + # CMK_NOTIFY_RESTART=1 + if notify_data_available(): - if not g_notify_readahead_buffer: - current_config_timestamp = notify_config_timestamp() - if current_config_timestamp > config_timestamp: - notify_log("Configuration has changed. Restarting myself.") - os.execvp("cmk", sys.argv) - - new_data = os.read(0, 20000) - if not new_data: - sys.exit(0) # closed stdin - g_notify_readahead_buffer += new_data - if g_notify_readahead_buffer.startswith('\n\n'): - sys.exit(0) - while '\n\n' in g_notify_readahead_buffer: + current_config_timestamp = notify_config_timestamp() + if current_config_timestamp > config_timestamp: + notify_log("Configuration has changed. Restarting myself.") + os.putenv("CMK_NOTIFY_RESTART", "1") + os.execvp("cmk", sys.argv) + + data = "" + while not data.endswith("\n\n"): try: - notify_notify() + new_data = "" + new_data = os.read(0, 32768) + except IOError, e: + new_data = "" except Exception, e: if opt_debug: raise - notify_log("ERROR %s\n%s" % (e, format_exception())) - sys.stdout.write("*") - sys.stdout.flush() + notify_log("Cannot read data from CMC: %s" % e) + + if not new_data: + notify_log("CMC has closed the connection. Shutting down.") + sys.exit(0) # closed stdin, this is + data += new_data + + try: + context = notification_context_from_string(data.rstrip('\n')) + notify_notify(context) + except Exception, e: + if opt_debug: + raise + notify_log("ERROR %s\n%s" % (e, format_exception())) + + # Signal that we are ready for the next notification + sys.stdout.write("*") + sys.stdout.flush() except Exception, e: if opt_debug: raise notify_log("ERROR %s\n%s" % (e, format_exception())) -# Note: The values of the context are *always* unicode! -def notify_get_context(): - global g_notify_readahead_buffer - if opt_keepalive: - # Context is line-by-line in g_notify_readahead_buffer - this_part, rest = g_notify_readahead_buffer.split('\n\n', 1) - g_notify_readahead_buffer = rest - context = {} - try: - for line in this_part.split('\n'): - varname, value = line.strip().split("=", 1) - context[varname] = value - except Exception, e: # line without '=' ignored or alerted - if opt_debug: - raise - return context - else: - # Information about notification is excpected in the - # environment in variables with the prefix NOTIFY_ - return dict([ - (var[7:], value) - for (var, value) - in os.environ.items() - if var.startswith("NOTIFY_") - and not re.match('^\$[A-Z]+\$$', value)]) +def notification_context_from_string(data): + # Context is line-by-line in g_notify_readahead_buffer + context = {} + try: + for line in data.split('\n'): + varname, value = line.strip().split("=", 1) + context[varname] = value + except Exception, e: # line without '=' ignored or alerted + if opt_debug: + raise + return context + +def notification_context_from_env(): + # Information about notification is excpected in the + # environment in variables with the prefix NOTIFY_ + return dict([ + (var[7:], value) + for (var, value) + in os.environ.items() + if var.startswith("NOTIFY_") + and not re.match('^\$[A-Z]+\$$', value)]) def convert_context_to_unicode(context): @@ -435,8 +445,7 @@ def convert_context_to_unicode(context): value_unicode = u"(Invalid byte sequence)" context[key] = value_unicode -def notify_notify(): - context = notify_get_context() +def notify_notify(context): notify_log("Got notification context with %s variables" % len(context)) # Add a few further helper variables @@ -516,7 +525,7 @@ def notify_via_email(context, write_into_spoolfile): subject = substitute_context(subject_t, context) context["SUBJECT"] = subject body = substitute_context(notification_common_body + body_t, context) - command = substitute_context(notification_mail_command, context) + command = substitute_context(notification_mail_command, context) + " >/dev/null 2>&1" command_utf8 = command.encode("utf-8") if notification_logging >= 2: notify_log("Executing command: %s" % command) @@ -528,6 +537,10 @@ def notify_via_email(context, write_into_spoolfile): os.putenv("LANG", "C.UTF-8") if notification_logging >= 2: file(var_dir + "/notify/body.log", "w").write(body.encode("utf-8")) + + # Important: we must not output anything on stdout or stderr. Data of stdout + # goes back into the socket to the CMC in keepalive mode and garbles the + # handshake signal. return os.popen(command_utf8, "w").write(body.encode("utf-8"))