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plugins/mod_posix.lua @ 11523:5f15ab7c6ae5
Statistics: Rewrite statistics backends to use OpenMetrics
The metric subsystem of Prosody has had some shortcomings from
the perspective of the current state-of-the-art in metric
observability.
The OpenMetrics standard [0] is a formalization of the data
model (and serialization format) of the well-known and
widely-used Prometheus [1] software stack.
The previous stats subsystem of Prosody did not map well to that
format (see e.g. [2] and [3]); the key reason is that it was
trying to do too much math on its own ([2]) while lacking
first-class support for "families" of metrics ([3]) and
structured metric metadata (despite the `extra` argument to
metrics, there was no standard way of representing common things
like "tags" or "labels").
Even though OpenMetrics has grown from the Prometheus world of
monitoring, it maps well to other popular monitoring stacks
such as:
- InfluxDB (labels can be mapped to tags and fields as necessary)
- Carbon/Graphite (labels can be attached to the metric name with
dot-separation)
- StatsD (see graphite when assuming that graphite is used as
backend, which is the default)
The util.statsd module has been ported to use the OpenMetrics
model as a proof of concept. An implementation which exposes
the util.statistics backend data as Prometheus metrics is
ready for publishing in prosody-modules (most likely as
mod_openmetrics_prometheus to avoid breaking existing 0.11
deployments).
At the same time, the previous measure()-based API had one major
advantage: It is really simple and easy to use without requiring
lots of knowledge about OpenMetrics or similar concepts. For that
reason as well as compatibility with existing code, it is preserved
and may even be extended in the future.
However, code relying on the `stats-updated` event as well as
`get_stats` from `statsmanager` will break because the data
model has changed completely; in case of `stats-updated`, the
code will simply not run (as the event was renamed in order
to avoid conflicts); the `get_stats` function has been removed
completely (so it will cause a traceback when it is attempted
to be used).
Note that the measure_*_event methods have been removed from
the module API. I was unable to find any uses or documentation
and thus deemed they should not be ported. Re-implementation is
possible when necessary.
[0]: https://openmetrics.io/
[1]: https://prometheus.io/
[2]: #959
[3]: #960
author | Jonas Schäfer <jonas@wielicki.name> |
---|---|
date | Sun, 18 Apr 2021 11:47:41 +0200 |
parent | 11179:96da09c771a1 |
child | 11830:7fe2fbfbdb1c |
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-- Prosody IM -- Copyright (C) 2008-2010 Matthew Wild -- Copyright (C) 2008-2010 Waqas Hussain -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- local want_pposix_version = "0.4.0"; local pposix = assert(require "util.pposix"); if pposix._VERSION ~= want_pposix_version then module:log("warn", "Unknown version (%s) of binary pposix module, expected %s." .. "Perhaps you need to recompile?", tostring(pposix._VERSION), want_pposix_version); end local have_signal, signal = pcall(require, "util.signal"); if not have_signal then module:log("warn", "Couldn't load signal library, won't respond to SIGTERM"); end local lfs = require "lfs"; local stat = lfs.attributes; local prosody = _G.prosody; module:set_global(); -- we're a global module local umask = module:get_option_string("umask", "027"); pposix.umask(umask); -- Don't even think about it! if not prosody.start_time then -- server-starting if pposix.getuid() == 0 and not module:get_option_boolean("run_as_root") then module:log("error", "Danger, Will Robinson! Prosody doesn't need to be run as root, so don't do it!"); module:log("error", "For more information on running Prosody as root, see https://prosody.im/doc/root"); prosody.shutdown("Refusing to run as root"); end end local pidfile; local pidfile_handle; local function remove_pidfile() if pidfile_handle then pidfile_handle:close(); os.remove(pidfile); pidfile, pidfile_handle = nil, nil; end end local function write_pidfile() if pidfile_handle then remove_pidfile(); end pidfile = module:get_option_path("pidfile", nil, "data"); if pidfile then local err; local mode = stat(pidfile) and "r+" or "w+"; pidfile_handle, err = io.open(pidfile, mode); if not pidfile_handle then module:log("error", "Couldn't write pidfile at %s; %s", pidfile, err); prosody.shutdown("Couldn't write pidfile"); else if not lfs.lock(pidfile_handle, "w") then -- Exclusive lock local other_pid = pidfile_handle:read("*a"); module:log("error", "Another Prosody instance seems to be running with PID %s, quitting", other_pid); pidfile_handle = nil; prosody.shutdown("Prosody already running"); else pidfile_handle:close(); pidfile_handle, err = io.open(pidfile, "w+"); if not pidfile_handle then module:log("error", "Couldn't write pidfile at %s; %s", pidfile, err); prosody.shutdown("Couldn't write pidfile"); else if lfs.lock(pidfile_handle, "w") then pidfile_handle:write(tostring(pposix.getpid())); pidfile_handle:flush(); end end end end end end local daemonize = prosody.opts.daemonize; if daemonize == nil then -- Fall back to config file if not specified on command-line daemonize = module:get_option_boolean("daemonize", nil); if daemonize ~= nil then module:log("warn", "The 'daemonize' option has been deprecated, specify -D or -F on the command line instead."); -- TODO: Write some docs and include a link in the warning. end end local function remove_log_sinks() local lm = require "core.loggingmanager"; lm.register_sink_type("console", nil); lm.register_sink_type("stdout", nil); lm.reload_logging(); end if daemonize then local function daemonize_server() module:log("info", "Prosody is about to detach from the console, disabling further console output"); remove_log_sinks(); local ok, ret = pposix.daemonize(); if not ok then module:log("error", "Failed to daemonize: %s", ret); elseif ret and ret > 0 then os.exit(0); else module:log("info", "Successfully daemonized to PID %d", pposix.getpid()); write_pidfile(); end end module:hook("server-started", daemonize_server) else -- Not going to daemonize, so write the pid of this process write_pidfile(); end module:hook("server-stopped", remove_pidfile); -- Set signal handlers if have_signal then module:add_timer(0, function () signal.signal("SIGTERM", function () module:log("warn", "Received SIGTERM"); prosody.unlock_globals(); prosody.shutdown("Received SIGTERM"); prosody.lock_globals(); end); signal.signal("SIGHUP", function () module:log("info", "Received SIGHUP"); prosody.reload_config(); -- this also reloads logging end); signal.signal("SIGINT", function () module:log("info", "Received SIGINT"); prosody.unlock_globals(); prosody.shutdown("Received SIGINT"); prosody.lock_globals(); end); signal.signal("SIGUSR1", function () module:log("info", "Received SIGUSR1"); module:fire_event("signal/SIGUSR1"); end); signal.signal("SIGUSR2", function () module:log("info", "Received SIGUSR2"); module:fire_event("signal/SIGUSR2"); end); end); end -- For other modules to reference features = { signal_events = true; };