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prosody
File
net/http/errors.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 | 11225:8c17c08d100e |
child | 12974:ba409c67353b |
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-- This module returns a table that is suitable for use as a util.error registry, -- and a function to return a util.error object given callback 'code' and 'body' -- parameters. local codes = require "net.http.codes"; local util_error = require "util.error"; local error_templates = { -- This code is used by us to report a client-side or connection error. -- Instead of using the code, use the supplied body text to get one of -- the more detailed errors below. [0] = { code = 0, type = "cancel", condition = "internal-server-error"; text = "Connection or internal error"; }; -- These are net.http built-in errors, they are returned in -- the body parameter when code == 0 ["cancelled"] = { code = 0, type = "cancel", condition = "remote-server-timeout"; text = "Request cancelled"; }; ["connection-closed"] = { code = 0, type = "wait", condition = "remote-server-timeout"; text = "Connection closed"; }; ["certificate-chain-invalid"] = { code = 0, type = "cancel", condition = "remote-server-timeout"; text = "Server certificate not trusted"; }; ["certificate-verify-failed"] = { code = 0, type = "cancel", condition = "remote-server-timeout"; text = "Server certificate invalid"; }; ["connection failed"] = { code = 0, type = "cancel", condition = "remote-server-not-found"; text = "Connection failed"; }; ["invalid-url"] = { code = 0, type = "modify", condition = "bad-request"; text = "Invalid URL"; }; ["unable to resolve service"] = { code = 0, type = "cancel", condition = "remote-server-not-found"; text = "DNS resolution failed"; }; -- This doesn't attempt to map every single HTTP code (not all have sane mappings), -- but all the common ones should be covered. XEP-0086 was used as reference for -- most of these. [400] = { type = "modify", condition = "bad-request" }; [401] = { type = "auth", condition = "not-authorized" }; [402] = { type = "auth", condition = "payment-required" }; [403] = { type = "auth", condition = "forbidden" }; [404] = { type = "cancel", condition = "item-not-found" }; [405] = { type = "cancel", condition = "not-allowed" }; [406] = { type = "modify", condition = "not-acceptable" }; [407] = { type = "auth", condition = "registration-required" }; [408] = { type = "wait", condition = "remote-server-timeout" }; [409] = { type = "cancel", condition = "conflict" }; [410] = { type = "cancel", condition = "gone" }; [411] = { type = "modify", condition = "bad-request" }; [412] = { type = "cancel", condition = "conflict" }; [413] = { type = "modify", condition = "resource-constraint" }; [414] = { type = "modify", condition = "resource-constraint" }; [415] = { type = "cancel", condition = "feature-not-implemented" }; [416] = { type = "modify", condition = "bad-request" }; [422] = { type = "modify", condition = "bad-request" }; [423] = { type = "wait", condition = "resource-constraint" }; [429] = { type = "wait", condition = "resource-constraint" }; [431] = { type = "modify", condition = "resource-constraint" }; [451] = { type = "auth", condition = "forbidden" }; [500] = { type = "wait", condition = "internal-server-error" }; [501] = { type = "cancel", condition = "feature-not-implemented" }; [502] = { type = "wait", condition = "remote-server-timeout" }; [503] = { type = "cancel", condition = "service-unavailable" }; [504] = { type = "wait", condition = "remote-server-timeout" }; [507] = { type = "wait", condition = "resource-constraint" }; [511] = { type = "auth", condition = "not-authorized" }; }; for k, v in pairs(codes) do if error_templates[k] then error_templates[k].code = k; error_templates[k].text = v; else error_templates[k] = { type = "cancel", condition = "undefined-condition", text = v, code = k }; end end setmetatable(error_templates, { __index = function(_, k) if type(k) ~= "number" then return nil; end return { type = "cancel"; condition = "undefined-condition"; text = codes[k] or (k.." Unassigned"); code = k; }; end }); local function new(code, body, context) if code == 0 then return util_error.new(body, context, error_templates); else return util_error.new(code, context, error_templates); end end return { registry = error_templates; new = new; };