net.unbound: Show canonical name in textual format (e.g. in shell)
libunbound does not tell us the whole chain of CNAMEs, only the final
canonical name.
This is to aid in debugging since it will only be shown in the shell.
local time = require "prosody.util.time".now;
local new_metric_registry = require "prosody.util.openmetrics".new_metric_registry;
local render_histogram_le = require "prosody.util.openmetrics".render_histogram_le;
-- BEGIN of Metric implementations
-- Gauges
local gauge_metric_mt = {}
gauge_metric_mt.__index = gauge_metric_mt
local function new_gauge_metric()
local metric = { value = 0 }
setmetatable(metric, gauge_metric_mt)
return metric
end
function gauge_metric_mt:set(value)
self.value = value
end
function gauge_metric_mt:add(delta)
self.value = self.value + delta
end
function gauge_metric_mt:reset()
self.value = 0
end
function gauge_metric_mt:iter_samples()
local done = false
return function(_s)
if done then
return nil, true
end
done = true
return "", nil, _s.value
end, self
end
-- Counters
local counter_metric_mt = {}
counter_metric_mt.__index = counter_metric_mt
local function new_counter_metric()
local metric = {
_created = time(),
value = 0,
}
setmetatable(metric, counter_metric_mt)
return metric
end
function counter_metric_mt:set(value)
self.value = value
end
function counter_metric_mt:add(value)
self.value = (self.value or 0) + value
end
function counter_metric_mt:iter_samples()
local step = 0
return function(_s)
step = step + 1
if step == 1 then
return "_created", nil, _s._created
elseif step == 2 then
return "_total", nil, _s.value
else
return nil, nil, true
end
end, self
end
function counter_metric_mt:reset()
self.value = 0
end
-- Histograms
local histogram_metric_mt = {}
histogram_metric_mt.__index = histogram_metric_mt
local function new_histogram_metric(buckets)
local metric = {
_created = time(),
_sum = 0,
_count = 0,
}
-- the order of buckets matters unfortunately, so we cannot directly use
-- the thresholds as table keys
for i, threshold in ipairs(buckets) do
metric[i] = {
threshold = threshold,
threshold_s = render_histogram_le(threshold),
count = 0
}
end
setmetatable(metric, histogram_metric_mt)
return metric
end
function histogram_metric_mt:sample(value)
-- According to the I-D, values must be part of all buckets
for i, bucket in pairs(self) do
if "number" == type(i) and value <= bucket.threshold then
bucket.count = bucket.count + 1
end
end
self._sum = self._sum + value
self._count = self._count + 1
end
function histogram_metric_mt:iter_samples()
local key = nil
return function (_s)
local data
key, data = next(_s, key)
if key == "_created" or key == "_sum" or key == "_count" then
return key, nil, data
elseif key ~= nil then
return "_bucket", {["le"] = data.threshold_s}, data.count
else
return nil, nil, nil
end
end, self
end
function histogram_metric_mt:reset()
self._created = time()
self._count = 0
self._sum = 0
for i, bucket in pairs(self) do
if "number" == type(i) then
bucket.count = 0
end
end
end
-- Summary
local summary_metric_mt = {}
summary_metric_mt.__index = summary_metric_mt
local function new_summary_metric()
-- quantiles are not supported yet
local metric = {
_created = time(),
_sum = 0,
_count = 0,
}
setmetatable(metric, summary_metric_mt)
return metric
end
function summary_metric_mt:sample(value)
self._sum = self._sum + value
self._count = self._count + 1
end
function summary_metric_mt:iter_samples()
local key = nil
return function (_s)
local data
key, data = next(_s, key)
return key, nil, data
end, self
end
function summary_metric_mt:reset()
self._created = time()
self._count = 0
self._sum = 0
end
local pull_backend = {
gauge = new_gauge_metric,
counter = new_counter_metric,
histogram = new_histogram_metric,
summary = new_summary_metric,
}
-- END of Metric implementations
local function new()
return {
metric_registry = new_metric_registry(pull_backend),
}
end
return {
new = new;
}