From 8ec51bbede59e1fa6ac24de3607f6e7bb3e3a654 Mon Sep 17 00:00:00 2001 From: Dave Henderson Date: Thu, 17 Sep 2020 14:01:20 -0400 Subject: metrics: Initial integration of Prometheus metrics (#3709) Signed-off-by: Dave Henderson --- modules/metrics/adminmetrics.go | 55 ++++++++++++++++++++ modules/metrics/metrics.go | 109 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 164 insertions(+) create mode 100644 modules/metrics/adminmetrics.go create mode 100644 modules/metrics/metrics.go (limited to 'modules/metrics') diff --git a/modules/metrics/adminmetrics.go b/modules/metrics/adminmetrics.go new file mode 100644 index 0000000..f6a55e8 --- /dev/null +++ b/modules/metrics/adminmetrics.go @@ -0,0 +1,55 @@ +// Copyright 2020 Matthew Holt and The Caddy Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package metrics + +import ( + "net/http" + + "github.com/caddyserver/caddy/v2" +) + +func init() { + caddy.RegisterModule(AdminMetrics{}) +} + +// AdminMetrics is a module that serves a metrics endpoint so that any gathered +// metrics can be exposed for scraping. This module is not configurable, and +// is permanently mounted to the admin API endpoint at "/metrics". +// See the Metrics module for a configurable endpoint that is usable if the +// Admin API is disabled. +type AdminMetrics struct{} + +// CaddyModule returns the Caddy module information. +func (AdminMetrics) CaddyModule() caddy.ModuleInfo { + return caddy.ModuleInfo{ + ID: "admin.api.metrics", + New: func() caddy.Module { return new(AdminMetrics) }, + } +} + +// Routes returns a route for the /metrics endpoint. +func (m *AdminMetrics) Routes() []caddy.AdminRoute { + metricsHandler := createMetricsHandler(nil) + h := caddy.AdminHandlerFunc(func(w http.ResponseWriter, r *http.Request) error { + metricsHandler.ServeHTTP(w, r) + return nil + }) + return []caddy.AdminRoute{{Pattern: "/metrics", Handler: h}} +} + +// Interface guards +var ( + _ caddy.AdminRouter = (*AdminMetrics)(nil) +) diff --git a/modules/metrics/metrics.go b/modules/metrics/metrics.go new file mode 100644 index 0000000..eab6342 --- /dev/null +++ b/modules/metrics/metrics.go @@ -0,0 +1,109 @@ +// Copyright 2020 Matthew Holt and The Caddy Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package metrics + +import ( + "net/http" + + "github.com/caddyserver/caddy/v2" + "github.com/caddyserver/caddy/v2/caddyconfig/caddyfile" + "github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile" + "github.com/caddyserver/caddy/v2/modules/caddyhttp" + + "go.uber.org/zap" + + "github.com/prometheus/client_golang/prometheus" + "github.com/prometheus/client_golang/prometheus/promhttp" +) + +func init() { + caddy.RegisterModule(Metrics{}) + httpcaddyfile.RegisterHandlerDirective("metrics", parseCaddyfile) +} + +// Metrics is a module that serves a /metrics endpoint so that any gathered +// metrics can be exposed for scraping. This module is configurable by end-users +// unlike AdminMetrics. +type Metrics struct { + metricsHandler http.Handler +} + +// CaddyModule returns the Caddy module information. +func (Metrics) CaddyModule() caddy.ModuleInfo { + return caddy.ModuleInfo{ + ID: "http.handlers.metrics", + New: func() caddy.Module { return new(Metrics) }, + } +} + +type zapLogger struct { + zl *zap.Logger +} + +func (l *zapLogger) Println(v ...interface{}) { + l.zl.Sugar().Error(v...) +} + +// Provision sets up m. +func (m *Metrics) Provision(ctx caddy.Context) error { + log := ctx.Logger(m) + m.metricsHandler = createMetricsHandler(&zapLogger{log}) + return nil +} + +func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) { + var m Metrics + err := m.UnmarshalCaddyfile(h.Dispenser) + return m, err +} + +// UnmarshalCaddyfile sets up the handler from Caddyfile tokens. Syntax: +// +// metrics +// +func (m *Metrics) UnmarshalCaddyfile(d *caddyfile.Dispenser) error { + for d.Next() { + args := d.RemainingArgs() + if len(args) > 0 { + return d.ArgErr() + } + } + return nil +} + +func (m Metrics) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error { + m.metricsHandler.ServeHTTP(w, r) + return next.ServeHTTP(w, r) +} + +// Interface guards +var ( + _ caddy.Provisioner = (*Metrics)(nil) + _ caddyhttp.MiddlewareHandler = (*Metrics)(nil) + _ caddyfile.Unmarshaler = (*Metrics)(nil) +) + +func createMetricsHandler(logger promhttp.Logger) http.Handler { + return promhttp.InstrumentMetricHandler(prometheus.DefaultRegisterer, + promhttp.HandlerFor(prometheus.DefaultGatherer, promhttp.HandlerOpts{ + // will only log errors if logger is non-nil + ErrorLog: logger, + + // Allow OpenMetrics format to be negotiated - largely compatible, + // except quantile/le label values always have a decimal. + EnableOpenMetrics: true, + }), + ) +} -- cgit v1.2.3