metrics: scope metrics to active config, add optional per-host metrics (#6531)v2.9.0-beta.1

* Add per host config

* Pass host label when option is enabled

* Test per host enabled

* metrics: scope metrics per loaded config

* doc and linter

Signed-off-by: Mohammed Al Sahaf <[email protected]>

* inject the custom registry into the admin handler

Co-Authored-By: Dave Henderson <[email protected]>

* remove `TODO` comment

* fixes

Signed-off-by: Mohammed Al Sahaf <[email protected]>

* refactor to delay metrics admin handler provision

Signed-off-by: Mohammed Al Sahaf <[email protected]>

---------

Signed-off-by: Mohammed Al Sahaf <[email protected]>
Co-authored-by: Hussam Almarzooq <[email protected]>
Co-authored-by: Dave Henderson <[email protected]>

1 files changed, 16 insertions, 7 deletions

diff --git a/metrics.go b/metrics.go
index 0f8ea03cb..0ee3853eb 100644
--- a/metrics.go
+++ b/metrics.go
@@ -4,30 +4,33 @@ import (
 	"net/http"
 
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/collectors"
-	"github.com/prometheus/client_golang/prometheus/promauto"
 
 	"github.com/caddyserver/caddy/v2/internal/metrics"
 )
 
 // define and register the metrics used in this package.
 func init() {
-	prometheus.MustRegister(collectors.NewBuildInfoCollector())
-
 	const ns, sub = "caddy", "admin"
-
-	adminMetrics.requestCount = promauto.NewCounterVec(prometheus.CounterOpts{
+	adminMetrics.requestCount = prometheus.NewCounterVec(prometheus.CounterOpts{
 		Namespace: ns,
 		Subsystem: sub,
 		Name:      "http_requests_total",
 		Help:      "Counter of requests made to the Admin API's HTTP endpoints.",
 	}, []string{"handler", "path", "code", "method"})
-	adminMetrics.requestErrors = promauto.NewCounterVec(prometheus.CounterOpts{
+	adminMetrics.requestErrors = prometheus.NewCounterVec(prometheus.CounterOpts{
 		Namespace: ns,
 		Subsystem: sub,
 		Name:      "http_request_errors_total",
 		Help:      "Number of requests resulting in middleware errors.",
 	}, []string{"handler", "path", "method"})
+	globalMetrics.configSuccess = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "caddy_config_last_reload_successful",
+		Help: "Whether the last configuration reload attempt was successful.",
+	})
+	globalMetrics.configSuccessTime = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "caddy_config_last_reload_success_timestamp_seconds",
+		Help: "Timestamp of the last successful configuration reload.",
+	})
 }
 
 // adminMetrics is a collection of metrics that can be tracked for the admin API.
@@ -36,6 +39,12 @@ var adminMetrics = struct {
 	requestErrors *prometheus.CounterVec
 }{}
 
+// globalMetrics is a collection of metrics that can be tracked for Caddy global state
+var globalMetrics = struct {
+	configSuccess     prometheus.Gauge
+	configSuccessTime prometheus.Gauge
+}{}
+
 // Similar to promhttp.InstrumentHandlerCounter, but upper-cases method names
 // instead of lower-casing them.
 //