From 368a64546c97abdc7019f98cbc97eecdbda2b6a5 Mon Sep 17 00:00:00 2001
From: Igor Drozdov <idrozdov@gitlab.com>
Date: Wed, 21 Jul 2021 11:24:00 +0300
Subject: Prometheus metrics for HTTP requests

A RoundTripper for tracking the duration of an http request
is introduced
---
 internal/metrics/metrics.go | 63 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 internal/metrics/metrics.go

(limited to 'internal/metrics/metrics.go')

diff --git a/internal/metrics/metrics.go b/internal/metrics/metrics.go
new file mode 100644
index 0000000..6174bca
--- /dev/null
+++ b/internal/metrics/metrics.go
@@ -0,0 +1,63 @@
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+const (
+	namespace     = "gitlab_shell"
+	sshdSubsystem = "sshd"
+	httpSubsystem = "http"
+)
+
+var (
+	SshdConnectionDuration = promauto.NewHistogram(
+		prometheus.HistogramOpts{
+			Namespace: namespace,
+			Subsystem: sshdSubsystem,
+			Name:      "connection_duration_seconds",
+			Help:      "A histogram of latencies for connections to gitlab-shell sshd.",
+			Buckets: []float64{
+				0.005, /* 5ms */
+				0.025, /* 25ms */
+				0.1,   /* 100ms */
+				0.5,   /* 500ms */
+				1.0,   /* 1s */
+				10.0,  /* 10s */
+				30.0,  /* 30s */
+				60.0,  /* 1m */
+				300.0, /* 5m */
+			},
+		},
+	)
+
+	SshdHitMaxSessions = promauto.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: namespace,
+			Subsystem: sshdSubsystem,
+			Name:      "concurrent_limited_sessions_total",
+			Help:      "The number of times the concurrent sessions limit was hit in gitlab-shell sshd.",
+		},
+	)
+
+	HttpRequestDuration = promauto.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: namespace,
+			Subsystem: httpSubsystem,
+			Name:      "request_seconds",
+			Help:      "A histogram of latencies for gitlab-shell http requests",
+			Buckets: []float64{
+				0.01, /* 10ms */
+				0.05, /* 50ms */
+				0.1,  /* 100ms */
+				0.25, /* 250ms */
+				0.5,  /* 500ms */
+				1.0,  /* 1s */
+				5.0,  /* 5s */
+				10.0, /* 10s */
+			},
+		},
+		[]string{"code", "method"},
+	)
+)
-- 
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