Prometheus endpoint (#5256)

* Add prometheus collector and route

* dep ensure -add github.com/prometheus/client_golang/prometheus

* dep ensure -update github.com/golang/protobuf

* add metrics to reserved usernames

* add comment head in metrics package

* fix style imports

* add metrics settings

* add bearer token check

* mapping metrics configs

* fix lint

* update config cheat sheet

* update conf sample, typo fix

modules/metrics/collector.go

@@ -0,0 +1,299 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package metrics
+
+import (
+	"code.gitea.io/gitea/models"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const namespace = "gitea_"
+
+// Collector implements the prometheus.Collector interface and
+// exposes gitea metrics for prometheus
+type Collector struct {
+	Accesses      *prometheus.Desc
+	Actions       *prometheus.Desc
+	Attachments   *prometheus.Desc
+	Comments      *prometheus.Desc
+	Follows       *prometheus.Desc
+	HookTasks     *prometheus.Desc
+	Issues        *prometheus.Desc
+	Labels        *prometheus.Desc
+	LoginSources  *prometheus.Desc
+	Milestones    *prometheus.Desc
+	Mirrors       *prometheus.Desc
+	Oauths        *prometheus.Desc
+	Organizations *prometheus.Desc
+	PublicKeys    *prometheus.Desc
+	Releases      *prometheus.Desc
+	Repositories  *prometheus.Desc
+	Stars         *prometheus.Desc
+	Teams         *prometheus.Desc
+	UpdateTasks   *prometheus.Desc
+	Users         *prometheus.Desc
+	Watches       *prometheus.Desc
+	Webhooks      *prometheus.Desc
+}
+
+// NewCollector returns a new Collector with all prometheus.Desc initialized
+func NewCollector() Collector {
+	return Collector{
+		Accesses: prometheus.NewDesc(
+			namespace+"accesses",
+			"Number of Accesses",
+			nil, nil,
+		),
+		Actions: prometheus.NewDesc(
+			namespace+"actions",
+			"Number of Actions",
+			nil, nil,
+		),
+		Attachments: prometheus.NewDesc(
+			namespace+"attachments",
+			"Number of Attachments",
+			nil, nil,
+		),
+		Comments: prometheus.NewDesc(
+			namespace+"comments",
+			"Number of Comments",
+			nil, nil,
+		),
+		Follows: prometheus.NewDesc(
+			namespace+"follows",
+			"Number of Follows",
+			nil, nil,
+		),
+		HookTasks: prometheus.NewDesc(
+			namespace+"hooktasks",
+			"Number of HookTasks",
+			nil, nil,
+		),
+		Issues: prometheus.NewDesc(
+			namespace+"issues",
+			"Number of Issues",
+			nil, nil,
+		),
+		Labels: prometheus.NewDesc(
+			namespace+"labels",
+			"Number of Labels",
+			nil, nil,
+		),
+		LoginSources: prometheus.NewDesc(
+			namespace+"loginsources",
+			"Number of LoginSources",
+			nil, nil,
+		),
+		Milestones: prometheus.NewDesc(
+			namespace+"milestones",
+			"Number of Milestones",
+			nil, nil,
+		),
+		Mirrors: prometheus.NewDesc(
+			namespace+"mirrors",
+			"Number of Mirrors",
+			nil, nil,
+		),
+		Oauths: prometheus.NewDesc(
+			namespace+"oauths",
+			"Number of Oauths",
+			nil, nil,
+		),
+		Organizations: prometheus.NewDesc(
+			namespace+"organizations",
+			"Number of Organizations",
+			nil, nil,
+		),
+		PublicKeys: prometheus.NewDesc(
+			namespace+"publickeys",
+			"Number of PublicKeys",
+			nil, nil,
+		),
+		Releases: prometheus.NewDesc(
+			namespace+"releases",
+			"Number of Releases",
+			nil, nil,
+		),
+		Repositories: prometheus.NewDesc(
+			namespace+"repositories",
+			"Number of Repositories",
+			nil, nil,
+		),
+		Stars: prometheus.NewDesc(
+			namespace+"stars",
+			"Number of Stars",
+			nil, nil,
+		),
+		Teams: prometheus.NewDesc(
+			namespace+"teams",
+			"Number of Teams",
+			nil, nil,
+		),
+		UpdateTasks: prometheus.NewDesc(
+			namespace+"updatetasks",
+			"Number of UpdateTasks",
+			nil, nil,
+		),
+		Users: prometheus.NewDesc(
+			namespace+"users",
+			"Number of Users",
+			nil, nil,
+		),
+		Watches: prometheus.NewDesc(
+			namespace+"watches",
+			"Number of Watches",
+			nil, nil,
+		),
+		Webhooks: prometheus.NewDesc(
+			namespace+"webhooks",
+			"Number of Webhooks",
+			nil, nil,
+		),
+	}
+
+}
+
+// Describe returns all possible prometheus.Desc
+func (c Collector) Describe(ch chan<- *prometheus.Desc) {
+	ch <- c.Accesses
+	ch <- c.Actions
+	ch <- c.Attachments
+	ch <- c.Comments
+	ch <- c.Follows
+	ch <- c.HookTasks
+	ch <- c.Issues
+	ch <- c.Labels
+	ch <- c.LoginSources
+	ch <- c.Milestones
+	ch <- c.Mirrors
+	ch <- c.Oauths
+	ch <- c.Organizations
+	ch <- c.PublicKeys
+	ch <- c.Releases
+	ch <- c.Repositories
+	ch <- c.Stars
+	ch <- c.Teams
+	ch <- c.UpdateTasks
+	ch <- c.Users
+	ch <- c.Watches
+	ch <- c.Webhooks
+}
+
+// Collect returns the metrics with values
+func (c Collector) Collect(ch chan<- prometheus.Metric) {
+	stats := models.GetStatistic()
+
+	ch <- prometheus.MustNewConstMetric(
+		c.Accesses,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Access),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Actions,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Action),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Attachments,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Attachment),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Comments,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Comment),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Follows,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Follow),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.HookTasks,
+		prometheus.GaugeValue,
+		float64(stats.Counter.HookTask),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Issues,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Issue),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Labels,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Label),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.LoginSources,
+		prometheus.GaugeValue,
+		float64(stats.Counter.LoginSource),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Milestones,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Milestone),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Mirrors,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Mirror),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Oauths,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Oauth),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Organizations,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Org),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.PublicKeys,
+		prometheus.GaugeValue,
+		float64(stats.Counter.PublicKey),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Releases,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Release),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Repositories,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Repo),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Stars,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Star),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Teams,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Team),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.UpdateTasks,
+		prometheus.GaugeValue,
+		float64(stats.Counter.UpdateTask),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Users,
+		prometheus.GaugeValue,
+		float64(stats.Counter.User),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Watches,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Watch),
+	)
+	ch <- prometheus.MustNewConstMetric(
+		c.Webhooks,
+		prometheus.GaugeValue,
+		float64(stats.Counter.Webhook),
+	)
+}