MINOR: add prometheus endpoint for ingress controller

Author: ivanmatmati

controller/utils/flags.go

@@ -99,4 +99,5 @@ type OSArgs struct { //nolint:maligned
 	RuntimeDir                 string         `long:"runtime-dir" description:"path to HAProxy runtime directory. NOTE: works only in External mode"`
 	DisableServiceExternalName bool           `long:"disable-service-external-name" description:"disable forwarding to ExternalName Services due to CVE-2021-25740"`
 	UseWiths6Overlay           bool           `long:"with-s6-overlay" description:"use s6 overlay to start/stpop/reload HAProxy"`
+	PromotheusPort             int64          `long:"enable-prometheus-port" description:"port to listen on for Prometheus metrics"`
 }

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/haproxytech/config-parser/v4 v4.0.0-rc2.0.20211021093817-f9021b6ca61c
 	github.com/jessevdk/go-flags v1.4.0
 	github.com/pires/go-proxyproto v0.6.1
+	github.com/prometheus/client_golang v1.12.1
 	github.com/stretchr/testify v1.7.0
 	k8s.io/api v0.22.2
 	k8s.io/apimachinery v0.22.2
@@ -19,6 +20,8 @@ require (
 	github.com/PuerkitoBio/purell v1.1.1 // indirect
 	github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578 // indirect
 	github.com/asaskevich/govalidator v0.0.0-20200108200545-475eaeb16496 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/evanphx/json-patch v4.11.0+incompatible // indirect
 	github.com/go-logr/logr v0.4.0 // indirect
@@ -42,23 +45,27 @@ require (
 	github.com/googleapis/gnostic v0.5.5 // indirect
 	github.com/haproxytech/go-logger v1.0.0 // indirect
 	github.com/imdario/mergo v0.3.5 // indirect
-	github.com/json-iterator/go v1.1.11 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 // indirect
 	github.com/mailru/easyjson v0.7.1 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
 	github.com/mitchellh/mapstructure v1.2.2 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
-	github.com/modern-go/reflect2 v1.0.1 // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/prometheus/client_model v0.2.0 // indirect
+	github.com/prometheus/common v0.32.1 // indirect
+	github.com/prometheus/procfs v0.7.3 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	go.mongodb.org/mongo-driver v1.5.1 // indirect
-	golang.org/x/net v0.0.0-20210520170846-37e1c6afe023 // indirect
-	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d // indirect
-	golang.org/x/sys v0.0.0-20210817190340-bfb29a6856f2 // indirect
+	golang.org/x/net v0.0.0-20210525063256-abc453219eb5 // indirect
+	golang.org/x/oauth2 v0.0.0-20210514164344-f6687ab2804c // indirect
+	golang.org/x/sys v0.0.0-20220114195835-da31bd327af9 // indirect
 	golang.org/x/term v0.0.0-20210220032956-6a3ed077a48d // indirect
 	golang.org/x/text v0.3.6 // indirect
 	golang.org/x/time v0.0.0-20210723032227-1f47c861a9ac // indirect
-	google.golang.org/appengine v1.6.5 // indirect
+	google.golang.org/appengine v1.6.6 // indirect
 	google.golang.org/protobuf v1.26.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect