[#3] metrics: Move from node

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

go.mod

@@ -3,6 +3,9 @@ module git.frostfs.info/TrueCloudLab/frostfs-observability
 go 1.19
 
 require (
+	github.com/grpc-ecosystem/go-grpc-middleware/providers/prometheus v1.0.0-rc.0
+	github.com/prometheus/client_golang v1.15.1
+	github.com/prometheus/client_model v0.3.0
 	github.com/stretchr/testify v1.8.3
 	go.opentelemetry.io/otel v1.16.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.16.0
@@ -14,13 +17,20 @@ require (
 )
 
 require (
+	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cenkalti/backoff/v4 v4.2.1 // indirect
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/go-logr/logr v1.2.4 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.0.0-rc.3 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.7.0 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/prometheus/common v0.42.0 // indirect
+	github.com/prometheus/procfs v0.9.0 // indirect
+	github.com/rogpeppe/go-internal v1.10.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/internal/retry v1.16.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.16.0 // indirect
 	go.opentelemetry.io/otel/metric v1.16.0 // indirect

go.sum

@@ -35,11 +35,15 @@ github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
+github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
+github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cenkalti/backoff/v4 v4.2.1 h1:y4OZtCnogmCPw98Zjyt5a6+QwPLGkiQsYW5oUqylYbM=
 github.com/cenkalti/backoff/v4 v4.2.1/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
+github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
@@ -58,6 +62,7 @@ github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymF
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
+github.com/envoyproxy/go-control-plane v0.9.9-0.20210217033140-668b12f5399d/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20210512163311-63b5d3c536b0/go.mod h1:hliV/p42l8fGbc6Y9bQ70uLwIvmJyVE5k4iMKlh8wCQ=
 github.com/envoyproxy/go-control-plane v0.9.10-0.20210907150352-cf90f659a021/go.mod h1:AFq3mo9L8Lqqiid3OhADV3RfLJnjiw63cSpi+fDTRC0=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
@@ -126,6 +131,10 @@ github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm4
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/googleapis/gax-go/v2 v2.0.4/go.mod h1:0Wqv26UfaUD9n4G6kQubkQ+KchISgw+vpHVxEJEs9eg=
 github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5mhpdKc/us6bOk=
+github.com/grpc-ecosystem/go-grpc-middleware/providers/prometheus v1.0.0-rc.0 h1:mdLirNAJBxnGgyB6pjZLcs6ue/6eZGBui6gXspfq4ks=
+github.com/grpc-ecosystem/go-grpc-middleware/providers/prometheus v1.0.0-rc.0/go.mod h1:kdXbOySqcQeTxiqglW7aahTmWZy3Pgi6SYL36yvKeyA=
+github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.0.0-rc.3 h1:o95KDiV/b1xdkumY5YbLR0/n2+wBxUpgf3HgfKgTyLI=
+github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.0.0-rc.3/go.mod h1:hTxjzRcX49ogbTGVJ1sM5mz5s+SSgiGIyL3jjPxl32E=
 github.com/grpc-ecosystem/grpc-gateway v1.16.0/go.mod h1:BDjrQk3hbvj6Nolgz8mAMFbcEtjT1g+wF4CSlocrBnw=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.7.0 h1:BZHcxBETFHIdVyhyEfOvn/RdU/QGdLI4y34qQGjGWO0=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.7.0/go.mod h1:hgWBS7lorOAVIJEQMi4ZsPv9hVvWI6+ch50m39Pf2Ks=
@@ -135,16 +144,30 @@ github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:
 github.com/jstemmer/go-junit-report v0.0.0-20190106144839-af01ea7f8024/go.mod h1:6v2b51hI/fHJwM22ozAgKL4VKDeJcHhJFhtBdhmNjmU=
 github.com/jstemmer/go-junit-report v0.9.1/go.mod h1:Brl9GWCQeLvo8nXZwPNNblvFj/XSXhF0NWZEnDohbsk=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
-github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zkfA9PSy5pEvNWRP0ET0TIVo=
+github.com/matttproud/golang_protobuf_extensions v1.0.4/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/prometheus/client_golang v1.15.1 h1:8tXpTmJbyH5lydzFPoxSIJ0J46jdh3tylbvM1xCv0LI=
+github.com/prometheus/client_golang v1.15.1/go.mod h1:e9yaBhRPU2pPNsZwE+JdQl0KEt1N9XgF6zxWmaC0xOk=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
+github.com/prometheus/client_model v0.3.0 h1:UBgGFHqYdG/TPFD1B1ogZywDqEkwp3fBMvqdiQ7Xew4=
+github.com/prometheus/client_model v0.3.0/go.mod h1:LDGWKZIo7rky3hgvBe+caln+Dr3dPggB5dvjtD7w9+w=
+github.com/prometheus/common v0.42.0 h1:EKsfXEYo4JpWMHH5cg+KOUWeuJSov1Id8zGR8eeI1YM=
+github.com/prometheus/common v0.42.0/go.mod h1:xBwqVerjNdUDjgODMpudtOMwlOwf2SaTr1yjz4b7Zbc=
+github.com/prometheus/procfs v0.9.0 h1:wzCHvIvM5SxWqYvwgVL7yJY8Lz3PKn49KQtpgMYJfhI=
+github.com/prometheus/procfs v0.9.0/go.mod h1:+pB4zwohETzFnmlpe6yd2lSc+0/46IYZRB/chUwxUZY=
 github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
+github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
+github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
@@ -242,6 +265,7 @@ golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81R
 golang.org/x/net v0.0.0-20200707034311-ab3426394381/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20200822124328-c89045814202/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
+golang.org/x/net v0.0.0-20210423184538-5f58ad60dda6/go.mod h1:OJAsFXCWl8Ukc7SiCT/9KSuxbyM7479/AVlXFRxuMCk=
 golang.org/x/net v0.8.0 h1:Zrh2ngAOFYneWTAIAPethzeaQLuHwhuBkuV6ZiRnUaQ=
 golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
@@ -249,6 +273,7 @@ golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4Iltr
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20191202225959-858c2ad4c8b6/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
+golang.org/x/oauth2 v0.0.0-20210413134643-5e61552d6c78/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
 golang.org/x/oauth2 v0.0.0-20211104180415-d3ed0bb246c8/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -285,6 +310,7 @@ golang.org/x/sys v0.0.0-20200523222454-059865788121/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200803210538-64077c9b5642/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.8.0 h1:EBmGv8NaZBZTWvrbjNoL6HVt+IVy3QDQpJs7VRIw3tU=
 golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -295,6 +321,7 @@ golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.5/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.8.0 h1:57P1ETyNKtuIjB4SRd15iJxuhj8Gc416Y78H3qgMh68=
 golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
 golang.org/x/time v0.0.0-20181108054448-85acf8d2951c/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
@@ -395,6 +422,7 @@ google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEY
 google.golang.org/genproto v0.0.0-20200618031413-b414f8b61790/go.mod h1:jDfRM7FcilCzHH/e9qn6dsT145K34l5v+OpcnNgKAAA=
 google.golang.org/genproto v0.0.0-20200729003335-053ba62fc06f/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/genproto v0.0.0-20200804131852-c06518451d9c/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
+google.golang.org/genproto v0.0.0-20200806141610-86f49bd18e98/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/genproto v0.0.0-20200825200019-8632dd797987/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/genproto v0.0.0-20211118181313-81c1377c94b1/go.mod h1:5CzLGKJ67TSI2B9POpiiyGha0AjJvZIUgRMt1dSmuhc=
 google.golang.org/genproto v0.0.0-20230306155012-7f2fa6fef1f4 h1:DdoeryqhaXp1LtT/emMP1BRJPHHKFi5akj/nbx/zNTA=
@@ -413,10 +441,12 @@ google.golang.org/grpc v1.30.0/go.mod h1:N36X2cJ7JwdamYAgDz+s+rVMFjt3numwzf/HckM
 google.golang.org/grpc v1.31.0/go.mod h1:N36X2cJ7JwdamYAgDz+s+rVMFjt3numwzf/HckM8pak=
 google.golang.org/grpc v1.33.1/go.mod h1:fr5YgcSWrqhRRxogOsw7RzIpsmvOZ6IcH4kBYTpR3n0=
 google.golang.org/grpc v1.36.0/go.mod h1:qjiiYl8FncCW8feJPdyg3v6XW24KsRHe+dy9BAGRRjU=
+google.golang.org/grpc v1.37.0/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQdJfM=
 google.golang.org/grpc v1.40.0/go.mod h1:ogyxbiOoUXAkP+4+xa6PZSE9DZgIHtSpzjDTB9KAK34=
 google.golang.org/grpc v1.42.0/go.mod h1:k+4IHHFw41K8+bbowsex27ge2rCb65oeWqe4jJ590SU=
 google.golang.org/grpc v1.55.0 h1:3Oj82/tFSCeUrRTg/5E/7d/W5A1tj6Ky1ABAuZuv5ag=
 google.golang.org/grpc v1.55.0/go.mod h1:iYEXKGkEBhg1PjZQvoYEVPTDkHo1/bjTnfwTeGONTY8=
+google.golang.org/grpc/examples v0.0.0-20210424002626-9572fd6faeae/go.mod h1:Ly7ZA/ARzg8fnPU9TyZIxoz33sEUuWX7txiqs8lPTgE=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
 google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=
@@ -433,8 +463,8 @@ google.golang.org/protobuf v1.27.1/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQ
 google.golang.org/protobuf v1.30.0 h1:kPPoIgf3TsEvrm0PFe15JQ+570QVxYzEvvHqChK+cng=
 google.golang.org/protobuf v1.30.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.3/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

metrics/desc.go

@@ -0,0 +1,105 @@
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
+)
+
+// Descriptions contains metric Description suitable for further processing.
+// The only reason for it to exist is `prometheus.Desc` disallowing field access directly.
+// https://github.com/prometheus/client_golang/pull/326
+// https://github.com/prometheus/client_golang/issues/516
+// https://github.com/prometheus/client_golang/issues/222
+type Description struct {
+	Name           string            `json:"name"`
+	Help           string            `json:"help"`
+	Type           string            `json:"type"`
+	ConstantLabels prometheus.Labels `json:"constant_labels,omitempty"`
+	VariableLabels []string          `json:"variable_labels,omitempty"`
+}
+
+// NewGauge returns new registered prometheus.Gauge.
+func NewGauge(opts prometheus.GaugeOpts) prometheus.Gauge {
+	value := prometheus.NewGauge(opts)
+	mustRegister(value, Description{
+		Name:           prometheus.BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
+		Type:           dto.MetricType_GAUGE.String(),
+		Help:           opts.Help,
+		ConstantLabels: opts.ConstLabels,
+	})
+	return value
+}
+
+// NewGaugeVec returns new registered *prometheus.GaugeVec.
+func NewGaugeVec(opts prometheus.GaugeOpts, labelNames []string) *prometheus.GaugeVec {
+	value := prometheus.NewGaugeVec(opts, labelNames)
+	mustRegister(value, Description{
+		Name:           prometheus.BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
+		Type:           dto.MetricType_GAUGE.String(),
+		Help:           opts.Help,
+		ConstantLabels: opts.ConstLabels,
+		VariableLabels: labelNames,
+	})
+
+	return value
+}
+
+// NewGaugeFunc returns new registered prometheus.GaugeFunc.
+func NewGaugeFunc(opts prometheus.GaugeOpts, f func() float64) prometheus.GaugeFunc {
+	value := prometheus.NewGaugeFunc(opts, f)
+	mustRegister(value, Description{
+		Name:           prometheus.BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
+		Type:           dto.MetricType_GAUGE.String(),
+		Help:           opts.Help,
+		ConstantLabels: opts.ConstLabels,
+	})
+	return value
+}
+
+// NewCounter returns new registered prometheus.Counter.
+func NewCounter(opts prometheus.CounterOpts) prometheus.Counter {
+	value := prometheus.NewCounter(opts)
+	mustRegister(value, Description{
+		Name:           prometheus.BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
+		Type:           dto.MetricType_COUNTER.String(),
+		Help:           opts.Help,
+		ConstantLabels: opts.ConstLabels,
+	})
+	return value
+}
+
+// NewCounterVec returns new registered *prometheus.CounterVec.
+func NewCounterVec(opts prometheus.CounterOpts, labels []string) *prometheus.CounterVec {
+	value := prometheus.NewCounterVec(opts, labels)
+	mustRegister(value, Description{
+		Name:           prometheus.BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
+		Type:           dto.MetricType_COUNTER.String(),
+		Help:           opts.Help,
+		ConstantLabels: opts.ConstLabels,
+		VariableLabels: labels,
+	})
+	return value
+}
+
+// NewHistogramVec returns new registered *prometheus.HistogramVec.
+func NewHistogramVec(opts prometheus.HistogramOpts, labelNames []string) *prometheus.HistogramVec {
+	value := prometheus.NewHistogramVec(opts, labelNames)
+	mustRegister(value, Description{
+		Name:           prometheus.BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
+		Type:           dto.MetricType_HISTOGRAM.String(),
+		Help:           opts.Help,
+		ConstantLabels: opts.ConstLabels,
+		VariableLabels: labelNames,
+	})
+	return value
+}
+
+// DescribeAll returns descriptions for all registered metrics.
+func DescribeAll() []Description {
+	registeredDescriptionsMtx.Lock()
+	defer registeredDescriptionsMtx.Unlock()
+
+	ds := make([]Description, len(registeredDescriptions))
+	copy(ds, registeredDescriptions)
+	return ds
+}

metrics/desc_test.go

@@ -0,0 +1,64 @@
+package metrics
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDescribeAll(t *testing.T) {
+	const (
+		namespace = "my_ns"
+		subsystem = "mysub"
+	)
+	NewCounter(prometheus.CounterOpts{
+		Namespace: namespace,
+		Subsystem: subsystem,
+		Name:      "my_counter",
+	})
+
+	labels := []string{"label1", "label2"}
+	NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: namespace,
+		Subsystem: subsystem,
+		Name:      "my_gauge",
+	}, labels)
+
+	constLabels := prometheus.Labels{
+		"const1": "abc",
+		"const2": "xyz",
+	}
+	NewCounter(prometheus.CounterOpts{
+		Namespace:   namespace,
+		Subsystem:   subsystem,
+		Name:        "with_const_labels",
+		ConstLabels: constLabels,
+	})
+
+	descriptions := DescribeAll()
+
+	seen := make(map[string]bool)
+	for i := range descriptions {
+		if !strings.HasPrefix(descriptions[i].Name, namespace) {
+			continue
+		}
+
+		require.False(t, seen[descriptions[i].Name], "metric %s was seen twice", descriptions[i].Name)
+		seen[descriptions[i].Name] = true
+
+		switch descriptions[i].Name {
+		case prometheus.BuildFQName(namespace, subsystem, "my_counter"):
+			require.True(t, len(descriptions[i].VariableLabels) == 0)
+		case prometheus.BuildFQName(namespace, subsystem, "my_gauge"):
+			require.Equal(t, labels, descriptions[i].VariableLabels)
+		case prometheus.BuildFQName(namespace, subsystem, "with_const_labels"):
+			require.Equal(t, len(constLabels), len(descriptions[i].ConstantLabels))
+			require.Equal(t, constLabels, descriptions[i].ConstantLabels)
+		default:
+			require.FailNow(t, "unexpected metric name: %s", descriptions[i].Name)
+		}
+	}
+	require.Equal(t, 3, len(seen), "not all registered metrics were iterated over")
+}

metrics/registry.go

@@ -0,0 +1,44 @@
+package metrics
+
+import (
+	"net/http"
+	"sync"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/collectors"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+var (
+	registry = prometheus.NewRegistry()
+	// registeredDescriptionsMtx protects collectors slice.
+	// It should not be acessed concurrently, but we can easily forget this in future, thus this mutex.
+	registeredDescriptionsMtx sync.Mutex
+	registeredDescriptions    []Description
+)
+
+func init() {
+	registry.MustRegister(collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}))
+	registry.MustRegister(collectors.NewGoCollector())
+}
+
+// Register registers custom collectors to registry.
+// Should be used with metrics from other packages.
+func Register(customCollectors ...prometheus.Collector) {
+	registry.MustRegister(customCollectors...)
+}
+
+func mustRegister(c prometheus.Collector, desc Description) {
+	registry.MustRegister(c)
+	registeredDescriptionsMtx.Lock()
+	defer registeredDescriptionsMtx.Unlock()
+	registeredDescriptions = append(registeredDescriptions, desc)
+}
+
+// Handler returns an http.Handler for the local registry.
+func Handler() http.Handler {
+	promhttp.Handler()
+	return promhttp.InstrumentMetricHandler(
+		registry,
+		promhttp.HandlerFor(registry, promhttp.HandlerOpts{}))
+}