add http prometheus metrics (#3432)

This will add metrics to http endpoints to measure latency and to see if
other parts of infra are working

This will close #2421

Signed-off-by: Max Knee <max.knee@nytimes.com>

cmd/drone-server/inject_server.go

@@ -17,6 +17,7 @@ package main
 import (
 	"net/http"
 
+	chiprometheus "github.com/766b/chi-prometheus"
 	"github.com/drone/drone/cmd/drone-server/config"
 	"github.com/drone/drone/core"
 	"github.com/drone/drone/handler/api"
@@ -61,6 +62,8 @@ var serverSet = wire.NewSet(
 // router that is serves the provided handlers.
 func provideRouter(api api.Server, web web.Server, rpcv1 rpcHandlerV1, rpcv2 rpcHandlerV2, healthz healthzHandler, metrics *metric.Server, pprof pprofHandler) *chi.Mux {
 	r := chi.NewRouter()
+	m := chiprometheus.NewMiddleware("server")
+	r.Use(m)
 	r.Mount("/healthz", healthz)
 	r.Mount("/metrics", metrics)
 	r.Mount("/api", api.Handler())

go.mod

@@ -3,6 +3,7 @@ module github.com/drone/drone
 replace github.com/docker/docker => github.com/docker/engine v17.12.0-ce-rc1.0.20200309214505-aa6a9891b09c+incompatible
 
 require (
+	github.com/766b/chi-prometheus v0.0.0-20211217152057-87afa9aa2ca8
 	github.com/99designs/httpsignatures-go v0.0.0-20170731043157-88528bf4ca7e
 	github.com/Azure/azure-storage-blob-go v0.7.0
 	github.com/Azure/go-autorest/autorest/adal v0.8.3 // indirect

go.sum

@@ -1,5 +1,7 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 docker.io/go-docker v1.0.0/go.mod h1:7tiAn5a0LFmjbPDbyTPOaTTOuG1ZRNXdPA6RvKY+fpY=
+github.com/766b/chi-prometheus v0.0.0-20211217152057-87afa9aa2ca8 h1:hK1G69lDhhrGqJbRA5i1rmT2KI/W77MSdr7hEGHqWdQ=
+github.com/766b/chi-prometheus v0.0.0-20211217152057-87afa9aa2ca8/go.mod h1:X/LhbmoBoRu8TxoGIOIraVNhfz3hhikJoaelrOuhdPY=
 github.com/99designs/httpsignatures-go v0.0.0-20170731043157-88528bf4ca7e h1:rl2Aq4ZODqTDkeSqQBy+fzpZPamacO1Srp8zq7jf2Sc=
 github.com/99designs/httpsignatures-go v0.0.0-20170731043157-88528bf4ca7e/go.mod h1:Xa6lInWHNQnuWoF0YPSsx+INFA9qk7/7pTjwb3PInkY=
 github.com/Azure/azure-pipeline-go v0.2.1 h1:OLBdZJ3yvOn2MezlWvbrBMTEUQC72zAftRZOMdj5HYo=

handler/api/api.go

@@ -18,6 +18,7 @@ import (
 	"net/http"
 	"os"
 
+	chiprometheus "github.com/766b/chi-prometheus"
 	"github.com/drone/drone/core"
 	"github.com/drone/drone/handler/api/acl"
 	"github.com/drone/drone/handler/api/auth"
@@ -162,6 +163,8 @@ type Server struct {
 // Handler returns an http.Handler
 func (s Server) Handler() http.Handler {
 	r := chi.NewRouter()
+	m := chiprometheus.NewMiddleware("api")
+	r.Use(m)
 	r.Use(middleware.Recoverer)
 	r.Use(middleware.NoCache)
 	r.Use(logger.Middleware)

handler/web/web.go

@@ -25,6 +25,7 @@ import (
 	"github.com/drone/go-login/login"
 	"github.com/drone/go-scm/scm"
 
+	chiprometheus "github.com/766b/chi-prometheus"
 	"github.com/go-chi/chi"
 	"github.com/go-chi/chi/middleware"
 	"github.com/unrolled/secure"
@@ -94,6 +95,8 @@ type Server struct {
 // Handler returns an http.Handler
 func (s Server) Handler() http.Handler {
 	r := chi.NewRouter()
+	m := chiprometheus.NewMiddleware("web")
+	r.Use(m)
 	r.Use(middleware.Recoverer)
 	r.Use(middleware.NoCache)
 	r.Use(logger.Middleware)

operator/manager/rpc2/server.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by the Drone Non-Commercial License
 // that can be found in the LICENSE file.
 
+//go:build !oss
 // +build !oss
 
 package rpc2
@@ -9,6 +10,7 @@ package rpc2
 import (
 	"net/http"
 
+	chiprometheus "github.com/766b/chi-prometheus"
 	"github.com/drone/drone/operator/manager"
 
 	"github.com/go-chi/chi"
@@ -23,6 +25,8 @@ type Server http.Handler
 // interaction with the build controller using the http transport.
 func NewServer(manager manager.BuildManager, secret string) Server {
 	r := chi.NewRouter()
+	m := chiprometheus.NewMiddleware("drone")
+	r.Use(m)
 	r.Use(middleware.Recoverer)
 	r.Use(middleware.NoCache)
 	r.Use(authorization(secret))