From 48c7e3c172152dfa74ed4c2e6a031c48e66fc713 Mon Sep 17 00:00:00 2001
From: Kegan Dougal <kegan@matrix.org>
Date: Mon, 24 Feb 2020 17:53:02 +0000
Subject: [PATCH] Replace prometheus with a stub. sigh

---
 cmd/dendritejs/main.go                     |  9 ++---
 go.mod                                     |  2 ++
 go.sum                                     |  1 +
 prometheus/go.mod                          |  3 ++
 prometheus/prometheus/promauto/promauto.go |  7 ++++
 prometheus/prometheus/prometheus.go        | 38 ++++++++++++++++++++++
 prometheus/prometheus/promhttp/promhttp.go | 17 ++++++++++
 7 files changed, 73 insertions(+), 4 deletions(-)
 create mode 100644 prometheus/go.mod
 create mode 100644 prometheus/prometheus/promauto/promauto.go
 create mode 100644 prometheus/prometheus/prometheus.go
 create mode 100644 prometheus/prometheus/promhttp/promhttp.go

diff --git a/cmd/dendritejs/main.go b/cmd/dendritejs/main.go
index 6c18e4d75..0e8a07061 100644
--- a/cmd/dendritejs/main.go
+++ b/cmd/dendritejs/main.go
@@ -16,6 +16,7 @@ package main
 
 import (
 	"flag"
+	"fmt"
 	"net/http"
 
 	"github.com/matrix-org/dendrite/appservice"
@@ -33,12 +34,15 @@ import (
 	"github.com/matrix-org/dendrite/typingserver"
 	"github.com/matrix-org/dendrite/typingserver/cache"
 
-	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/sirupsen/logrus"
 
 	_ "github.com/matrix-org/go-sqlite3-js"
 )
 
+func init() {
+	fmt.Println("dendrite.js starting...")
+}
+
 var (
 	httpBindAddr  = flag.String("http-bind-address", ":8008", "The HTTP listening port for the server")
 	httpsBindAddr = flag.String("https-bind-address", ":8448", "The HTTPS listening port for the server")
@@ -76,9 +80,6 @@ func main() {
 
 	httpHandler := common.WrapHandlerInCORS(base.APIMux)
 
-	// Set up the API endpoints we handle. /metrics is for prometheus, and is
-	// not wrapped by CORS, while everything else is
-	http.Handle("/metrics", promhttp.Handler())
 	http.Handle("/", httpHandler)
 
 	// Expose the matrix APIs directly rather than putting them under a /api path.
diff --git a/go.mod b/go.mod
index e9038228a..6065dafa9 100644
--- a/go.mod
+++ b/go.mod
@@ -2,6 +2,8 @@ module github.com/matrix-org/dendrite
 
 replace github.com/lib/pq => github.com/matrix-org/pq v1.3.2
 
+replace github.com/prometheus/client_golang => ./prometheus
+
 require (
 	github.com/DataDog/zstd v1.4.4 // indirect
 	github.com/Shopify/toxiproxy v2.1.4+incompatible // indirect
diff --git a/go.sum b/go.sum
index 4e92dabc0..f411baeb8 100644
--- a/go.sum
+++ b/go.sum
@@ -178,6 +178,7 @@ golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20181116152217-5ac8a444bdc5/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190422165155-953cdadca894 h1:Cz4ceDQGXuKRnVBDTS23GTn/pU5OE2C0WrNTOYK1Uuc=
 golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191010194322-b09406accb47 h1:/XfQ9z7ib8eEJX2hdgFTZJ/ntt0swNk5oYBziWeTCvY=
 golang.org/x/sys v0.0.0-20191010194322-b09406accb47/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
diff --git a/prometheus/go.mod b/prometheus/go.mod
new file mode 100644
index 000000000..dd6c7bda0
--- /dev/null
+++ b/prometheus/go.mod
@@ -0,0 +1,3 @@
+module github.com/prometheus/client_golang
+
+go 1.13
diff --git a/prometheus/prometheus/promauto/promauto.go b/prometheus/prometheus/promauto/promauto.go
new file mode 100644
index 000000000..74d46c78e
--- /dev/null
+++ b/prometheus/prometheus/promauto/promauto.go
@@ -0,0 +1,7 @@
+package promauto
+
+import "github.com/prometheus/client_golang/prometheus"
+
+func NewCounterVec(opts prometheus.CounterOpts, arr []string) *prometheus.CounterVec {
+	return nil
+}
diff --git a/prometheus/prometheus/prometheus.go b/prometheus/prometheus/prometheus.go
new file mode 100644
index 000000000..1193d5ceb
--- /dev/null
+++ b/prometheus/prometheus/prometheus.go
@@ -0,0 +1,38 @@
+package prometheus
+
+type CounterOpts struct {
+	Name string
+	Help string
+}
+type SummaryOpts struct {
+	Namespace string
+	Subsystem string
+	Name      string
+	Help      string
+}
+
+type CounterVec struct{}
+
+type Collector interface {
+	WithLabelValues(a string, b string) Collector
+	Observe(c float64)
+	Inc()
+}
+
+type col struct{}
+
+func (c col) WithLabelValues(a, b string) Collector {
+	return c
+}
+func (c col) Observe(d float64) {}
+func (c col) Inc()              {}
+
+func NewSummaryVec(opts SummaryOpts, arr []string) Collector {
+	return col{}
+}
+
+func MustRegister(...Collector) {}
+
+func NewCounter(opt CounterOpts) col {
+	return col{}
+}
diff --git a/prometheus/prometheus/promhttp/promhttp.go b/prometheus/prometheus/promhttp/promhttp.go
new file mode 100644
index 000000000..3a4c5d26c
--- /dev/null
+++ b/prometheus/prometheus/promhttp/promhttp.go
@@ -0,0 +1,17 @@
+package promhttp
+
+import (
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+func InstrumentHandlerCounter(v *prometheus.CounterVec, next http.Handler) http.HandlerFunc {
+	return next.ServeHTTP
+}
+
+func Handler() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(400)
+	})
+}