feat(api): create api proxy/ratelimiting/metrics

services/web-proxy/util.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"net/http/httputil"
+	"net/url"
+	"os"
+	"regexp"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var metric = prometheus.NewHistogramVec(
+	prometheus.HistogramOpts{
+		Name:    "pk_http_requests",
+		Buckets: []float64{.1, .25, 1, 2.5, 5, 20},
+	},
+	[]string{"domain", "method", "status", "route"},
+)
+
+func proxyTo(host string) *httputil.ReverseProxy {
+	rp := httputil.NewSingleHostReverseProxy(&url.URL{
+		Scheme:   "http",
+		Host:     host,
+		RawQuery: "",
+	})
+	rp.ModifyResponse = logTimeElapsed
+	return rp
+}
+
+var systemsRegex = regexp.MustCompile("systems/[^/]+")
+var membersRegex = regexp.MustCompile("members/[^/]+")
+var groupsRegex = regexp.MustCompile("groups/[^/]+")
+var switchesRegex = regexp.MustCompile("switches/[^/]+")
+var guildsRegex = regexp.MustCompile("guilds/[^/]+")
+var messagesRegex = regexp.MustCompile("messages/[^/]+")
+
+func cleanPath(host, path string) string {
+	if host != "api.pluralkit.me" {
+		return ""
+	}
+
+	if !(strings.HasPrefix(host, "/v2") || strings.HasPrefix(host, "/private")) {
+		return ""
+	}
+
+	path = systemsRegex.ReplaceAllString(path, "{systemRef}")
+	path = membersRegex.ReplaceAllString(path, "{memberRef}")
+	path = groupsRegex.ReplaceAllString(path, "{groupRef}")
+	path = switchesRegex.ReplaceAllString(path, "{switchRef}")
+	path = guildsRegex.ReplaceAllString(path, "{guild_id}")
+	path = messagesRegex.ReplaceAllString(path, "{message_id}")
+
+	return path
+}
+
+func requireEnv(key string) string {
+	if val, ok := os.LookupEnv(key); !ok {
+		panic("missing `" + key + "` in environment")
+	} else {
+		return val
+	}
+}