Proxy: use a global switch for Filter Middleware

cmd/proxy/actions/app.go

@@ -113,7 +113,9 @@ func App() (*buffalo.App, error) {
 		app.Stop(err)
 	}
 	app.Use(T.Middleware())
-	app.Use(newFilterMiddleware(mf))
+	if !env.FilterOff() {
+		app.Use(newFilterMiddleware(mf))
+	}
 	user, pass, ok := env.BasicAuth()
 	if ok {
 		app.Use(basicAuth(user, pass))

pkg/config/env/filter.go

@@ -9,3 +9,11 @@ const defaultConfigurationFileName = "filter.conf"
 func FilterConfigurationFileName() string {
 	return envy.Get("ATHENS_FILTER_FILENAME", defaultConfigurationFileName)
 }
+
+// FilterOff checks PROXY_FILTER_OFF env and returns
+// true of it's equal to "true", otherwise false always.
+// It defaults to "true" until Olympus is the default
+// place to grab modules before the Proxy.
+func FilterOff() bool {
+	return envy.Get("PROXY_FILTER_OFF", "true") == "true"
+}