From d87931745d099bacb7c8ef34a47bccc25222e006 Mon Sep 17 00:00:00 2001
From: Cam Saul <cammsaul@gmail.com>
Date: Fri, 19 Apr 2019 20:54:28 -0400
Subject: [PATCH] Set X-Accel-Buffering header in streaming resp so nginx
doesn't buffer :speaking_head_in_silhouette:
---
src/metabase/async/api_response.clj | 10 ++++------
src/metabase/handler.clj | 1 +
src/metabase/middleware/misc.clj | 21 ++++++++++++++++++++-
3 files changed, 25 insertions(+), 7 deletions(-)
diff --git a/src/metabase/async/api_response.clj b/src/metabase/async/api_response.clj
index 46b5fc9b5c9..16f5730becf 100644
--- a/src/metabase/async/api_response.clj
+++ b/src/metabase/async/api_response.clj
@@ -186,12 +186,10 @@
(log/debug (u/format-color 'green (trs "starting streaming response")))
(write-chan-vals-to-writer! (async-keepalive-channel chan) (io/writer output-stream))))
+;; `defendpoint-async` responses
(extend-protocol Sendable
ManyToManyChannel
(send* [input-chan _ respond _]
- (respond (-> (response/response input-chan)
- (assoc :content-type "applicaton/json; charset=utf-8")
- ;; tell nginx not to batch streaming responses -- otherwise the keepalive bytes aren't written and
- ;; the entire purpose is defeated. See
- ;; https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_cache
- (assoc-in [:headers "X-Accel-Buffering"] "no")))))
+ (respond
+ (assoc (response/response input-chan)
+ :content-type "applicaton/json; charset=utf-8"))))
diff --git a/src/metabase/handler.clj b/src/metabase/handler.clj
index d82c3ded88d..bf0614c6717 100644
--- a/src/metabase/handler.clj
+++ b/src/metabase/handler.clj
@@ -40,5 +40,6 @@
mw.misc/bind-user-locale ; Binds *locale* for i18n
wrap-cookies ; Parses cookies in the request map and assocs as :cookies
mw.misc/add-content-type ; Adds a Content-Type header for any response that doesn't already have one
+ mw.misc/disable-streaming-buffering ; Add header to streaming (async) responses so ngnix doesn't buffer keepalive bytes
mw.misc/wrap-gzip)) ; GZIP response if client can handle it
;; ▲▲▲ PRE-PROCESSING ▲▲▲ happens from BOTTOM-TO-TOP
diff --git a/src/metabase/middleware/misc.clj b/src/metabase/middleware/misc.clj
index bee301fd081..7f8d8d862c4 100644
--- a/src/metabase/middleware/misc.clj
+++ b/src/metabase/middleware/misc.clj
@@ -8,7 +8,8 @@
[metabase.util.i18n :refer [trs]]
[puppetlabs.i18n.core :as puppet-i18n]
[ring.middleware.gzip :as ring.gzip])
- (:import [java.io File InputStream]))
+ (:import clojure.core.async.impl.channels.ManyToManyChannel
+ [java.io File InputStream]))
(defn- add-content-type* [request response]
(update-in
@@ -98,3 +99,21 @@
request
(comp respond (partial wrap-gzip* request))
raise)))
+
+
+;;; ------------------------------------------ Disable Streaming Buffering -------------------------------------------
+
+(defn- maybe-add-disable-buffering-header [{:keys [body], :as response}]
+ (cond-> response
+ (instance? ManyToManyChannel body)
+ (assoc-in [:headers "X-Accel-Buffering"] "no")))
+
+(defn disable-streaming-buffering
+ "Tell nginx not to batch streaming responses -- otherwise the keepalive bytes aren't written and
+ the entire purpose is defeated. See https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_cache"
+ [handler]
+ (fn [request respond raise]
+ (handler
+ request
+ (comp respond maybe-add-disable-buffering-header)
+ raise)))
--
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