fix(apisix/prometheus): patch to support custom default_buckets (#42)

* fix(apisix/prometheus): patch to support custom default_buckets

* feat(prometheus/enable_official): add option enable_official

Dockerfile

@@ -28,6 +28,10 @@ RUN luarocks install multipart --tree=/usr/local/apisix/deps && \
 
 ADD ./build/config-watcher ./src/build/bin/apisix-start.sh ./src/build/bin/config-watcher-start.sh /data/bkgateway/bin/
 ADD ./src/apisix/plugins/ /usr/local/apisix/apisix/plugins/
+# FIXME: remove the patch if upgrade to >=3.4.x, while the patch is only for 3.2.x ---
+ADD ./src/build/patches /usr/local/apisix/patches
+RUN ls /usr/local/apisix/patches | sort | xargs -L1 -I __patch_file__ sh -c 'cat ./patches/__patch_file__ | patch -t -p1'
+# FIXME: remove the patch if upgrade to >=3.4.x, while the patch is only for 3.2.x ---
 
 RUN chmod 755 /data/bkgateway/bin/* && chmod 777 /usr/local/apisix/logs
 

src/build/patches/001_change_prometheus_default_buckets.patch

@@ -0,0 +1,33 @@
+diff --git a/apisix/plugins/prometheus/exporter.lua b/apisix/plugins/prometheus/exporter.lua
+index 45ff94c3..5434ce56 100644
+--- a/apisix/plugins/prometheus/exporter.lua
++++ b/apisix/plugins/prometheus/exporter.lua
+@@ -168,10 +168,15 @@ function _M.http_init(prometheus_enabled_in_stream)
+             {"code", "route", "matched_uri", "matched_host", "service", "consumer", "node",
+             unpack(extra_labels("http_status"))})
+
++    local buckets = DEFAULT_BUCKETS
++    if attr and attr.default_buckets then
++        buckets = attr.default_buckets
++    end
++
+     metrics.latency = prometheus:histogram("http_latency",
+         "HTTP request latency in milliseconds per service in APISIX",
+         {"type", "route", "service", "consumer", "node", unpack(extra_labels("http_latency"))},
+-        DEFAULT_BUCKETS)
++        buckets)
+
+     metrics.bandwidth = prometheus:counter("bandwidth",
+             "Total bandwidth in bytes consumed per service in APISIX",
+@@ -208,6 +213,11 @@ end
+
+
+ function _M.http_log(conf, ctx)
++    local attr = plugin.plugin_attr("prometheus")
++    if attr and not attr.enable_official then
++        return
++    end
++
+     local vars = ctx.var
+
+     local route_id = ""