apache · spacewander · Nov 27, 2020 · Nov 22, 2020 · Nov 22, 2020 · Nov 22, 2020
diff --git a/apisix/init.lua b/apisix/init.lua
@@ -36,6 +36,7 @@ local type          = type
 local ngx_now       = ngx.now
 local str_byte      = string.byte
 local str_sub       = string.sub
+local tonumber      = tonumber
 local load_balancer
 local local_conf
 local dns_resolver
@@ -626,9 +627,28 @@ local function common_phase(phase_name)
 end
 
 
+local function set_resp_upstream_status(up_status)
+    core.response.set_header("X-APISIX-Upstream-Status", up_status)
+    core.log.info("X-APISIX-Upstream-Status: ", up_status)
+end
+
+
 function _M.http_header_filter_phase()
     core.response.set_header("Server", ver_header)
 
+    local up_status = get_var("upstream_status")
+    if up_status and #up_status == 3
+       and tonumber(up_status) >= 500
+       and tonumber(up_status) <= 599
+    then
+        set_resp_upstream_status(up_status)
+    elseif up_status and #up_status > 3 then
+        local last_status = str_sub(up_status, -3)
+        if tonumber(last_status) >= 500 and tonumber(last_status) <= 599 then
+            set_resp_upstream_status(up_status)
+        end
+    end
+
     common_phase("header_filter")
 end
 

diff --git a/doc/README.md b/doc/README.md
@@ -35,6 +35,7 @@
 * [Changelog](../CHANGELOG.md)
 * [Benchmark](benchmark.md)
 * [Code Style](../CODE_STYLE.md)
+* [Debug Function](./debug-function.md)
 * [FAQ](../FAQ.md)
 
 ## Plugins

diff --git a/doc/debug-function.md b/doc/debug-function.md
@@ -0,0 +1,151 @@
+<!--
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+-->
+
+[Chinese](zh-cn/debug-function.md)
+
+## `5xx` response status code
+
+Similar `5xx` status codes such as 500, 502, 503, etc., are the status codes in response to a server error. When a request has a `5xx` status code; it may come from `APISIX` or `Upstream`. How to identify the source of these response status codes is a very meaningful thing. It can quickly help us determine the problem.
+
+## How to identify the source of the `5xx` response status code
+
+In the response header of the request, through the response header of `X-APISIX-Upstream-Status`, we can effectively identify the source of the `5xx` status code. When the `5xx` status code comes from `Upstream`, the response header `X-APISIX-Upstream-Status` can be seen in the response header, and the value of this response header is the response status code. When the `5xx` status code is derived from `APISIX`, there is no response header information of `X-APISIX-Upstream-Status` in the response header. That is, only when the status code of `5xx` is derived from Upstream will the `X-APISIX-Upstream-Status` response header appear.
+
+## Example
+
+>Example 1: `502` response status code comes from `Upstream` (IP address is not available)
+
+```shell
+$ curl http://127.0.0.1:9080/apisix/admin/routes/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
+{
+    "methods": ["GET"],
+    "upstream": {
+        "nodes": {
+            "127.0.0.1:1": 1
+        },
+        "type": "roundrobin"
+    },
+    "uri": "/hello"
+}'
+```
+
+Test:
+
+```shell
+$ curl http://127.0.0.1:9080/hello -v
+......
+< HTTP/1.1 502 Bad Gateway
+< Date: Wed, 25 Nov 2020 14:40:22 GMT
+< Content-Type: text/html; charset=utf-8
+< Content-Length: 154
+< Connection: keep-alive
+< Server: APISIX/2.0
+< X-APISIX-Upstream-Status: 502
+<
+<html>
+<head><title>502 Bad Gateway</title></head>
+<body>
+<center><h1>502 Bad Gateway</h1></center>
+<hr><center>openresty</center>
+</body>
+</html>
+
+```
+
+It has a response header of `X-APISIX-Upstream-Status: 502`.
+
+>Example 2: `502` response status code comes from `APISIX`
+
+```shell
+$ curl http://127.0.0.1:9080/apisix/admin/routes/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
+{
+    "plugins": {
+        "fault-injection": {
+            "abort": {
+                "http_status": 500,
+                "body": "Fault Injection!\n"
+            }
+        }
+    },
+    "uri": "/hello"
+}'
+```
+
+Test：
+
+```shell
+$ curl http://127.0.0.1:9080/hello -v
+......
+< HTTP/1.1 500 Internal Server Error
+< Date: Wed, 25 Nov 2020 14:50:20 GMT
+< Content-Type: text/plain; charset=utf-8
+< Transfer-Encoding: chunked
+< Connection: keep-alive
+< Server: APISIX/2.0
+<
+Fault Injection!
+```
+
+There is no response header for `X-APISIX-Upstream-Status`.
+
+>Example 3: `Upstream` has multiple nodes, and all nodes are unavailable
+
+```shell
+$ curl http://127.0.0.1:9080/apisix/admin/upstreams/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
+{
+    "nodes": {
+        "127.0.0.3:1": 1,
+        "127.0.0.2:1": 1,
+        "127.0.0.1:1": 1
+    },
+    "retries": 2,
+    "type": "roundrobin"
+}'
+```
+
+```shell
+$ curl http://127.0.0.1:9080/apisix/admin/routes/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
+{
+    "uri": "/hello",
+    "upstream_id": "1"
+}'
+```
+
+Test：
+
+```shell
+$ curl http://127.0.0.1:9080/hello -v
+< HTTP/1.1 502 Bad Gateway
+< Date: Wed, 25 Nov 2020 15:07:34 GMT
+< Content-Type: text/html; charset=utf-8
+< Content-Length: 154
+< Connection: keep-alive
+< Server: APISIX/2.0
+< X-APISIX-Upstream-Status: 502, 502, 502
+<
+<html>
+<head><title>502 Bad Gateway</title></head>
+<body>
+<center><h1>502 Bad Gateway</h1></center>
+<hr><center>openresty</center>
+</body>
+</html>
+```
+
+It has a response header of `X-APISIX-Upstream-Status: 502, 502, 502`.
diff --git a/doc/zh-cn/README.md b/doc/zh-cn/README.md
@@ -34,6 +34,7 @@
 * [变更日志](../../CHANGELOG_CN.md)
 * [压力测试](benchmark.md)
 * [代码风格](../../CODE_STYLE_CN.md)
+* [调试功能](./debug-function.md)
 * [常见问答](../../FAQ_CN.md)
 
 ## 插件

diff --git a/doc/zh-cn/debug-function.md b/doc/zh-cn/debug-function.md
@@ -0,0 +1,151 @@
+<!--
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+-->
+
+[English](../debug-function.md)
+
+## `5xx` 响应状态码
+
+500、502、503等类似的 `5xx` 状态码，是由于服务器错误而响应的状态码，当一个请求出现 `5xx` 状态码时；它可能来源于 `APISIX` 或 `Upstream` 。如何识别这些响应状态码的来源，是一件很有意义的事，它能够快速的帮助我们确定问题的所在。
+
+## 如何识别 `5xx` 响应状态码的来源
+
+在请求的响应头中，通过 `X-APISIX-Upstream-Status` 这个响应头，我们可以有效的识别 `5xx` 状态码的来源。当 `5xx` 状态码来源于 `Upstream` 时，在响应头中可以看到 `X-APISIX-Upstream-Status` 这个响应头，并且这个响应头的值为响应的状态码。当 `5xx` 状态码来源于 `APISIX` 时，响应头中没有 `X-APISIX-Upstream-Status` 的响应头信息。也就是只有 `5xx` 状态码来源于 `Upstream` 时，才会有 `X-APISIX-Upstream-Status` 响应头。
+
+## 示例
+
+示例1：`502` 响应状态码来源于 `Upstream` (IP地址不可用)
+
+```shell
+$ curl http://127.0.0.1:9080/apisix/admin/routes/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
+{
+    "methods": ["GET"],
+    "upstream": {
+        "nodes": {
+            "127.0.0.1:1": 1
+        },
+        "type": "roundrobin"
+    },
+    "uri": "/hello"
+}'
+```
+
+测试：
+
+```shell
+$ curl http://127.0.0.1:9080/hello -v
+......
+< HTTP/1.1 502 Bad Gateway
+< Date: Wed, 25 Nov 2020 14:40:22 GMT
+< Content-Type: text/html; charset=utf-8
+< Content-Length: 154
+< Connection: keep-alive
+< Server: APISIX/2.0
+< X-APISIX-Upstream-Status: 502
+<
+<html>
+<head><title>502 Bad Gateway</title></head>
+<body>
+<center><h1>502 Bad Gateway</h1></center>
+<hr><center>openresty</center>
+</body>
+</html>
+
+```
+
+具有 `X-APISIX-Upstream-Status: 502` 的响应头。
+
+示例2: `502` 响应状态码来源于 `APISIX`
+
+```shell
+$ curl http://127.0.0.1:9080/apisix/admin/routes/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
+{
+    "plugins": {
+        "fault-injection": {
+            "abort": {
+                "http_status": 500,
+                "body": "Fault Injection!\n"
+            }
+        }
+    },
+    "uri": "/hello"
+}'
+```
+
+测试：
+
+```shell
+$ curl http://127.0.0.1:9080/hello -v
+......
+< HTTP/1.1 500 Internal Server Error
+< Date: Wed, 25 Nov 2020 14:50:20 GMT
+< Content-Type: text/plain; charset=utf-8
+< Transfer-Encoding: chunked
+< Connection: keep-alive
+< Server: APISIX/2.0
+<
+Fault Injection!
+```
+
+没有 `X-APISIX-Upstream-Status` 的响应头。
+
+示例3：`Upstream` 具有多节点，并且所有节点不可用
+
+```shell
+$ curl http://127.0.0.1:9080/apisix/admin/upstreams/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
+{
+    "nodes": {
+        "127.0.0.3:1": 1,
+        "127.0.0.2:1": 1,
+        "127.0.0.1:1": 1
+    },
+    "retries": 2,
+    "type": "roundrobin"
+}'
+```
+
+```shell
+$ curl http://127.0.0.1:9080/apisix/admin/routes/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
+{
+    "uri": "/hello",
+    "upstream_id": "1"
+}'
+```
+
+测试：
+
+```shell
+$ curl http://127.0.0.1:9080/hello -v
+< HTTP/1.1 502 Bad Gateway
+< Date: Wed, 25 Nov 2020 15:07:34 GMT
+< Content-Type: text/html; charset=utf-8
+< Content-Length: 154
+< Connection: keep-alive
+< Server: APISIX/2.0
+< X-APISIX-Upstream-Status: 502, 502, 502
+<
+<html>
+<head><title>502 Bad Gateway</title></head>
+<body>
+<center><h1>502 Bad Gateway</h1></center>
+<hr><center>openresty</center>
+</body>
+</html>
+```
+
+具有 `X-APISIX-Upstream-Status: 502, 502, 502` 的响应头。
diff --git a/t/lib/server.lua b/t/lib/server.lua
@@ -365,4 +365,9 @@ function _M.log()
 end
 
 
+function _M.server_error()
+    error("500 Internal Server Error")
+end
+
+
 return _M