feat: How to distinguish whether the 5xx status code (eg 500) comes f…

…rom upstream or apisix.

close apache#2501

apisix/init.lua

@@ -629,6 +629,12 @@ end
 function _M.http_header_filter_phase()
     core.response.set_header("Server", ver_header)
 
+    local status_code = tonumber(get_var("upstream_status"))
+    if status_code >= 500 and status_code <=599 then
+        core.response.set_header("X-Apisix-Upstream-Status", status_code)
+        core.log.info("X-Apisix-Upstream-Status:", status_code)
+    end
+
     common_phase("header_filter")
 end
 

t/lib/server.lua

@@ -365,4 +365,8 @@ function _M.log()
 end
 
 
+function _M.server_error()
+    error("500 Internal Server Error")
+end
+
 return _M

t/node/upstream-status-5xx.t

@@ -0,0 +1,165 @@
+#
+# 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.
+#
+use t::APISIX 'no_plan';
+
+repeat_each(1);
+log_level('info');
+worker_connections(256);
+no_root_location();
+no_shuffle();
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: set route(id: 1)
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/routes/1',
+                 ngx.HTTP_PUT,
+                 [[{
+                        "methods": ["GET"],
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1980": 1
+                            },
+                            "type": "roundrobin",
+                            "timeout": {
+                                "connect": 0.5,
+                                "send": 0.5,
+                                "read": 0.5
+                            }
+                        },
+                        "uri": "/sleep1"
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+--- no_error_log
+[error]
+
+
+
+=== TEST 2: hit routes (timeout)
+--- request
+GET /sleep1
+--- error_code: 504
+--- response_body eval
+qr/504 Gateway Time-out/
+--- error_log
+X-Apisix-Upstream-Status:504 
+
+
+
+=== TEST 3: set route(id: 1), upstream service is not available
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/routes/1',
+                 ngx.HTTP_PUT,
+                 [[{
+                        "methods": ["GET"],
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1880": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uri": "/hello"
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+--- no_error_log
+[error]
+
+
+
+=== TEST 4: hit routes (502 Bad Gateway)
+--- request
+GET /hello
+--- error_code: 502
+--- response_body eval
+qr/502 Bad Gateway/
+--- error_log
+X-Apisix-Upstream-Status:502
+
+
+
+=== TEST 5: set route(id: 1)
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/routes/1',
+                 ngx.HTTP_PUT,
+                 [[{
+                        "methods": ["GET"],
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1980": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uri": "/server_error"
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+--- no_error_log
+[error]
+
+
+
+=== TEST 6: hit routes(500 Internal Server Error)
+--- request
+GET /server_error
+--- error_code: 500
+--- response_body eval
+qr/>500 Internal Server Error/
+--- error_log
+X-Apisix-Upstream-Status:500