api-breaker plugin returns default response body

apisix/plugins/api-breaker.lua

@@ -20,6 +20,8 @@ local plugin_name = "api-breaker"
 local ngx = ngx
 local math = math
 local error = error
+local ipairs = ipairs
+
 
 local shared_buffer = ngx.shared["plugin-".. plugin_name]
 if not shared_buffer then
@@ -38,9 +40,19 @@ local schema = {
         break_response_body = {
             type = "string"
         },
-        break_response_content_type = {
-            type = "string",
-            default = "application/json"
+        headers = {
+            type = "array",
+            items = {
+                type = "object",
+                properties = {
+                    key = {
+                        type = "string"
+                    },
+                    value = {
+                        type = "string"
+                    }
+                }
+            }
         },
         max_breaker_sec = {
             type = "integer",
@@ -120,7 +132,12 @@ local _M = {
 
 
 function _M.check_schema(conf)
-    return core.schema.check(schema, conf)
+    local ok, err = core.schema.check(schema, conf)
+    if not ok then
+        return false, err
+    end
+
+    return true
 end
 
 
@@ -166,9 +183,11 @@ function _M.access(conf, ctx)
     -- breaker
     if lasttime + breaker_time >= ngx.time() then
         if conf.break_response_body then
-            core.response.clear_header_as_body_modified()
-            if conf.break_response_content_type then
-                core.response.set_header("Content-Type", conf.break_response_content_type)
+            if conf.headers then
+                for _, value in ipairs(conf.headers) do
+                    local val = core.utils.resolve_var(value.value, ctx.var)
+                    core.response.add_header(value.key, val)
+                end
             end
             return conf.break_response_code, conf.break_response_body
         end

docs/en/latest/plugins/api-breaker.md

@@ -45,7 +45,7 @@ In an unhealthy state, when a request is forwarded to an upstream service and th
 | ----------------------- | ------------- | ----------- | -------- | --------------- | --------------------------------------------------------------------------- |
 | break_response_code     | integer        | required |            | [200, ..., 599] | Return error code when unhealthy |
 | break_response_body     | string         | optional |            |                 | Return response body when unhealthy |
-| break_response_content_type     | string        | optional | application/json |    | Return body's content type when unhealthy. This field is in effective only if `break_response_body` is configured. |
+| headers                 | array[object]  | optional |            |                 | New headers for the response. The values in the header can contain Nginx variables like `$remote_addr` and `$balancer_ip`. This field is in effective only if `break_response_body` is configured. |
 | max_breaker_sec         | integer        | optional | 300        | >=3             | Maximum breaker time(seconds) |
 | unhealthy.http_statuses | array[integer] | optional | {500}      | [500, ..., 599] | Status codes when unhealthy |
 | unhealthy.failures      | integer        | optional | 3          | >=1             | Number of consecutive error requests that triggered an unhealthy state |

docs/zh/latest/plugins/api-breaker.md

@@ -45,7 +45,7 @@ title: api-breaker
 | ----------------------- | -------------- | ------ | ---------- | --------------- | -------------------------------- |
 | break_response_code     | integer        | 必须   | 无         | [200, ..., 599] | 不健康返回错误码                 |
 | break_response_body     | string         | 可选   | 无         |                 | 不健康返回报文                   |
-| break_response_content_type     | string | 可选   | application/json |           | 不健康返回报文的内容类型，该字段仅在 `break_response_body` 被配置时生效 |
+| headers                 | array[object]  | 可选   | 无         |                 | 不健康返回报文头，这里可以设置多个。这个值能够以 `$var` 的格式包含 Nginx 变量，比如 `$remote_addr $balancer_ip`。该字段仅在 `break_response_body` 被配置时生效 |
 | max_breaker_sec         | integer        | 可选   | 300        | >=3             | 最大熔断持续时间                 |
 | unhealthy.http_statuses | array[integer] | 可选   | {500}      | [500, ..., 599] | 不健康时候的状态码               |
 | unhealthy.failures      | integer        | 可选   | 3          | >=1             | 触发不健康状态的连续错误请求次数 |

t/plugin/api-breaker.t

@@ -77,7 +77,7 @@ done
 --- request
 GET /t
 --- response_body
-{"break_response_code":502,"break_response_content_type":"application/json","healthy":{"http_statuses":[200],"successes":3},"max_breaker_sec":300,"unhealthy":{"failures":3,"http_statuses":[500]}}
+{"break_response_code":502,"healthy":{"http_statuses":[200],"successes":3},"max_breaker_sec":300,"unhealthy":{"failures":3,"http_statuses":[500]}}
 --- no_error_log
 [error]
 
@@ -104,7 +104,7 @@ GET /t
 --- request
 GET /t
 --- response_body
-{"break_response_code":502,"break_response_content_type":"application/json","healthy":{"http_statuses":[200],"successes":3},"max_breaker_sec":300,"unhealthy":{"failures":3,"http_statuses":[500]}}
+{"break_response_code":502,"healthy":{"http_statuses":[200],"successes":3},"max_breaker_sec":300,"unhealthy":{"failures":3,"http_statuses":[500]}}
 --- no_error_log
 [error]
 
@@ -131,7 +131,7 @@ GET /t
 --- request
 GET /t
 --- response_body
-{"break_response_code":502,"break_response_content_type":"application/json","healthy":{"http_statuses":[200],"successes":3},"max_breaker_sec":300,"unhealthy":{"failures":3,"http_statuses":[500]}}
+{"break_response_code":502,"healthy":{"http_statuses":[200],"successes":3},"max_breaker_sec":300,"unhealthy":{"failures":3,"http_statuses":[500]}}
 --- no_error_log
 [error]
 
@@ -459,7 +459,7 @@ breaker_time: 2
                         "api-breaker": {
                             "break_response_code": 502,
                             "break_response_body": "{\"message\":\"breaker opened.\"}",
-                            "break_response_content_type": "application/json+v1",
+                            "headers": [{"key":"Content-Type","value":"application/json"},{"key":"Content-Type","value":"application/json+v1"}],
                             "unhealthy": {
                                 "failures": 3
                             },