当前位置：首页 > news >正文

自定义Grafana错误率面板No Data问题排查

news 2025/9/18 9:57:38

一、现象

最近基于Grafana新建了一个Http请求错误率展示面板，具体的PromQL语句如下：

sum(rate(http_server_request_duration_seconds_count{exported_job="${job}", http_route="${http_route}", 
http_request_method="${http_method}", http_response_status_code=~"4..|5.."}[$__rate_interval])) 
by (exported_job, http_route, http_request_method)
/
sum(rate(http_server_request_duration_seconds_count{exported_job="${job}", http_route="${http_route}", 
http_request_method="${http_method}"}[$__rate_interval])) 
by (exported_job, http_route, http_request_method)

即按照exported_job, http_route, http_request_method维度统计http status code为4xx、5xx请求所占的百分比。

以如下3个指标为例：

http_server_request_duration_seconds_count (exported_job="app-aggr", http_route=“/api/v1/sample/list”,
http_request_method=“GET”, http_response_status_code="200" )
http_server_request_duration_seconds_count (exported_job="app-aggr", http_route=“/api/v1/sample/list”,
http_request_method=“GET”, http_response_status_code="400")
http_server_request_duration_seconds_count (exported_job="app-atom", http_route=“/api/v1/sample/{id}|”,
http_request_method=“GET”, http_response_status_code="200")

在统计app-aggr应用的/api/v1/sample/listHttp请求错误率时，可以正确显示错误率百分比：
在这里插入图片描述

在统计app-atom应用的/api/v1/sample/{id}Http请求错误率时，却提示No Data：在这里插入图片描述

二、问题分析

实际通过promethues查询指标：

http_server_request_duration_seconds_count (
exported_job="app-atom",
http_route="/api/v1/sample/{id}|",
http_request_method="GET"
)

在这里插入图片描述

可以发现app-atom应用的/api/v1/sample/{id}请求没有http_response_status_code为4xx或5xx的指标记录，仅有http_response_status_code为200的指标记录。Prometheus 查询分子没有数据时，Grafana 面板会显示 No data 而不是显示为 0，而我的需求是在分子没有数据时要让面板显示为 0。

三、解决方案

最终调整为如下PromQL语句：

(sum(rate(http_server_request_duration_seconds_count{exported_job="${job}", http_route="${http_route}", http_request_method="${http_method}", http_response_status_code=~"4..|5.."}[$__rate_interval])) by (exported_job, http_route, http_request_method)or	sum(rate(http_server_request_duration_seconds_count{exported_job="${job}", http_route="${http_route}", http_request_method="${http_method}"}[$__rate_interval])) by (exported_job, http_route, http_request_method) * 0
)
/
sum(rate(http_server_request_duration_seconds_count{exported_job="${job}", http_route="${http_route}", 
http_request_method="${http_method}"}[$__rate_interval])) 
by (exported_job, http_route, http_request_method)