Prometheus+Micrometer集成SpringBoot遇到的空指针问题及解决方案

工匠人生 2019-07-17

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一期一会，一个执着于技术的公众号

历史Prometheus文章：

【译文】Thanos 灭霸- a Scalable Prometheus with Unlimited Storage

Prometheus 的九个坑【评注版】

全面学习Prometheus

Prometheus 入门与实践

性能工具之JMeter+InfluxDB+Grafana打造压测可视化实时监控

Prometheus实战：关于Redis序列化及压缩对性能的影响

问题：java.lang.NullPointerException org.apache.catalina.authenticator.AuthenticatorBase.getJaspicProvider(AuthenticatorBase.java:1192)

猪猪今天基于SpringBoot 1.5.X集成Prometheus的过程中，没有任何问题，示例代码托管在GitHub

https://github.com/CharlesMaster/prometheus-springboot1.5.x-demo

核心依赖如下：

<!--springboot单元测试工具-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>


        <!--监控系统健康情况的工具-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <!--web模块-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--低版本1.5.x版本springboot兼容micrometer-->
        <dependency>
            <groupId>io.micrometer</groupId>
            <artifactId>micrometer-spring-legacy</artifactId>
            <version>1.2.0</version>
        </dependency>

        <!--micrometer核心包，桥接Prometheus-->
        <dependency>
            <groupId>io.micrometer</groupId>
            <artifactId>micrometer-registry-prometheus</artifactId>
            <version>1.2.0</version>
        </dependency>

        <!--micrometer获取jvm相关信息，用于展示在Grafana上-->
        <dependency>
            <groupId>io.github.mweirauch</groupId>
            <artifactId>micrometer-jvm-extras</artifactId>
            <version>0.1.4</version>
        </dependency>

这里可以特别强调一下，最新版本的Micrometer已经不需要手动设置MeterRegistryCustomizer的Bean，只需要application.properties配置即可。

但是我在集成复杂的支付系统的过程中，我们是k8s集群，第一次部署测试环境报了如下错误：

<!DOCTYPE html><html><head><title>Apache Tomcat/8.5.11 - Error report</title><style type="text/css">h1 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:22px;} h2 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:16px;} h3 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:14px;} body {font-family:Tahoma,Arial,sans-serif;color:black;background-color:white;} b {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;} p {font-family:Tahoma,Arial,sans-serif;background:white;color:black;font-size:12px;} a {color:black;} a.name {color:black;} .line {height:1px;background-color:#525D76;border:none;}</style> </head><body><h1>HTTP Status 500 - </h1><div class="line"></div><p><b>type</b> Exception report</p><p><b>message</b> <u></u></p><p><b>description</b> <u>The server encountered an internal error that prevented it from fulfilling this request.</u></p><p><b>exception</b></p><pre>java.lang.NullPointerException
        org.apache.catalina.authenticator.AuthenticatorBase.getJaspicProvider(AuthenticatorBase.java:1192)
        org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:465)
        org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.InstMethodsInter.intercept(InstMethodsInter.java:93)
        org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
        org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
        org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783)
        org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
        org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798)
        org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434)
        org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
        java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        java.lang.Thread.run(Thread.java:748)
</pre><p><b>note</b> <u>The full stack trace of the root cause is available in the Apache Tomcat/8.5.11 logs.</u></p><hr class="line"><h3>Apache Tomcat/8.5.11</h3></body></html>

为了摆脱skywalking的影响，我在不启动skywalking的情况下重启了支付应用，报了不一样的错误：

<!DOCTYPE html><html><head><title>Apache Tomcat/8.5.11 - Error report</title><style type="text/css">h1 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:22px;} h2 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:16px;} h3 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:14px;} body {font-family:Tahoma,Arial,sans-serif;color:black;background-color:white;} b {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;} p {font-family:Tahoma,Arial,sans-serif;background:white;color:black;font-size:12px;} a {color:black;} a.name {color:black;} .line {height:1px;background-color:#525D76;border:none;}</style> </head><body><h1>HTTP Status 500 - </h1><div class="line"></div><p><b>type</b> Exception report</p><p><b>message</b> <u></u></p><p><b>description</b> <u>The server encountered an internal error that prevented it from fulfilling this request.</u></p><p><b>exception</b></p><pre>java.lang.NullPointerException
        org.apache.catalina.authenticator.AuthenticatorBase.getJaspicProvider(AuthenticatorBase.java:1192)
        org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:465)
        org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
        org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
        org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783)
        org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
        org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798)
        org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434)
        org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
        java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        java.lang.Thread.run(Thread.java:748)
</pre><p><b>note</b> <u>The full stack trace of the root cause is available in the Apache Tomcat/8.5.11 logs.</u></p><hr class="line"><h3>Apache Tomcat/8.5.11</h3></body></html>

但是这两个错误一致的原因都是

org.apache.catalina.authenticator.AuthenticatorBase.getJaspicProvider(AuthenticatorBase.java:1192)

是不是一脸懵逼？

解决方法很简单，将支付应用里的javaee-api依赖删除即可

然后就搞定啦。

这个问题可以参看https://stackoverflow.com/questions/38802437/upgrading-spring-boot-from-1-3-7-to-1-4-0-causing-nullpointerexception-in-authen

解决方法是三个：

方法一

Set authConfigFactory to default AuthConfigFactory implementation used by Tomcat 8.5 (example basic implementation):

package com.example;

import org.apache.catalina.authenticator.jaspic.AuthConfigFactoryImpl;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import javax.security.auth.message.config.AuthConfigFactory;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        if (AuthConfigFactory.getFactory() == null) {
            AuthConfigFactory.setFactory(new AuthConfigFactoryImpl());
        }
        SpringApplication.run(DemoApplication.class, args);
    }
}

方法二

Remove duplicated AuthConfigFactory class from your classpath. In my case there were two different implementations of the same class:

org.apache.tomcat.embed/tomcat-embed-core/8.5.4/tomcat-embed-core-8.5.4.jar!/javax/security/auth/message/config/AuthConfigFactory.class
javax/javaee-api/7.0/javaee-api-7.0.jar!/javax/security/auth/message/config/AuthConfigFactory.class

javaee-api-7.0.jar has it's own AuthConfigFactory implementation which is not fully compatible with Tomcat 8.5 and causes that NullPointerException (in Tomcat's version there is constant which defines default jaspic implementation class) Remove javaee-api dependency (or any other which contains different AuthConfigFactory implementation) from your gradle/mvn project (if you can)

方法三

Downgrade Tomcat to 8.0 or 7.0:

http://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#howto-use-tomcat-

Explanation:

The problem is related with Tomcat upgrade (from 8.0.x to 8.5.x) which has been made during Spring Boot upgrade from 1.3.x to 1.4. The problem is that Tomcat 8.5 introduces jaspic support (https://tomcat.apache.org/tomcat-8.5-doc/config/jaspic.html) and provides it's own implementation of AuthConfigFactory. This implementation defines default jaspic auth factory implementation:

private static final String DEFAULT_JASPI_AUTHCONFIGFACTORYIMPL =
            "org.apache.catalina.authenticator.jaspic.AuthConfigFactoryImpl";

which is not defined in other implementations (e.g. that one from javaee-api-7.0) and causes NullPointerException because no AuthConfigFactory were instantiated.