防止log4j2 JsonTemplateLayout将堆栈跟踪追加到其他JSON字段

Question

我正在使用JsonTemplateLayout，并设置了一个JSON模板，该模板将堆栈跟踪信息添加到stack字段。

但是，在记录异常时，除了放置在堆栈字段中的字符串化堆栈跟踪之外，它还会附加到模板中指定的其他自定义字段中。

我不确定是哪一点配置(或缺少配置)导致了这种情况。

我无法在模板中找到可以避免这种情况的设置。

下面是我的模板：

{
  "level": {
    "$resolver": "level",
    "field": "name"
  },
  "message": {
    "$resolver": "message",
    "stringified": true
  },
  "timestamp": {
    "$resolver": "timestamp",
    "pattern": {
      "format": "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",
      "timeZone": "UTC"
    }
  },
  "logger": {
    "$resolver": "logger",
    "field": "name"
  },
  "service": {
    "$resolver": "pattern",
    "pattern": "${env:FOO_SERVICE}"
  },
  "component": {
    "$resolver": "pattern",
    "pattern": "${env:FOO_COMPONENT}"
  },
  "exception": {
    "exception_class": {
      "$resolver": "exception",
      "field": "className"
    },
    "exception_message": {
      "$resolver": "exception",
      "field": "message"
    },
    "stacktrace": {
      "$resolver": "exception",
      "field": "stackTrace",
      "stackTrace": {
        "stringified": true
      }
    }
  },
  "line_number": {
    "$resolver": "source",
    "field": "lineNumber"
  }
}

控制台附录是设置的，默认情况下包括堆栈跟踪信息。它引用了位于类路径上的上述log4j2布局。

<Appenders>
  <Console name="Console" target="SYSTEM_OUT">
    <JsonTemplateLayout eventTemplateUri="classpath:log4j2-layout.json"/>
  </Console>
</Appenders>

下面是一个记录异常的示例。如果仔细观察，您将看到一些字段(如service和component )正在设置它们指定的环境变量值，但它们也有字符串化的堆栈跟踪。

{"level":"INFO","message":"Force trigger exception","timestamp":"2022-11-02T20:37:35.270Z","logger":"foo.example.acme.system.connector.dataset.EchoAPI","service":"example1 java.lang.Exception: This is a forced exception\n\tat foo.example.acme.system.connector.dataset.EchoAPI.handle(EchoAPI.java:18) ~[classes/:?]\n\tat foo.example.acme.system.connector.ConnectorApi.handle(ConnectorApi.java:33) ~[classes/:?]\n\tat somesystem.com.connector.undertow.UndertowHandler.handleBody(UndertowHandler.java:131) ~[classes/:?]\n\tat io.undertow.io.AsyncReceiverImpl.receiveFullBytes(AsyncReceiverImpl.java:366) ~[undertow-core-2.2.19.Final.jar:2.2.19.Final]\n\tat somesystem.com.connector.undertow.UndertowHandler.handleRequest(UndertowHandler.java:61) ~[classes/:?]\n\tat io.undertow.server.Connectors.executeRootHandler(Connectors.java:387) ~[undertow-core-2.2.19.Final.jar:2.2.19.Final]\n\tat io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:852) ~[undertow-core-2.2.19.Final.jar:2.2.19.Final]\n\tat org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]\n\tat org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:2019) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]\n\tat org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1558) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]\n\tat org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1423) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]\n\tat org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1282) ~[xnio-api-3.8.7.Final.jar:3.8.7.Final]\n\tat java.lang.Thread.run(Thread.java:832) ~[?:?]\n","component":"example2 java.lang.Exception: This is a forced exception\n\tat foo.example.acme.system.connector.dataset.EchoAPI.handle(EchoAPI.java:18) ~[classes/:?]\n\tat foo.example.acme.system.connector.ConnectorApi.handle(ConnectorApi.java:33) ~[classes/:?]\n\tat somesystem.com.connector.undertow.UndertowHandler.handleBody(UndertowHandler.java:131) ~[classes/:?]\n\tat io.undertow.io.AsyncReceiverImpl.receiveFullBytes(AsyncReceiverImpl.java:366) ~[undertow-core-2.2.19.Final.jar:2.2.19.Final]\n\tat somesystem.com.connector.undertow.UndertowHandler.handleRequest(UndertowHandler.java:61) ~[classes/:?]\n\tat io.undertow.server.Connectors.executeRootHandler(Connectors.java:387) ~[undertow-core-2.2.19.Final.jar:2.2.19.Final]\n\tat io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:852) ~[undertow-core-2.2.19.Final.jar:2.2.19.Final]\n\tat org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]\n\tat org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:2019) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]\n\tat org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1558) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]\n\tat org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1423) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]\n\tat org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1282) ~[xnio-api-3.8.7.Final.jar:3.8.7.Final]\n\tat java.lang.Thread.run(Thread.java:832) ~[?:?]\n","exception":{"exception_class":"java.lang.Exception","exception_message":"This is a forced exception","stacktrace":"java.lang.Exception: This is a forced exception\n\tat foo.example.acme.system.connector.dataset.EchoAPI.handle(EchoAPI.java:18)\n\tat foo.example.acme.system.connector.ConnectorApi.handle(ConnectorApi.java:33)\n\tat somesystem.com.connector.undertow.UndertowHandler.handleBody(UndertowHandler.java:131)\n\tat io.undertow.io.AsyncReceiverImpl.receiveFullBytes(AsyncReceiverImpl.java:366)\n\tat somesystem.com.connector.undertow.UndertowHandler.handleRequest(UndertowHandler.java:61)\n\tat io.undertow.server.Connectors.executeRootHandler(Connectors.java:387)\n\tat io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:852)\n\tat org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)\n\tat org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:2019)\n\tat org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1558)\n\tat org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1423)\n\tat org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1282)\n\tat java.base/java.lang.Thread.run(Thread.java:832)\n"}}

我还尝试将stringified设置为false，并设置添加到的自定义字段，以便嵌套--例如foo.component和foo.service，但这也没有帮助。

我使用的是最新的log4j2版本-- 2.19.0 (也尝试了稍早的版本)。

Answer 1

经过相当一段时间的堆叠溢出后，我发现了这种行为的原因。

请参阅：使用json模板布局log4j2在Json日志中写入串行no时处理异常堆栈跟踪

tldr;

堆栈跟踪被附加到使用pattern解析器的所有字段。

例如：

"component": {
    "$resolver": "pattern",
    "pattern": "${env:FOO_COMPONENT}"
}

之所以会发生这种情况，是因为在为每个包含异常堆栈跟踪的日志事件从主JsonTemplateLayout委托给PatternLayout时，会继承JsonTemplateLayout(默认情况下是真/启用)。

快速解决方法是对每个使用pattern解析器的字段禁用它。

例如：

"component": {
    "$resolver": "pattern",
    "pattern": "${env:FOO_COMPONENT}",
    "stackTraceEnabled": false
}