LOGBACK：如何使用 JSONLayout 记录整个 msg

Question

We are changing our logs from Text to JSON. I used below code to implement JSON logs :

    LayoutWrappingEncoder layoutEncoder = new LayoutWrappingEncoder();
    ch.qos.logback.contrib.json.classic.JsonLayout layout= new ch.qos.logback.contrib.json.classic.JsonLayout();

    ch.qos.logback.contrib.jackson.JacksonJsonFormatter jsonFormatter=new ch.qos.logback.contrib.jackson.JacksonJsonFormatter();
    jsonFormatter.setPrettyPrint(true);

    layout.setJsonFormatter(jsonFormatter);
    layout.setTimestampFormat("yyyy-MM-dd' 'HH:mm:ss.SSS");
    layoutEncoder.setLayout(layout);

But I see that JSON logs are not printed entirely.

{
    "timestamp" : "2019-08-22 10:12:15.790", 
    "level" : "ERROR",
    "thread" : "qtp1346354118-22",  
    "logger" :"com.SomeClass",
    "message" : "Exception  from : com.class.method() \n",
    "context" : "default",
    "exception" : "java.lang.NullPointerException: null\r\n"
}

Now, the exception are not printed with complete stack trace, like how they use to get logs in text logs. Also I could see new line escape sequence getting printed which also does not happen in text logs.

I tried exploring some properties in JSONLayout but none of them solved my problem.

So what else can I try here.

Answer 1

Define a CustomThrowableProxyConverter as follows and set it into your JsonLayout. It does the trick.

CustomThrowableProxyConverter extends ThrowableHandlingConverter {

    public CustomThrowableProxyConverter() {
    }

    @Override
    public String convert(ILoggingEvent event) {
        StringBuilder sb = new StringBuilder();
        IThrowableProxy itp = event.getThrowableProxy();
        if (itp instanceof ThrowableProxy) {
            ThrowableProxy tp = (ThrowableProxy)itp;
            sb.append(tp.getClassName() + ": " + tp.getMessage());
            for (StackTraceElementProxy element : tp.getStackTraceElementProxyArray()) {
                sb.append("\t\n");
                sb.append(element.getSTEAsString());
            }
            return sb.toString();
        }

        return "";
    }
}

Then set this into jsonLayout instance.

JsonLayout jsonLayout = new JsonLayout();
jsonLayout.setThrowableProxyConverter(new CustomThrowableProxyConverter());
jsonEncoder.setLayout(jsonLayout);