Weird stacktrace for some java applications

[redsigma]

Some java logs have a exception field which looks like this when i tried to add it to the always_print_fields

exception > exceptionType: java.lang.NullPointerException
exception > frames[0] > class: org.services.resources.Resource
exception > frames[0] > line: 181
exception > frames[0] > method: addTopLevelGroup
exception > frames[1] > class: org.services.resources.admin.GroupsResource$invoker$addTopLevelGroup_b1454f0b6d09a55fc9fa006f5850e4f8ea300cbb
exception > frames[1] > method: invoke
exception > frames[2] > class: org.jboss.resteasy.reactive.server.handlers.InvocationHandler
exception > frames[2] > line: 29
exception > frames[2] > method: handle
exception > frames[3] > class: io.resteasy.reactive.server.runtime.ReactiveRequestContext
exception > frames[3] > line: 141
exception > frames[3] > method: invokeHandler
exception > frames[4] > class: org.jboss.resteasy.reactive.common.core.AbstractResteasyReactiveContext
exception > frames[4] > line: 147
exception > frames[4] > method: run
exception > frames[5] > class: io.vertx.core.runtime.VertxCoreRecorder$14
exception > frames[5] > line: 635
exception > frames[5] > method: runWith
exception > frames[6] > class: org.jboss.threads.EnhancedQueueExecutor$Task
exception > frames[6] > line: 2516
exception > frames[6] > method: doRunWith
exception > frames[7] > class: org.jboss.threads.EnhancedQueueExecutor$Task
exception > frames[7] > line: 2495
exception > frames[7] > method: run
exception > frames[8] > class: org.jboss.threads.EnhancedQueueExecutor$ThreadBody
exception > frames[8] > line: 1521
exception > frames[8] > method: run
exception > frames[9] > class: org.jboss.threads.DelegatingRunnable
exception > frames[9] > line: 11
exception > frames[9] > method: run
exception > frames[10] > class: org.jboss.threads.ThreadLocalResettingRunnable
exception > frames[10] > line: 11
exception > frames[10] > method: run
exception > frames[11] > class: io.netty.util.concurrent.FastThreadLocalRunnable
exception > frames[11] > line: 30
exception > frames[11] > method: run
exception > frames[12] > class: java.lang.Thread
exception > frames[12] > line: 1583
exception > frames[12] > method: run
      exception > message: Cannot invoke "org.representations.Representation.getName()" because "rep" is null
        exception > refId: 1

This is how the raw json looks like (but i did a pretty format on it)

{
    "exception": {
        "refId": 1,
        "exceptionType": "java.lang.NullPointerException",
        "message": "Cannot invoke \"org.representations.Representation.getName()\" because \"rep\" is null",
        "frames": [
            {
                "class": "org.services.resources.admin.GroupsResource",
                "method": "addTopLevelGroup",
                "line": 181
            },
            {
                "class": "org.services.resources.GroupsResource$invoker$addTopLevelGroup_b1454f0b6d09a55fc9fa006f5850e4f8ea300cbb",
                "method": "invoke"
            },
            {
                "class": "org.jboss.resteasy.reactive.server.handlers.InvocationHandler",
                "method": "handle",
                "line": 29
            },
            {
                "class": "io.resteasy.reactive.server.runtime.ReactiveRequestContext",
                "method": "invokeHandler",
                "line": 141
            },
            {
                "class": "org.jboss.resteasy.reactive.common.core.AbstractResteasyReactiveContext",
                "method": "run",
                "line": 147
            },
            {
                "class": "io.vertx.core.runtime.VertxCoreRecorder$14",
                "method": "runWith",
                "line": 635
            },
            {
                "class": "org.jboss.threads.EnhancedQueueExecutor$Task",
                "method": "doRunWith",
                "line": 2516
            },
            {
                "class": "org.jboss.threads.EnhancedQueueExecutor$Task",
                "method": "run",
                "line": 2495
            },
            {
                "class": "org.jboss.threads.EnhancedQueueExecutor$ThreadBody",
                "method": "run",
                "line": 1521
            },
            {
                "class": "org.jboss.threads.DelegatingRunnable",
                "method": "run",
                "line": 11
            },
            {
                "class": "org.jboss.threads.ThreadLocalResettingRunnable",
                "method": "run",
                "line": 11
            },
            {
                "class": "io.netty.util.concurrent.FastThreadLocalRunnable",
                "method": "run",
                "line": 30
            },
            {
                "class": "java.lang.Thread",
                "method": "run",
                "line": 1583
            }
        ]
    }
}

[bomgar]

So far I had exceptions as a single string including the stacktrace. That works fine. If you have an entire object everything is going to be treated as individual log elements by fblog

[redsigma]

Is it possible to make it so sequential properties are concatenated with a new line ? In the example above it is frames property .

It could be something configurable in the .toml file , maybe something like

sequential_fields = ["exception > frames > class "]

I was thinking an approach to make this is to check if the next class field has a exception > frames parent, then it will concatenate it with the previous class field, and it will use a newline as a separator between each concatenation. I am not sure if this is feasible to do or it's more complicated with the current architecture ?

[bomgar]

Currently I don't have anything to transform and compose fields. I was usually able to adjust the logging config because I never needed stack lines as individual fields. In the rare cases I needed to transform the input first I piped it through jq first.

I think this is something that could be added. But it is not easy to build a generic solution here.

[bomgar]

cat test2.log | jq -c '.exception = .exception.exceptionType + ": " + .exception.message + "\n" + ([.exception.frames[] | "    at " + .class + "." + .method + ":" + (.line | tostring) ] | join("\\n"))' | fblog -d

this kind of works. I know it is not perfect. But this is a complex expression and I'm not sure how I would integrate it. Maybe you could define an alias for that jq call.

[redsigma]

cat test2.log | jq -c '.exception = .exception.exceptionType + ": " + .exception.message + "\n" + ([.exception.frames[] | "    at " + .class + "." + .method + ":" + (.line | tostring) ] | join("\\n"))' | fblog -d

this kind of works. I know it is not perfect. But this is a complex expression and I'm not sure how I would integrate it. Maybe you could define an alias for that jq call.

Hm maybe an approach is to have a way in the app to run external commands per log , before showing its output. This way i could define a command runs jq based on some conditions like:

• has field .exception
• has nested subfields under .exception

[bomgar]

I don't think I want to support calling external commands. Using a pipe seems like a better solution and follows the unix philosophy.