Add Sentry-compatible output flag and handling for reverse command

[zandercodes]

Adding support for deobfuscate Sentry/Bugsink stack trace.

Example:
For Plaintext

Traceback (most recent call last):
  File ajB5WpM.go, line 1, in main
    
  File YVDM2UvBa1pK.go, line 1, in (*GcPJXBo0O).Msg
    
  File PmRYfUF7fV.go, line 1, in (*GcPJXBo0O).ia6J1v
    
  File QR8skLy.go, line 1, in (*GcPJXBo0O).jqLodorEA6
    
  File u9qkupM.go, line 1, in g6qBd3.WriteLevel
    
  File vAaFg7om.go, line 1, in (*TkPbGafI).WriteLevel
    
  File nQS6ZC5.go, line 1, in zZKJ7aezE
    
  File HY7R3HYUYbp0.go, line 1, in Sh0RufN
    
  File A8_tfqaEPrO.go, line 1, in zZKJ7aezE.func1
    
  File sAof1b2PSs.go, line 1, in NTSkDRlZS

in this

Traceback (most recent call last):
  File app/cmd/app/main.go, line 56, in main
    
  File github.com/rs/zerolog/event.go, line 110, in (*Event).Msg
    
  File github.com/rs/zerolog/event.go, line 151, in (*Event).msg
    
  File github.com/rs/zerolog/event.go, line 80, in (*Event).write
    
  File github.com/rs/zerolog/writer.go, line 98, in multiLevelWriter.WriteLevel
    
  File github.com/getsentry/sentry-go/zerolog/sentryzerolog.go, line 213, in (*Writer).WriteLevel
    
  File github.com/getsentry/sentry-go/zerolog/sentryzerolog.go, line 263, in parseLogEvent
    
  File github.com/buger/jsonparser/parser.go, line 1128, in ObjectEach
    
  File github.com/getsentry/sentry-go/zerolog/sentryzerolog.go, line 271, in parseLogEvent.func1
    
  File github.com/getsentry/sentry-go/stacktrace.go, line 29, in NewStacktrace

and for json:

{
  "exception": [
    {
      "value": "can't continue",
      "stacktrace": {
        "frames": [
          {
            "function": "main",
            "module": "main",
            "filename": "ajB5WpM.go",
            "lineno": 1,
            "in_app": true
          },
          {
            "function": "(*GcPJXBo0O).Msg",
            "module": "pNelqfz",
            "filename": "YVDM2UvBa1pK.go",
            "lineno": 1,
            "in_app": true
          },
          {
            "function": "(*GcPJXBo0O).ia6J1v",
            "module": "pNelqfz",
            "filename": "PmRYfUF7fV.go",
            "lineno": 1,
            "in_app": true
          },
          {
            "function": "(*GcPJXBo0O).jqLodorEA6",
            "module": "pNelqfz",
            "filename": "QR8skLy.go",
            "lineno": 1,
            "in_app": true
          },
          {
            "function": "g6qBd3.WriteLevel",
            "module": "pNelqfz",
            "filename": "u9qkupM.go",
            "lineno": 1,
            "in_app": true
          },
          {
            "function": "(*TkPbGafI).WriteLevel",
            "module": "AHvhwz",
            "filename": "vAaFg7om.go",
            "lineno": 1,
            "in_app": true
          },
          {
            "function": "zZKJ7aezE",
            "module": "AHvhwz",
            "filename": "nQS6ZC5.go",
            "lineno": 1,
            "in_app": true
          },
          {
            "function": "Sh0RufN",
            "module": "xojCOs6D",
            "filename": "HY7R3HYUYbp0.go",
            "lineno": 1,
            "in_app": true
          },
          {
            "function": "zZKJ7aezE.func1",
            "module": "AHvhwz",
            "filename": "A8_tfqaEPrO.go",
            "lineno": 1,
            "in_app": true
          },
          {
            "function": "NTSkDRlZS",
            "module": "NkEMIOCQ",
            "filename": "sAof1b2PSs.go",
            "lineno": 1,
            "in_app": true
          }
        ]
      }
    }
  ]
}

in this

{
  "exception": [
    {
      "value": "can't continue",
      "stacktrace": {
        "frames": [
          {
            "function": "main",
            "module": "main",
            "filename": "app/cmd/app/main.go",
            "lineno": 56,
            "in_app": true
          },
          {
            "function": "(*Event).Msg",
            "module": "github.com/rs/zerolog",
            "filename": "github.com/rs/zerolog/event.go",
            "lineno": 110,
            "in_app": true
          },
          {
            "function": "(*Event).msg",
            "module": "github.com/rs/zerolog",
            "filename": "github.com/rs/zerolog/event.go",
            "lineno": 151,
            "in_app": true
          },
          {
            "function": "(*Event).write",
            "module": "github.com/rs/zerolog",
            "filename": "github.com/rs/zerolog/event.go",
            "lineno": 80,
            "in_app": true
          },
          {
            "function": "multiLevelWriter.WriteLevel",
            "module": "github.com/rs/zerolog",
            "filename": "github.com/rs/zerolog/writer.go",
            "lineno": 98,
            "in_app": true
          },
          {
            "function": "(*Writer).WriteLevel",
            "module": "github.com/getsentry/sentry-go/zerolog",
            "filename": "github.com/getsentry/sentry-go/zerolog/sentryzerolog.go",
            "lineno": 213,
            "in_app": true
          },
          {
            "function": "parseLogEvent",
            "module": "github.com/getsentry/sentry-go/zerolog",
            "filename": "github.com/getsentry/sentry-go/zerolog/sentryzerolog.go",
            "lineno": 263,
            "in_app": true
          },
          {
            "function": "ObjectEach",
            "module": "github.com/buger/jsonparser",
            "filename": "github.com/buger/jsonparser/parser.go",
            "lineno": 1128,
            "in_app": true
          },
          {
            "function": "parseLogEvent.func1",
            "module": "github.com/getsentry/sentry-go/zerolog",
            "filename": "github.com/getsentry/sentry-go/zerolog/sentryzerolog.go",
            "lineno": 271,
            "in_app": true
          },
          {
            "function": "NewStacktrace",
            "module": "github.com/getsentry/sentry-go",
            "filename": "github.com/getsentry/sentry-go/stacktrace.go",
            "lineno": 29,
            "in_app": true
          }
        ]
      }
    }
  ]
}

[luantak]

I think if we want to support this reverse should detect automatically whether its a sentry stack trace.

Also this needs to be added to the reverse.txtar test.

@mvdan what's your opinion on this?

[zandercodes]

I think if we want to support this reverse should detect automatically whether its a sentry stack trace.

Also this needs to be added to the reverse.txtar test.

@mvdan what's your opinion on this?

Yes, it would make sense to recognize this automatically, but this would require almost the entire reverse function to be rewritten.
And I have no idea how to add a test in txtar.
have never done anything with txtar.

[luantak]

Testscript is relatively straightforward it's basically just some commands at the top and then multiple files delimited by --- filename ---, details here
:
https://pkg.go.dev/github.com/rogpeppe/go-internal/testscript

Also have a look at https://github.com/burrowers/garble/blob/master/CONTRIBUTING.md

Basically you need to add a new block like this:

stdin main.stderr
exec garble reverse .
cmp stdout reverse.stdout

Where the stdin is a file you want to reverse and stout a new one with the output you expect.

Then just run go test -run=Script/reverse -u to update the output.

For syntax highlighting use: https://marketplace.visualstudio.com/items?itemName=twpayne.vscode-testscript

As for the entire reverse function having to be rewritten, can't you detect it somewhere at the beginning and then basically set some variable to trigger your current block.

[zandercodes]

@lu4p I created the testdata in the file "reverse-sentry.txtar"

[luantak]

Great that you figured out how to use testscript!

You'll still need to remove the -sentry flag and detect it from input instead.

I would probably use simple regex which matches the format of a sentry traceback line. https://regexr.com/ is helpful

Also the test you wrote is currently not passing and you still need to test the json input.

[zandercodes]

Great that you figured out how to use testscript!

You'll still need to remove the -sentry flag and detect it from input instead.

I would probably use simple regex which matches the format of a sentry traceback line. https://regexr.com/ is helpful

Also the test you wrote is currently not passing.

I thought if the command “go test -run=Script/reverse-sentry -u” worked and returned an OK everything would be fine.

vscode ➜ /workspaces/garble (master) $ go test -run=Script/reverse-sentry -u
PASS
ok      mvdan.cc/garble 1.969s

Ok, I have removed the Sentry flag and implement this directly in the reverse function

[luantak]

-u tells it to automatically update the output

You'll need to run it one more time without -u to verify your output is consistent.

You can look at the failing CI it shows a diff of expected and actual output

[mvdan]

Adding this seems fine, but don't hide it behind a flag. If the number of replacements growing too large is a problem, we just need a better algorithm for them, but I think what we have now should scale well enough.

[zandercodes]

Adding this seems fine, but don't hide it behind a flag. If the number of replacements growing too large is a problem, we just need a better algorithm for them, but I think what we have now should scale well enough.

If I have time in the next few days I will change the approach I implemented.
I think it would make the most sense to work with a kind of pattern which you can possibly specify as a flag, e.g. -format File %file%, line %line%, in %class% etc perhaps.
I will try something around and if I have a solution then release it for review.

[mvdan]

That's fine. If you want to go that route, I'd consider regular expressions, which already support named groups to match with, and replace: https://pkg.go.dev/regexp/syntax