June 2021 status?

[simonhf]

Is go-trace still a thing even though we're up to 1.16 now? If this package is no longer maintained, is it already out-of-date? If so, is there an alternative package somewhere which has similar-ish functionality?

[cstockton]

I just checked and it looks like I started a version4 fix:

git status .
On branch master
Your branch is up to date with 'origin/master'.

Changes not staged for commit:
  (use "git add/rm <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
	deleted:    cmd/tracecat/main.go
	deleted:    cmd/tracegrep/main.go
	modified:   doc.go
	modified:   encoding/decoder.go
	modified:   encoding/decoder_test.go
	modified:   encoding/encoder.go
	modified:   encoding/encoder_test.go
	modified:   encoding/encoding.go
	modified:   encoding/encoding_test.go
	deleted:    encoding/event.go
	modified:   encoding/example_test.go
	deleted:    encoding/state.go
	deleted:    encoding/state_test.go


Untracked files:
  (use "git add <file>..." to include in what will be committed)
	correlate/
	encoding/benchmark_test.go
	event/
	example_test.go
	internal/
	trace.go
	trace_test.go
	tracegentest.go

no changes added to commit (use "git add" and/or "git commit -a")

This was feb 2018, so I don't know how many trace versions have been released since then. It looks like this is the last trace version I supported:

 // encodeHeader will encode a valid trace version object into a well formed
 // trace header.
-func encodeHeader(w io.Writer, v Version) (err error) {
+func encodeHeader(w io.Writer, v event.Version) (err error) {
        var n int
        switch v {
-       case Version1:
+       case event.Version1:
                n, err = w.Write([]byte("go 1.5 trace\x00\x00\x00\x00"))
-       case Version2:
+       case event.Version2:
                n, err = w.Write([]byte("go 1.7 trace\x00\x00\x00\x00"))
-       case Version3:
+       case event.Version3:
                n, err = w.Write([]byte("go 1.8 trace\x00\x00\x00\x00"))
+       case event.Version4:
+               n, err = w.Write([]byte("go 1.9 trace\x00\x00\x00\x00"))
+       default:
+               err = errors.New(`trace header version was invalid`)
        }
        if err == nil && n != 16 {
                err = io.ErrShortWrite

Looks like this "Version4" (go ver 1.9) had the same frame size and arg offset as the previous version, with only two new events:

	schema{"EvGCMarkAssistStart", Version4, []string{ArgTimestamp, ArgStackID}},
	schema{"EvGCMarkAssistDone", Version4, []string{ArgTimestamp}},

Checking out the current runtime, there are only a few more:

	traceEvUserTaskCreate    = 45 // trace.NewContext [timestamp, internal task id, internal parent task id, stack, name string]
	traceEvUserTaskEnd       = 46 // end of a task [timestamp, internal task id, stack]
	traceEvUserRegion        = 47 // trace.WithRegion [timestamp, internal task id, mode(0:start, 1:end), stack, name string]
	traceEvUserLog           = 48 // trace.Log [timestamp, internal task id, key string id, stack, value string]

I'm not familiar with the trace.NewContext API, but these could potentially be fairly straight forward to add on. I imagine I started this work one weekend but couldn't finish and got busy at my day job, I could commit it for you but it is definitely incomplete. It appears I mixed it up with some refactoring as well >_< as it comes in at around 7K loc.

Let me know if you want to take a stab at it, I'll add ya to repo.