trace: Record snapshot trace of main modules when using xgo e

[xhd2015]

Need to add an extra flag to enable this mode

[xhd2015]

We would like to make xgo test --strace ./some_pkg mock and collect trace only of main module, and collect trace in snapshot mode.

We currently have 5 options related to trap, mock and trace:

• --trap-stdlib=true|false
• --mock-rule '{"action": "include" | "exclude"}'
• --options-from-file OPTION_FILE.json(which contains {"filter_rules": [{...}]}
• --strace=true|false
• --strace-dir=dir

To make these default behavior happen, we'd like to add two flags:

• --strace-main-module-only=true|false only main module trace collected, default is true if --strace is on
• --strace-snapshot-main-module=true main module trace collected with snapshot

But I'd more likely to only implement the snapshot tracing of main module first. Reducing trace of non-main module does not gain extra benefit currently.

[xhd2015]

Setup:

mkdir tmp
cd tmp
go mod init github.com/xhd2015/xgo/tmp
go get github.com/xhd2015/xgo/runtime/trace
# in.mod:
#  replace github.com/xhd2015/xgo/runtime => ../runtime

snapshot.go

package snapshot

type User struct {
	Count int
}

func updateUser(user *User) *User {
	user.Count++
	return user
}

snapshot_test.go

package snapshot

import (
	"testing"
	_ "github.com/xhd2015/xgo/runtime/trace"
)

// go run ./cmd/xgo test --project-dir ./tmp --strace ./snapshot_main
func TestSnapshot(t *testing.T) {
	user := &User{}

	updateUser(user)
	updateUser(user)
	updateUser(user)
}

Test:

# in xgo's root
go run ./cmd/xgo test --project-dir ./tmp --log-debug --strace -v --reset-instrument ./

go run ./cmd/xgo tool trace tmp/TestSnapshot.json

Result: