Refactor code to allow for other languages #117
Conversation
| } | ||
|
|
||
| func attachSocketFilter(filter *ebpf.Program) (int, error) { | ||
| fd, err := unix.Socket(unix.AF_PACKET, unix.SOCK_RAW, int(htons(unix.ETH_P_ALL))) |
There was a problem hiding this comment.
Wow. I cannot understand why the Go API doesn't handle this htons conversion internally.
pkg/ebpf/instrumenter.go
Outdated
| func htons(a uint16) uint16 { | ||
| var arr [2]byte | ||
| binary.LittleEndian.PutUint16(arr[:], a) | ||
| return binary.BigEndian.Uint16(arr[:]) | ||
| } |
There was a problem hiding this comment.
I think this will break current compatibility with ARM. Maybe you can either:
- Move this to respective
instrumenter_arm64.goandinstrumenter_amd64.gofiles, and write different implementations (the ARM would be just return the value). - Copy this endian-independent implementation: https://github.com/songgao/ether/blob/master/afpacket.go#L14-L23
There was a problem hiding this comment.
Great catch! I'm going to steal the implementation above, very cool trick.
pkg/ebpf/grpc/grpc.go
Outdated
| func (p *Tracer) KProbes() map[string]ebpfcommon.FunctionPrograms { | ||
| return map[string]ebpfcommon.FunctionPrograms{} | ||
| } | ||
|
|
||
| func (p *Tracer) SocketFilters() []*ebpf.Program { | ||
| return []*ebpf.Program{} | ||
| } | ||
|
|
There was a problem hiding this comment.
Nit: you can safely return nil arrays and nil slices. Go accepts operations such as range and len over them: https://go.dev/play/p/0s6WRbXWCPK
In the case of slices, it even accepts append.
pkg/ebpf/tracer.go
Outdated
| "github.com/grafana/ebpf-autoinstrument/pkg/goexec" | ||
|
|
||
| "github.com/grafana/ebpf-autoinstrument/pkg/ebpf/nethttp" | ||
| "github.com/mariomac/pipes/pkg/node" | ||
| "golang.org/x/exp/slog" | ||
| ) | ||
|
|
||
| var log = slog.With("component", "ebpf.TracerProvider") |
There was a problem hiding this comment.
If you move this here, the logger will be created with the default level before you load the configuration and set the new log level. In this case, debug logs won't be visible.
To reuse the logger from different functions, in other files I did:
func logger() *slog.Logger {
return slog.With("component", "ebpf.TracerProvider")
}Then just taking care to invoke it only once at the beginning of critical functions, like the long-lived functions that iterate the channels.
There was a problem hiding this comment.
Ah good point, I'll revert that and make sure I can use the logger where I needed it.
|
Thanks Mario! |
This PR lays the ground work to allow us to add support for other languages than Go. I moved some code around and made not finding the Go runtime and offsets non-fatal.
There's no eBPF code yet that uses non-Golang support, but if I made all the changes at once it would be very hard to review :).