albatross/app/vmmd.ml

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(* (c) 2017 Hannes Mehnert, all rights reserved *)
type stats = {
start : Ptime.t ;
vm_created : int ;
vm_destroyed : int ;
}
let s = ref { start = Ptime_clock.now () ; vm_created = 0 ; vm_destroyed = 0 }
let pp_stats ppf s =
let diff = Ptime.(diff (Ptime_clock.now ()) s.start) in
Fmt.pf ppf "up %a: %d vms created, %d vms destroyed, %d running"
Ptime.Span.pp diff
s.vm_created s.vm_destroyed (s.vm_created - s.vm_destroyed)
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open Lwt.Infix
type out = [
| `Cons of Cstruct.t
| `Stat of Cstruct.t
| `Log of Cstruct.t
]
let handle state out c_fd fd addr =
(* out is for `Log | `Stat | `Cons (including reconnect semantics) *)
(* need to handle data out (+ die on write failure) *)
Logs.debug (fun m -> m "connection from %a" Vmm_lwt.pp_sockaddr addr) ;
(* now we need to read a packet and handle it
(1)
(a) easy for info (look up name/prefix in resources)
(b) destroy looks up vm in resources, executes kill (wait for pid will do the cleanup)
logs "destroy issued"
(c) create initiates the vm startup procedure:
write image file, create fifo, create tap(s), send fifo to console
-- Lwt effects happen (console) --
executes ukvm-bin + waiter, send stats pid and taps, inserts await into state, logs "created vm"
-- Lwt effects happen (stats, logs, wait_and_clear) --
(2) goto (1)
*)
let process xs =
Lwt_list.iter_p (function
| #out as o -> out o
| `Data cs ->
(* rather: terminate connection *)
Vmm_lwt.write_wire fd cs >|= fun _ -> ()) xs
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in
Logs.debug (fun m -> m "now reading") ;
(Vmm_lwt.read_wire fd >>= function
| Error _ ->
Logs.err (fun m -> m "error while reading") ;
Lwt.return_unit
| Ok (hdr, buf) ->
Logs.debug (fun m -> m "read sth") ;
let state', data, next = Vmm_engine.handle_command !state hdr buf in
state := state' ;
process data >>= fun () ->
match next with
| `End -> Lwt.return_unit
| `Wait (task, out) -> task >>= fun () -> process out
| `Create cont ->
(* data contained a write to console, we need to wait for its reply first *)
Vmm_lwt.read_wire c_fd >>= function
| Ok (hdr, data) ->
if Vmm_wire.is_fail hdr then begin
Logs.err (fun m -> m "console failed with %s" (Cstruct.to_string data)) ;
Lwt.return_unit
end else if Vmm_wire.is_reply hdr then begin
(* assert hdr.id = id! *)
let await, wakeme = Lwt.wait () in
begin match cont !state await with
| Error (`Msg msg) ->
Logs.err (fun m -> m "create continuation failed %s" msg) ;
Lwt.return_unit
| Ok (state'', out, vm) ->
state := state'' ;
s := { !s with vm_created = succ !s.vm_created } ;
Lwt.async (fun () ->
Vmm_lwt.wait_and_clear vm.Vmm_core.pid vm.Vmm_core.stdout >>= fun r ->
let state', out' = Vmm_engine.handle_shutdown !state vm r in
s := { !s with vm_destroyed = succ !s.vm_destroyed } ;
state := state' ;
process out' >|= fun () ->
Lwt.wakeup wakeme ()) ;
process out >>= fun () ->
begin match Vmm_engine.setup_stats !state vm with
| Ok (state', out) ->
state := state' ;
process out (* TODO: need to read from stats socket! *)
| Error (`Msg e) ->
Logs.warn (fun m -> m "(ignored) error %s while setting up statistics" e) ;
Lwt.return_unit
end
end
end else begin
Logs.err (fun m -> m "reading from console %lx, %a" hdr.Vmm_wire.tag Cstruct.hexdump_pp data) ;
Lwt.return_unit
end
| Error (`Msg msg) ->
Logs.err (fun m -> m "error %s while reading from console" msg) ;
Lwt.return_unit
| Error _ ->
Logs.err (fun m -> m "error while reading from console") ;
Lwt.return_unit ) >>= fun () ->
Vmm_lwt.safe_close fd
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let init_sock sock =
let name = Vmm_core.socket_path sock in
let c = Lwt_unix.(socket PF_UNIX SOCK_STREAM 0) in
Lwt_unix.set_close_on_exec c ;
Lwt.catch (fun () ->
Lwt_unix.(connect c (ADDR_UNIX name)) >|= fun () -> Some c)
(fun e ->
Logs.warn (fun m -> m "error %s connecting to socket %s"
(Printexc.to_string e) name) ;
(Lwt.catch (fun () -> Lwt_unix.close c) (fun _ -> Lwt.return_unit)) >|= fun () ->
None)
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let create_mbox sock =
init_sock sock >|= function
| None -> None
| Some fd ->
let mvar = Lwt_mvar.create_empty () in
(* could be more elaborate:
if <log> fails, we can reconnect and spit our more log messages to the new socket
if <console> fails, all running VMs terminate, so we can terminate as well ;)
if <stat> fails, we'd need to retransmit all VM info to stat (or stat has to ask at connect) *)
let rec loop () =
Lwt_mvar.take mvar >>= fun data ->
Vmm_lwt.write_wire fd data >>= function
| Ok () -> loop ()
| Error `Exception -> invalid_arg ("exception while writing to " ^ Fmt.to_to_string Vmm_core.pp_socket sock) ;
in
Lwt.async loop ;
Some (mvar, fd)
let server_socket sock =
let name = Vmm_core.socket_path sock in
(Lwt_unix.file_exists name >>= function
| true -> Lwt_unix.unlink name
| false -> Lwt.return_unit) >>= fun () ->
let s = Lwt_unix.(socket PF_UNIX SOCK_STREAM 0) in
Lwt_unix.(bind s (ADDR_UNIX name)) >|= fun () ->
Lwt_unix.listen s 1 ;
s
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let rec stats_loop () =
Logs.info (fun m -> m "%a" pp_stats !s) ;
Lwt_unix.sleep 600. >>= fun () ->
stats_loop ()
(* TODO nobody reads stat and log file descriptors - that's likely a bad idea!
- create_mbox could after take & write do a read and check for failures! *)
let jump _ =
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Sys.(set_signal sigpipe Signal_ignore) ;
Lwt_main.run
(server_socket `Vmmd >>= fun ss ->
(create_mbox `Console >|= function
| None -> invalid_arg "cannot connect to console socket"
| Some c -> c) >>= fun (c, c_fd) ->
create_mbox `Stats >>= fun s ->
(create_mbox `Log >|= function
| None -> invalid_arg "cannot connect to log socket"
| Some l -> l) >>= fun (l, _l_fd) ->
let state = ref (Vmm_engine.init ()) in
let out = function
| `Stat data -> (match s with None -> Lwt.return_unit | Some (s, _s_fd) -> Lwt_mvar.put s data)
| `Log data -> Lwt_mvar.put l data
| `Cons data -> Lwt_mvar.put c data
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in
Lwt.async stats_loop ;
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let rec loop () =
Lwt_unix.accept ss >>= fun (fd, addr) ->
Lwt_unix.set_close_on_exec fd ;
Lwt.async (fun () -> handle state out c_fd fd addr) ;
loop ()
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in
loop ())
let setup_log style_renderer level =
Fmt_tty.setup_std_outputs ?style_renderer ();
Logs.set_level level;
Logs.set_reporter (Logs_fmt.reporter ~dst:Format.std_formatter ())
open Cmdliner
let setup_log =
Term.(const setup_log
$ Fmt_cli.style_renderer ()
$ Logs_cli.level ())
let cmd =
Term.(ret (const jump $ setup_log)),
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Term.info "vmmd" ~version:"%%VERSION_NUM%%"
let () = match Term.eval cmd with `Ok () -> exit 0 | _ -> exit 1