vmm_influxdb: improve connection handling (next attempt to not leak fds and reconnect on demand)
This commit is contained in:
Hannes Mehnert
parent
43ee0cf4e0
commit
9e4cb94884
1
.merlin
1
.merlin
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@ -7,3 +7,4 @@ B _build/**
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PKG topkg logs ipaddr x509 tls rresult bos lwt cmdliner hex cstruct.ppx duration
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PKG ptime ptime.clock.os ipaddr.unix decompress
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PKG lwt.unix
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@ -160,94 +160,114 @@ let safe_close s =
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Logs.err (fun m -> m "exception %s while closing" (Printexc.to_string e)) ;
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Lwt.return_unit)
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let rec read_sock_write_tcp db c ?fd addr addrtype =
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let rec read_sock_write_tcp closing db c ?fd addr addrtype =
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match fd with
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| None ->
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Logs.debug (fun m -> m "new connection to TCP") ;
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let fd = Lwt_unix.socket addrtype Lwt_unix.SOCK_STREAM 0 in
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Lwt_unix.setsockopt fd Lwt_unix.SO_KEEPALIVE true ;
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Lwt.catch
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(fun () ->
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Lwt_unix.connect fd addr >|= fun () ->
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Logs.debug (fun m -> m "connected to TCP"))
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(fun e ->
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let addr', port = match addr with
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| Lwt_unix.ADDR_INET (ip, port) -> Unix.string_of_inet_addr ip, port
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| Lwt_unix.ADDR_UNIX addr -> addr, 0
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in
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Logs.warn (fun m -> m "error %s connecting to influxd %s:%d, retrying in 5s"
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(Printexc.to_string e) addr' port) ;
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safe_close fd >>= fun () ->
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Lwt_unix.sleep 5.0 >>= fun () ->
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read_sock_write_tcp db c addr addrtype) >>= fun () ->
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read_sock_write_tcp db c ~fd addr addrtype
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if !closing then
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Lwt.return_unit
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else begin
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Logs.debug (fun m -> m "new connection to TCP") ;
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let fd = Lwt_unix.socket addrtype Lwt_unix.SOCK_STREAM 0 in
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Lwt_unix.setsockopt fd Lwt_unix.SO_KEEPALIVE true ;
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Lwt.catch
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(fun () ->
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Lwt_unix.connect fd addr >|= fun () ->
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Logs.debug (fun m -> m "connected to TCP") ;
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Some fd)
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(fun e ->
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let addr', port = match addr with
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| Lwt_unix.ADDR_INET (ip, port) -> Unix.string_of_inet_addr ip, port
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| Lwt_unix.ADDR_UNIX addr -> addr, 0
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in
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Logs.warn (fun m -> m "error %s connecting to influxd %s:%d, retrying in 5s"
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(Printexc.to_string e) addr' port) ;
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safe_close fd >>= fun () ->
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Lwt_unix.sleep 5.0 >|= fun () ->
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None) >>= fun fd ->
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read_sock_write_tcp closing db c ?fd addr addrtype
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end
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| Some fd ->
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let open Vmm_wire in
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Logs.debug (fun m -> m "reading from unix socket") ;
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Vmm_lwt.read_exactly c >>= function
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| Error e ->
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Logs.err (fun m -> m "error %s while reading vmm socket (return)"
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(str_of_e e)) ;
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if !closing then
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safe_close fd
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| Ok (hdr, data) ->
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if not (version_eq hdr.version my_version) then begin
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Logs.err (fun m -> m "unknown wire protocol version") ;
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safe_close fd
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end else
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let name = IM.find hdr.id !req in
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req := IM.remove hdr.id !req ;
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match Stats.int_to_op hdr.tag with
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| Some Stats.Stat_reply ->
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begin match Vmm_wire.Stats.decode_stats (Cstruct.of_string data) with
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| Error (`Msg msg) ->
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Logs.warn (fun m -> m "error %s while decoding stats %s, ignoring"
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msg name) ;
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read_sock_write_tcp db c ~fd addr addrtype
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| Ok (ru, vmm, ifs) ->
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let ru = P.encode_ru name ru in
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let vmm = P.encode_vmm name vmm in
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let taps = List.map (P.encode_if name) ifs in
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let out = (String.concat ~sep:"\n" (ru :: vmm :: taps)) ^ "\n" in
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Logs.debug (fun m -> m "writing %d via tcp" (String.length out)) ;
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Vmm_lwt.write_raw fd out >>= function
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| Ok () ->
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Logs.debug (fun m -> m "wrote successfully") ;
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read_sock_write_tcp db c ~fd addr addrtype
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| Error e ->
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Logs.err (fun m -> m "error %s while writing to tcp (%s)"
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(str_of_e e) name) ;
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safe_close fd >>= fun () ->
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read_sock_write_tcp db c addr addrtype
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end
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| _ when hdr.tag = fail_tag ->
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Logs.err (fun m -> m "failed to retrieve statistics for %s" name) ;
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read_sock_write_tcp db c ~fd addr addrtype
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| _ ->
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Logs.err (fun m -> m "unhandled tag %d for %s" hdr.tag name) ;
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read_sock_write_tcp db c ~fd addr addrtype
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let rec query_sock prefix db c interval =
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(* query c for everyone in db *)
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Lwt_list.iter_s (fun (id, name) ->
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let id = identifier id in
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let id = match prefix with None -> id | Some p -> p ^ "." ^ id in
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let request = Vmm_wire.Stats.stat !command my_version id in
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req := IM.add !command name !req ;
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incr command ;
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Logs.debug (fun m -> m "%d requesting %s via socket" !command id) ;
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Vmm_lwt.write_raw c request >>= function
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| Ok () ->
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Logs.debug (fun m -> m "%d done" !command) ;
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Lwt.return_unit
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else begin
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let open Vmm_wire in
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Logs.debug (fun m -> m "reading from unix socket") ;
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Vmm_lwt.read_exactly c >>= function
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| Error e ->
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Logs.err (fun m -> m "error while writing to vmm socket %s: %s"
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id (str_of_e e)) ;
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Lwt.fail_with "exception while writing")
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db >>= fun () ->
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Lwt_unix.sleep (float_of_int interval) >>= fun () ->
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query_sock prefix db c interval
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Logs.err (fun m -> m "error %s while reading vmm socket (return)"
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(str_of_e e)) ;
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closing := true ;
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safe_close fd
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| Ok (hdr, data) ->
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if not (version_eq hdr.version my_version) then begin
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Logs.err (fun m -> m "unknown wire protocol version") ;
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closing := true ;
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safe_close fd
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end else
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let name =
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try IM.find hdr.id !req
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with Not_found -> "not found"
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in
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req := IM.remove hdr.id !req ;
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begin match Stats.int_to_op hdr.tag with
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| Some Stats.Stat_reply ->
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begin match Vmm_wire.Stats.decode_stats (Cstruct.of_string data) with
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| Error (`Msg msg) ->
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Logs.warn (fun m -> m "error %s while decoding stats %s, ignoring"
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msg name) ;
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Lwt.return (Some fd)
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| Ok (ru, vmm, ifs) ->
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let ru = P.encode_ru name ru in
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let vmm = P.encode_vmm name vmm in
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let taps = List.map (P.encode_if name) ifs in
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let out = (String.concat ~sep:"\n" (ru :: vmm :: taps)) ^ "\n" in
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Logs.debug (fun m -> m "writing %d via tcp" (String.length out)) ;
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Vmm_lwt.write_raw fd out >>= function
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| Ok () ->
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Logs.debug (fun m -> m "wrote successfully") ;
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Lwt.return (Some fd)
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| Error e ->
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Logs.err (fun m -> m "error %s while writing to tcp (%s)"
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(str_of_e e) name) ;
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safe_close fd >|= fun () ->
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None
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end
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| _ when hdr.tag = fail_tag ->
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Logs.err (fun m -> m "failed to retrieve statistics for %s" name) ;
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Lwt.return (Some fd)
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| _ ->
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Logs.err (fun m -> m "unhandled tag %d for %s" hdr.tag name) ;
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Lwt.return (Some fd)
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end >>= fun fd ->
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read_sock_write_tcp closing db c ?fd addr addrtype
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end
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let maybe_connect stat_socket =
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let rec query_sock closing prefix db c interval =
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(* query c for everyone in db *)
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if !closing then
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Lwt.return_unit
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else
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Lwt_list.fold_left_s (fun r (id, name) ->
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match r with
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| Error e -> Lwt.return (Error e)
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| Ok () ->
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let id = identifier id in
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let id = match prefix with None -> id | Some p -> p ^ "." ^ id in
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let request = Vmm_wire.Stats.stat !command my_version id in
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req := IM.add !command name !req ;
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incr command ;
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Logs.debug (fun m -> m "%d requesting %s via socket" !command id) ;
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Vmm_lwt.write_raw c request)
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(Ok ()) db >>= function
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| Error e ->
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Logs.err (fun m -> m "error %s while writing to vmm socket" (str_of_e e)) ;
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closing := true ;
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Lwt.return_unit
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| Ok () ->
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Lwt_unix.sleep (float_of_int interval) >>= fun () ->
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query_sock closing prefix db c interval
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let rec maybe_connect stat_socket =
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let c = Lwt_unix.(socket PF_UNIX SOCK_STREAM 0) in
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Lwt.catch
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(fun () ->
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@ -258,7 +278,9 @@ let maybe_connect stat_socket =
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(fun e ->
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Logs.warn (fun m -> m "error %s connecting to socket %s"
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(Printexc.to_string e) stat_socket) ;
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Lwt.fail_with "cannot connect to stat socket")
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safe_close c >>= fun () ->
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Lwt_unix.sleep (float_of_int 5) >>= fun () ->
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maybe_connect stat_socket)
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let client stat_socket influxhost influxport db prefix interval =
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(* start a socket connection to vmm_stats *)
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@ -272,16 +294,27 @@ let client stat_socket influxhost influxport db prefix interval =
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in
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(* loop *)
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(* the query task queries the stat_socket at each interval
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- if this fails, closing is set to true (and unit is returned)
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the read_sock reads the stat_socket, and forwards to a TCP socket
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- if closing is true, the TCP socket is closed and unit is returned
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- if read on the unix domain socket fails, closing is set to true
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(and unit is returned) *)
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(* connection to the unix domain socket is managed in this loop only:
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- maybe_connect attempts to establishes to it
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- query_sock/read_sock_write_tcp write an read from it
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- on failure in read or write, the TCP connection is closed, and loop
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takes control: safe_close, maybe_connect, rinse, repeat *)
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let rec loop c =
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Lwt.catch (fun () ->
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Lwt.pick [ query_sock prefix db c interval ; read_sock_write_tcp db c addr addrtype ] >>= fun () ->
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safe_close c >>= fun () ->
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maybe_connect stat_socket >>= fun c ->
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loop c)
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(fun _ ->
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safe_close c >>= fun () ->
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maybe_connect stat_socket >>= fun c ->
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loop c)
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let closing = ref false in
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Lwt.join [
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query_sock closing prefix db c interval ;
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read_sock_write_tcp closing db c addr addrtype
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] >>= fun () ->
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safe_close c >>= fun () ->
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maybe_connect stat_socket >>= fun c ->
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loop c
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in
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loop c
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@ -322,15 +355,16 @@ let host_port : (string * int) Arg.converter =
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let socket =
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let doc = "Stat socket to connect onto" in
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Arg.(required & pos 0 (some string) None & info [] ~doc)
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let sock = Fpath.(to_string (Vmm_core.tmpdir / "stat" + "sock")) in
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Arg.(value & opt string sock & info [ "s" ; "socket" ] ~doc)
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let influx =
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Arg.(required & pos 1 (some host_port) None & info [] ~docv:"influx"
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Arg.(required & pos 0 (some host_port) None & info [] ~docv:"influx"
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~doc:"the influx hostname:port to connect to")
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let db =
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let doc = "VMID database" in
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Arg.(required & pos 2 (some file) None & info [] ~doc)
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Arg.(required & pos 1 (some file) None & info [] ~doc)
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let prefix =
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let doc = "prefix" in
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