opam-mirror/mirage/unikernel.ml

697 lines
27 KiB
OCaml

open Lwt.Infix
let argument_error = 64
external reraise : exn -> 'a = "%reraise"
module Make
(BLOCK : Mirage_block.S)
(Time : Mirage_time.S)
(Pclock : Mirage_clock.PCLOCK)
(Stack : Tcpip.Stack.V4V6)
(HTTP : Http_mirage_client.S) = struct
module Part = Mirage_block_partition.Make(BLOCK)
module KV = Tar_mirage.Make_KV_RW(Part)
module Cache = OneFFS.Make(Part)
module SM = Map.Make(String)
module SSet = Set.Make(String)
module HM = Map.Make(struct
type t = Mirage_crypto.Hash.hash
let compare = compare (* TODO remove polymorphic compare *)
end)
let hash_to_string = function
| `MD5 -> "md5"
| `SHA1 -> "sha1"
| `SHA224 -> "sha224"
| `SHA256 -> "sha256"
| `SHA384 -> "sha384"
| `SHA512 -> "sha512"
let hash_of_string = function
| "md5" -> Ok `MD5
| "sha256" -> Ok `SHA256
| "sha512" -> Ok `SHA512
| h -> Error (`Msg ("unknown hash algorithm: " ^ h))
let hex_to_string h =
let `Hex h = Hex.of_string h in
h
let hex_of_string s =
match Hex.to_string (`Hex s) with
| d -> Ok d
| exception Invalid_argument err -> Error (`Msg err)
let hm_to_s hm =
HM.fold (fun h v acc ->
hash_to_string h ^ "=" ^ hex_to_string v ^ "\n" ^ acc)
hm ""
module Git = struct
let decode_digest filename str =
let hex h s =
match hex_of_string s with
| Ok d -> Some (h, d)
| Error `Msg msg ->
Logs.warn (fun m -> m "%s invalid hex (%s) %s" filename msg s); None
in
match String.split_on_char '=' str with
| [ data ] -> hex `MD5 data
| [ "md5" ; data ] -> hex `MD5 data
| [ "sha256" ; data ] -> hex `SHA256 data
| [ "sha512" ; data ] -> hex `SHA512 data
| [ hash ; _ ] -> Logs.warn (fun m -> m "%s unknown hash %s" filename hash); None
| _ -> Logs.warn (fun m -> m "%s unexpected hash format %S" filename str); None
let extract_urls filename str =
(* in an opam file, there may be:
url { src: <string> checksum: [ STRING ] } <- list of hash
url { src: <string> checksum: STRING } <- single hash
url { archive: <string> checksum: STRING } <- MD5
*)
let open OpamParserTypes.FullPos in
let opamfile = OpamParser.FullPos.string str filename in
let url_section =
List.find_opt (function
| { pelem = Section ({ section_kind = { pelem = "url" ; _ } ; _ }) ; _} -> true | _ -> false)
opamfile.file_contents
in
match url_section with
| Some { pelem = Section ({ section_items = { pelem = items ; _ }; _}) ; _ } ->
begin
let url =
List.find_opt
(function { pelem = Variable ({ pelem = "src" ; _ }, _); _ } -> true | _ -> false)
items
and archive =
List.find_opt
(function { pelem = Variable ({ pelem = "archive" ; _ }, _); _ } -> true | _ -> false)
items
and checksum =
List.find_opt
(function { pelem = Variable ({ pelem = "checksum" ; _ }, _); _ } -> true | _ -> false)
items
in
let url =
match url, archive with
| Some { pelem = Variable (_, { pelem = String url ; _ }) ; _ }, None -> Some url
| None, Some { pelem = Variable (_, { pelem = String url ; _ }); _ } -> Some url
| _ ->
Logs.warn (fun m -> m "%s neither src nor archive present" filename); None
in
let csum =
match checksum with
| Some { pelem = Variable (_, { pelem = List { pelem = csums ; _ } ; _ }); _ } ->
let csums =
List.fold_left (fun acc ->
function
| { pelem = String csum ; _ } ->
begin match decode_digest filename csum with
| None -> acc
| Some (h, v) ->
HM.update h (function
| None -> Some v
| Some v' when String.equal v v' -> None
| Some v' ->
Logs.warn (fun m -> m "for %s, hash %s, multiple keys are present: %s %s"
(Option.value ~default:"NONE" url) (hash_to_string h) (hex_to_string v) (hex_to_string v'));
None)
acc
end
| _ -> acc) HM.empty csums
in
Some csums
| Some { pelem = Variable (_, { pelem = String csum ; _ }) ; _ } ->
begin match decode_digest filename csum with
| None -> None
| Some (h, v) -> Some (HM.singleton h v)
end
| _ ->
Logs.warn (fun m -> m "couldn't decode checksum in %s" filename);
None
in
match url, csum with
| Some url, Some cs -> Some (url, cs)
| _ -> None
end
| _ -> Logs.debug (fun m -> m "no url section for %s" filename); None
module Null_write = struct
(* we have to provide a WRITER, but we don't actually want to write. *)
type out_channel = |
type 'a t = 'a Lwt.t
let really_write o _ = match o with (_ : out_channel) -> .
end
module String_read = struct
type in_channel = {
data : string;
mutable offset : int;
}
type 'a t = 'a Lwt.t
let really_read t buf =
let buf_len = Cstruct.length buf in
if String.length t.data - t.offset < buf_len then
raise Stdlib.End_of_file;
Cstruct.blit_from_string t.data t.offset buf 0 buf_len;
t.offset <- t.offset + buf_len;
Lwt.pause ()
let read t buf =
let len = min (String.length t.data - t.offset) (Cstruct.length buf) in
Cstruct.blit_from_string t.data t.offset buf 0 len;
Lwt.pause () >>= fun () ->
t.offset <- t.offset + len;
Lwt.return len
let skip t n =
t.offset <- t.offset + n; Lwt.pause ()
end
module Index = Tar_gz.Make(Lwt)(Null_write)(String_read)
let find_urls index =
let ic =
Index.of_in_channel ~internal:(Cstruct.create 0x1000)
{ String_read.data = index ; offset = 0 ; }
in
let rec do_it acc =
Lwt.try_bind
(fun () -> Index.get_next_header ic)
(fun hdr ->
(* XXX: Int64.to_int *)
let file_size = Int64.to_int hdr.file_size in
Logs.debug (fun m -> m "%s: %Ld" hdr.file_name hdr.file_size);
if String.starts_with hdr.Tar.Header.file_name ~prefix:"/packages/" &&
String.ends_with hdr.Tar.Header.file_name ~suffix:"/opam" then begin
let buf = Cstruct.create file_size in
Index.really_read ic buf >>= fun () ->
Index.skip ic (Tar.Header.compute_zero_padding_length hdr) >>= fun () ->
let data = Cstruct.to_string buf in
(* TODO report parser errors *)
let acc =
try
let url_csums = extract_urls hdr.file_name data in
Option.fold ~none:acc ~some:(fun (url, csums) ->
if HM.cardinal csums = 0 then
(Logs.warn (fun m -> m "no checksums for %s, ignoring" url); acc)
else
SM.update url (function
| None -> Some csums
| Some csums' ->
if HM.for_all (fun h v ->
match HM.find_opt h csums with
| None -> true | Some v' -> String.equal v v')
csums'
then
Some (HM.union (fun _h v _v' -> Some v) csums csums')
else begin
Logs.warn (fun m -> m "mismatching hashes for %s: %s vs %s"
url (hm_to_s csums') (hm_to_s csums));
None
end) acc) url_csums
with _ ->
Logs.warn (fun m -> m "some error in %s, ignoring" hdr.file_name);
acc
in
(do_it [@tailcall]) acc
end else begin
Logs.debug (fun m -> m "skipping %d bytes" file_size);
Index.skip ic file_size >>= fun () ->
Index.skip ic (Tar.Header.compute_zero_padding_length hdr) >>= fun () ->
(do_it [@tailcall]) acc
end
)
(function
| Tar.Header.End_of_stream ->
Lwt.return acc
| e -> reraise e)
in
do_it SM.empty
end
module Disk = struct
type t = {
mutable md5s : string SM.t ;
mutable sha512s : string SM.t ;
dev : KV.t ;
dev_md5s : Cache.t ;
dev_sha512s : Cache.t ;
}
let empty dev dev_md5s dev_sha512s = { md5s = SM.empty ; sha512s = SM.empty ; dev; dev_md5s; dev_sha512s }
let to_hex d =
let d = Cstruct.to_string d in
hex_to_string d
let marshal_sm (sm : string SM.t) =
let version = char_of_int 1 in
String.make 1 version ^ Marshal.to_string sm []
let unmarshal_sm s =
let version = int_of_char s.[0] in
match version with
| 1 -> Ok (Marshal.from_string s 1 : string SM.t)
| _ -> Error ("Unsupported version " ^ string_of_int version)
let update_caches t =
Cache.write t.dev_md5s (marshal_sm t.md5s) >>= fun r ->
(match r with
| Ok () -> Logs.info (fun m -> m "Set 'md5s'")
| Error e -> Logs.warn (fun m -> m "Failed to write 'md5s': %a" Cache.pp_write_error e));
Cache.write t.dev_sha512s (marshal_sm t.sha512s) >>= fun r ->
match r with
| Ok () -> Logs.info (fun m -> m "Set 'sha512s'"); Lwt.return_unit
| Error e ->
Logs.warn (fun m -> m "Failed to write 'sha512s': %a" Cache.pp_write_error e);
Lwt.return_unit
let find_key t h key =
match
match h with
| `MD5 -> SM.find_opt key t.md5s
| `SHA512 -> SM.find_opt key t.sha512s
| `SHA256 -> Some key
| _ -> None
with
| None -> Error `Not_found
| Some x -> Ok x
let read_chunked t h v f a =
match find_key t h v with
| Error `Not_found ->
Lwt.return (Error (`Not_found (Mirage_kv.Key.v v)))
| Ok x ->
let key = Mirage_kv.Key.v x in
KV.size t.dev key >>= function
| Error e ->
Logs.err (fun m -> m "error %a while reading %s %s"
KV.pp_error e (hash_to_string h) v);
Lwt.return (Error (`Not_found key))
| Ok len ->
let chunk_size = 4096 in
let rec read_more a offset =
if offset < len then
KV.get_partial t.dev key ~offset ~length:chunk_size >>= function
| Ok data ->
f a data >>= fun a ->
read_more a (offset + chunk_size)
| Error e ->
Logs.err (fun m -> m "error %a while reading %s %s"
KV.pp_error e (hash_to_string h) v);
Lwt.return (Error e)
else
Lwt.return (Ok a)
in
read_more a 0
(* on disk, we use a flat file system where the filename is the sha256 of the data *)
let init ~verify dev dev_md5s dev_sha512s =
KV.list dev Mirage_kv.Key.empty >>= function
| Error e -> Logs.err (fun m -> m "error %a listing kv" KV.pp_error e); assert false
| Ok entries ->
let t = empty dev dev_md5s dev_sha512s in
Cache.read t.dev_md5s >>= fun r ->
(match r with
| Ok Some s -> Result.iter (fun md5s -> t.md5s <- md5s) (unmarshal_sm s)
| Ok None -> Logs.debug (fun m -> m "No md5s cached")
| Error e -> Logs.warn (fun m -> m "Error reading md5s cache: %a" Cache.pp_error e));
Cache.read t.dev_sha512s >>= fun r ->
(match r with
| Ok Some s -> Result.iter (fun sha512s -> t.sha512s <- sha512s) (unmarshal_sm s)
| Ok None -> Logs.debug (fun m -> m "No sha512s cached")
| Error e -> Logs.warn (fun m -> m "Error reading sha512s cache: %a" Cache.pp_error e));
let md5s = SSet.of_list (List.map snd (SM.bindings t.md5s))
and sha512s = SSet.of_list (List.map snd (SM.bindings t.sha512s)) in
let idx = ref 1 in
Lwt_list.iter_s (fun (name, typ) ->
if !idx mod 10 = 0 then Gc.full_major () ;
match typ with
| `Dictionary ->
Logs.warn (fun m -> m "unexpected dictionary at %s" name);
Lwt.return_unit
| `Value ->
let open Mirage_crypto.Hash in
let sha256_final =
if verify then
let f s =
let digest = SHA256.get s in
if not (String.equal name (to_hex digest)) then
Logs.err (fun m -> m "corrupt SHA256 data for %s, \
computed %s (should remove)"
name (to_hex digest))
in
Some f
else
None
and md5_final =
if not (SSet.mem name md5s) then
let f s =
let digest = MD5.get s in
t.md5s <- SM.add (to_hex digest) name t.md5s
in
Some f
else if verify then
let f s =
let digest = MD5.get s |> to_hex in
match SM.find_opt digest t.md5s with
| Some x when String.equal name x -> ()
| y ->
Logs.err (fun m -> m "corrupt MD5 data for %s, \
expected %a, computed %s"
name Fmt.(option ~none:(any "NONE") string) y
digest)
in
Some f
else
None
and sha512_final =
if not (SSet.mem name sha512s) then
let f s =
let digest = SHA512.get s in
t.sha512s <- SM.add (to_hex digest) name t.sha512s
in
Some f
else if verify then
let f s =
let digest = SHA512.get s |> to_hex in
match SM.find_opt digest t.sha512s with
| Some x when String.equal name x -> ()
| y ->
Logs.err (fun m -> m "corrupt SHA512 data for %s, \
expected %a, computed %s"
name Fmt.(option ~none:(any "NONE") string) y
digest)
in
Some f
else
None
in
match sha256_final, md5_final, sha512_final with
| None, None, None -> Lwt.return_unit
| _ ->
read_chunked t `SHA256 name
(fun (sha256, md5, sha512) data ->
let cs = Cstruct.of_string data in
Lwt.return
(Option.map (fun t -> SHA256.feed t cs) sha256,
Option.map (fun t -> MD5.feed t cs) md5,
Option.map (fun t -> SHA512.feed t cs) sha512))
(Option.map (fun _ -> SHA256.empty) sha256_final,
Option.map (fun _ -> MD5.empty) md5_final,
Option.map (fun _ -> SHA512.empty) sha512_final) >|= function
| Error e ->
Logs.err (fun m -> m "error %a of %s while computing digests"
KV.pp_error e name)
| Ok (sha256, md5, sha512) ->
Option.iter (fun f -> f (Option.get sha256)) sha256_final;
Option.iter (fun f -> f (Option.get md5)) md5_final;
Option.iter (fun f -> f (Option.get sha512)) sha512_final;
Logs.info (fun m -> m "added %s" name))
entries >>= fun () ->
update_caches t >|= fun () ->
t
let write t ~url data hm =
let cs = Cstruct.of_string data in
let sha256 = Mirage_crypto.Hash.digest `SHA256 cs |> to_hex
and md5 = Mirage_crypto.Hash.digest `MD5 cs |> to_hex
and sha512 = Mirage_crypto.Hash.digest `SHA512 cs |> to_hex
in
if
HM.for_all (fun h v ->
let v' =
match h with `MD5 -> md5 | `SHA256 -> sha256 | `SHA512 -> sha512 | _ -> assert false
in
let v = hex_to_string v in
if String.equal v v' then
true
else begin
Logs.err (fun m -> m "%s hash mismatch %s: expected %s, got %s" url
(hash_to_string h) v v');
false
end) hm
then begin
KV.set t.dev (Mirage_kv.Key.v sha256) data >|= function
| Ok () ->
t.md5s <- SM.add md5 sha256 t.md5s;
t.sha512s <- SM.add sha512 sha256 t.sha512s;
Logs.debug (fun m -> m "wrote %s (%d bytes)" sha256
(String.length data))
| Error e ->
Logs.err (fun m -> m "error %a while writing %s (key %s)"
KV.pp_write_error e url sha256)
end else
Lwt.return_unit
let exists t h v =
match find_key t h v with
| Error _ -> Lwt.return false
| Ok x ->
KV.exists t.dev (Mirage_kv.Key.v x) >|= function
| Ok Some `Value -> true
| Ok Some `Dictionary ->
Logs.err (fun m -> m "unexpected dictionary for %s %s"
(hash_to_string h) v);
false
| Ok None -> false
| Error e ->
Logs.err (fun m -> m "exists %s %s returned %a"
(hash_to_string h) v KV.pp_error e);
false
let last_modified t h v =
match find_key t h v with
| Error _ as e -> Lwt.return e
| Ok x ->
KV.last_modified t.dev (Mirage_kv.Key.v x) >|= function
| Ok data -> Ok data
| Error e ->
Logs.err (fun m -> m "error %a while last_modified %s %s"
KV.pp_error e (hash_to_string h) v);
Error `Not_found
let size t h v =
match find_key t h v with
| Error _ as e -> Lwt.return e
| Ok x ->
KV.size t.dev (Mirage_kv.Key.v x) >|= function
| Ok s -> Ok s
| Error e ->
Logs.err (fun m -> m "error %a while size %s %s"
KV.pp_error e (hash_to_string h) v);
Error `Not_found
end
module Serve = struct
let ptime_to_http_date ptime =
let (y, m, d), ((hh, mm, ss), _) = Ptime.to_date_time ptime
and weekday = match Ptime.weekday ptime with
| `Mon -> "Mon" | `Tue -> "Tue" | `Wed -> "Wed" | `Thu -> "Thu"
| `Fri -> "Fri" | `Sat -> "Sat" | `Sun -> "Sun"
and month =
[| "Jan" ; "Feb" ; "Mar" ; "Apr" ; "May" ; "Jun" ;
"Jul" ; "Aug" ; "Sep" ; "Oct" ; "Nov" ; "Dec" |]
in
let m' = Array.get month (pred m) in
Printf.sprintf "%s, %02d %s %04d %02d:%02d:%02d GMT" weekday d m' y hh mm ss
let update_lock = Lwt_mutex.create ()
let not_modified request (modified, etag) =
match Httpaf.Headers.get request.Httpaf.Request.headers "if-modified-since" with
| Some ts -> String.equal ts modified
| None -> match Httpaf.Headers.get request.Httpaf.Request.headers "if-none-match" with
| Some etags -> List.mem etag (String.split_on_char ',' etags)
| None -> false
let not_found reqd path =
let data = "Resource not found " ^ path in
let headers = Httpaf.Headers.of_list
[ "content-length", string_of_int (String.length data) ] in
let resp = Httpaf.Response.create ~headers `Not_found in
Httpaf.Reqd.respond_with_string reqd resp data
let respond_with_empty reqd resp =
let hdr =
Httpaf.Headers.add_unless_exists resp.Httpaf.Response.headers
"connection" "close"
in
let resp = { resp with Httpaf.Response.headers = hdr } in
Httpaf.Reqd.respond_with_string reqd resp ""
(* From the OPAM manual, all we need:
/repo -- repository configuration file
/cache -- cached archives
/index.tar.gz -- archive containing the whole repository contents
*)
(* may include "announce: [ string { filter } ... ]" *)
(* use Key_gen.remote for browse & upstream *)
(* for repo and index.tar.gz:
if Last_modified.not_modified request then
let resp = Httpaf.Response.create `Not_modified in
respond_with_empty reqd resp
else *)
let dispatch store hook_url update _flow _conn reqd =
let request = Httpaf.Reqd.request reqd in
Logs.info (fun f -> f "requested %s" request.Httpaf.Request.target);
match String.split_on_char '/' request.Httpaf.Request.target with
| [ ""; x ] when String.equal x hook_url ->
Lwt.async update;
let data = "Update in progress" in
let mime_type = "text/plain" in
let headers = [
"content-type", mime_type ;
"content-length", string_of_int (String.length data) ;
] in
let headers = Httpaf.Headers.of_list headers in
let resp = Httpaf.Response.create ~headers `OK in
Httpaf.Reqd.respond_with_string reqd resp data
| "" :: "cache" :: hash_algo :: _ :: hash :: [] ->
(* `<hash-algo>/<first-2-hash-characters>/<hash>` *)
begin
match hash_of_string hash_algo with
| Error `Msg msg ->
Logs.warn (fun m -> m "error decoding hash algo: %s" msg);
not_found reqd request.Httpaf.Request.target
| Ok h ->
Lwt.async (fun () ->
(Disk.last_modified store h hash >|= function
| Error _ ->
Logs.warn (fun m -> m "error retrieving last modified");
(* XXX *)
ptime_to_http_date (Ptime.v (Pclock.now_d_ps ()))
| Ok v -> ptime_to_http_date (Ptime.v v)) >>= fun last_modified ->
if not_modified request (last_modified, hash) then
let resp = Httpaf.Response.create `Not_modified in
respond_with_empty reqd resp;
Lwt.return_unit
else
Disk.size store h hash >>= function
| Error _ ->
Logs.warn (fun m -> m "error retrieving size");
not_found reqd request.Httpaf.Request.target;
Lwt.return_unit
| Ok size ->
let size = string_of_int size in
let mime_type = "application/octet-stream" in
let headers = [
"content-type", mime_type ;
"etag", hash ;
"last-modified", last_modified ;
"content-length", size ;
]
in
let headers = Httpaf.Headers.of_list headers in
let resp = Httpaf.Response.create ~headers `OK in
let body = Httpaf.Reqd.respond_with_streaming reqd resp in
Disk.read_chunked store h hash (fun () chunk ->
let wait, wakeup = Lwt.task () in
Httpaf.Body.write_string body chunk;
Httpaf.Body.flush body (Lwt.wakeup wakeup);
wait) () >|= fun _ ->
Httpaf.Body.close_writer body)
end
| _ ->
Logs.warn (fun m -> m "unknown request %s" request.Httpaf.Request.target);
not_found reqd request.Httpaf.Request.target
end
let bad_archives = SSet.of_list Bad.archives
let download_archives disk http_ctx store =
Git.find_urls store >>= fun urls ->
let urls = SM.filter (fun k _ -> not (SSet.mem k bad_archives)) urls in
let pool = Lwt_pool.create (Key_gen.parallel_downloads ()) (Fun.const Lwt.return_unit) in
let idx = ref 0 in
Lwt_list.iter_p (fun (url, csums) ->
Lwt_pool.use pool @@ fun () ->
HM.fold (fun h v r ->
r >>= function
| true -> Disk.exists disk h (hex_to_string v)
| false -> Lwt.return false)
csums (Lwt.return true) >>= function
| true ->
Logs.debug (fun m -> m "ignoring %s (already present)" url);
Lwt.return_unit
| false ->
incr idx;
if !idx mod 10 = 0 then Gc.full_major () ;
Logs.info (fun m -> m "downloading %s" url);
Http_mirage_client.one_request
~alpn_protocol:HTTP.alpn_protocol
~authenticator:HTTP.authenticator
~ctx:http_ctx url >>= function
| Ok (resp, Some str) ->
if resp.status = `OK then begin
Logs.info (fun m -> m "downloaded %s" url);
Disk.write disk ~url str csums
end else begin
Logs.warn (fun m -> m "%s: %a (reason %s)"
url H2.Status.pp_hum resp.status resp.reason);
Lwt.return_unit
end
| _ -> Lwt.return_unit)
(SM.bindings urls) >>= fun () ->
Disk.update_caches disk >|= fun () ->
Logs.info (fun m -> m "downloading of %d urls done" (SM.cardinal urls))
module Paf = Paf_mirage.Make(Stack.TCP)
let start block _time _pclock stack http_ctx =
BLOCK.get_info block >>= fun info ->
let sectors_cache = Key_gen.sectors_cache () in
let sectors =
let cache_size = Int64.(mul 2L sectors_cache) in
Int64.(sub info.size_sectors cache_size)
in
Part.connect sectors block >>= fun (kv, rest) ->
let md5s, sha512s = Part.subpartition sectors_cache rest in
KV.connect kv >>= fun kv ->
Cache.connect md5s >>= fun md5s ->
Cache.connect sha512s >>= fun sha512s ->
Logs.info (fun m -> m "Available bytes in tar storage: %Ld" (KV.free kv));
Disk.init ~verify:(Key_gen.verify ()) kv md5s sha512s >>= fun disk ->
if Key_gen.check () then
Lwt.return_unit
else
begin
let url = Key_gen.remote () ^ "/index.tar.gz" in
Paf.init ~port:(Key_gen.port ()) (Stack.tcp stack) >>= fun t ->
let update () =
Http_mirage_client.one_request
~alpn_protocol:HTTP.alpn_protocol
~authenticator:HTTP.authenticator
~ctx:http_ctx url >>= function
| Ok (resp, Some str) ->
if resp.status = `OK then
download_archives disk http_ctx str
else begin
Logs.warn (fun m -> m "%s: %a (reason %s)"
url H2.Status.pp_hum resp.status resp.reason);
Lwt.return_unit
end
| _ -> Lwt.return_unit
in
let service =
Paf.http_service
~error_handler:(fun _ ?request:_ _ _ -> ())
(Serve.dispatch disk (Key_gen.hook_url ()) update)
in
let `Initialized th = Paf.serve service t in
Logs.info (fun f -> f "listening on %d/HTTP" (Key_gen.port ()));
Lwt.async (fun () ->
let rec go () =
Time.sleep_ns (Duration.of_hour 1) >>= fun () ->
update () >>= fun () ->
go ()
in
go ());
update () >>= fun () ->
(th >|= fun _v -> ())
end
end