This commit is contained in:
Craig Everett 2018-03-22 19:04:34 +09:00
parent c26f6737dc
commit 08972f0160
3 changed files with 296 additions and 212 deletions

Binary file not shown.

View File

@ -303,3 +303,109 @@ handle_timeout(Socket) ->
terminate() -> terminate() ->
exit(normal). exit(normal).
%-spec do_query_latest(Object, State) -> {Result, NewState}
% when Object :: zx:package() | zx:package_id(),
% State :: state(),
% Result :: {ok, zx:version()}
% | {error, Reason},
% Reason :: bad_realm
% | bad_package
% | bad_version,
% NewState :: state().
%% @private
%% Queries a zomp realm for the latest version of a package or package
%% version (complete or incomplete version number).
%
%do_query_latest(Socket, {Realm, Name}) ->
% ok = zx_net:send(Socket, {latest, Realm, Name}),
% receive
% {tcp, Socket, Bin} -> binary_to_term(Bin)
% after 5000 -> {error, timeout}
% end;
%do_query_latest(Socket, {Realm, Name, Version}) ->
% ok = zx_net:send(Socket, {latest, Realm, Name, Version}),
% receive
% {tcp, Socket, Bin} -> binary_to_term(Bin)
% after 5000 -> {error, timeout}
% end.
%-spec do_fetch(PackageIDs, State) -> NewState
% when PackageIDs :: [zx:package_id()],
% State :: state(),
% NewState :: state(),
% Result :: ok
% | {error, Reason},
% Reason :: bad_realm
% | bad_package
% | bad_version
% | network.
%% @private
%%
%
%do_fetch(PackageIDs, State) ->
% FIXME: Need to create a job queue divided by realm and dispatched to connectors,
% and cleared from the master pending queue kept here by the daemon as the
% workers succeed. Basic task queue management stuff... which never existed
% in ZX before... grrr...
% case scrub(PackageIDs) of
% [] ->
% ok;
% Needed ->
% Partitioned = partition_by_realm(Needed),
% EnsureDeps =
% fun({Realm, Packages}) ->
% ok = zx_conn:queue_package(Pid, Realm, Packages),
% log(info, "Disconnecting from realm: ~ts", [Realm])
% end,
% lists:foreach(EnsureDeps, Partitioned)
% end.
%
%
%partition_by_realm(PackageIDs) ->
% PartitionMap = lists:foldl(fun partition_by_realm/2, #{}, PackageIDs),
% maps:to_list(PartitionMap).
%
%
%partition_by_realm({R, P, V}, M) ->
% maps:update_with(R, fun(Ps) -> [{P, V} | Ps] end, [{P, V}], M).
%
%
%ensure_deps(_, _, []) ->
% ok;
%ensure_deps(Socket, Realm, [{Name, Version} | Rest]) ->
% ok = ensure_dep(Socket, {Realm, Name, Version}),
% ensure_deps(Socket, Realm, Rest).
%
%
%-spec ensure_dep(gen_tcp:socket(), package_id()) -> ok | no_return().
%% @private
%% Given an PackageID as an argument, check whether its package file exists in the
%% system cache, and if not download it. Should return `ok' whenever the file is
%% sourced, but exit with an error if it cannot locate or acquire the package.
%
%ensure_dep(Socket, PackageID) ->
% ZrpFile = filename:join("zrp", namify_zrp(PackageID)),
% ok =
% case filelib:is_regular(ZrpFile) of
% true -> ok;
% false -> fetch(Socket, PackageID)
% end,
% ok = install(PackageID),
% build(PackageID).
%
%
%-spec scrub(Deps) -> Scrubbed
% when Deps :: [package_id()],
% Scrubbed :: [package_id()].
%% @private
%% Take a list of dependencies and return a list of dependencies that are not yet
%% installed on the system.
%
%scrub([]) ->
% [];
%scrub(Deps) ->
% lists:filter(fun(PackageID) -> not zx_lib:installed(PackageID) end, Deps).

View File

@ -1,30 +1,31 @@
%%% @doc %%% @doc
%%% ZX Daemon %%% ZX Daemon
%%% %%%
%%% Resident execution daemon and runtime interface to Zomp. %%% Resident task daemon and runtime interface to Zomp.
%%% %%%
%%% The daemon resides in the background once started and awaits query requests and %%% The daemon resides in the background once started and awaits query requests and
%%% subscriptions from from other processes. The daemon is only capable of handling %%% subscriptions from other processes. The daemon is only capable of handling
%%% unprivileged (user) actions. %%% unprivileged (user) actions.
%%% %%%
%%% %%%
%%% Discrete state and local abstract data types %%% Discrete state and local abstract data types
%%% %%%
%%% The daemon must keep track of requestors, subscribers, and zx_conn processes by %%% The daemon must keep track of requestors, subscribers, and zx_conn processes by
%%% using monitors, and because the various types of clients are found in different %%% using monitors. Because these various types of clients are found in different
%%% locations the monitors are maintained in a data type called monitor_index(), %%% structures the monitors are maintained in a data type called monitor_index(),
%%% shortened to "mx" throughout the module. This structure is treated as an opaque %%% shortened to "mx" throughout the module. This structure is treated as an opaque
%%% data type and is handled by a set of functions defined toward the end of the module %%% data type and is handled by a set of functions defined toward the end of the module
%%% as mx_*/N. %%% as mx_*/N.
%%% %%%
%%% Node connections (cx_conn processes) must also be tracked for status and realm %%% Node connections (zx_conn processes) must also be tracked for status and realm
%%% availability. This is done using a type called conn_index(), shortened to "cx" %%% availability. This is done using a type called conn_index(), shortened to "cx"
%%% throughout the module. conn_index() is treated as an abstract, opaque datatype %%% throughout the module. conn_index() is treated as an abstract, opaque datatype
%%% throughout the module, and is handled via a set of cx_*/N functions (after the %%% throughout the module, and is handled via a set of cx_*/N functions (after the
%%% mx_*/N section). %%% mx_*/N section).
%%% %%%
%%% Do NOT directly access data within these structures, use (or write) an accessor %%% Do NOT directly access data within these structures, use (or write) an accessor
%%% function that does what you want. %%% function that does what you want. Accessor functions MUST be pure with the sole
%%% exception of the mx_* functions that create and destroy monitors.
%%% %%%
%%% %%%
%%% Connection handling %%% Connection handling
@ -40,7 +41,7 @@
%%% determine what realms must be available and what cached Zomp nodes it is aware of. %%% determine what realms must be available and what cached Zomp nodes it is aware of.
%%% It populates the CX (conn_index(), mentioned above) with realm config and host %%% It populates the CX (conn_index(), mentioned above) with realm config and host
%%% cache data, and then immediately initiates three connection attempts to cached %%% cache data, and then immediately initiates three connection attempts to cached
%%% nodes for each realm configured (if possible; see init_connections/0). %%% nodes for each realm configured if possible (see init_connections/0).
%%% %%%
%%% Once connection attempts have been initiated the daemon waits in receive for %%% Once connection attempts have been initiated the daemon waits in receive for
%%% either a connection report (success or failure) or an action request from %%% either a connection report (success or failure) or an action request from
@ -90,6 +91,44 @@
%%% a blocking way, establishing its own receive timeouts or implementing either an %%% a blocking way, establishing its own receive timeouts or implementing either an
%%% asynchronous or synchronous interface library atop zx_daemon interface function, %%% asynchronous or synchronous interface library atop zx_daemon interface function,
%%% but leaving zx_daemon and zx_conn alone to work asynchronously with one another. %%% but leaving zx_daemon and zx_conn alone to work asynchronously with one another.
%%%
%%%
%%% Race Avoidance
%%%
%%% Each runtime can only have one zx_daemon alive at a time, and each system can
%%% only have one zx_daemon directly performing actions at a time. This is to prevent
%%% problems where multiple zx instances are running at the same time using the same
%%% home directory and might clash with one another (overwriting each other's data,
%%% corrupting package or key files, etc.). OTP makes running a single registered
%%% process simple within a single runtime, but there is no standard cross-platform
%%% method for ensuring a given process is the only one of its type in a given scope
%%% within a host system.
%%%
%%% When zx starts the daemon will attempt an exclusive write to a lock file called
%%% $ZOMP_HOME/zomp.lock using file:open(LockFile, [exclusive]), writing a system
%%% timestamp. If the write succeeds then the daemon knows it is the master for the
%%% system and will begin initiating connections as described above as well as open a
%%% local socket to listen for other zx instances which will need to proxy their own
%%% actions through the master. Once the socket is open, the lock file is updated with
%%% the local port number. If the write fails then the file is read and if a port
%%% number is indicated then the daemon connects to the master zx_daemon and proxies
%%% its requests through it. If no port number exists then the daemon waits 5 seconds,
%%% checks again, and if there is still no port number then it checks whether the
%%% timestamp is more than 5 seconds old or in the future. If the timestamp is more
%%% than 5 seconds old or in the future then the file is deleted and the process
%%% of master identification starts again.
%%%
%%% If a master daemon's runtime is shutting down it will designate its oldest peer
%%% daemon connection as the new master. At that point the new master will open a port
%%% and rewrite the lock file. Once written the old master will drop all its node
%%% connections and dequeue all current requests, then pass a local redirect message
%%% to the subordinate daemons telling them the new port to which they should connect.
%%%
%%% Even if there is considrable churn within a system from, for example, scripted
%%% initiation of several small utilities that have never been executed before, the
%%% longest-living daemon should always become the master. This is not the most
%%% efficient procedure, but it is the easiest to understand and debug across various
%%% platforms.
%%% @end %%% @end
-module(zx_daemon). -module(zx_daemon).
@ -274,12 +313,6 @@
%% the filesystem. This step allows running development code from any location in %% the filesystem. This step allows running development code from any location in
%% the filesystem against installed dependencies without requiring any magical %% the filesystem against installed dependencies without requiring any magical
%% references. %% references.
%%
%% This call blocks specifically so that we can be certain that the target application
%% cannot be started before the impact of this call has taken full effect. It cannot
%% be known whether the very first thing the target application will do is send this
%% process an async message. That implies that this should only ever be called once,
%% by the launching process (which normally terminates shortly thereafter).
pass_meta(Meta, Dir, ArgV) -> pass_meta(Meta, Dir, ArgV) ->
gen_server:cast(?MODULE, {pass_meta, Meta, Dir, ArgV}). gen_server:cast(?MODULE, {pass_meta, Meta, Dir, ArgV}).
@ -288,11 +321,11 @@ pass_meta(Meta, Dir, ArgV) ->
-spec subscribe(Package) -> ok -spec subscribe(Package) -> ok
when Package :: zx:package(). when Package :: zx:package().
%% @doc %% @doc
%% Subscribe to update notifications for a for a particular package. %% Subscribe to update notifications for a for a package.
%% The caller will receive update notifications of type `sub_message()' as Erlang %% The caller will receive update notifications of type `sub_message()' as Erlang
%% messages whenever an update occurs. %% messages whenever an update occurs.
%% Crashes the caller if the Realm or Name of the Package argument are illegal %% Crashes the caller if the Realm or Name of the Package argument are illegal
%% `zx:lower0_9' strings. %% `zx:lower0_9()' strings.
subscribe(Package = {Realm, Name}) -> subscribe(Package = {Realm, Name}) ->
true = zx_lib:valid_lower0_9(Realm), true = zx_lib:valid_lower0_9(Realm),
@ -558,6 +591,8 @@ start_link() ->
-spec init(none) -> {ok, state()}. -spec init(none) -> {ok, state()}.
%% @private
%% TODO: Implement lockfile checking and master lock acquisition.
init(none) -> init(none) ->
Blank = blank_state(), Blank = blank_state(),
@ -674,7 +709,8 @@ handle_cast({result, Ref, Result}, State) ->
{noreply, NewState}; {noreply, NewState};
handle_cast({notify, Conn, Package, Update}, State) -> handle_cast({notify, Conn, Package, Update}, State) ->
ok = do_notify(Conn, Package, Update, State), ok = do_notify(Conn, Package, Update, State),
{noreply, State}; NewState = eval_queue(State),
{noreply, NewState};
handle_cast(stop, State) -> handle_cast(stop, State) ->
{stop, normal, State}; {stop, normal, State};
handle_cast(Unexpected, State) -> handle_cast(Unexpected, State) ->
@ -704,6 +740,7 @@ code_change(_, State, _) ->
%% @private %% @private
%% gen_server callback to handle shutdown/cleanup tasks on receipt of a clean %% gen_server callback to handle shutdown/cleanup tasks on receipt of a clean
%% termination request. %% termination request.
%% TODO: Implement new master selection, dequeuing and request queue passing.
terminate(normal, #s{cx = CX}) -> terminate(normal, #s{cx = CX}) ->
ok = log(info, "zx_daemon shutting down..."), ok = log(info, "zx_daemon shutting down..."),
@ -778,7 +815,7 @@ do_request(Requestor, Action, State = #s{id = ID, actions = Actions}) ->
State :: state(), State :: state(),
NewState :: state(). NewState :: state().
%% @private %% @private
%% Receive a report from a connection process, and update the connection index and %% Receive a report from a connection process, update the connection index and
%% possibly retry connections. %% possibly retry connections.
do_report(Conn, {connected, Realms}, State = #s{mx = MX, cx = CX}) -> do_report(Conn, {connected, Realms}, State = #s{mx = MX, cx = CX}) ->
@ -788,7 +825,7 @@ do_report(Conn, {connected, Realms}, State = #s{mx = MX, cx = CX}) ->
{assigned, NextCX} -> {assigned, NextCX} ->
{NextMX, NextCX}; {NextMX, NextCX};
{unassigned, NextCX} -> {unassigned, NextCX} ->
{ok, ScrubbedMX} = mx_del_monitor(Conn, conn, NextMX), ScrubbedMX = mx_del_monitor(Conn, conn, NextMX),
ok = zx_conn:stop(Conn), ok = zx_conn:stop(Conn),
{ScrubbedMX, NextCX} {ScrubbedMX, NextCX}
end, end,
@ -796,9 +833,9 @@ do_report(Conn, {connected, Realms}, State = #s{mx = MX, cx = CX}) ->
do_report(Conn, {redirect, Hosts}, State = #s{mx = MX, cx = CX}) -> do_report(Conn, {redirect, Hosts}, State = #s{mx = MX, cx = CX}) ->
NextMX = mx_del_monitor(Conn, attempt, MX), NextMX = mx_del_monitor(Conn, attempt, MX),
{Unassigned, NextCX} = cx_redirect(Conn, Hosts, CX), {Unassigned, NextCX} = cx_redirect(Conn, Hosts, CX),
{NewMX, NewCX} = ensure_connection(Unassigned, NextMX, NextCX), {NewMX, NewCX} = ensure_connections(Unassigned, NextMX, NextCX),
State#s{mx = NewMX, cx = NewCX}; State#s{mx = NewMX, cx = NewCX};
do_report(Conn, failed, State = #s{mx = MX, cx = CX}) -> do_report(Conn, failed, State = #s{mx = MX}) ->
NewMX = mx_del_monitor(Conn, attempt, MX), NewMX = mx_del_monitor(Conn, attempt, MX),
failed(Conn, State#s{mx = NewMX}); failed(Conn, State#s{mx = NewMX});
do_report(Conn, disconnected, State = #s{mx = MX}) -> do_report(Conn, disconnected, State = #s{mx = MX}) ->
@ -806,21 +843,30 @@ do_report(Conn, disconnected, State = #s{mx = MX}) ->
disconnected(Conn, State#s{mx = NewMX}). disconnected(Conn, State#s{mx = NewMX}).
failed(Conn, State#s{mx = MX, cx = CX}) -> -spec failed(Conn, State) -> NewState
when Conn :: pid(),
State :: state(),
NewState :: state().
failed(Conn, State = #s{mx = MX, cx = CX}) ->
{Realms, NextCX} = cx_failed(Conn, CX), {Realms, NextCX} = cx_failed(Conn, CX),
{NewMX, NewCX} = ensure_connection(Realms, MX, NextCX), {NewMX, NewCX} = ensure_connections(Realms, MX, NextCX),
State#s{mx = NewMX, cx = NewCX}. State#s{mx = NewMX, cx = NewCX}.
-spec disconnected(Conn, State) -> NewState
when Conn :: pid(),
State :: state(),
NewState :: state().
disconnected(Conn, disconnected(Conn,
State = #s{actions = Actions, requests = Requests, mx = MX, cx = CX}) -> State = #s{actions = Actions, requests = Requests, mx = MX, cx = CX}) ->
{Pending, LostSubs, ScrubbedCX} = cx_disconnected(Conn, CX), {Pending, LostSubs, Unassigned, ScrubbedCX} = cx_disconnected(Conn, CX),
Unassigned = cx_unassigned(ScrubbedCX),
ReSubs = [{S, {subscribe, P}} || {S, P} <- LostSubs], ReSubs = [{S, {subscribe, P}} || {S, P} <- LostSubs],
{Dequeued, NewRequests} = maps:fold(dequeue(Pending), {#{}, #{}}, Requests), {Dequeued, NewRequests} = maps:fold(dequeue(Pending), {#{}, #{}}, Requests),
ReReqs = maps:to_list(Dequeued), ReReqs = maps:to_list(Dequeued),
NewActions = ReReqs ++ ReSubs ++ Actions, NewActions = ReReqs ++ ReSubs ++ Actions,
{NewMX, NewCX} = ensure_connection(Unassigned, ScrubbedMX, ScrubbedCX), {NewMX, NewCX} = ensure_connections(Unassigned, MX, ScrubbedCX),
State#s{actions = NewActions, State#s{actions = NewActions,
requests = NewRequests, requests = NewRequests,
mx = NewMX, mx = NewMX,
@ -848,32 +894,48 @@ dequeue(Pending) ->
end. end.
-spec ensure_connection(Realms, MX, CX) -> {NewMX, NewCX} -spec ensure_connections(Realms, MX, CX) -> {NewMX, NewCX}
when Realms :: [zx:realm()], when Realms :: [zx:realm()],
MX :: monitor_index(), MX :: monitor_index(),
CX :: conn_index(), CX :: conn_index(),
NewMX :: monitor_index(), NewMX :: monitor_index(),
NewCX :: conn_index(). NewCX :: conn_index().
%% @private %% @private
%% Initiates a connection to a single realm at a time, taking into account whether %% Check the list of unprovided realms with all available connections that can provide
%% connected but unassigned nodes are alterantive providers of the needed realm. %% it, and allocate accordingly. If any realms cannot be provided by existing
%% Returns updated monitor and connection indices. %% connections, new connections are initiated for all unprovided realms.
ensure_connection([Realm | Realms], MX, CX = #cx{realms = RMetas}) -> ensure_connections(Realms, MX, CX) ->
{NewMX, NewCX} = {NextCX, Unavailable} = reassign_conns(Realms, CX, []),
{ok, NewMX, NewCX} = init_connections(Unavailable, MX, NextCX),
{NewMX, NewCX}.
-spec reassign_conns(Realms, CX, Unavailable) -> {NewCX, NewUnavailable}
when Realms :: [zx:realm()],
CX :: conn_index(),
Unavailable :: [zx:realm()],
NewCX :: conn_index(),
NewUnavailable :: [zx:realm()].
%% @private
%% Finds connections that provide a requested realm and assigns that connection to
%% take over realm provision. Returns the updated CX and a list of all the realms
%% that could not be provided by any available connection.
reassign_conns([Realm | Realms], CX = #cx{realms = RMetas}, Unassigned) ->
{NewUnassigned, NewCX} =
case maps:get(Realm, RMetas) of case maps:get(Realm, RMetas) of
#rmeta{available = []} -> #rmeta{available = []} ->
{ok, NextMX, NextCX} = init_connections([Realm], MX, CX), {[Realm | Unassigned], CX};
{NextMX, NextCX};
Meta = #rmeta{available = [Conn | Conns]} -> Meta = #rmeta{available = [Conn | Conns]} ->
NewMeta = Meta#rmeta{assigned = Conn, available = Conns}, NewMeta = Meta#rmeta{assigned = Conn, available = Conns},
NewRMetas = maps:put(Realm, NewMeta, RMetas), NewRMetas = maps:put(Realm, NewMeta, RMetas),
NextCX = CX#cx{realms = NewRMetas}, NextCX = CX#cx{realms = NewRMetas},
{MX, NextCX} {Unassigned, NextCX}
end, end,
ensure_connection(Realms, NewMX, NewCX); reassign_conns(Realms, NewCX, NewUnassigned);
ensure_connection([], MX, CX) -> reassign_conns([], CX, Unassigned) ->
{MX, CX}. {CX, Unassigned}.
-spec do_result(ID, Result, State) -> NewState -spec do_result(ID, Result, State) -> NewState
@ -915,7 +977,7 @@ handle_orphan_result(ID, Result, Dropped) ->
ok = log(info, Message, [ID, Request, Result]), ok = log(info, Message, [ID, Request, Result]),
NewDropped; NewDropped;
error -> error ->
Message = "Received unknown request result ~tp: ~tp", Message = "Received untracked request result ~tp: ~tp",
ok = log(warning, Message, [ID, Result]), ok = log(warning, Message, [ID, Result]),
Dropped Dropped
end. end.
@ -954,6 +1016,16 @@ eval_queue(State = #s{actions = Actions}) ->
eval_queue(InOrder, State#s{actions = []}). eval_queue(InOrder, State#s{actions = []}).
-spec eval_queue(Actions, State) -> NewState
when Actions :: [action()],
State :: state(),
NewState :: state().
%% @private
%% This is essentially a big, gnarly fold over the action list with State as the
%% accumulator. It repacks the State#s.actions list with whatever requests were not
%% able to be handled and updates State in whatever way necessary according to the
%% handled requests.
eval_queue([], State) -> eval_queue([], State) ->
State; State;
eval_queue([Action = {request, Pid, ID, Message} | Rest], eval_queue([Action = {request, Pid, ID, Message} | Rest],
@ -966,7 +1038,7 @@ eval_queue([Action = {request, Pid, ID, Message} | Rest],
{Actions, NextRequests, NextMX, NextCX}; {Actions, NextRequests, NextMX, NextCX};
{result, Response} -> {result, Response} ->
Pid ! Response, Pid ! Response,
{Actions, Requests, CX}; {Actions, Requests, MX, CX};
wait -> wait ->
NextActions = [Action | Actions], NextActions = [Action | Actions],
NextMX = mx_add_monitor(Pid, requestor, MX), NextMX = mx_add_monitor(Pid, requestor, MX),
@ -986,7 +1058,7 @@ eval_queue([Action = {subscribe, Pid, Package} | Rest],
ok = zx_conn:subscribe(Conn, Package), ok = zx_conn:subscribe(Conn, Package),
NextMX = mx_add_monitor(Pid, subscriber, MX), NextMX = mx_add_monitor(Pid, subscriber, MX),
{Actions, NextMX, NextCX}; {Actions, NextMX, NextCX};
{have_sub, NextCX} {have_sub, NextCX} ->
NextMX = mx_add_monitor(Pid, subscriber, MX), NextMX = mx_add_monitor(Pid, subscriber, MX),
{Actions, NextMX, NextCX}; {Actions, NextMX, NextCX};
unassigned -> unassigned ->
@ -1002,8 +1074,8 @@ eval_queue([{unsubscribe, Pid, Package} | Rest],
{ok, NewMX} = mx_del_monitor(Pid, {subscription, Package}, MX), {ok, NewMX} = mx_del_monitor(Pid, {subscription, Package}, MX),
NewCX = NewCX =
case cx_del_sub(Pid, Package, CX) of case cx_del_sub(Pid, Package, CX) of
{drop_sub, NextCX} -> {{drop_sub, ConnPid}, NextCX} ->
ok = zx_conn:unsubscribe(Conn, Package), ok = zx_conn:unsubscribe(ConnPid, Package),
NextCX; NextCX;
{keep_sub, NextCX} -> {keep_sub, NextCX} ->
NextCX; NextCX;
@ -1026,10 +1098,13 @@ eval_queue([{unsubscribe, Pid, Package} | Rest],
| wait, | wait,
NewCX :: conn_index(), NewCX :: conn_index(),
Response :: result(). Response :: result().
%% @private
%% Routes a request to the correct realm connector, if it is available. If it is not
%% available but configured it will return `wait' indicating that the caller should
%% repack the request and attempt to re-evaluate it later. If the realm is not
%% configured at all, the process is short-circuited by forming an error response
%% directly.
dispatch_request(list, ID, CX) ->
Realms = cx_realms(CX),
{result, ID, Realms};
dispatch_request(Action, ID, CX) -> dispatch_request(Action, ID, CX) ->
Realm = element(2, Action), Realm = element(2, Action),
case cx_pre_send(Realm, ID, CX) of case cx_pre_send(Realm, ID, CX) of
@ -1062,27 +1137,20 @@ clear_monitor(Pid,
mx = MX, mx = MX,
cx = CX}) -> cx = CX}) ->
case mx_crashed_monitor(Pid, MX) of case mx_crashed_monitor(Pid, MX) of
{attempt, NextMX} -> {attempt, NewMX} ->
failed( failed(Pid, State#s{mx = NewMX});
{conn, NextMX} -> {conn, NewMX} ->
disconnected(Pid, State#s{mx = NextMX}); disconnected(Pid, State#s{mx = NewMX});
{{Reqs, Subs}, NextMX} -> {{Reqs, Subs}, NewMX} ->
case mx_lookup_category(Pid, MX) of
attempt ->
do_report(Pid, failed, State);
conn ->
do_report(Pid, disconnected, State);
{Reqs, Subs} ->
NewActions = drop_actions(Pid, Actions), NewActions = drop_actions(Pid, Actions),
{NewDropped, NewRequests} = drop_requests(Pid, Dropped, Requests), {NewDropped, NewRequests} = drop_requests(Pid, Dropped, Requests),
NewCX = cx_clear_client(Pid, Reqs, Subs, CX), NewCX = cx_clear_client(Pid, Reqs, Subs, CX),
NewMX = mx_del_monitor(Pid, crashed, MX),
State#s{actions = NewActions, State#s{actions = NewActions,
requests = NewRequests, requests = NewRequests,
dropped = NewDropped, dropped = NewDropped,
mx = NewMX, mx = NewMX,
cx = NewCX}; cx = NewCX};
error -> unknown ->
Unexpected = {'DOWN', Ref, process, Pid, Reason}, Unexpected = {'DOWN', Ref, process, Pid, Reason},
ok = log(warning, "Unexpected info: ~tp", [Unexpected]), ok = log(warning, "Unexpected info: ~tp", [Unexpected]),
State State
@ -1121,116 +1189,8 @@ drop_requests(ReqIDs, Dropped, Requests) ->
lists:fold(Partition, {Dropped, Requests}, ReqIDs). lists:fold(Partition, {Dropped, Requests}, ReqIDs).
%-spec do_query_latest(Object, State) -> {Result, NewState}
% when Object :: zx:package() | zx:package_id(),
% State :: state(),
% Result :: {ok, zx:version()}
% | {error, Reason},
% Reason :: bad_realm
% | bad_package
% | bad_version,
% NewState :: state().
%% @private
%% Queries a zomp realm for the latest version of a package or package
%% version (complete or incomplete version number).
%
%do_query_latest(Socket, {Realm, Name}) ->
% ok = zx_net:send(Socket, {latest, Realm, Name}),
% receive
% {tcp, Socket, Bin} -> binary_to_term(Bin)
% after 5000 -> {error, timeout}
% end;
%do_query_latest(Socket, {Realm, Name, Version}) ->
% ok = zx_net:send(Socket, {latest, Realm, Name, Version}),
% receive
% {tcp, Socket, Bin} -> binary_to_term(Bin)
% after 5000 -> {error, timeout}
% end.
%-spec do_fetch(PackageIDs, State) -> NewState
% when PackageIDs :: [zx:package_id()],
% State :: state(),
% NewState :: state(),
% Result :: ok
% | {error, Reason},
% Reason :: bad_realm
% | bad_package
% | bad_version
% | network.
%% @private
%%
%
%do_fetch(PackageIDs, State) ->
% FIXME: Need to create a job queue divided by realm and dispatched to connectors,
% and cleared from the master pending queue kept here by the daemon as the
% workers succeed. Basic task queue management stuff... which never existed
% in ZX before... grrr...
% case scrub(PackageIDs) of
% [] ->
% ok;
% Needed ->
% Partitioned = partition_by_realm(Needed),
% EnsureDeps =
% fun({Realm, Packages}) ->
% ok = zx_conn:queue_package(Pid, Realm, Packages),
% log(info, "Disconnecting from realm: ~ts", [Realm])
% end,
% lists:foreach(EnsureDeps, Partitioned)
% end.
%
%
%partition_by_realm(PackageIDs) ->
% PartitionMap = lists:foldl(fun partition_by_realm/2, #{}, PackageIDs),
% maps:to_list(PartitionMap).
%
%
%partition_by_realm({R, P, V}, M) ->
% maps:update_with(R, fun(Ps) -> [{P, V} | Ps] end, [{P, V}], M).
%
%
%ensure_deps(_, _, []) ->
% ok;
%ensure_deps(Socket, Realm, [{Name, Version} | Rest]) ->
% ok = ensure_dep(Socket, {Realm, Name, Version}),
% ensure_deps(Socket, Realm, Rest).
%
%
%-spec ensure_dep(gen_tcp:socket(), package_id()) -> ok | no_return().
%% @private
%% Given an PackageID as an argument, check whether its package file exists in the
%% system cache, and if not download it. Should return `ok' whenever the file is
%% sourced, but exit with an error if it cannot locate or acquire the package.
%
%ensure_dep(Socket, PackageID) ->
% ZrpFile = filename:join("zrp", namify_zrp(PackageID)),
% ok =
% case filelib:is_regular(ZrpFile) of
% true -> ok;
% false -> fetch(Socket, PackageID)
% end,
% ok = install(PackageID),
% build(PackageID).
%
%
%-spec scrub(Deps) -> Scrubbed
% when Deps :: [package_id()],
% Scrubbed :: [package_id()].
%% @private
%% Take a list of dependencies and return a list of dependencies that are not yet
%% installed on the system.
%
%scrub([]) ->
% [];
%scrub(Deps) ->
% lists:filter(fun(PackageID) -> not zx_lib:installed(PackageID) end, Deps).
%%% Monitor Index ADT Interface Functions %%% Monitor Index ADT Interface Functions
%%%
%%% Very simple structure, but explicit handling of it becomes bothersome in other
%%% code, so it is all just packed down here.
-spec mx_new() -> monitor_index(). -spec mx_new() -> monitor_index().
%% @private %% @private
@ -1288,7 +1248,7 @@ mx_upgrade_conn(Pid, MX) ->
when Conn :: pid(), when Conn :: pid(),
Category :: attempt Category :: attempt
| conn | conn
| {requestor, id()}, | {requestor, id()}
| {subscriber, Sub :: tuple()}, | {subscriber, Sub :: tuple()},
MX :: monitor_index(), MX :: monitor_index(),
NewMX :: monitor_index(). NewMX :: monitor_index().
@ -1311,12 +1271,12 @@ mx_del_monitor(Pid, {requestor, ID}, MX) ->
true = demonitor(Ref, [flush]), true = demonitor(Ref, [flush]),
NextMX; NextMX;
{{Ref, {Reqs, Subs}}, NextMX} when Reqs > 0 -> {{Ref, {Reqs, Subs}}, NextMX} when Reqs > 0 ->
NewReqs = lists:subtract(ID, Reqs), NewReqs = lists:delete(ID, Reqs),
maps:put(Pid, {NewReqs, Subs}, NextMX) maps:put(Pid, {Ref, {NewReqs, Subs}}, NextMX)
end, end;
mx_del_monitor(Pid, {subscriber, Sub}, MX) -> mx_del_monitor(Pid, {subscriber, Sub}, MX) ->
case maps:take(Pid, MX) of case maps:take(Pid, MX) of
{{Ref, {[], [Package]}}, NextMX} -> {{Ref, {[], [Sub]}}, NextMX} ->
true = demonitor(Ref, [flush]), true = demonitor(Ref, [flush]),
NextMX; NextMX;
{{Ref, {Reqs, Subs}}, NextMX} when Subs > 0 -> {{Ref, {Reqs, Subs}}, NextMX} when Subs > 0 ->
@ -1338,27 +1298,10 @@ mx_del_monitor(Pid, {subscriber, Sub}, MX) ->
mx_crashed_monitor(Pid, MX) -> mx_crashed_monitor(Pid, MX) ->
case maps:take(Pid, MX) of case maps:take(Pid, MX) of
{{Ref, Type}, NewMX} -> {{Ref, Type}, NewMX} ->
true = demonitor(Mon, [flush]), true = demonitor(Ref, [flush]),
{Type, NewMX}; {Type, NewMX};
error -> error ->
error unknown
end.
-spec mx_lookup_category(Pid, MX) -> Result
when Pid :: pid(),
MX :: monitor_index(),
Result :: attempt
| conn
| {Reqs :: [reference()], Subs :: [zx:package()]}
| error.
%% @private
%% Lookup a monitor's categories.
mx_lookup_category(Pid, MX) ->
case maps:find(Pid, MX) of
{ok, Mon} -> element(2, Mon);
error -> error
end. end.
@ -1672,7 +1615,7 @@ cx_connected(Available, Pid, CX = #cx{attempts = Attempts}) ->
-spec cx_connected(A, Available, Conn, CX) -> {NewA, NewCX} -spec cx_connected(A, Available, Conn, CX) -> {NewA, NewCX}
when A :: unassigned | assigned, when A :: unassigned | assigned,
Available :: [{zx:realm(), zx:serial()}], Available :: [{zx:realm(), zx:serial()}],
Conn :: {pid(), zx:host(), [zx:realm()]}, Conn :: connection(),
CX :: conn_index(), CX :: conn_index(),
NewA :: unassigned | assigned, NewA :: unassigned | assigned,
NewCX :: conn_index(). NewCX :: conn_index().
@ -1704,7 +1647,7 @@ cx_connected(A,
-spec cx_connected(A, Realm, Conn, Meta, CX) -> {NewA, NewCX} -spec cx_connected(A, Realm, Conn, Meta, CX) -> {NewA, NewCX}
when A :: unassigned | assigned, when A :: unassigned | assigned,
Realm :: zx:host(), Realm :: zx:host(),
Conn :: {pid(), zx:host(), [zx:realm()]}, Conn :: connection(),
Meta :: realm_meta(), Meta :: realm_meta(),
CX :: conn_index(), CX :: conn_index(),
NewA :: unassigned | assigned, NewA :: unassigned | assigned,
@ -1785,6 +1728,12 @@ cx_failed(Conn, CX = #cx{attempts = Attempts}) ->
CX :: conn_index(), CX :: conn_index(),
Unassigned :: [zx:realm()], Unassigned :: [zx:realm()],
NewCX :: conn_index(). NewCX :: conn_index().
%% @private
%% Remove a redirected connection attempt from CX, add its redirect hosts to the
%% mirror queue, and proceed to make further connection atempts to all unassigned
%% realms. This can cause an inflationary number of new connection attempts, but this
%% is considered preferrable because the more mirrors fail the longer the user is
%% waiting and the more urgent the need to discover a working node becomes.
cx_redirect(Conn, Hosts, CX = #cx{attempts = Attempts}) -> cx_redirect(Conn, Hosts, CX = #cx{attempts = Attempts}) ->
NewAttempts = lists:keydelete(Conn, 1, Attempts), NewAttempts = lists:keydelete(Conn, 1, Attempts),
@ -1810,7 +1759,7 @@ cx_redirect([{Host, Provided} | Rest], CX = #cx{realms = Realms}) ->
NewMeta = Meta#rmeta{mirrors = NewMirrors}, NewMeta = Meta#rmeta{mirrors = NewMirrors},
maps:put(R, NewMeta, Rs); maps:put(R, NewMeta, Rs);
error -> error ->
R Rs
end end
end, end,
NewRealms = lists:foldl(Apply, Realms, Provided), NewRealms = lists:foldl(Apply, Realms, Provided),
@ -1823,7 +1772,7 @@ cx_redirect([], CX) ->
when CX :: conn_index(), when CX :: conn_index(),
Unassigned :: [zx:realm()]. Unassigned :: [zx:realm()].
%% @private %% @private
%% Scan the CX record for unassigned realms;return a list of all unassigned %% Scan CX#cx.realms for unassigned realms and return a list of all unassigned
%% realm names. %% realm names.
cx_unassigned(#cx{realms = Realms}) -> cx_unassigned(#cx{realms = Realms}) ->
@ -1837,12 +1786,13 @@ cx_unassigned(#cx{realms = Realms}) ->
maps:fold(NotAssigned, [], Realms). maps:fold(NotAssigned, [], Realms).
-spec cx_disconnected(Conn, CX) -> {Requests, Subs, NewCX} -spec cx_disconnected(Conn, CX) -> {Requests, Subs, Unassigned, NewCX}
when Conn :: pid(), when Conn :: pid(),
CX :: conn_index(), CX :: conn_index(),
Requests :: [reference()], Requests :: [id()],
Subs :: [zx:package()], Subs :: [zx:package()],
NewCX :: conn_index(). Unassigned :: [zx:realm()],
NewCX :: conn_index().
%% @private %% @private
%% An abstract data handler which is called whenever a connection terminates. %% An abstract data handler which is called whenever a connection terminates.
%% This function removes all data related to the disconnected pid and its assigned %% This function removes all data related to the disconnected pid and its assigned
@ -1854,7 +1804,8 @@ cx_disconnected(Pid, CX = #cx{realms = Realms, conns = Conns}) ->
#conn{host = Host, requests = Requests, subs = Subs} = Conn, #conn{host = Host, requests = Requests, subs = Subs} = Conn,
NewRealms = cx_scrub_assigned(Pid, Host, Realms), NewRealms = cx_scrub_assigned(Pid, Host, Realms),
NewCX = CX#cx{realms = NewRealms, conns = NewConns}, NewCX = CX#cx{realms = NewRealms, conns = NewConns},
{Requests, Subs, NewCX}. Unassigned = cx_unassigned(NewCX),
{Requests, Subs, Unassigned, NewCX}.
-spec cx_scrub_assigned(Pid, Host, Realms) -> NewRealms -spec cx_scrub_assigned(Pid, Host, Realms) -> NewRealms
@ -1960,11 +1911,11 @@ cx_add_sub(Subscriber, Channel, CX = #cx{conns = Conns}) ->
NewCX :: conn_index(). NewCX :: conn_index().
cx_maybe_new_sub(Conn = #conn{pid = ConnPid, subs = Subs}, cx_maybe_new_sub(Conn = #conn{pid = ConnPid, subs = Subs},
Sub = {Subscriber, Channel}, Sub = {_, Channel},
CX = #cx{conns = Conns}) -> CX = #cx{conns = Conns}) ->
NewSubs = [{Subscriber, Channel} | Subs], NewSubs = [Sub | Subs],
NewConn = Conn#conn{subs = NewSubs}, NewConn = Conn#conn{subs = NewSubs},
NewConns = [NewConn | NextConns], NewConns = [NewConn | Conns],
NewCX = CX#cx{conns = NewConns}, NewCX = CX#cx{conns = NewConns},
case lists:keymember(Channel, 2, Subs) of case lists:keymember(Channel, 2, Subs) of
false -> {need_sub, ConnPid, NewCX}; false -> {need_sub, ConnPid, NewCX};
@ -1990,25 +1941,35 @@ cx_del_sub(Subscriber, Channel, CX = #cx{conns = Conns}) ->
case cx_resolve(Realm, CX) of case cx_resolve(Realm, CX) of
{ok, Pid} -> {ok, Pid} ->
{value, Conn, NewConns} = lists:keytake(Pid, #conn.pid, Conns), {value, Conn, NewConns} = lists:keytake(Pid, #conn.pid, Conns),
cx_maybe_last_sub(Conn, {Subscriber, Channel}, CX#cx{conns = NewConns}; cx_maybe_last_sub(Conn, {Subscriber, Channel}, CX#cx{conns = NewConns});
Other -> Other ->
Other Other
end. end.
-spec cx_maybe_last_sub(Conn, Sub, CX) -> {Verdict, NewCX}
when Conn :: connection(),
Sub :: {pid(), term()},
CX :: conn_index(),
Verdict :: {drop_sub, Conn :: pid()} | keep_sub,
NewCX :: conn_index().
%% @private
%% Tells us whether a sub is still valid for any clients. If a sub is unsubbed by all
%% then it needs to be unsubscribed at the upstream node.
cx_maybe_last_sub(Conn = #conn{pid = ConnPid, subs = Subs}, cx_maybe_last_sub(Conn = #conn{pid = ConnPid, subs = Subs},
Sub = {Subscriber, Channel}, Sub = {_, Channel},
CX = #cx{conns = Conns}) -> CX = #cx{conns = Conns}) ->
NewSubs = lists:delete(Sub, Subs), NewSubs = lists:delete(Sub, Subs),
NewConn = Conn#conn{subs = NewSubs}, NewConn = Conn#conn{subs = NewSubs},
NewConns = [NewConn | NextConns], NewConns = [NewConn | Conns],
NewCX = CX#cx{conns = NewConns}, NewCX = CX#cx{conns = NewConns},
MaybeDrop = Verdict =
case lists:keymember(Channel, 2, NewSubs) of case lists:keymember(Channel, 2, NewSubs) of
false -> drop_sub; false -> {drop_sub, ConnPid};
true -> keep_sub true -> keep_sub
end, end,
{MaybeDrop, NewCX}. {Verdict, NewCX}.
-spec cx_get_subscribers(Conn, Channel, CX) -> Subscribers -spec cx_get_subscribers(Conn, Channel, CX) -> Subscribers
@ -2022,6 +1983,16 @@ cx_get_subscribers(Conn, Channel, #cx{conns = Conns}) ->
lists:fold(registered_to(Channel), [], Subs). lists:fold(registered_to(Channel), [], Subs).
-spec registered_to(Channel) -> fun(({P, C}, A) -> NewA)
when Channel :: term(),
P :: pid(),
C :: term(),
A :: [pid()],
NewA :: [pid()].
%% @private
%% Matching function that closes over a given channel in a subscriber list.
%% This function exists mostly to make its parent function read nicely.
registered_to(Channel) -> registered_to(Channel) ->
fun({P, C}, A) -> fun({P, C}, A) ->
case C == Channel of case C == Channel of
@ -2031,8 +2002,15 @@ registered_to(Channel) ->
end. end.
-spec cx_clear_client(Pid, DeadReqs, DeadSubs, CX) -> NewCX
when Pid :: pid(),
DeadReqs :: [id()],
DeadSubs :: [term()],
CX :: conn_index(),
NewCX :: conn_index().
cx_clear_client(Pid, DeadReqs, DeadSubs, CX = #cx{conns = Conns}) -> cx_clear_client(Pid, DeadReqs, DeadSubs, CX = #cx{conns = Conns}) ->
DropSubs = [{S, Pid} || S <- DeadSubs], DropSubs = [{Pid, Sub} || Sub <- DeadSubs],
Clear = Clear =
fun(C = #conn{requests = Requests, subs = Subs}) -> fun(C = #conn{requests = Requests, subs = Subs}) ->
NewSubs = lists:subtract(Subs, DropSubs), NewSubs = lists:subtract(Subs, DropSubs),