factotum/nats.zig
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all: don't automatically convert userdata types to pointer types

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One of the things I have done a better job of internalizing while
working with zig over the last few months is that the less magic that
exists, the better. In the case of parameterized functions, this means
that it is much better to restrict the range of types that are
permitted to be passed than to perform type manipulation. In other
words, it's more confusing to see a function that is parameterized
with `SomeType` taking a pointer to that type than having it be
parameterized directly to take the pointer. Obviously there are
exceptions to this rule, like std.mem.eql taking slices of its
parameterized type.

In fact, this new approach fixes some edge cases. Null userdata may now
be passed in, since the user can now actually specify an optional
pointer type (e.g. `?*void` may be used to provide always-null
userdata). Additionally, a pointer to a constant value can now be
passed in, which wasn't possible before (this could have been worked
around by use of constCast and being careful, but that's an
exceedingly bad option compared to having the type system work for
you).
This commit is contained in:
torque 2024-01-01 15:11:21 -08:00
parent b28a91b97f
commit 3462b3cdb6
Signed by: torque
SSH Key Fingerprint: SHA256:nCrXefBNo6EbjNSQhv0nXmEg/VuNq3sMF5b8zETw3Tk
6 changed files with 102 additions and 66 deletions
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4
examples/request_reply.zig
View File

@ -29,10 +29,10 @@ pub fn main() !void {
defer connection.destroy();
var count: u32 = 0;
const subscription = try connection.subscribe(u32, "channel", onMessage, &count);
const subscription = try connection.subscribe(*u32, "channel", onMessage, &count);
defer subscription.destroy();
while (count < 10) : (nats.sleep(1000)) {
while (count < 10) : (nats.sleep(100)) {
const reply = try connection.request("channel", "greetings", 1000);
defer reply.destroy();

103
src/connection.zig
View File

@ -18,24 +18,21 @@ pub const nats_c = @cImport({
@cInclude("nats/nats.h");
});
const sub_ = @import("./subscription.zig");
const Subscription = sub_.Subscription;
const SubscriptionCallbackSignature = sub_.SubscriptionCallbackSignature;
const makeSubscriptionCallbackThunk = sub_.makeSubscriptionCallbackThunk;
const Subscription = @import("./subscription.zig").Subscription;
const SubscriptionCallbackSignature = @import("./subscription.zig").SubscriptionCallbackSignature;
const makeSubscriptionCallbackThunk = @import("./subscription.zig").makeSubscriptionCallbackThunk;
const msg_ = @import("./message.zig");
const Message = msg_.Message;
const Message = @import("./message.zig").Message;
const err_ = @import("./error.zig");
const Error = err_.Error;
const Status = err_.Status;
const ErrorInfo = err_.ErrorInfo;
const Error = @import("./error.zig").Error;
const Status = @import("./error.zig").Status;
const ErrorInfo = @import("./error.zig").ErrorInfo;
const sta_ = @import("./statistics.zig");
const Statistics = sta_.Statistics;
const StatsCounts = sta_.StatsCounts;
const Statistics = @import("./statistics.zig").Statistics;
const StatsCounts = @import("./statistics.zig").StatsCounts;
const thunk = @import("./thunk.zig");
const checkUserDataType = @import("./thunk.zig").checkUserDataType;
pub const default_server_url: [:0]const u8 = nats_c.NATS_DEFAULT_URL;
@ -343,7 +340,7 @@ pub const Connection = opaque {
comptime T: type,
subject: [:0]const u8,
callback: SubscriptionCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!*Subscription {
var sub: *Subscription = undefined;
const status = Status.fromInt(nats_c.natsConnection_Subscribe(
@ -362,7 +359,7 @@ pub const Connection = opaque {
subject: [:0]const u8,
timeout: i64,
callback: SubscriptionCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!*Subscription {
var sub: *Subscription = undefined;
@ -396,7 +393,7 @@ pub const Connection = opaque {
subject: [:0]const u8,
queue_group: [:0]const u8,
callback: SubscriptionCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!*Subscription {
var sub: *Subscription = undefined;
@ -419,7 +416,7 @@ pub const Connection = opaque {
queue_group: [:0]const u8,
timeout: i64,
callback: SubscriptionCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!*Subscription {
var sub: *Subscription = undefined;
@ -502,7 +499,7 @@ pub const ConnectionOptions = opaque {
self: *ConnectionOptions,
comptime T: type,
comptime callback: *const TokenCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetTokenHandler(
@ptrCast(self),
@ -641,7 +638,7 @@ pub const ConnectionOptions = opaque {
self: *ConnectionOptions,
comptime T: type,
comptime callback: *const ReconnectDelayCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!void {
return Status.fromInt(
nats_c.natsOptions_SetCustomReconnectDelay(
@ -668,7 +665,7 @@ pub const ConnectionOptions = opaque {
self: *ConnectionOptions,
comptime T: type,
comptime callback: *const ErrorHandlerCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!void {
return Status.fromInt(
nats_c.natsOptions_SetErrorHandler(
@ -683,7 +680,7 @@ pub const ConnectionOptions = opaque {
self: *ConnectionOptions,
comptime T: type,
comptime callback: *const ConnectionCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetClosedCB(
@ptrCast(self),
@ -696,7 +693,7 @@ pub const ConnectionOptions = opaque {
self: *ConnectionOptions,
comptime T: type,
comptime callback: *const ConnectionCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetClosedCB(
@ptrCast(self),
@ -709,7 +706,7 @@ pub const ConnectionOptions = opaque {
self: *ConnectionOptions,
comptime T: type,
comptime callback: *const ConnectionCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetClosedCB(
@ptrCast(self),
@ -722,7 +719,7 @@ pub const ConnectionOptions = opaque {
self: *ConnectionOptions,
comptime T: type,
comptime callback: *const ConnectionCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetClosedCB(
@ptrCast(self),
@ -735,7 +732,7 @@ pub const ConnectionOptions = opaque {
self: *ConnectionOptions,
comptime T: type,
comptime callback: *const ConnectionCallbackSignature(T),
userdata: *T,
userdata: T,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetClosedCB(
@ptrCast(self),
@ -752,7 +749,7 @@ pub const ConnectionOptions = opaque {
comptime read_callback: *const AttachEventLoopCallbackSignature(T),
comptime write_callback: *const AttachEventLoopCallbackSignature(T),
comptime detach_callback: *const thunk.SimpleCallbackSignature(T),
loop: *L,
loop: L,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetEventLoop(
@ptrCast(self),
@ -819,7 +816,7 @@ pub const ConnectionOptions = opaque {
comptime T: type,
comptime callback: *const ConnectionCallbackSignature(T),
retry: bool,
userdata: *T,
userdata: T,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetRetryOnFailedConnect(
@ptrCast(self),
@ -835,8 +832,8 @@ pub const ConnectionOptions = opaque {
comptime U: type,
comptime jwt_callback: *const JwtHandlerCallbackSignature(T),
comptime sig_callback: *const SignatureHandlerCallbackSignature(U),
jwt_userdata: *T,
sig_userdata: *U,
jwt_userdata: T,
sig_userdata: U,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetUserCredentialsCallbacks(
@ptrCast(self),
@ -871,7 +868,7 @@ pub const ConnectionOptions = opaque {
comptime T: type,
comptime sig_callback: *const SignatureHandlerCallbackSignature(T),
pub_key: [:0]const u8,
sig_userdata: *T,
sig_userdata: T,
) Error!void {
return Status.fromInt(nats_c.natsOptions_SetUserCredentialsCallbacks(
@ptrCast(self),
@ -919,16 +916,17 @@ pub const ConnectionOptions = opaque {
const TokenCallback = fn (?*anyopaque) callconv(.C) [*c]const u8;
pub fn TokenCallbackSignature(comptime T: type) type {
return fn (*T) [:0]const u8;
return fn (T) [:0]const u8;
}
fn makeTokenCallbackThunk(
comptime T: type,
comptime callback: *const TokenCallbackSignature(T),
) *const TokenCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(userdata: ?*anyopaque) callconv(.C) [*c]const u8 {
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const data: T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
return callback(data).ptr;
}
}.thunk;
@ -937,17 +935,18 @@ fn makeTokenCallbackThunk(
const ConnectionCallback = fn (?*nats_c.natsConnection, ?*anyopaque) callconv(.C) void;
pub fn ConnectionCallbackSignature(comptime T: type) type {
return fn (*T, *Connection) void;
return fn (T, *Connection) void;
}
fn makeConnectionCallbackThunk(
comptime T: type,
comptime callback: *const ConnectionCallbackSignature(T),
) *const ConnectionCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(conn: ?*nats_c.natsConnection, userdata: ?*anyopaque) callconv(.C) void {
const connection: *Connection = if (conn) |c| @ptrCast(c) else unreachable;
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const data: T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
callback(data, connection);
}
}.thunk;
@ -956,13 +955,14 @@ fn makeConnectionCallbackThunk(
const ReconnectDelayCallback = fn (?*nats_c.natsConnection, c_int, ?*anyopaque) callconv(.C) i64;
pub fn ReconnectDelayCallbackSignature(comptime T: type) type {
return fn (*T, *Connection, c_int) i64;
return fn (T, *Connection, c_int) i64;
}
fn makeReconnectDelayCallbackThunk(
comptime T: type,
comptime callback: *const ReconnectDelayCallbackSignature(T),
) *const ReconnectDelayCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(
conn: ?*nats_c.natsConnection,
@ -970,7 +970,7 @@ fn makeReconnectDelayCallbackThunk(
userdata: ?*anyopaque,
) callconv(.C) i64 {
const connection: *Connection = if (conn) |c| @ptrCast(c) else unreachable;
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const data: T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
return callback(data, connection, attempts);
}
}.thunk;
@ -984,13 +984,14 @@ const ErrorHandlerCallback = fn (
) callconv(.C) void;
pub fn ErrorHandlerCallbackSignature(comptime T: type) type {
return fn (*T, *Connection, *Subscription, Status) void;
return fn (T, *Connection, *Subscription, Status) void;
}
fn makeErrorHandlerCallbackThunk(
comptime T: type,
comptime callback: *const ErrorHandlerCallbackSignature(T),
) *const ErrorHandlerCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(
conn: ?*nats_c.natsConnection,
@ -1000,7 +1001,7 @@ fn makeErrorHandlerCallbackThunk(
) callconv(.C) void {
const connection: *Connection = if (conn) |c| @ptrCast(c) else unreachable;
const subscription: *Subscription = if (sub) |s| @ptrCast(s) else unreachable;
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const data: T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
callback(data, connection, subscription, Status.fromInt(status));
}
@ -1016,7 +1017,7 @@ const AttachEventLoopCallback = fn (
) callconv(.C) nats_c.natsStatus;
pub fn AttachEventLoopCallbackSignature(comptime T: type, comptime L: type) type {
return fn (*L, *Connection, c_int) anyerror!*T;
return fn (L, *Connection, c_int) anyerror!T;
}
fn makeAttachEventLoopCallbackThunk(
@ -1024,6 +1025,8 @@ fn makeAttachEventLoopCallbackThunk(
comptime L: type,
comptime callback: *const AttachEventLoopCallbackSignature(T, L),
) *const ReconnectDelayCallback {
comptime checkUserDataType(T);
comptime checkUserDataType(L);
return struct {
fn thunk(
userdata: *?*anyopaque,
@ -1032,7 +1035,7 @@ fn makeAttachEventLoopCallbackThunk(
sock: ?*nats_c.natsSock,
) callconv(.C) nats_c.natsStatus {
const connection: *Connection = if (conn) |c| @ptrCast(c) else unreachable;
const ev_loop: *L = if (loop) |l| @ptrCast(l) else unreachable;
const ev_loop: L = if (loop) |l| @alignCast(@ptrCast(l)) else unreachable;
userdata.* = callback(ev_loop, connection, sock) catch |err|
return Status.fromError(err).toInt();
@ -1045,13 +1048,14 @@ fn makeAttachEventLoopCallbackThunk(
const EventLoopAddRemoveCallback = fn (?*nats_c.natsConnection, c_int, ?*anyopaque) callconv(.C) nats_c.natsStatus;
pub fn EventLoopAddRemoveCallbackSignature(comptime T: type) type {
return fn (*T, *Connection, c_int) anyerror!void;
return fn (T, *Connection, c_int) anyerror!void;
}
fn makeEventLoopAddRemoveCallbackThunk(
comptime T: type,
comptime callback: *const EventLoopAddRemoveCallbackSignature(T),
) *const ReconnectDelayCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(
conn: ?*nats_c.natsConnection,
@ -1059,7 +1063,7 @@ fn makeEventLoopAddRemoveCallbackThunk(
userdata: ?*anyopaque,
) callconv(.C) nats_c.natsStatus {
const connection: *Connection = if (conn) |c| @ptrCast(c) else unreachable;
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const data: T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
callback(data, connection, attempts) catch |err|
return Status.fromError(err).toInt();
@ -1071,18 +1075,19 @@ fn makeEventLoopAddRemoveCallbackThunk(
const EventLoopDetachCallback = fn (?*anyopaque) callconv(.C) nats_c.natsStatus;
pub fn EventLoopDetachCallbackSignature(comptime T: type) type {
return fn (*T) anyerror!void;
return fn (T) anyerror!void;
}
fn makeEventLoopDetachCallbackThunk(
comptime T: type,
comptime callback: *const EventLoopDetachCallbackSignature(T),
) *const ReconnectDelayCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(
userdata: ?*anyopaque,
) callconv(.C) nats_c.natsStatus {
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const data: T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
callback(data) catch |err| return Status.fromError(err).toInt();
return nats_c.NATS_OK;
}
@ -1099,20 +1104,21 @@ pub const JwtResponseOrError = union(enum) {
};
pub fn JwtHandlerCallbackSignature(comptime T: type) type {
return fn (*T) JwtResponseOrError;
return fn (T) JwtResponseOrError;
}
fn makeJwtHandlerCallbackThunk(
comptime T: type,
comptime callback: *const JwtHandlerCallbackSignature(T),
) *const JwtHandlerCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(
jwt_out_raw: ?*?[*:0]u8,
err_out_raw: ?*?[*:0]u8,
userdata: ?*anyopaque,
) callconv(.C) nats_c.natsStatus {
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const data: T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const err_out = err_out_raw orelse unreachable;
const jwt_out = jwt_out_raw orelse unreachable;
@ -1140,13 +1146,14 @@ pub const SignatureResponseOrError = union(enum) {
};
pub fn SignatureHandlerCallbackSignature(comptime T: type) type {
return fn (*T, [:0]const u8) SignatureResponseOrError;
return fn (T, [:0]const u8) SignatureResponseOrError;
}
fn makeSignatureHandlerCallbackThunk(
comptime T: type,
comptime callback: *const SignatureHandlerCallbackSignature(T),
) *const SignatureHandlerCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(
err_out_raw: ?*?[*:0]u8,
@ -1155,7 +1162,7 @@ fn makeSignatureHandlerCallbackThunk(
nonsense: ?[*:0]const u8,
userdata: ?*anyopaque,
) callconv(.C) nats_c.natsStatus {
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const data: T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const nonce = nonsense orelse unreachable;
const err_out = err_out_raw orelse unreachable;
const sig_out = sig_out_raw orelse unreachable;

6
src/subscription.zig
View File

@ -27,6 +27,7 @@ const Error = err_.Error;
const Status = err_.Status;
const thunk = @import("./thunk.zig");
const checkUserDataType = @import("./thunk.zig").checkUserDataType;
pub const Subscription = opaque {
pub const MessageCount = struct {
@ -191,13 +192,14 @@ const SubscriptionCallback = fn (
) callconv(.C) void;
pub fn SubscriptionCallbackSignature(comptime T: type) type {
return fn (*T, *Connection, *Subscription, *Message) void;
return fn (T, *Connection, *Subscription, *Message) void;
}
pub fn makeSubscriptionCallbackThunk(
comptime T: type,
comptime callback: *const SubscriptionCallbackSignature(T),
) *const SubscriptionCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(
conn: ?*nats_c.natsConnection,
@ -211,7 +213,7 @@ pub fn makeSubscriptionCallbackThunk(
const connection: *Connection = if (conn) |c| @ptrCast(c) else unreachable;
const subscription: *Subscription = if (sub) |s| @ptrCast(s) else unreachable;
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
const data: T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;
callback(data, connection, subscription, message);
}

29
src/thunk.zig
View File

@ -18,16 +18,43 @@ pub const nats_c = @cImport({
@cInclude("nats/nats.h");
});
pub fn checkUserDataType(comptime T: type) void {
switch (@typeInfo(T)) {
.Optional => |info| switch (@typeInfo(info.child)) {
.Optional => @compileError(
"nats callbacks can only accept an (optional) single, many," ++
" or c pointer as userdata, not slices. \"" ++
@typeName(T) ++ "\" has more than one optional specifier.",
),
else => checkUserDataType(info.child),
},
.Pointer => |info| switch (info.size) {
.Slice => @compileError(
"nats callbacks can only accept an (optional) single, many," ++
" or c pointer as userdata, not slices. \"" ++
@typeName(T) ++ "\" appears to be a slice.",
),
else => {},
},
else => @compileError(
"nats callbacks can only accept an (optional) single, many," ++
" or c pointer as userdata, not slices. \"" ++
@typeName(T) ++ "\" is not a pointer type.",
),
}
}
const SimpleCallback = fn (?*anyopaque) callconv(.C) void;
pub fn SimpleCallbackThunkSignature(comptime T: type) type {
return fn (*T) void;
return fn (T) void;
}
pub fn makeSimpleCallbackThunk(
comptime T: type,
comptime callback: *const SimpleCallbackThunkSignature(T),
) *const SimpleCallback {
comptime checkUserDataType(T);
return struct {
fn thunk(userdata: ?*anyopaque) callconv(.C) void {
const data: *T = if (userdata) |u| @alignCast(@ptrCast(u)) else unreachable;

18
tests/connection.zig
View File

@ -164,14 +164,14 @@ test "nats.ConnectionOptions" {
try options.setMaxReconnect(10);
try options.setReconnectWait(500);
try options.setReconnectJitter(100, 200);
try options.setCustomReconnectDelay(u32, reconnectDelayHandler, &userdata);
try options.setCustomReconnectDelay(*u32, reconnectDelayHandler, &userdata);
try options.setReconnectBufSize(1024);
try options.setMaxPendingMessages(50);
try options.setErrorHandler(u32, errorHandler, &userdata);
try options.setClosedCallback(u32, connectionHandler, &userdata);
try options.setDisconnectedCallback(u32, connectionHandler, &userdata);
try options.setDiscoveredServersCallback(u32, connectionHandler, &userdata);
try options.setLameDuckModeCallback(u32, connectionHandler, &userdata);
try options.setErrorHandler(*u32, errorHandler, &userdata);
try options.setClosedCallback(*u32, connectionHandler, &userdata);
try options.setDisconnectedCallback(*u32, connectionHandler, &userdata);
try options.setDiscoveredServersCallback(*u32, connectionHandler, &userdata);
try options.setLameDuckModeCallback(*u32, connectionHandler, &userdata);
try options.ignoreDiscoveredServers(true);
try options.useGlobalMessageDelivery(false);
try options.ipResolutionOrder(.ipv4_first);
@ -179,8 +179,8 @@ test "nats.ConnectionOptions" {
try options.useOldRequestStyle(false);
try options.setFailRequestsOnDisconnect(true);
try options.setNoEcho(true);
try options.setRetryOnFailedConnect(u32, connectionHandler, true, &userdata);
try options.setUserCredentialsCallbacks(u32, u32, jwtHandler, signatureHandler, &userdata, &userdata);
try options.setRetryOnFailedConnect(*u32, connectionHandler, true, &userdata);
try options.setUserCredentialsCallbacks(*u32, *u32, jwtHandler, signatureHandler, &userdata, &userdata);
try options.setWriteDeadline(5);
try options.disableNoResponders(true);
try options.setCustomInboxPrefix("_FOOBOX");
@ -200,7 +200,7 @@ test "nats.ConnectionOptions (crypto edition)" {
defer options.destroy();
var userdata: u32 = 0;
try options.setTokenHandler(u32, tokenHandler, &userdata);
try options.setTokenHandler(*u32, tokenHandler, &userdata);
try options.setSecure(false);
try options.setCertificatesChain(rsa_cert, rsa_key);
try options.setCiphers("-ALL:HIGH");

8
tests/subscription.zig
View File

@ -113,7 +113,7 @@ test "nats.Subscription (async)" {
{
var count: u32 = 0;
const subscription = try connection.subscribe(u32, message_subject, onMessage, &count);
const subscription = try connection.subscribe(*u32, message_subject, onMessage, &count);
defer subscription.destroy();
const response = try connection.requestMessage(message, 1000);
@ -126,7 +126,7 @@ test "nats.Subscription (async)" {
{
var count: u32 = 0;
const subscription = try connection.subscribeTimeout(
u32,
*u32,
message_subject,
1000,
onMessage,
@ -144,7 +144,7 @@ test "nats.Subscription (async)" {
{
var count: u32 = 0;
const subscription = try connection.queueSubscribe(
u32,
*u32,
message_subject,
"queuegroup",
onMessage,
@ -162,7 +162,7 @@ test "nats.Subscription (async)" {
{
var count: u32 = 0;
const subscription = try connection.queueSubscribeTimeout(
u32,
*u32,
message_subject,
"queuegroup",
1000,