Files
logos-protocol/cpp/logos_transport_factory.cpp
T
Dario LipicarandClaude Opus 5 ae2f7e1b58 fix(lp): create Qt-affine clients on the Qt main thread (#28)
lp_client_create() made the CALLING thread the client's owner thread. Callers
reach it through a lazily-created wrapper (the generated bind_<iface>() ->
LpClient::ensure()), so the first thread to make an outbound call captured the
whole transport for the life of the process.

For the qt_remote transport that thread also ends up owning the
QRemoteObjectNode and its QLocalSocket, which are only serviced by a thread
running a Qt event loop. A module whose first call came from a worker — an HTTP
handler, a timer thread — bound its transport to a thread that only pumps
events while it is already blocked inside a call. Replica acquisition then
never completed: every requestObject() burned its full 20s timeout and returned
nullptr, and since a failed acquire yields an empty result the data loss was
silent. openmetrics-module hit exactly this: one GET /metrics took 40s (2 x 20s)
and came back missing a module, /health went unanswered behind the wedged
libmicrohttpd thread, and the follow-up stop RPC failed.

Construct the client on the Qt main thread when the transport needs a Qt event
loop, so the per-call marshal that already exists (logos::runOnOwnerThread)
lands somewhere that can actually service it. This is the anchor the Qt path
always had — LogosAPI::getClient marshals construction to the LogosAPI's thread
— given to the lp path.

Plain (tcp/tcp_ssl) and mock transports are Qt-free and thread-agnostic, so
they keep the calling thread: a worker-thread consumer stays off the main
thread's back. LogosTransportFactory::needsQtEventLoop() carries that rule next
to the createConnection resolution it mirrors. When there is nothing to anchor
to (a Qt-affine transport with no QCoreApplication) we now warn instead of
letting it surface as a mute timeout.

Tests: a worker thread creates an lp client over qt_remote and calls a provider
published on the main thread; passes in ~0.15s, and with the construction hop
reverted fails after 24.8s / 49.9s — the acquire timeouts themselves. Plus a
truth table for needsQtEventLoop. 183/183 protocol tests pass.

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
2026-07-26 08:31:00 -03:00

104 lines
3.8 KiB
C++

#include "logos_transport_factory.h"
#include "logos_transport.h"
#include "logos_mode.h"
#include "logos_transport_config.h"
#include "implementations/qt_local/local_transport.h"
#include "implementations/qt_remote/remote_transport.h"
#include "implementations/mock/mock_transport.h"
#include "implementations/plain/plain_transport_connection.h"
#include "implementations/plain/plain_transport_host.h"
#include <QDebug>
namespace LogosTransportFactory {
// Single resolution rule for both `createHost` overloads:
// LogosMode::Mock → MockTransportHost (cfg ignored)
// LogosMode::Local → LocalTransportHost (cfg ignored)
// LogosMode::Remote + LocalSocket → RemoteTransportHost (QRO)
// LogosMode::Remote + Tcp/TcpSsl → PlainTransportHost(cfg)
//
// Mode is consulted *first* so test fixtures setting Mock/Local always
// get the right transport regardless of which createHost overload (or
// LogosAPIProvider constructor) was used. The no-cfg overload below
// just delegates with `LogosTransportConfigGlobal::getDefault()` so
// there's exactly one path.
std::unique_ptr<LogosTransportHost>
createHost(const LogosTransportConfig& cfg, const QString& registryUrl)
{
if (LogosModeConfig::isLocal()) {
return std::make_unique<LocalTransportHost>();
}
if (LogosModeConfig::isMock()) {
return std::make_unique<MockTransportHost>();
}
switch (cfg.protocol) {
case LogosProtocol::Tcp:
case LogosProtocol::TcpSsl: {
auto host = std::make_unique<logos::plain::PlainTransportHost>(cfg);
if (!host->start()) {
qCritical() << "LogosTransportFactory: PlainTransportHost::start() failed";
return nullptr;
}
return host;
}
case LogosProtocol::LocalSocket:
default:
return std::make_unique<RemoteTransportHost>(registryUrl);
}
}
std::unique_ptr<LogosTransportHost> createHost(const QString& registryUrl)
{
return createHost(LogosTransportConfigGlobal::getDefault(), registryUrl);
}
// Same resolution rule as createHost — see the comment block above.
std::unique_ptr<LogosTransportConnection>
createConnection(const LogosTransportConfig& cfg, const QString& registryUrl)
{
if (LogosModeConfig::isLocal()) {
return std::make_unique<LocalTransportConnection>();
}
if (LogosModeConfig::isMock()) {
return std::make_unique<MockTransportConnection>();
}
switch (cfg.protocol) {
case LogosProtocol::Tcp:
case LogosProtocol::TcpSsl:
return std::make_unique<logos::plain::PlainTransportConnection>(cfg);
case LogosProtocol::LocalSocket:
default:
return std::make_unique<RemoteTransportConnection>(registryUrl);
}
}
std::unique_ptr<LogosTransportConnection> createConnection(const QString& registryUrl)
{
return createConnection(LogosTransportConfigGlobal::getDefault(), registryUrl);
}
// Same resolution rule as createConnection, answering "does the connection this
// cfg resolves to have to live on a thread with a Qt event loop?".
// Local → LocalTransportConnection: invokes in-process QObjects owned by
// the module's main thread. → yes
// Mock → MockTransportConnection: no Qt objects, no sockets. → no
// LocalSocket→ RemoteTransportConnection: QRemoteObjectNode + QLocalSocket;
// acquire and reply delivery both need the owner's loop. → yes
// Tcp/TcpSsl → PlainTransportConnection: Qt-free by design. → no
bool needsQtEventLoop(const LogosTransportConfig& cfg)
{
if (LogosModeConfig::isLocal()) return true;
if (LogosModeConfig::isMock()) return false;
switch (cfg.protocol) {
case LogosProtocol::Tcp:
case LogosProtocol::TcpSsl:
return false;
case LogosProtocol::LocalSocket:
default:
return true;
}
}
}