structured compute basics (#714)

this change adds the `zencompute` component, which can be used to distribute work dispatched from UE using the DDB (Derived Data Build) APIs via zenserver

this change also adds a distinct zenserver compute mode (`zenserver compute`) which is intended to be used for leaf compute nodes

to exercise the compute functionality without directly involving UE, a `zen exec` subcommand is also added, which can be used to feed replays through the system

all new functionality is considered *experimental* and disabled by default at this time, behind the `zencompute` option in xmake config

1 files changed, 100 insertions, 0 deletions

diff --git a/src/zenserver/compute/computeservice.cpp b/src/zenserver/compute/computeservice.cpp
new file mode 100644
index 000000000..2c0bc0ae9
--- /dev/null
+++ b/src/zenserver/compute/computeservice.cpp
@@ -0,0 +1,100 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include "computeservice.h"
+
+#if ZEN_WITH_COMPUTE_SERVICES
+
+#	include <zencore/compactbinarybuilder.h>
+#	include <zencore/filesystem.h>
+#	include <zencore/fmtutils.h>
+#	include <zencore/logging.h>
+#	include <zencore/system.h>
+#	include <zenutil/zenserverprocess.h>
+
+ZEN_THIRD_PARTY_INCLUDES_START
+#	include <EASTL/fixed_vector.h>
+#	include <asio.hpp>
+ZEN_THIRD_PARTY_INCLUDES_END
+
+#	include <unordered_map>
+
+namespace zen {
+
+//////////////////////////////////////////////////////////////////////////
+
+struct ResourceMetrics
+{
+	uint64_t DiskUsageBytes	  = 0;
+	uint64_t MemoryUsageBytes = 0;
+};
+
+//////////////////////////////////////////////////////////////////////////
+
+struct HttpComputeService::Impl
+{
+	Impl(const Impl&) = delete;
+	Impl& operator=(const Impl&) = delete;
+
+	Impl();
+	~Impl();
+
+	void Initialize(std::filesystem::path BaseDir) { ZEN_UNUSED(BaseDir); }
+
+	void Cleanup() {}
+
+private:
+};
+
+HttpComputeService::Impl::Impl()
+{
+}
+
+HttpComputeService::Impl::~Impl()
+{
+}
+
+///////////////////////////////////////////////////////////////////////////
+
+HttpComputeService::HttpComputeService(std::filesystem::path BaseDir) : m_Impl(std::make_unique<Impl>())
+{
+	using namespace std::literals;
+
+	m_Impl->Initialize(BaseDir);
+
+	m_Router.RegisterRoute(
+		"status",
+		[this](HttpRouterRequest& Req) {
+			CbObjectWriter Obj;
+			Obj.BeginArray("modules");
+			Obj.EndArray();
+			Req.ServerRequest().WriteResponse(HttpResponseCode::OK, Obj.Save());
+		},
+		HttpVerb::kGet);
+
+	m_Router.RegisterRoute(
+		"stats",
+		[this](HttpRouterRequest& Req) {
+			CbObjectWriter Obj;
+			Req.ServerRequest().WriteResponse(HttpResponseCode::OK, Obj.Save());
+		},
+		HttpVerb::kGet);
+}
+
+HttpComputeService::~HttpComputeService()
+{
+}
+
+const char*
+HttpComputeService::BaseUri() const
+{
+	return "/compute/";
+}
+
+void
+HttpComputeService::HandleRequest(zen::HttpServerRequest& Request)
+{
+	m_Router.HandleRequest(Request);
+}
+
+}  // namespace zen
+#endif	// ZEN_WITH_COMPUTE_SERVICES