From 149a5c2faa8d59290b8b44717e504532e906aae2 Mon Sep 17 00:00:00 2001
From: Stefan Boberg <stefan.boberg@epicgames.com>
Date: Wed, 18 Feb 2026 11:28:03 +0100
Subject: 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
---
 src/zennet/beacon.cpp | 170 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 170 insertions(+)
 create mode 100644 src/zennet/beacon.cpp

(limited to 'src/zennet/beacon.cpp')

diff --git a/src/zennet/beacon.cpp b/src/zennet/beacon.cpp
new file mode 100644
index 000000000..394a4afbb
--- /dev/null
+++ b/src/zennet/beacon.cpp
@@ -0,0 +1,170 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zennet/beacon.h>
+
+#include <zencore/basicfile.h>
+#include <zencore/compactbinary.h>
+#include <zencore/compactbinaryfile.h>
+#include <zencore/filesystem.h>
+#include <zencore/fmtutils.h>
+#include <zencore/session.h>
+#include <zencore/uid.h>
+
+#include <fmt/format.h>
+#include <asio.hpp>
+#include <map>
+
+namespace zen {
+
+//////////////////////////////////////////////////////////////////////////
+
+struct FsBeacon::Impl
+{
+	Impl(std::filesystem::path ShareRoot);
+	~Impl();
+
+	void EnsureValid();
+
+	void AddGroup(std::string_view GroupId, CbObject Metadata);
+	void ScanGroup(std::string_view GroupId, std::vector<Oid>& OutSessions);
+	void ReadMetadata(std::string_view GroupId, const std::vector<Oid>& InSessions, std::vector<CbObject>& OutMetadata);
+
+private:
+	std::filesystem::path m_ShareRoot;
+	zen::Oid			  m_SessionId;
+
+	struct GroupData
+	{
+		CbObject  Metadata;
+		BasicFile LockFile;
+	};
+
+	std::map<std::string, GroupData> m_Registration;
+
+	std::filesystem::path GetSessionMarkerPath(std::string_view GroupId, const Oid& SessionId)
+	{
+		Oid::String_t SessionIdString;
+		SessionId.ToString(SessionIdString);
+
+		return m_ShareRoot / GroupId / SessionIdString;
+	}
+};
+
+FsBeacon::Impl::Impl(std::filesystem::path ShareRoot) : m_ShareRoot(ShareRoot), m_SessionId(GetSessionId())
+{
+}
+
+FsBeacon::Impl::~Impl()
+{
+}
+
+void
+FsBeacon::Impl::EnsureValid()
+{
+}
+
+void
+FsBeacon::Impl::AddGroup(std::string_view GroupId, CbObject Metadata)
+{
+	zen::CreateDirectories(m_ShareRoot / GroupId);
+	std::filesystem::path MarkerFile = GetSessionMarkerPath(GroupId, m_SessionId);
+
+	GroupData& Group = m_Registration[std::string(GroupId)];
+
+	Group.Metadata = Metadata;
+
+	std::error_code Ec;
+	Group.LockFile.Open(MarkerFile,
+						BasicFile::Mode::kTruncate | BasicFile::Mode::kPreventDelete |
+							BasicFile::Mode::kPreventWrite /* | BasicFile::Mode::kDeleteOnClose */,
+						Ec);
+
+	if (Ec)
+	{
+		throw std::system_error(Ec, fmt::format("failed to open beacon marker file '{}' for write", MarkerFile));
+	}
+
+	Group.LockFile.WriteAll(Metadata.GetBuffer().AsIoBuffer(), Ec);
+
+	if (Ec)
+	{
+		throw std::system_error(Ec, fmt::format("failed to write to beacon marker file '{}'", MarkerFile));
+	}
+
+	Group.LockFile.Flush();
+}
+
+void
+FsBeacon::Impl::ScanGroup(std::string_view GroupId, std::vector<Oid>& OutSessions)
+{
+	DirectoryContent Dc;
+	zen::GetDirectoryContent(m_ShareRoot / GroupId, zen::DirectoryContentFlags::IncludeFiles, /* out */ Dc);
+
+	for (const std::filesystem::path& FilePath : Dc.Files)
+	{
+		std::filesystem::path File = FilePath.filename();
+
+		std::error_code Ec;
+		if (std::filesystem::remove(FilePath, Ec) == false)
+		{
+			auto FileString = File.generic_string();
+
+			if (FileString.length() != Oid::StringLength)
+				continue;
+
+			if (const Oid SessionId = Oid::FromHexString(FileString))
+			{
+				if (std::filesystem::file_size(File, Ec) > 0)
+				{
+					OutSessions.push_back(SessionId);
+				}
+			}
+		}
+	}
+}
+
+void
+FsBeacon::Impl::ReadMetadata(std::string_view GroupId, const std::vector<Oid>& InSessions, std::vector<CbObject>& OutMetadata)
+{
+	for (const Oid& SessionId : InSessions)
+	{
+		const std::filesystem::path MarkerFile = GetSessionMarkerPath(GroupId, SessionId);
+
+		if (CbObject Metadata = LoadCompactBinaryObject(MarkerFile).Object)
+		{
+			OutMetadata.push_back(std::move(Metadata));
+		}
+	}
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+FsBeacon::FsBeacon(std::filesystem::path ShareRoot) : m_Impl(std::make_unique<Impl>(ShareRoot))
+{
+}
+
+FsBeacon::~FsBeacon()
+{
+}
+
+void
+FsBeacon::AddGroup(std::string_view GroupId, CbObject Metadata)
+{
+	m_Impl->AddGroup(GroupId, Metadata);
+}
+
+void
+FsBeacon::ScanGroup(std::string_view GroupId, std::vector<Oid>& OutSessions)
+{
+	m_Impl->ScanGroup(GroupId, OutSessions);
+}
+
+void
+FsBeacon::ReadMetadata(std::string_view GroupId, const std::vector<Oid>& InSessions, std::vector<CbObject>& OutMetadata)
+{
+	m_Impl->ReadMetadata(GroupId, InSessions, OutMetadata);
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+}  // namespace zen
-- 
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