zen build cache service (#318)

- **EXPERIMENTAL** `zen builds`
  - Feature: `--zen-cache-host` option for `upload` and `download` operations to use a zenserver host `/builds` endpoint for storing build blob and blob metadata
  - Feature: New `/builds` endpoint for caching build blobs and blob metadata
    - `/builds/{namespace}/{bucket}/{buildid}/blobs/{hash}` `GET` and `PUT` method for storing and fetching blobs
    - `/builds/{namespace}/{bucket}/{buildid}/blobs/putBlobMetadata` `POST` method for storing metadata about blobs
    - `/builds/{namespace}/{bucket}/{buildid}/blobs/getBlobMetadata` `POST` method for fetching metadata about blobs
    - `/builds/{namespace}/{bucket}/{buildid}/blobs/exists` `POST` method for checking existance of blobs

1 files changed, 362 insertions, 0 deletions

diff --git a/src/zenutil/buildstoragecache.cpp b/src/zenutil/buildstoragecache.cpp
new file mode 100644
index 000000000..c95215889
--- /dev/null
+++ b/src/zenutil/buildstoragecache.cpp
@@ -0,0 +1,362 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zenutil/buildstoragecache.h>
+
+#include <zencore/compactbinarybuilder.h>
+#include <zencore/compactbinaryvalidation.h>
+#include <zencore/fmtutils.h>
+#include <zencore/scopeguard.h>
+#include <zencore/timer.h>
+#include <zencore/trace.h>
+#include <zencore/workthreadpool.h>
+#include <zenhttp/httpclient.h>
+#include <zenhttp/packageformat.h>
+
+ZEN_THIRD_PARTY_INCLUDES_START
+#include <tsl/robin_set.h>
+ZEN_THIRD_PARTY_INCLUDES_END
+
+namespace zen {
+
+using namespace std::literals;
+
+class ZenBuildStorageCache : public BuildStorageCache
+{
+public:
+	explicit ZenBuildStorageCache(HttpClient&					 HttpClient,
+								  BuildStorageCache::Statistics& Stats,
+								  std::string_view				 Namespace,
+								  std::string_view				 Bucket,
+								  const std::filesystem::path&	 TempFolderPath)
+	: m_HttpClient(HttpClient)
+	, m_Stats(Stats)
+	, m_Namespace(Namespace.empty() ? "none" : Namespace)
+	, m_Bucket(Bucket.empty() ? "none" : Bucket)
+	, m_TempFolderPath(std::filesystem::path(TempFolderPath).make_preferred())
+	, m_BackgroundWorkPool(1)
+	, m_PendingBackgroundWorkCount(1)
+	, m_CancelBackgroundWork(false)
+	{
+	}
+
+	virtual ~ZenBuildStorageCache()
+	{
+		try
+		{
+			m_CancelBackgroundWork.store(true);
+			m_PendingBackgroundWorkCount.CountDown();
+			m_PendingBackgroundWorkCount.Wait();
+		}
+		catch (const std::exception& Ex)
+		{
+			ZEN_ERROR("~ZenBuildStorageCache() failed with: {}", Ex.what());
+		}
+	}
+
+	void ScheduleBackgroundWork(std::function<void()>&& Work)
+	{
+		m_PendingBackgroundWorkCount.AddCount(1);
+		try
+		{
+			m_BackgroundWorkPool.ScheduleWork([this, Work = std::move(Work)]() {
+				ZEN_TRACE_CPU("ZenBuildStorageCache::BackgroundWork");
+				auto _ = MakeGuard([this]() { m_PendingBackgroundWorkCount.CountDown(); });
+				if (!m_CancelBackgroundWork)
+				{
+					try
+					{
+						Work();
+					}
+					catch (const std::exception& Ex)
+					{
+						ZEN_ERROR("Failed executing background upload to build cache. Reason: {}", Ex.what());
+					}
+				}
+			});
+		}
+		catch (const std::exception& Ex)
+		{
+			m_PendingBackgroundWorkCount.CountDown();
+			ZEN_ERROR("Failed scheduling background upload to build cache. Reason: {}", Ex.what());
+		}
+	}
+
+	virtual void PutBuildBlob(const Oid&			 BuildId,
+							  const IoHash&			 RawHash,
+							  ZenContentType		 ContentType,
+							  const CompositeBuffer& Payload) override
+	{
+		ZEN_ASSERT(ContentType == ZenContentType::kCompressedBinary);
+		ScheduleBackgroundWork(
+			[this, BuildId = Oid(BuildId), RawHash = IoHash(RawHash), ContentType, Payload = CompositeBuffer(Payload)]() {
+				ZEN_TRACE_CPU("ZenBuildStorageCache::PutBuildBlob");
+				Stopwatch ExecutionTimer;
+				auto	  _ = MakeGuard([&]() { m_Stats.TotalExecutionTimeUs += ExecutionTimer.GetElapsedTimeUs(); });
+
+				HttpClient::Response CacheResponse =
+					m_HttpClient.Upload(fmt::format("/builds/{}/{}/{}/blobs/{}", m_Namespace, m_Bucket, BuildId, RawHash.ToHexString()),
+										Payload,
+										ContentType);
+				AddStatistic(CacheResponse);
+				if (!CacheResponse.IsSuccess())
+				{
+					ZEN_DEBUG("Failed posting blob to cache: {}", CacheResponse.ErrorMessage(""sv));
+				}
+			});
+	}
+
+	virtual IoBuffer GetBuildBlob(const Oid& BuildId, const IoHash& RawHash, uint64_t RangeOffset, uint64_t RangeBytes) override
+	{
+		ZEN_TRACE_CPU("ZenBuildStorageCache::GetBuildBlob");
+
+		Stopwatch ExecutionTimer;
+		auto	  _ = MakeGuard([&]() { m_Stats.TotalExecutionTimeUs += ExecutionTimer.GetElapsedTimeUs(); });
+
+		HttpClient::KeyValueMap Headers;
+		if (RangeOffset != 0 || RangeBytes != (uint64_t)-1)
+		{
+			Headers.Entries.insert({"Range", fmt::format("bytes={}-{}", RangeOffset, RangeOffset + RangeBytes - 1)});
+		}
+		CreateDirectories(m_TempFolderPath);
+		HttpClient::Response CacheResponse =
+			m_HttpClient.Download(fmt::format("/builds/{}/{}/{}/blobs/{}", m_Namespace, m_Bucket, BuildId, RawHash.ToHexString()),
+								  m_TempFolderPath,
+								  Headers);
+		AddStatistic(CacheResponse);
+		if (CacheResponse.IsSuccess())
+		{
+			return CacheResponse.ResponsePayload;
+		}
+		return {};
+	}
+
+	virtual void PutBlobMetadatas(const Oid& BuildId, std::span<const IoHash> BlobHashes, std::span<const CbObject> MetaDatas) override
+	{
+		ScheduleBackgroundWork([this,
+								BuildId		  = Oid(BuildId),
+								BlobRawHashes = std::vector<IoHash>(BlobHashes.begin(), BlobHashes.end()),
+								MetaDatas	  = std::vector<CbObject>(MetaDatas.begin(), MetaDatas.end())]() {
+			ZEN_TRACE_CPU("ZenBuildStorageCache::PutBlobMetadatas");
+
+			Stopwatch ExecutionTimer;
+			auto	  _ = MakeGuard([&]() { m_Stats.TotalExecutionTimeUs += ExecutionTimer.GetElapsedTimeUs(); });
+
+			const uint64_t BlobCount = BlobRawHashes.size();
+
+			CbPackage							   RequestPackage;
+			std::vector<CbAttachment>			   Attachments;
+			tsl::robin_set<IoHash, IoHash::Hasher> AttachmentHashes;
+			Attachments.reserve(BlobCount);
+			AttachmentHashes.reserve(BlobCount);
+			{
+				CbObjectWriter RequestWriter;
+				RequestWriter.BeginArray("blobHashes");
+				for (size_t BlockHashIndex = 0; BlockHashIndex < BlobRawHashes.size(); BlockHashIndex++)
+				{
+					RequestWriter.AddHash(BlobRawHashes[BlockHashIndex]);
+				}
+				RequestWriter.EndArray();  // blobHashes
+
+				RequestWriter.BeginArray("metadatas");
+				for (size_t BlockHashIndex = 0; BlockHashIndex < BlobRawHashes.size(); BlockHashIndex++)
+				{
+					const IoHash ObjectHash = MetaDatas[BlockHashIndex].GetHash();
+					RequestWriter.AddBinaryAttachment(ObjectHash);
+					if (!AttachmentHashes.contains(ObjectHash))
+					{
+						Attachments.push_back(CbAttachment(MetaDatas[BlockHashIndex], ObjectHash));
+						AttachmentHashes.insert(ObjectHash);
+					}
+				}
+
+				RequestWriter.EndArray();  // metadatas
+
+				RequestPackage.SetObject(RequestWriter.Save());
+			}
+			RequestPackage.AddAttachments(Attachments);
+
+			CompositeBuffer RpcRequestBuffer = FormatPackageMessageBuffer(RequestPackage);
+
+			HttpClient::Response CacheResponse =
+				m_HttpClient.Post(fmt::format("/builds/{}/{}/{}/blobs/putBlobMetadata", m_Namespace, m_Bucket, BuildId),
+								  RpcRequestBuffer,
+								  ZenContentType::kCbPackage);
+			AddStatistic(CacheResponse);
+			if (!CacheResponse.IsSuccess())
+			{
+				ZEN_DEBUG("Failed posting blob metadata to cache: {}", CacheResponse.ErrorMessage(""sv));
+			}
+		});
+	}
+
+	virtual std::vector<CbObject> GetBlobMetadatas(const Oid& BuildId, std::span<const IoHash> BlobHashes) override
+	{
+		ZEN_TRACE_CPU("ZenBuildStorageCache::GetBlobMetadatas");
+
+		Stopwatch ExecutionTimer;
+		auto	  _ = MakeGuard([&]() { m_Stats.TotalExecutionTimeUs += ExecutionTimer.GetElapsedTimeUs(); });
+
+		CbObjectWriter Request;
+
+		Request.BeginArray("blobHashes"sv);
+		for (const IoHash& BlobHash : BlobHashes)
+		{
+			Request.AddHash(BlobHash);
+		}
+		Request.EndArray();
+
+		IoBuffer Payload = Request.Save().GetBuffer().AsIoBuffer();
+		Payload.SetContentType(ZenContentType::kCbObject);
+
+		HttpClient::Response Response =
+			m_HttpClient.Post(fmt::format("/builds/{}/{}/{}/blobs/getBlobMetadata", m_Namespace, m_Bucket, BuildId),
+							  Payload,
+							  HttpClient::Accept(ZenContentType::kCbObject));
+		AddStatistic(Response);
+		if (Response.IsSuccess())
+		{
+			std::vector<CbObject> Result;
+
+			CbPackage ResponsePackage = ParsePackageMessage(Response.ResponsePayload);
+			CbObject  ResponseObject  = ResponsePackage.GetObject();
+
+			CbArrayView BlobHashArray  = ResponseObject["blobHashes"sv].AsArrayView();
+			CbArrayView MetadatasArray = ResponseObject["metadatas"sv].AsArrayView();
+			Result.reserve(MetadatasArray.Num());
+			auto BlobHashesIt	 = BlobHashes.begin();
+			auto BlobHashArrayIt = begin(BlobHashArray);
+			auto MetadataArrayIt = begin(MetadatasArray);
+			while (MetadataArrayIt != end(MetadatasArray))
+			{
+				const IoHash BlobHash = (*BlobHashArrayIt).AsHash();
+				while (BlobHash != *BlobHashesIt)
+				{
+					ZEN_ASSERT(BlobHashesIt != BlobHashes.end());
+					BlobHashesIt++;
+				}
+
+				ZEN_ASSERT(BlobHash == *BlobHashesIt);
+
+				const IoHash		MetaHash	   = (*MetadataArrayIt).AsAttachment();
+				const CbAttachment* MetaAttachment = ResponsePackage.FindAttachment(MetaHash);
+				ZEN_ASSERT(MetaAttachment);
+
+				CbObject Metadata = MetaAttachment->AsObject();
+				Result.emplace_back(std::move(Metadata));
+
+				BlobHashArrayIt++;
+				MetadataArrayIt++;
+				BlobHashesIt++;
+			}
+			return Result;
+		}
+		return {};
+	}
+
+	virtual std::vector<BlobExistsResult> BlobsExists(const Oid& BuildId, std::span<const IoHash> BlobHashes) override
+	{
+		ZEN_TRACE_CPU("ZenBuildStorageCache::BlobsExists");
+
+		Stopwatch ExecutionTimer;
+		auto	  _ = MakeGuard([&]() { m_Stats.TotalExecutionTimeUs += ExecutionTimer.GetElapsedTimeUs(); });
+
+		CbObjectWriter Request;
+
+		Request.BeginArray("blobHashes"sv);
+		for (const IoHash& BlobHash : BlobHashes)
+		{
+			Request.AddHash(BlobHash);
+		}
+		Request.EndArray();
+
+		IoBuffer Payload = Request.Save().GetBuffer().AsIoBuffer();
+		Payload.SetContentType(ZenContentType::kCbObject);
+
+		HttpClient::Response Response = m_HttpClient.Post(fmt::format("/builds/{}/{}/{}/blobs/exists", m_Namespace, m_Bucket, BuildId),
+														  Payload,
+														  HttpClient::Accept(ZenContentType::kCbObject));
+		AddStatistic(Response);
+		if (Response.IsSuccess())
+		{
+			CbObject ResponseObject = LoadCompactBinaryObject(Response.ResponsePayload);
+			if (!ResponseObject)
+			{
+				throw std::runtime_error("BlobExists reponse is invalid, failed to load payload as compact binary object");
+			}
+			CbArrayView BlobsExistsArray = ResponseObject["blobExists"sv].AsArrayView();
+			if (!BlobsExistsArray)
+			{
+				throw std::runtime_error("BlobExists reponse is invalid, 'blobExists' array is missing");
+			}
+			if (BlobsExistsArray.Num() != BlobHashes.size())
+			{
+				throw std::runtime_error(fmt::format("BlobExists reponse is invalid, 'blobExists' array contains {} entries, expected {}",
+													 BlobsExistsArray.Num(),
+													 BlobHashes.size()));
+			}
+
+			CbArrayView MetadatasExistsArray = ResponseObject["metadataExists"sv].AsArrayView();
+			if (!MetadatasExistsArray)
+			{
+				throw std::runtime_error("BlobExists reponse is invalid, 'metadataExists' array is missing");
+			}
+			if (MetadatasExistsArray.Num() != BlobHashes.size())
+			{
+				throw std::runtime_error(
+					fmt::format("BlobExists reponse is invalid, 'metadataExists' array contains {} entries, expected {}",
+								MetadatasExistsArray.Num(),
+								BlobHashes.size()));
+			}
+
+			std::vector<BlobExistsResult> Result;
+			Result.reserve(BlobHashes.size());
+			auto BlobExistsIt	  = begin(BlobsExistsArray);
+			auto MetadataExistsIt = begin(MetadatasExistsArray);
+			while (BlobExistsIt != end(BlobsExistsArray))
+			{
+				ZEN_ASSERT(MetadataExistsIt != end(MetadatasExistsArray));
+
+				const bool HasBody	   = (*BlobExistsIt).AsBool();
+				const bool HasMetadata = (*MetadataExistsIt).AsBool();
+
+				Result.push_back({.HasBody = HasBody, .HasMetadata = HasMetadata});
+
+				BlobExistsIt++;
+				MetadataExistsIt++;
+			}
+			return Result;
+		}
+		return {};
+	}
+
+private:
+	void AddStatistic(const HttpClient::Response& Result)
+	{
+		m_Stats.TotalBytesWritten += Result.UploadedBytes;
+		m_Stats.TotalBytesRead += Result.DownloadedBytes;
+		m_Stats.TotalRequestTimeUs += uint64_t(Result.ElapsedSeconds * 1000000.0);
+		m_Stats.TotalRequestCount++;
+	}
+
+	HttpClient&					   m_HttpClient;
+	BuildStorageCache::Statistics& m_Stats;
+	const std::string			   m_Namespace;
+	const std::string			   m_Bucket;
+	const std::filesystem::path	   m_TempFolderPath;
+
+	WorkerThreadPool  m_BackgroundWorkPool;
+	Latch			  m_PendingBackgroundWorkCount;
+	std::atomic<bool> m_CancelBackgroundWork;
+};
+
+std::unique_ptr<BuildStorageCache>
+CreateZenBuildStorageCache(HttpClient&					  HttpClient,
+						   BuildStorageCache::Statistics& Stats,
+						   std::string_view				  Namespace,
+						   std::string_view				  Bucket,
+						   const std::filesystem::path&	  TempFolderPath)
+{
+	return std::make_unique<ZenBuildStorageCache>(HttpClient, Stats, Namespace, Bucket, TempFolderPath);
+}
+
+}  // namespace zen