add --buildstore-disksizelimit-percent to zenstorageserver (#966)

- Improvement: Add option `--buildstore-disksizelimit-percent` - Max percentage of total drive capacity (of --data-dir drive) for build storage. When combined with `--buildstore-disksizelimit`, the lower value wins.

4 files changed, 45 insertions, 3 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7f0bca49c..0fd880bb5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 - Improvement: Session service and endpoint moved from storage server to base server class; now available in hub, compute, and proxy modes
 - Improvement: HTTP client Content-Type in additional headers now overrides the payload content type
 - Improvement: Dashboard copy-to-clipboard buttons on hub module IDs and ports, compute worker/action IDs and queue tokens, orchestrator client IDs, cache namespace names and directories, project names and directories, and workspace IDs
+- Improvement: `--buildstore-disksizelimit-percent` - Max percentage of total drive capacity (of --data-dir drive) for build storage. When combined with `--buildstore-disksizelimit`, the lower value wins.
 - Bugfix: OAuth client credentials token request now sends correct `application/x-www-form-urlencoded` content type
 - Bugfix: `builds download` with cache upload enabled no longer holds downloaded blobs in memory when boost-worker-memory is active; blobs are written to disk before upload
 - Bugfix: Removed obsolete `--cache-prime-only` flag from `builds download`
diff --git a/src/zenserver/storage/storageconfig.cpp b/src/zenserver/storage/storageconfig.cpp
index b615af280..bb4f053e4 100644
--- a/src/zenserver/storage/storageconfig.cpp
+++ b/src/zenserver/storage/storageconfig.cpp
@@ -57,6 +57,12 @@ ZenStorageServerConfigurator::ValidateOptions()
 		ZEN_WARN("'--gc-v2=false' is deprecated, reverting to '--gc-v2=true'");
 		ServerOptions.GcConfig.UseGCV2 = true;
 	}
+	if (ServerOptions.BuildStoreConfig.MaxDiskSpaceLimitPercent > 100)
+	{
+		throw OptionParseException(fmt::format("'--buildstore-disksizelimit-percent' ('{}') is invalid, must be between 1 and 100.",
+											   ServerOptions.BuildStoreConfig.MaxDiskSpaceLimitPercent),
+								   {});
+	}
 }
 
 class ZenStructuredCacheBucketsConfigOption : public LuaConfig::OptionValue
@@ -382,6 +388,9 @@ ZenStorageServerConfigurator::AddConfigOptions(LuaConfig::Options& LuaOptions)
 	////// buildsstore
 	LuaOptions.AddOption("server.buildstore.enabled"sv, ServerOptions.BuildStoreConfig.Enabled, "buildstore-enabled"sv);
 	LuaOptions.AddOption("server.buildstore.disksizelimit"sv, ServerOptions.BuildStoreConfig.MaxDiskSpaceLimit, "buildstore-disksizelimit");
+	LuaOptions.AddOption("server.buildstore.disksizelimitpercent"sv,
+						 ServerOptions.BuildStoreConfig.MaxDiskSpaceLimitPercent,
+						 "buildstore-disksizelimit-percent");
 
 	////// cache
 	LuaOptions.AddOption("cache.enable"sv, ServerOptions.StructuredCacheConfig.Enabled);
@@ -1035,6 +1044,13 @@ ZenStorageServerCmdLineOptions::AddBuildStoreOptions(cxxopts::Options& options,
 					   "Max number of bytes before build store entries get evicted. Default set to 1099511627776 (1TB week)",
 					   cxxopts::value<uint64_t>(ServerOptions.BuildStoreConfig.MaxDiskSpaceLimit)->default_value("1099511627776"),
 					   "");
+	options.add_option("buildstore",
+					   "",
+					   "buildstore-disksizelimit-percent",
+					   "Max percentage (1-100) of total drive capacity (of --data-dir drive) before build store entries get evicted. "
+					   "0 (default) disables this limit. When combined with --buildstore-disksizelimit, the lower value wins.",
+					   cxxopts::value<uint32_t>(ServerOptions.BuildStoreConfig.MaxDiskSpaceLimitPercent)->default_value("0"),
+					   "");
 }
 
 void
diff --git a/src/zenserver/storage/storageconfig.h b/src/zenserver/storage/storageconfig.h
index 18af4f096..fec8fd70b 100644
--- a/src/zenserver/storage/storageconfig.h
+++ b/src/zenserver/storage/storageconfig.h
@@ -135,8 +135,9 @@ struct ZenProjectStoreConfig
 
 struct ZenBuildStoreConfig
 {
-	bool	 Enabled		   = false;
-	uint64_t MaxDiskSpaceLimit = 1u * 1024u * 1024u * 1024u * 1024u;  // 1TB
+	bool	 Enabled				  = false;
+	uint64_t MaxDiskSpaceLimit		  = 1u * 1024u * 1024u * 1024u * 1024u;	 // 1TB
+	uint32_t MaxDiskSpaceLimitPercent = 0;
 };
 
 struct ZenWorkspacesConfig
diff --git a/src/zenserver/storage/zenstorageserver.cpp b/src/zenserver/storage/zenstorageserver.cpp
index 34f413639..e53678005 100644
--- a/src/zenserver/storage/zenstorageserver.cpp
+++ b/src/zenserver/storage/zenstorageserver.cpp
@@ -266,7 +266,31 @@ ZenStorageServer::InitializeServices(const ZenStorageServerConfig& ServerOptions
 		BuildStoreConfig BuildsCfg;
 		BuildsCfg.RootDirectory		= m_DataRoot / "builds";
 		BuildsCfg.MaxDiskSpaceLimit = ServerOptions.BuildStoreConfig.MaxDiskSpaceLimit;
-		m_BuildStore				= std::make_unique<BuildStore>(std::move(BuildsCfg), m_GcManager, *m_BuildCidStore);
+
+		if (ServerOptions.BuildStoreConfig.MaxDiskSpaceLimitPercent > 0)
+		{
+			DiskSpace Space;
+			if (DiskSpaceInfo(m_DataRoot, Space) && Space.Total > 0)
+			{
+				uint64_t PercentLimit		= Space.Total * ServerOptions.BuildStoreConfig.MaxDiskSpaceLimitPercent / 100;
+				BuildsCfg.MaxDiskSpaceLimit = ServerOptions.BuildStoreConfig.MaxDiskSpaceLimit > 0
+												  ? std::min(ServerOptions.BuildStoreConfig.MaxDiskSpaceLimit, PercentLimit)
+												  : PercentLimit;
+				ZEN_INFO("buildstore disk limit: {}% of {} = {} (effective limit: {})",
+						 ServerOptions.BuildStoreConfig.MaxDiskSpaceLimitPercent,
+						 NiceBytes(Space.Total),
+						 NiceBytes(PercentLimit),
+						 NiceBytes(BuildsCfg.MaxDiskSpaceLimit));
+			}
+			else
+			{
+				ZEN_WARN("buildstore-disksizelimit-percent: failed to query disk space for {}, using absolute limit {}",
+						 m_DataRoot.string(),
+						 NiceBytes(BuildsCfg.MaxDiskSpaceLimit));
+			}
+		}
+
+		m_BuildStore = std::make_unique<BuildStore>(std::move(BuildsCfg), m_GcManager, *m_BuildCidStore);
 	}
 
 	if (ServerOptions.StructuredCacheConfig.Enabled)