[Common] Add unique label making utility to metadata (#12938)

Author: njacazio

Common/Core/MetadataHelper.cxx

@@ -124,3 +124,19 @@ bool MetadataHelper::isInitialized() const
   }
   return mIsInitialized;
 }
+
+std::string MetadataHelper::makeMetadataLabel() const
+{
+  if (!mIsInitialized) {
+    LOG(fatal) << "Metadata not initialized";
+  }
+  std::string label = get("DataType");
+  label += "_" + get("LPMProductionTag");
+  if (isMC()) {
+    label += "_" + get("AnchorPassName");
+    label += "_" + get("AnchorProduction");
+  } else {
+    label += "_" + get("RecoPassName");
+  }
+  return label;
+}

Common/Core/MetadataHelper.h

@@ -8,10 +8,10 @@
 // In applying this license CERN does not waive the privileges and immunities
 // granted to it by virtue of its status as an Intergovernmental Organization
 // or submit itself to any jurisdiction.
-/// \file   TableHelper.h
+
+/// \file MetadataHelper.h
+/// \brief Utility to handle the metadata from the AOD
 /// \author Nicolò Jacazio nicolo.jacazio@cern.ch
-/// \brief  Utility to handle the metadata from the AOD
-///
 
 #ifndef COMMON_CORE_METADATAHELPER_H_
 #define COMMON_CORE_METADATAHELPER_H_
@@ -61,6 +61,9 @@ struct MetadataHelper {
   /// @return true if the key is defined, false otherwise. Throws an exception if the key is not found
   bool isKeyDefined(const std::string& key) const;
 
+  /// @brief Function to create a label with the metadata information, useful e.g. for histogram naming
+  std::string makeMetadataLabel() const;
+
  private:
   std::map<std::string, std::string> mMetadata; /// < The metadata map
   bool mIsInitialized = false;                  /// < Flag to check if the metadata has been initialized

Common/Core/macros/testMetadataHelper.C

@@ -0,0 +1,84 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+/// \file   testMetadataHelper.C
+/// \author Nicolò Jacazio nicolo.jacazio@cern.ch
+/// \brief  Test the MetadataHelper functionality
+
+#include "Common/Core/MetadataHelper.h"
+
+#include <Framework/ConfigContext.h>
+#include <Framework/ConfigParamRegistry.h>
+#include <Framework/ConfigParamStore.h>
+#include <Framework/ServiceRegistry.h>
+#include <Framework/ServiceRegistryRef.h>
+
+#include <TFile.h>
+#include <TMap.h>
+#include <TObjString.h>
+
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+// Taken from O2/Framework/AnalysisSupport/src/Plugin.cxx
+auto readMetadata(std::unique_ptr<TFile>& currentFile) -> std::vector<o2::framework::ConfigParamSpec>
+{
+  // Get the metadata, if any
+  auto m = (TMap*)currentFile->Get("metaData");
+  if (!m) {
+    return {};
+  }
+  std::vector<o2::framework::ConfigParamSpec> results;
+  auto it = m->MakeIterator();
+
+  // Serialise metadata into a ; separated string with : separating key and value
+  bool first = true;
+  while (auto obj = it->Next()) {
+    if (first) {
+      LOGP(info, "Metadata for file \"{}\":", currentFile->GetName());
+      first = false;
+    }
+    auto objString = (TObjString*)m->GetValue(obj);
+    std::string key = "aod-metadata-" + std::string(obj->GetName());
+    LOGP(info, "- {}: {} goes into key {}", obj->GetName(), objString->String().Data(), key);
+    char const* value = strdup(objString->String());
+    results.push_back(o2::framework::ConfigParamSpec{key, o2::framework::VariantType::String, value, {"Metadata in AOD"}});
+  }
+  return results;
+}
+
+void testMetadataHelper(std::string aod = "/tmp/AO2D.root")
+{
+
+  TFile* file = TFile::Open(aod.c_str());
+  if (!file || file->IsZombie()) {
+    LOG(fatal) << "Could not open file " << aod;
+  }
+  std::unique_ptr<TFile> currentFile{file};
+  std::vector<o2::framework::ConfigParamSpec> specs = readMetadata(currentFile);
+
+  std::vector<std::unique_ptr<o2::framework::ParamRetriever>> retrievers;
+  auto paramStore = std::make_unique<o2::framework::ConfigParamStore>(specs, std::move(retrievers));
+  paramStore->preload();
+  paramStore->activate();
+  o2::framework::ConfigParamRegistry paramRegistry(std::move(paramStore));
+  o2::framework::ServiceRegistry serviceRegistry;
+  o2::framework::ServiceRegistryRef services(serviceRegistry);
+  o2::framework::ConfigContext aodCfg(paramRegistry, services, 0, nullptr);
+  LOG(info) << "Loaded " << aodCfg.options().specs().size() << " configuration entries from file " << aod;
+  aodCfg.options().get<std::string>("aod-metadata-DataType");
+  o2::common::core::MetadataHelper metadataInfo;
+  metadataInfo.initMetadata(aodCfg);
+  metadataInfo.print();
+  LOG(info) << "Metadata label: " << metadataInfo.makeMetadataLabel();
+}