Event format meta data

Picking up from the discussion at !33803 (closed)

@akraszna implemented a very nice start to handling xAOD::EventFormat metadata in athenaMT. @gemmeren Pointed out that we should adopt a uniform approach to handling EventStreamInfo and xAOD::EventFormat. This leaves some approaches:

• Write multithreaded service maintaining one shared EventStreamInfo object in a thread-safe manner.
• Maintain a xAOD::EventFormat object for each output stream.
• Something we have not yet thought of Here we choose the second, i.e. maintain a xAOD::EventFormat object for each output stream. That means the key of the xAOD::EventFormat object now is a function of the stream name. Trying to adopt the EventStreamInfo style I went for something like:

AthenaOutputStream(
    name=name,
    HelperTools=[
        CfgMgr.xAODMaker__EventFormatStreamHelperTool(
            name="EventFormatStreamHelper"
            Key='Format{}'.format(name),
        ),
    ],
)

Of course any client looking up xAOD::EventFormat by key will have to adjust for that, as you can see in the read test. How much of a nightmare will this be?

I have not yet included recording and retrieving xAOD::EventFormat though the MetaDataSvc as implemented for EventStreamInfo. Is that desirable @mnowak

As you can see by the hacky approach and the title this is still a construction site and needs cleaning up.

Thoughts?

@tsulaia

Event/xAOD/xAODEventFormatCnv/src/EventFormatMetaDataTool.cxx

@@ -45,6 +45,9 @@ StatusCode
 
 StatusCode
     EventFormatMetaDataTool::beginInputFile() {
+      // lock the tool, so metaDataStop will wait for write to finish
+      std::lock_guard< std::mutex > guard(m_outputMutex);
+
       // Create object to hold information from the new file
       auto format = std::make_unique< xAOD::EventFormat >();
 
@@ -63,13 +66,7 @@ StatusCode
 
 StatusCode
     EventFormatMetaDataTool::metaDataStop() {
-      // StatusCode sc = writeMetaData();
-      // if( sc.isFailure() ) {
-      //   REPORT_ERROR( sc )
-      //       << "Failed to write metadata to the output store";
-      //   throw std::runtime_error( "Failed write xAOD::EventFormat "
-      //                            "to the output" );
-      // }
+      // wait for threads currenly writing to finish
       std::lock_guard< std::mutex > guard(m_outputMutex);
 
       return StatusCode::SUCCESS;
@@ -133,7 +130,6 @@ StatusCode
 
       // Record the event format metadata, if any was found in the
       // processed input files.
-      std::lock_guard< std::mutex > guard(m_outputMutex);
       ATH_MSG_DEBUG("Recording event format metadata");
       ATH_CHECK(m_outputMetaStore->record(std::move(format), m_outputKey));
 
@@ -146,8 +142,6 @@ StatusCode
         const std::unique_ptr< xAOD::EventFormat >& format) {
       ATH_MSG_DEBUG("Updateing with EventFormat from new input file");
 
-      std::lock_guard< std::mutex > guard(m_outputMutex);
-
       // Retrieve existing object from MetaDataStore
       xAOD::EventFormat * output = nullptr;
       ATH_CHECK(m_outputMetaStore->retrieve(output, m_outputKey));