feat(CCDB): add getForRunMiddleTimeStamp method

Adds a new method `getForRunMiddleTimeStamp` to the `CCDBManagerInstance`
class. This method retrieves an object of type `T` from the CCDB using the
path and the middle timestamp of the given run number. This is a useful
utility method for cases where the exact timestamp does not matter and the
run number is available.
Optionally use metadata in the query
Rename the function
Fix setting of the metadata

Author: mpuccio

CCDB/include/CCDB/BasicCCDBManager.h

@@ -102,6 +102,10 @@ class CCDBManagerInstance
   template <typename T>
   T* getForTimeStamp(std::string const& path, long timestamp);
 
+  /// retrieve an object of type T from CCDB as stored under path and using the timestamp in the middle of the run
+  template <typename T>
+  T* getForRun(std::string const& path, int runNumber, bool setRunMetadata = false);
+
   /// retrieve an object of type T from CCDB as stored under path, timestamp and metaData
   template <typename T>
   T* getSpecific(std::string const& path, long timestamp = -1, MD metaData = MD())
@@ -311,6 +315,20 @@ T* CCDBManagerInstance::getForTimeStamp(std::string const& path, long timestamp)
   return ptr;
 }
 
+template <typename T>
+T* CCDBManagerInstance::getForRun(std::string const& path, int runNumber, bool setRunMetadata)
+{
+  auto [start, stop] = getRunDuration(runNumber);
+  if (start < 0 || stop < 0) {
+    if (mFatalWhenNull) {
+      reportFatal(std::string("Failed to get run duration for run ") + std::to_string(runNumber));
+    }
+    return nullptr;
+  }
+  mMetaData = setRunMetadata ? MD{{"runNumber", std::to_string(runNumber)}} : MD{};
+  return getForTimeStamp<T>(path, start / 2 + stop / 2);
+}
+
 class BasicCCDBManager : public CCDBManagerInstance
 {
  public: