FileCatalog Class Reference

This class provides an interface to the file (metadata) catalog. More...

#include <FileCatalog.h>

Collaboration diagram for FileCatalog:

Public Member Functions
virtual bool	registerFile (const std::string &fileName, FileMetaData &metaData, const std::string &oldLFN="")
	Register a file in the (local) file catalog.
virtual bool	getMetaData (std::string &fileName, FileMetaData &metaData)
	Get the metadata of a file with given (logical) file name.
virtual std::string	getPhysicalFileName (const std::string &lfn)
	Get the physical file name for the LFN.

Static Public Member Functions
static FileCatalog &	Instance ()
	Static method to get a reference to the FileCatalog instance.

Private Types
typedef std::map< std::string, std::pair< std::string, FileMetaData > >	FileMap
	Map with file catalog content.

Private Member Functions
	FileCatalog ()
	Constructor: locate local database file.
bool	readCatalog (FileMap &fileMap)
	Read the file catalog from the local file.
bool	writeCatalog (const FileMap &fileMap)
	Write the file catalog to the local file.

Private Attributes
std::string	m_fileName
	Name of the file catalog file.

Detailed Description

This class provides an interface to the file (metadata) catalog.

Definition at line 24 of file FileCatalog.h.

Member Typedef Documentation

FileMap

typedef std::map<std::string, std::pair<std::string, FileMetaData> > FileMap

private

Map with file catalog content.

Definition at line 71 of file FileCatalog.h.

Constructor & Destructor Documentation

FileCatalog()

FileCatalog ( )

private

Constructor: locate local database file.

Definition at line 30 of file FileCatalog.cc.

                         : m_fileName("")
{
  // check for BELLE2_FILECATALOG environment variable
  std::string fileCatalog = EnvironmentVariables::get("BELLE2_FILECATALOG", "");
  if (fileCatalog == "NONE") return;
 
  // check for file catalog in home directory
  if (fileCatalog.empty()) {
    const std::string path{"~/Belle2FileCatalog.xml"};
    if (fs::exists(path)) {
      fileCatalog = path;
    }
  }
 
  // use file catalog in current directory if nothing else found
  if (fileCatalog.empty()) {
    fileCatalog = "Belle2FileCatalog.xml";
  }
 
  // get absolute path name
  m_fileName = fs::absolute(fileCatalog).c_str();
}

Member Function Documentation

getMetaData()

bool getMetaData ( std::string &  fileName, FileMetaData &  metaData  )

virtual

Get the metadata of a file with given (logical) file name.

Parameters

fileName	The (logical) name of the file. Will be set to the physical file name.
metaData	The meta data information of the file.

Returns

True if the file was found in the catalog.

Definition at line 142 of file FileCatalog.cc.

{
  metaData = FileMetaData();
  if (m_fileName.empty()) return false;
  if (!fs::exists(m_fileName)) return false;
 
  // get lock for read access to file catalog
  FileSystem::Lock lock(m_fileName, true);
  if (!lock.lock()) {
    B2ERROR("Locking of file catalog " << m_fileName << " failed.");
    return false;
  }
 
  // read the file catalog
  FileMap fileMap;
  if (!readCatalog(fileMap)) {
    B2ERROR("Failed to read file catalog " << m_fileName);
    return false;
  }
 
  // find the entry with given LFN
  auto iEntry = fileMap.find(fileName);
  if (iEntry != fileMap.end()) {
    metaData = iEntry->second.second;
    if (!iEntry->second.first.empty()) fileName = iEntry->second.first;
    return true;
  }
  for (const auto& entry : fileMap) {
    if (fileName.compare(entry.second.first) == 0) {
      metaData = entry.second.second;
      return true;
    }
  }
 
  return false;
}

getPhysicalFileName()

std::string getPhysicalFileName ( const std::string &  lfn )

virtual

Get the physical file name for the LFN.

Parameters

lfn	The logical file name.

Returns

the physical file name or an empty string if the lfn is not in the catalog.

Definition at line 180 of file FileCatalog.cc.

{
  std::string fileName = lfn;
  FileMetaData metaData;
  if (!getMetaData(fileName, metaData)) {
    B2DEBUG(100, "No LFN " << lfn << " found in the file catalog.");
  }
  return fileName;
}

Instance()

FileCatalog & Instance ( )

static

Static method to get a reference to the FileCatalog instance.

Returns

A reference to an instance of this class.

Definition at line 23 of file FileCatalog.cc.

{
  static FileCatalog instance;
  return instance;
}

readCatalog()

bool readCatalog ( FileCatalog::FileMap &  fileMap )

private

Read the file catalog from the local file.

Parameters

fileMap

The map of file catalog entries.

Returns

True if the catalog was read successfully.

Definition at line 54 of file FileCatalog.cc.

{
  fileMap.clear();
 
  std::ifstream file(m_fileName.c_str());
  if (!file.is_open()) return false;
 
  try {
    while (!file.eof()) {
      FileMetaData entry;
      std::string physicalFileName;
      if (entry.read(file, physicalFileName)) fileMap[entry.getLfn()] = std::make_pair(physicalFileName, entry);
    }
  } catch (std::exception& e) {
    B2ERROR("Errors occured while reading " << m_fileName <<
            ", maybe it is corrupted? Note that your .root files should be unaffected. (Error details: " << e.what() << ")");
    return false;
  }
 
  return true;
}

registerFile()

bool registerFile ( const std::string &  fileName, FileMetaData &  metaData, const std::string &  oldLFN = ""  )

virtual

Register a file in the (local) file catalog.

Parameters

fileName	The name of the file to be registered.
metaData	The meta data information of the file to be registered. Will be updated.
oldLFN	If not empty, update the file catalog: only register the file if the oldLFN is found in the catalog and if so, also remove any file with the old LFN from the catalog.

Returns

True if the registration succeeded.

Definition at line 90 of file FileCatalog.cc.

{
  if (m_fileName.empty()) return false;
 
  // make sure we have an LFN
  if (metaData.getLfn().empty()) {
    B2ERROR("Cannot register a file without a valid LFN");
    return false;
  }
 
  // get lock for write access to file catalog
  FileSystem::Lock lock(m_fileName);
  if (!lock.lock()) {
    B2ERROR("Locking of file catalog " << m_fileName << " failed.");
    return false;
  }
 
  // read the file catalog
  FileMap fileMap;
  if (!readCatalog(fileMap)) {
    B2ERROR("Failed to read file catalog " << m_fileName);
    return false;
  }
 
  // check whether a file with this name is already registered and remove if so
  for (auto it = fileMap.begin(); it != fileMap.end(); ++it) {
    auto&& lfn = (*it).first;
    if (!oldLFN.empty() and oldLFN == lfn) {
      // old LFN exists and we requested an update so no warning, just remove
      fileMap.erase(it);
      break;
    }
    if (metaData.getLfn() == lfn) {
      B2WARNING("A file with the same LFN is already registered and will be overwritten in the catalog."
                << LogVar("LFN", lfn) << LogVar("old PFN", (*it).second.first) << LogVar("new PFN", fileName));
      fileMap.erase(it);
      break;
    }
  }
 
  // add the new entry and write the file catalog
  fileMap[metaData.getLfn()] = std::make_pair(fileName, metaData);
 
  if (!writeCatalog(fileMap)) {
    B2ERROR("Failed to write file catalog " << m_fileName);
    return false;
  }
 
  return true;
}

writeCatalog()

bool writeCatalog ( const FileMap &  fileMap )

private

Write the file catalog to the local file.

Parameters

fileMap

The map of file catalog entries.

Returns

True if the catalog was written successfully.

Definition at line 77 of file FileCatalog.cc.

{
  std::ofstream file(m_fileName.c_str());
  if (!file.is_open()) return false;
 
  file << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
  file << "<FileCatalog>\n";
  for (const auto& entry : fileMap) entry.second.second.write(file, entry.second.first);
  file << "</FileCatalog>\n";
 
  return true;
}

Member Data Documentation

m_fileName

std::string m_fileName

private

Name of the file catalog file.

Definition at line 89 of file FileCatalog.h.

---

The documentation for this class was generated from the following files:

• framework/core/include/FileCatalog.h
• framework/core/src/FileCatalog.cc