ana::SAMQuerySource Class Reference

File source based on a SAM query or dataset (definition) More...

#include <SAMQuerySource.h>

Inheritance diagram for ana::SAMQuerySource:

Public Member Functions
	SAMQuerySource (const std::string &query, int stride=-1, int offset=-1)
virtual	~SAMQuerySource ()
Public Member Functions inherited from ana::FileListSource
	FileListSource (const std::vector< std::string > &files, int stride=-1, int offset=-1)
	default offset and stride mean obey cmd-line options More...
virtual	~FileListSource ()
virtual TFile *	GetNextFile () override
	Returns the next file in sequence, ready for reading. More...
int	NFiles () const override
	May return -1 indicating the number of files is not known. More...
Public Member Functions inherited from ana::IFileSource
virtual	~IFileSource ()

Protected Member Functions
std::vector< std::string >	LocationsForSAMQuery (const std::string &str, int stride, int offset)
std::vector< std::string >	LocateSAMFiles (const std::vector< std::string > &fnames)
	Take filenames, return locations suitable for TFile::Open() More...
std::string	IFDHBaseURI () const
std::string	EnsureDataset (const std::string &query) const
std::string	EnsureSnapshot (const std::string &def) const

Additional Inherited Members
Protected Attributes inherited from ana::FileListSource
std::vector< std::string >	fFileNames
	The list of files. More...
std::vector< std::string > ::iterator	fIt
	Iterator into fFileNames. More...
int	fStride
int	fN
	Number of files that will actually be returned. More...
TFile *	fFile
	The most-recently-returned file. More...
Static Protected Attributes inherited from ana::FileListSource
static bool	fgGotTickets = false
	Have we renewed our tickets? More...

Detailed Description

File source based on a SAM query or dataset (definition)

Locates the files on bluearc or pnfs (bluearc preferred).

Definition at line 8 of file SAMQuerySource.h.

Constructor & Destructor Documentation

ana::SAMQuerySource::SAMQuerySource	(	const std::string &	query,
		int	stride = -1,
		int	offset = -1
	)

Parameters

query

May be a SAM dataset name or a SAM query string

Definition at line 19 of file SAMQuerySource.cxx.

    : FileListSource(LocationsForSAMQuery(query, stride, offset), 1, 0)
  {
  }

ana::SAMQuerySource::~SAMQuerySource ( )

virtual

Definition at line 27 of file SAMQuerySource.cxx.

  {
  }

Member Function Documentation

std::string ana::SAMQuerySource::EnsureDataset ( const std::string &  query ) const

protected

Definition at line 32 of file SAMQuerySource.cxx.

  {
    const char* user = getenv("GRID_USER");
    assert(user);

    TString dset = TString::Format("%s_cafana_%s", user, query.c_str());
    // Sanitize various special characters that can appear in queries
    dset.ReplaceAll(" ", "_");
    dset.ReplaceAll("(", "_OPEN_");
    dset.ReplaceAll(")", "_CLOSE_");
    dset.ReplaceAll(":", "_COLON_");
    dset.ReplaceAll("'", "_SQUOTE_");
    dset.ReplaceAll("\"", "_DQUOTE_");

    std::cout << "Creating dataset " << dset << " for query " << query << std::endl;

    // I would be much much happier to do this in proper code, but I'm not sure
    // how, there's no samweb C++ API?
    system(TString::Format("samweb -e %s list-definitions --defname %s | grep %s || samweb -e %s create-definition %s %s",
                           SAMExperiment().c_str(),
                           dset.Data(),
                           dset.Data(),
                           SAMExperiment().c_str(),
                           dset.Data(),
                           query.c_str()).Data());

    return dset.Data();
  }

std::string ana::SAMQuerySource::EnsureSnapshot ( const std::string &  def ) const

protected

Definition at line 62 of file SAMQuerySource.cxx.

  {
    const char* user = getenv("GRID_USER");
    assert(user);
    const char* cluster = getenv("CLUSTER");
    assert(cluster);
    const char* process = getenv("PROCESS");
    assert(process);

    // Jobs in the same cluster should share the same snapshot of the dataset
    // so as not to hammer SAM with multiple requests for the same file list,
    // but so that the dataset snapshot is updated with every new submission.
    const std::string snap = TString::Format("%s_cafana_snap_%s_%s",
                                             user, def.c_str(), cluster).Data();

    // I'd love to do all this with a proper API, but samweb doesn't seem to
    // have a C++ one? So we get this stew of system() calls...

    // Use this name as an indication that someone is working on creating the
    // snapshot and every one else should stand by.
    const std::string snaplock = TString::Format("%s_cafana_snap_lock_%s_%s",
                                                 user, def.c_str(), cluster).Data();

    // Try to create the lock. Success means we have to create the snapshot,
    // failure means someone else is working on it. The content of the
    // definition (the nova.special) doesn't matter, except it has to be unique
    // between the jobs, because trying to create an exact duplicate of an
    // existing definition counts as success.
    std::cout << "Checking lock " << snaplock << std::endl;
    if(system(TString::Format("samweb -e %s create-definition %s file_name %s",
                              SAMExperiment().c_str(),
                              snaplock.c_str(),
                              process).Data()) == 0){
      // No one took the lock, it's up to us. Make the actual snapshot
      std::cout << "Snapshotting " << def << " as " << snap << std::endl;
      system(TString::Format("samweb -e %s take-snapshot %s | xargs samweb -e %s create-definition %s snapshot_id",
                             SAMExperiment().c_str(),
                             def.c_str(),
                             SAMExperiment().c_str(),
                             snap.c_str()).Data());
    }
    else{
      // Lock already exists, just wait for the real snapshot to be created
      double period = 1;
      while(system(TString::Format("samweb -e %s list-definitions --defname %s | grep %s",
                                   SAMExperiment().c_str(),
                                   snap.c_str(),
                                   snap.c_str()).Data()) != 0){
        sleep(int(period));
        period *= 1.5;
        if(period > 60*30){
          std::cout << "We've been waiting a real long time for " << snap << " to be created. I don't think it's happening." << std::endl;
          abort();
        }
      }
    }
    std::cout << "Will use " << snap << std::endl;

    return snap;
  }

std::string ana::SAMQuerySource::IFDHBaseURI ( ) const

protected

Definition at line 124 of file SAMQuerySource.cxx.

  {
    // This is the same logic as implemented in the default ifdh() constructor,
    // but using $SAM_EXPERIMENT in place of $EXPERIMENT

    // Allow user to override to arbitrary value
    if(getenv("IFDH_BASE_URI")) return getenv("IFDH_BASE_URI");

    return ifdh::_default_base_uri + SAMExperiment() + "/api";
  }

std::vector< std::string > ana::SAMQuerySource::LocateSAMFiles ( const std::vector< std::string > &  fnames )

protected

Take filenames, return locations suitable for TFile::Open()

Definition at line 199 of file SAMQuerySource.cxx.

  {
    std::vector<std::string> ret;

    // We're going to fill this map of locations for all the files
    std::map<std::string, std::vector<std::string>> locmap;

    Progress prog(TString::Format("Looking up locations of %ld files using SAM", fnames.size()).Data());

    ifdh i(IFDHBaseURI());
    i.set_debug("0"); // shut up

    // locateFiles() saves the roundtrip time of talking to the server about
    // every file individually, but it seems to bog down for large
    // queries. Split the query into chunks. Experimentally this is about the
    // sweet spot.
    const unsigned int kStep = 50;
    for(unsigned int fIdx = 0; fIdx < fnames.size(); fIdx += kStep){
      prog.SetProgress(double(fIdx)/fnames.size());

      // The files we're looking up right now. Careful not to run off the end
      // of the vector.
      const std::vector<std::string> fslice(fnames.begin()+fIdx, fIdx+kStep < fnames.size() ? fnames.begin()+fIdx+kStep : fnames.end());

      const auto locslice = i.locateFiles(fslice);

      locmap.insert(locslice.begin(), locslice.end());
    }

    prog.Done();


    // Now go through the map and pick our favourite location for each file,
    // and do some cleanup.
    for(auto it: locmap){
      const std::string& f = it.first;
      const std::vector<std::string>& locs = it.second;

      int best = 0;

      std::string resolved;
      for(TString loc: locs){
        // Never try to access bluearc locations from the grid
        if(!RunningOnGrid() && loc.BeginsWith("novadata:") && best < 3){
          loc.Remove(0, 9);

          // Rewrite FNAL bluearc paths so users with matching directory
          // structures offsite can access their local copies.
          if(std::getenv("NOVA_ANA" )) loc.ReplaceAll("/nova/ana",  std::getenv("NOVA_ANA"));
          if(std::getenv("NOVA_APP" )) loc.ReplaceAll("/nova/app",  std::getenv("NOVA_APP"));
          if(std::getenv("NOVA_DATA")) loc.ReplaceAll("/nova/data", std::getenv("NOVA_DATA"));
          if(std::getenv("NOVA_PROD")) loc.ReplaceAll("/nova/prod", std::getenv("NOVA_PROD"));

          // Check if the file exists at that location. If not, maybe pnfs has
          // it.
          struct stat junk;
          if(stat((resolved+'/'+f).c_str(), &junk) == 0){
            best = 3; // Prefer bluearc locations
            resolved = loc;
          }
        }

        if(loc.BeginsWith("dcache:") && best < 2){
          // Otherwise, used xrootd. Prefer "dache:" to "enstore:" because
          // "dcache:" probably means /pnfs/nova/persistent/ so no chance of a
          // huge wait for tape.
          best = 2;

          // FileListSource does the actual conversion to xrootd
          loc.ReplaceAll("dcache:/pnfs/", "/pnfs/");
          // Strip the bit in brackets from the end
          if(loc.First('(') >= 0) loc.Resize(loc.First('('));
          resolved = loc;
        }

        if(loc.BeginsWith("enstore:") && best < 1){
          best = 1;

          loc.ReplaceAll("enstore:/pnfs/", "/pnfs/");
          if(loc.First('(') >= 0) loc.Resize(loc.First('('));
          resolved = loc;
        }

      } // end for loc

      if(best == 0 || resolved.empty()){
        std::cerr << "\nCouldn't find a usable location for " << f
                  << "'. Aborting..." << std::endl;
        abort();
      }

      ret.push_back((resolved+'/'+f));
    } // end for fIdx

    return ret;
  }

std::vector< std::string > ana::SAMQuerySource::LocationsForSAMQuery ( const std::string &  str, int  stride, int  offset  )

protected

Definition at line 137 of file SAMQuerySource.cxx.

  {
    TString query = str;

    // This is an actual query
    if(query.Contains(' ') && RunningOnGrid()){
      // On the grid we want to convert that to a dataset we can snapshot below
      query = EnsureDataset(query.Data());
    }

    // This is a dataset name
    if(!query.Contains(' ')){
      if(getenv("CAFANA_USE_SNAPSHOTS")){
        query = "dataset_def_name_newest_snapshot "+query;
      }
      else{
        // Take one snapshot between all the jobs and share that
        if(RunningOnGrid()) query = EnsureSnapshot(query.Data());

        query = "defname: "+query;
      }
    }

    if(stride > 1){
      query += TString::Format(" with stride %d", stride).Data();
      if(offset > 0){
        query += TString::Format(" offset %d", offset).Data();
      }
    }


    std::cout << "Looking up files matching '" << query << "' using SAM...\n";

    std::vector<std::string> files;

    ifdh i(IFDHBaseURI());
    i.set_debug("0"); // shut up
    try{
      files = i.translateConstraints(query.Data());
    }
    catch(ifdh_util_ns::WebAPIException& e){
      // I like my error message below better, since this could well be a
      // mistyped filename.
    }

    if(files.empty()){
      std::cerr << "\nCan't find any files matching '" << str
                << "'. Aborting..." << std::endl;
      abort();
    }

    // IFDH likes to give back an empty string as the last response
    // https://cdcvs.fnal.gov/redmine/issues/6718
    if(!files.empty() && files.back().empty()){
      files.pop_back();
    }

    return LocateSAMFiles(files);
  }

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

• SAMQuerySource.h
• SAMQuerySource.cxx