ExternalLHEProducer.cc

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// -*- C++ -*-
//
// Package:    ExternalLHEProducer
// Class:      ExternalLHEProducer
//
//
// Original Author:  Brian Paul Bockelman,8 R-018,+41227670861,
//         Created:  Fri Oct 21 11:37:26 CEST 2011
//
//

// system include files
#include "oneapi/tbb/task_arena.h"
#include "oneapi/tbb/task_group.h"
#include <cstdio>
#include <cstdlib>
#include <dirent.h>
#include <fcntl.h>
#include <filesystem>
#include <fstream>
#include <memory>
#include <string>
#include <sys/resource.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <system_error>
#include <unistd.h>
#include <vector>

#include "boost/ptr_container/ptr_deque.hpp"

// user include files
#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/one/EDProducer.h"
#include "FWCore/Framework/interface/LuminosityBlock.h"

#include "FWCore/Framework/interface/Run.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/MakerMacros.h"

#include "FWCore/ParameterSet/interface/FileInPath.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"

#include "SimDataFormats/GeneratorProducts/interface/LesHouches.h"
#include "SimDataFormats/GeneratorProducts/interface/LHERunInfoProduct.h"
#include "SimDataFormats/GeneratorProducts/interface/LHEEventProduct.h"
#include "SimDataFormats/GeneratorProducts/interface/LHEXMLStringProduct.h"

#include "GeneratorInterface/LHEInterface/interface/LHERunInfo.h"
#include "GeneratorInterface/LHEInterface/interface/LHEEvent.h"
#include "GeneratorInterface/LHEInterface/interface/LHEReader.h"

#include "FWCore/ServiceRegistry/interface/Service.h"
#include "FWCore/Utilities/interface/RandomNumberGenerator.h"

#include "FWCore/MessageLogger/interface/MessageLogger.h"

//
// class declaration
//

class ExternalLHEProducer : public edm::one::EDProducer<edm::BeginRunProducer, edm::one::WatchRuns> {
public:
  explicit ExternalLHEProducer(const edm::ParameterSet& iConfig);

  static void fillDescriptions(edm::ConfigurationDescriptions& descriptions);

private:
  void produce(edm::Event&, const edm::EventSetup&) override;
  void beginRunProduce(edm::Run& run, edm::EventSetup const& es) override;
  void beginRun(edm::Run const&, edm::EventSetup const&) override;
  void endRun(edm::Run const&, edm::EventSetup const&) override;
  void preallocThreads(unsigned int) override;

  std::vector<std::string> makeArgs(uint32_t nEvents, unsigned int nThreads, std::uint32_t seed) const;
  int closeDescriptors(int preserve) const;
  void executeScript(std::vector<std::string> const& args, int id, bool isPost) const;

  void nextEvent();
  std::unique_ptr<LHERunInfoProduct> generateRunInfo(std::vector<std::string> const& files) const;

  // ----------member data ---------------------------
  std::string scriptName_;
  std::string outputFile_;
  const std::vector<std::string> args_;
  uint32_t npars_;
  uint32_t nEvents_;
  bool storeXML_;
  unsigned int nThreads_{1};
  std::string outputContents_;
  bool generateConcurrently_{false};
  const std::vector<std::string> postGenerationCommand_;

  // Used only if nPartonMapping is in the configuration
  std::map<unsigned, std::pair<unsigned, unsigned>> nPartonMapping_{};

  std::unique_ptr<lhef::LHEReader> reader_;
  std::shared_ptr<lhef::LHEEvent> partonLevel_;
  bool wasMerged_;

  edm::EDPutTokenT<LHEXMLStringProduct> xmlPutToken_;
  edm::EDPutTokenT<LHEEventProduct> eventPutToken_;
  edm::EDPutTokenT<LHERunInfoProduct> beginRunPutToken_;
  class FileCloseSentry {
  public:
    explicit FileCloseSentry(int fd) : fd_(fd){};

    ~FileCloseSentry() { close(fd_); }

    //Make this noncopyable
    FileCloseSentry(const FileCloseSentry&) = delete;
    FileCloseSentry& operator=(const FileCloseSentry&) = delete;

  private:
    int fd_;
  };
};

//
// constructors and destructor
//
ExternalLHEProducer::ExternalLHEProducer(const edm::ParameterSet& iConfig)
    : scriptName_((iConfig.getParameter<edm::FileInPath>("scriptName")).fullPath()),
      outputFile_(iConfig.getParameter<std::string>("outputFile")),
      args_(iConfig.getParameter<std::vector<std::string>>("args")),
      npars_(iConfig.getParameter<uint32_t>("numberOfParameters")),
      nEvents_(iConfig.getUntrackedParameter<uint32_t>("nEvents")),
      storeXML_(iConfig.getUntrackedParameter<bool>("storeXML")),
      generateConcurrently_(iConfig.getUntrackedParameter<bool>("generateConcurrently")),
      postGenerationCommand_(iConfig.getUntrackedParameter<std::vector<std::string>>("postGenerationCommand")) {
  if (npars_ != args_.size())
    throw cms::Exception("ExternalLHEProducer")
        << "Problem with configuration: " << args_.size() << " script arguments given, expected " << npars_;

  if (iConfig.exists("nPartonMapping")) {
    auto& processMap(iConfig.getParameterSetVector("nPartonMapping"));
    for (auto& cfg : processMap) {
      unsigned processId(cfg.getParameter<unsigned>("idprup"));

      auto orderStr(cfg.getParameter<std::string>("order"));
      unsigned order(0);
      if (orderStr == "LO")
        order = 0;
      else if (orderStr == "NLO")
        order = 1;
      else
        throw cms::Exception("ExternalLHEProducer")
            << "Invalid order specification for process " << processId << ": " << orderStr;

      unsigned np(cfg.getParameter<unsigned>("np"));

      nPartonMapping_.emplace(processId, std::make_pair(order, np));
    }
  }

  xmlPutToken_ = produces<LHEXMLStringProduct, edm::Transition::BeginRun>("LHEScriptOutput");

  eventPutToken_ = produces<LHEEventProduct>();
  beginRunPutToken_ = produces<LHERunInfoProduct, edm::Transition::BeginRun>();
}

//
// member functions
//

// ------------ method called with number of threads in job --
void ExternalLHEProducer::preallocThreads(unsigned int iThreads) { nThreads_ = iThreads; }

// ------------ method called to produce the data  ------------
void ExternalLHEProducer::produce(edm::Event& iEvent, const edm::EventSetup& iSetup) {
  nextEvent();
  if (!partonLevel_) {
    throw edm::Exception(edm::errors::EventGenerationFailure)
        << "No lhe event found in ExternalLHEProducer::produce().  "
        << "The likely cause is that the lhe file contains fewer events than were requested, which is possible "
        << "in case of phase space integration or uneweighting efficiency problems.";
  }

  std::unique_ptr<LHEEventProduct> product(
      new LHEEventProduct(*partonLevel_->getHEPEUP(), partonLevel_->originalXWGTUP()));
  if (partonLevel_->getPDF()) {
    product->setPDF(*partonLevel_->getPDF());
  }
  std::for_each(partonLevel_->weights().begin(),
                partonLevel_->weights().end(),
                std::bind(&LHEEventProduct::addWeight, product.get(), std::placeholders::_1));
  product->setScales(partonLevel_->scales());
  if (nPartonMapping_.empty()) {
    product->setNpLO(partonLevel_->npLO());
    product->setNpNLO(partonLevel_->npNLO());
  } else {
    // overwrite npLO and npNLO values by user-specified mapping
    unsigned processId(partonLevel_->getHEPEUP()->IDPRUP);
    unsigned order(0);
    unsigned np(0);
    try {
      auto procDef(nPartonMapping_.at(processId));
      order = procDef.first;
      np = procDef.second;
    } catch (std::out_of_range&) {
      throw cms::Exception("ExternalLHEProducer")
          << "Unexpected IDPRUP encountered: " << partonLevel_->getHEPEUP()->IDPRUP;
    }

    switch (order) {
      case 0:
        product->setNpLO(np);
        product->setNpNLO(-1);
        break;
      case 1:
        product->setNpLO(-1);
        product->setNpNLO(np);
        break;
      default:
        break;
    }
  }

  std::for_each(partonLevel_->getComments().begin(),
                partonLevel_->getComments().end(),
                std::bind(&LHEEventProduct::addComment, product.get(), std::placeholders::_1));

  iEvent.put(eventPutToken_, std::move(product));

  partonLevel_.reset();
  return;
}

// ------------ method called when starting to processes a run  ------------
void ExternalLHEProducer::beginRunProduce(edm::Run& run, edm::EventSetup const& es) {
  // pass the number of events as previous to last argument

  // pass the random number generator seed as last argument

  edm::Service<edm::RandomNumberGenerator> rng;

  if (!rng.isAvailable()) {
    throw cms::Exception("Configuration")
        << "The ExternalLHEProducer module requires the RandomNumberGeneratorService\n"
           "which is not present in the configuration file.  You must add the service\n"
           "in the configuration file if you want to run ExternalLHEProducer";
  }

  std::vector<std::string> infiles;
  auto const seed = rng->mySeed();
  if (generateConcurrently_) {
    infiles.resize(nThreads_);
    auto const nEventsAve = nEvents_ / nThreads_;
    unsigned int const overflow = nThreads_ - (nEvents_ % nThreads_);
    std::exception_ptr except;
    std::atomic<char> exceptSet{0};

    tbb::this_task_arena::isolate([this, &except, &infiles, &exceptSet, nEventsAve, overflow, seed]() {
      tbb::task_group group;
      for (unsigned int t = 0; t < nThreads_; ++t) {
        uint32_t nEvents = nEventsAve;
        if (nEvents_ % nThreads_ != 0 and t >= overflow) {
          nEvents += 1;
        }
        group.run([t, this, &infiles, seed, nEvents, &except, &exceptSet]() {
          CMS_SA_ALLOW try {
            using namespace std::filesystem;
            using namespace std::string_literals;
            auto out = path("thread"s + std::to_string(t)) / path(outputFile_);
            infiles[t] = out.native();
            executeScript(makeArgs(nEvents, 1, seed + t), t, false);
          } catch (...) {
            char expected = 0;
            if (exceptSet.compare_exchange_strong(expected, 1)) {
              except = std::current_exception();
              exceptSet.store(2);
            }
          }
        });
      }
      group.wait();
    });
    if (exceptSet != 0) {
      std::rethrow_exception(except);
    }
  } else {
    infiles = std::vector<std::string>(1, outputFile_);
    executeScript(makeArgs(nEvents_, nThreads_, seed), 0, false);
  }

  //run post-generation command if specified
  if (!postGenerationCommand_.empty()) {
    std::vector<std::string> postcmd = postGenerationCommand_;
    try {
      postcmd[0] = edm::FileInPath(postcmd[0]).fullPath();
    } catch (const edm::Exception& e) {
      edm::LogWarning("ExternalLHEProducer") << postcmd[0] << " is not a relative path. Run it as a shell command.";
    }
    executeScript(postcmd, 0, true);
  }

  //fill LHEXMLProduct (streaming read directly into compressed buffer to save memory)
  std::unique_ptr<LHEXMLStringProduct> p(new LHEXMLStringProduct);

  //store the XML file only if explictly requested
  if (storeXML_) {
    std::string file;
    if (generateConcurrently_) {
      using namespace std::filesystem;
      file = (path("thread0") / path(outputFile_)).native();
    } else {
      file = outputFile_;
    }
    std::ifstream instream(file);
    if (!instream) {
      throw cms::Exception("OutputOpenError") << "Unable to open script output file " << outputFile_ << ".";
    }
    instream.seekg(0, instream.end);
    int insize = instream.tellg();
    instream.seekg(0, instream.beg);
    p->fillCompressedContent(instream, 0.25 * insize);
    instream.close();
  }
  run.put(xmlPutToken_, std::move(p));

  //Read the beginning of each file to get the run info in order to do the merge
  auto runInfo = generateRunInfo(infiles);
  if (runInfo) {
    run.put(beginRunPutToken_, std::move(runInfo));
  }

  // LHE C++ classes translation
  // (read back uncompressed file from disk in streaming mode again to save memory)
  unsigned int skip = 0;
  reader_ = std::make_unique<lhef::LHEReader>(infiles, skip);

  nextEvent();
}

void ExternalLHEProducer::beginRun(edm::Run const& run, edm::EventSetup const& es) {}
// ------------ method called when ending the processing of a run  ------------
void ExternalLHEProducer::endRun(edm::Run const& run, edm::EventSetup const& es) {
  nextEvent();
  if (partonLevel_) {
    // VALIDATION_RUN env variable allows to finish event processing early without errors by sending SIGINT
    if (std::getenv("VALIDATION_RUN") != nullptr) {
      edm::LogWarning("ExternalLHEProducer")
          << "Event loop is over, but there are still lhe events to process, ignoring...";
    } else {
      throw edm::Exception(edm::errors::EventGenerationFailure)
          << "Error in ExternalLHEProducer::endRunProduce().  "
          << "Event loop is over, but there are still lhe events to process."
          << "This could happen if lhe file contains more events than requested.  This is never expected to happen.";
    }
  }

  reader_.reset();
  if (generateConcurrently_) {
    for (unsigned int t = 0; t < nThreads_; ++t) {
      using namespace std::filesystem;
      using namespace std::string_literals;
      auto out = path("thread"s + std::to_string(t)) / path(outputFile_);
      if (unlink(out.c_str())) {
        throw cms::Exception("OutputDeleteError") << "Unable to delete original script output file " << out
                                                  << " (errno=" << errno << ", " << strerror(errno) << ").";
      }
    }
  } else {
    if (unlink(outputFile_.c_str())) {
      throw cms::Exception("OutputDeleteError") << "Unable to delete original script output file " << outputFile_
                                                << " (errno=" << errno << ", " << strerror(errno) << ").";
    }
  }
}

std::vector<std::string> ExternalLHEProducer::makeArgs(uint32_t nEvents,
                                                       unsigned int nThreads,
                                                       std::uint32_t seed) const {
  std::vector<std::string> args;
  args.reserve(3 + args_.size());

  args.push_back(args_.front());
  args.push_back(std::to_string(nEvents));

  args.push_back(std::to_string(seed));

  args.push_back(std::to_string(nThreads));
  std::copy(args_.begin() + 1, args_.end(), std::back_inserter(args));

  for (unsigned int iArg = 0; iArg < args.size(); iArg++) {
    LogDebug("LHEInputArgs") << "arg [" << iArg << "] = " << args[iArg];
  }

  return args;
}

// ------------ Close all the open file descriptors ------------
int ExternalLHEProducer::closeDescriptors(int preserve) const {
  int maxfd = 1024;
  int fd;
#ifdef __linux__
  DIR* dir;
  struct dirent* dp;
  maxfd = preserve;
  if ((dir = opendir("/proc/self/fd"))) {
    errno = 0;
    while ((dp = readdir(dir)) != nullptr) {
      if ((strcmp(dp->d_name, ".") == 0) || (strcmp(dp->d_name, "..") == 0)) {
        continue;
      }
      if (sscanf(dp->d_name, "%d", &fd) != 1) {
        //throw cms::Exception("closeDescriptors") << "Found unexpected filename in /proc/self/fd: " << dp->d_name;
        return -1;
      }
      if (fd > maxfd) {
        maxfd = fd;
      }
    }
    if (errno) {
      //throw cms::Exception("closeDescriptors") << "Unable to determine the number of fd (errno=" << errno << ", " << strerror(errno) << ").";
      return errno;
    }
    closedir(dir);
  }
#endif
  // TODO: assert for an unreasonable number of fds?
  for (fd = 3; fd < maxfd + 1; fd++) {
    if (fd != preserve)
      close(fd);
  }
  return 0;
}

// ------------ Execute the script associated with this producer ------------
void ExternalLHEProducer::executeScript(std::vector<std::string> const& args, int id, bool isPost) const {
  // Fork a script, wait until it finishes.

  int rc = 0, rc2 = 0;
  int filedes[2], fd_flags;

  if (pipe(filedes)) {
    throw cms::Exception("Unable to create a new pipe");
  }
  FileCloseSentry sentry1(filedes[0]), sentry2(filedes[1]);

  if ((fd_flags = fcntl(filedes[1], F_GETFD, NULL)) == -1) {
    throw cms::Exception("ExternalLHEProducer")
        << "Failed to get pipe file descriptor flags (errno=" << rc << ", " << strerror(rc) << ")";
  }
  if (fcntl(filedes[1], F_SETFD, fd_flags | FD_CLOEXEC) == -1) {
    throw cms::Exception("ExternalLHEProducer")
        << "Failed to set pipe file descriptor flags (errno=" << rc << ", " << strerror(rc) << ")";
  }

  unsigned int argc_pre = 0;
  // For generation command the first argument gives to the scriptName
  if (!isPost) {
    argc_pre = 1;
  }
  unsigned int argc = argc_pre + args.size();
  // TODO: assert that we have a reasonable number of arguments
  char** argv = new char*[argc + 1];
  if (!isPost) {
    argv[0] = strdup(scriptName_.c_str());
  }
  for (unsigned int i = 0; i < args.size(); i++) {
    argv[argc_pre + i] = strdup(args[i].c_str());
  }
  argv[argc] = nullptr;

  pid_t pid = fork();
  if (pid == 0) {
    // The child process
    if (!(rc = closeDescriptors(filedes[1]))) {
      if (!isPost && generateConcurrently_) {
        using namespace std::filesystem;
        using namespace std::string_literals;
        std::error_code ec;
        auto newDir = path("thread"s + std::to_string(id));
        create_directory(newDir, ec);
        current_path(newDir, ec);
      }
      execvp(argv[0], argv);  // If execv returns, we have an error.
      rc = errno;
    }
    while ((write(filedes[1], &rc, sizeof(int)) == -1) && (errno == EINTR)) {
    }
    _exit(1);
  }

  // Free the arg vector ASAP
  for (unsigned int i = 0; i < args.size() + 1; i++) {
    free(argv[i]);
  }
  delete[] argv;

  if (pid == -1) {
    throw cms::Exception("ForkException")
        << "Unable to fork a child (errno=" << errno << ", " << strerror(errno) << ")";
  }

  close(filedes[1]);
  // If the exec succeeds, the read will fail.
  while (((rc2 = read(filedes[0], &rc, sizeof(int))) == -1) && (errno == EINTR)) {
    rc2 = 0;
  }
  if ((rc2 == sizeof(int)) && rc) {
    throw cms::Exception("ExternalLHEProducer")
        << "Failed to execute script (errno=" << rc << ", " << strerror(rc) << ")";
  }
  close(filedes[0]);

  int status = 0;
  errno = 0;
  do {
    if (waitpid(pid, &status, 0) < 0) {
      if (errno == EINTR) {
        continue;
      } else {
        throw cms::Exception("ExternalLHEProducer")
            << "Failed to read child status (errno=" << errno << ", " << strerror(errno) << ")";
      }
    }
    if (WIFSIGNALED(status)) {
      throw cms::Exception("ExternalLHEProducer") << "Child exited due to signal " << WTERMSIG(status) << ".";
    }
    if (WIFEXITED(status)) {
      rc = WEXITSTATUS(status);
      break;
    }
  } while (true);
  if (rc) {
    throw cms::Exception("ExternalLHEProducer") << "Child failed with exit code " << rc << ".";
  }
}

// ------------ method fills 'descriptions' with the allowed parameters for the module  ------------
void ExternalLHEProducer::fillDescriptions(edm::ConfigurationDescriptions& descriptions) {
  //The following says we do not know what parameters are allowed so do no validation
  // Please change this to state exactly what you do use, even if it is no parameters
  edm::ParameterSetDescription desc;
  desc.setComment("Executes an external script and places its output file into an EDM collection");

  edm::FileInPath thePath;
  desc.add<edm::FileInPath>("scriptName", thePath);
  desc.add<std::string>("outputFile", "myoutput");
  desc.add<std::vector<std::string>>("args");
  desc.add<uint32_t>("numberOfParameters");
  desc.addUntracked<uint32_t>("nEvents");
  desc.addUntracked<bool>("storeXML", false);
  desc.addUntracked<bool>("generateConcurrently", false)
      ->setComment("If true, run the script concurrently in separate processes.");
  desc.addUntracked<std::vector<std::string>>("postGenerationCommand", std::vector<std::string>())
      ->setComment(
          "Command to run after the generation script has completed. The first argument can be a relative path.");

  edm::ParameterSetDescription nPartonMappingDesc;
  nPartonMappingDesc.add<unsigned>("idprup");
  nPartonMappingDesc.add<std::string>("order");
  nPartonMappingDesc.add<unsigned>("np");
  desc.addVPSetOptional("nPartonMapping", nPartonMappingDesc);

  descriptions.addDefault(desc);
}

std::unique_ptr<LHERunInfoProduct> ExternalLHEProducer::generateRunInfo(std::vector<std::string> const& iFiles) const {
  std::unique_ptr<LHERunInfoProduct> retValue;
  //read each file in turn and only get the header info
  for (auto const& file : iFiles) {
    unsigned int skip = 0;
    std::vector<std::string> infiles(1, file);
    auto reader = std::make_unique<lhef::LHEReader>(infiles, skip);
    auto parton = reader->next();
    if (!parton) {
      break;
    }
    auto runInfo = parton->getRunInfo();
    LHERunInfoProduct product(*runInfo->getHEPRUP());

    std::for_each(runInfo->getHeaders().begin(),
                  runInfo->getHeaders().end(),
                  std::bind(&LHERunInfoProduct::addHeader, &product, std::placeholders::_1));
    std::for_each(runInfo->getComments().begin(),
                  runInfo->getComments().end(),
                  std::bind(&LHERunInfoProduct::addComment, &product, std::placeholders::_1));
    if (not retValue) {
      retValue = std::make_unique<LHERunInfoProduct>(std::move(product));
    } else {
      retValue->mergeProduct(product);
    }
  }

  return retValue;
}

void ExternalLHEProducer::nextEvent() {
  if (partonLevel_)
    return;

  if (not reader_) {
    return;
  }

  partonLevel_ = reader_->next();
  if (!partonLevel_) {
    //see if we have another file to read;
    bool newFileOpened;
    do {
      newFileOpened = false;
      partonLevel_ = reader_->next(&newFileOpened);
    } while (newFileOpened && !partonLevel_);
  }
}

//define this as a plug-in
DEFINE_FWK_MODULE(ExternalLHEProducer);