BESInterface.cc

// BESInterface.cc
 
// This file is part of bes, A C++ back-end server implementation framework
// for the OPeNDAP Data Access Protocol.
 
// Copyright (c) 2004-2009 University Corporation for Atmospheric Research
// Author: Patrick West <pwest@ucar.edu> and Jose Garcia <jgarcia@ucar.edu>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// You can contact University Corporation for Atmospheric Research at
// 3080 Center Green Drive, Boulder, CO 80301
 
// (c) COPYRIGHT University Corporation for Atmospheric Research 2004-2005
// Please read the full copyright statement in the file COPYRIGHT_UCAR.
//
// Authors:
//      pwest       Patrick West <pwest@ucar.edu>
//      jgarcia     Jose Garcia <jgarcia@ucar.edu>
 
#include "config.h"
 
#include <cstdlib>
 
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
 
#include <string>
#include <sstream>
#include <future>         // std::async, std::future
#include <chrono>         // std::chrono::milliseconds
#include <algorithm>
 
#include "BESInterface.h"
 
#include "TheBESKeys.h"
#include "BESContextManager.h"
 
#include "BESTransmitterNames.h"
#include "BESDataNames.h"
#include "BESReturnManager.h"
 
#include "BESInfoList.h"
#include "BESXMLInfo.h"
 
#include "BESUtil.h"
#include "BESDebug.h"
#include "BESStopWatch.h"
#include "BESInternalError.h"
#include "BESInternalFatalError.h"
#include "ServerAdministrator.h"
#include "RequestServiceTimer.h"
 
#include "BESLog.h"
 
// If not defined, this is false (source code file names are logged). jhrg 10/4/18
#define EXCLUDE_FILE_INFO_FROM_LOG "BES.DoNotLogSourceFilenames"
#define prolog std::string("BESInterface::").append(__func__).append("() - ")
 
using namespace std;
 
// Define this to use sigwait() in a child thread to detect that SIGALRM
// has been raised (i.e., that the timeout interval has elapsed). This
// does not currently work, but could be a way to get information about
// a timeout back to the BES's client if the BES itself were structured
// differently. See my comment further down. jhrg 12/28/15
#define USE_SIGWAIT 0
 
#if 0
// timeout period in seconds; 0 --> no timeout. This is a global value so
// that it can be accessed by the signal handler. jhrg 1/4/16
// I've made this globally visible so that other code that might want to
// alter the timeout value can do so and this variable can be kept consistent.
// See BESStreamResponseHandler::execute() for an example. jhrg 1/24/17
volatile int bes_timeout = 0;
#endif
 
#define BES_TIMEOUT_KEY "BES.TimeOutInSeconds"
 
static inline void downcase(string &s)
{
    transform(s.begin(), s.end(), s.begin(), [](int c) { return std::toupper(c); });
}
 
ostream &add_memory_info(ostream &out)
{
    long mem_size = BESUtil::get_current_memory_usage();
    if (mem_size) {
        out << ", current memory usage is " << mem_size << " KB.";
    }
    else {
        out << ", current memory usage is unknown.";
    }
 
    return out;
}
 
static void log_error(const BESError &e)
{
    string error_name;
 
    switch (e.get_bes_error_type()) {
    case BES_INTERNAL_FATAL_ERROR:
        error_name = "BES Internal Fatal Error";
        break;
 
    case BES_INTERNAL_ERROR:
        error_name = "BES Internal Error";
        break;
 
    case BES_SYNTAX_USER_ERROR:
        error_name = "BES User Syntax Error";
        break;
 
    case BES_FORBIDDEN_ERROR:
        error_name = "BES Forbidden Error";
        break;
 
    case BES_NOT_FOUND_ERROR:
        error_name = "BES Not Found Error";
        break;
 
    default:
        error_name = "BES Error";
        break;
    }
 
    if (TheBESKeys::TheKeys()->read_bool_key(EXCLUDE_FILE_INFO_FROM_LOG, false)) {
        ERROR_LOG("ERROR: " << error_name << ": " << e.get_message() << add_memory_info << endl);
    }
    else {
        ERROR_LOG("ERROR: " << error_name << ": " << e.get_message()
            << " (" << e.get_file() << ":" << e.get_line() << ")"
            << add_memory_info << endl);
    }
}
 
#if USE_SIGWAIT
// If the BES is changed so that the plan built here is run in a child thread,
// then we can have a much more flexible signal catching scheme, including catching
// the alarm signal used for the timeout. It's not possible to throw from a child
// thread to a parent thread, but if the parent thread sees that SIGALRM is
// raised, then it can stop the child thread (which is running the 'plan') and
// return a suitable message to the front end. Similarly, the BES could also
// handle a number of other signals using this scheme. These signals (SIGPIPE, ...)
// are currently processed using while/for loop(s) in the bes/server code. It may
// be that these signals are caught only in the master listener, but I can't
// quite figure that out now... jhrg 12/28/15
//
// NB: It might be possible to edit this so that it writes info to the OLFS and
// then uses the 'raise SIGTERM' technique to exit. That way the OLFS will at least
// get a message about the timeout. I'm not sure how to close up the PPT part
// of the conversation, however. The idea would be that the current command's DHI
// would be passed in as an arg and then the stream accessed that way. The BESError
// would be written to the stream and the child process killed. jhrg 12/2/9/15
 
#include <pthread.h>
 
// An alternative to a function that catches the signal; use sigwait()
// in a child thread after marking the signal as blocked. When/if sigwait()
// returns, look at the signal number and if it is the alarm, sort out
// what to do (throw an exception, ...). NB: A signal handler cannot
// portably throw an exception, but this code can.
 
static pthread_t alarm_thread;
 
static void* alarm_wait(void * /* arg */)
{
    BESDEBUG("bes", "Starting: " << __PRETTY_FUNCTION__ << endl);
 
    // block SIGALRM
    sigset_t sigset;
    sigemptyset(&sigset);
    sigaddset(&sigset, SIGALRM);
    sigprocmask(SIG_BLOCK, &sigset, NULL);
 
    // Might replace this with a while loop. Not sure about interactions
    // with other signal processing code in the BES. jhrg 12/28/15
    int sig;
    int result = sigwait(&sigset, &sig);
    if (result != 0) {
        BESDEBUG("bes", "Fatal error establishing timeout: " << strerror(result) << endl);
        throw BESInternalFatalError(string("Fatal error establishing timeout: ") + strerror(result), __FILE__, __LINE__);
    }
    else if (result == 0 && sig == SIGALRM) {
        BESDEBUG("bes", "Timeout found in " << __PRETTY_FUNCTION__ << endl);
        throw BESTimeoutError("Timeout", __FILE__, __LINE__);
    }
    else {
        stringstream oss;
        oss << "While waiting for a timeout, found signal '" << result << "' in " << __PRETTY_FUNCTION__ << ends;
        BESDEBUG("bes", oss.str() << endl);
        throw BESInternalFatalError(oss.str(), __FILE__, __LINE__);
    }
}
 
static void wait_for_timeout()
{
    BESDEBUG("bes", "Entering: " << __PRETTY_FUNCTION__ << endl);
 
    pthread_attr_t thread_attr;
 
    if (pthread_attr_init(&thread_attr) != 0)
    throw BESInternalFatalError("Failed to initialize pthread attributes.", __FILE__, __LINE__);
    if (pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED /*PTHREAD_CREATE_JOINABLE*/) != 0)
    throw BESInternalFatalError("Failed to complete pthread attribute initialization.", __FILE__, __LINE__);
 
    int status = pthread_create(&alarm_thread, &thread_attr, alarm_wait, NULL);
    if (status != 0)
    throw BESInternalFatalError("Failed to start the timeout wait thread.", __FILE__, __LINE__);
}
#endif
 
BESInterface::BESInterface(ostream *output_stream) :
    d_strm(output_stream)
{
    if (!d_strm) {
        throw BESInternalError("Output stream must be set in order to output responses", __FILE__, __LINE__);
    }
 
#if 0
    // Grab the BES Key for the timeout. Note that the Hyrax server generally
    // overrides this value using a 'context' that is set/sent by the OLFS.
    // Also note that a value of zero means no timeout, but that the context
    // can override that too. jhrg 1/4/16
    d_timeout_from_keys = TheBESKeys::TheKeys()->read_int_key(BES_TIMEOUT_KEY, 0);
#endif
#if 0
    bool found;
    string timeout_key_value;
    TheBESKeys::TheKeys()->get_value(BES_TIMEOUT_KEY, timeout_key_value, found);
    if (found) {
        istringstream iss(timeout_key_value);
        iss >> d_timeout_from_keys;
    }
#endif
}
 
int BESInterface::handleException(const BESError &e, BESDataHandlerInterface &dhi)
{
    bool found = false;
    string context = BESContextManager::TheManager()->get_context("errors", found);
    downcase(context);
    if (found && context == XML_ERRORS)
        dhi.error_info = new BESXMLInfo();
    else
        dhi.error_info = BESInfoList::TheList()->build_info();
 
    log_error(e);
 
    string admin_email;
    try {
        bes::ServerAdministrator sd;
        admin_email = sd.get_email();
    }
    catch (...) {
        admin_email = "support@opendap.org";
    }
    if (admin_email.empty()) {
        admin_email = "support@opendap.org";
    }
 
    dhi.error_info->begin_response(dhi.action_name.empty() ? "BES" : dhi.action_name, dhi);
 
    dhi.error_info->add_exception(e, admin_email);
 
    dhi.error_info->end_response();
 
    return (int)e.get_bes_error_type();
}
 
void BESInterface::set_bes_timeout()
{
    // Set timeout? Use either the value from the keys or a context
    bool found = false;
    string context = BESContextManager::TheManager()->get_context("bes_timeout", found);
    if (found) {
        d_bes_timeout = strtol(context.c_str(), NULL, 10);
        VERBOSE(d_dhi_ptr->data[REQUEST_FROM] << "Set request timeout to " << d_bes_timeout << " seconds (from context)." << endl);
 
    }
    else {
        // Grab the BES Key for the timeout. Note that the Hyrax server generally
        // overrides this value using a 'context' that is set/sent by the OLFS.
        // Also note that a value of zero means no timeout, but that the context
        // can override that too. jhrg 1/4/16
        //
        // If the value is not set in teh BES keys, d_timeout_from_keys will get the
        // default value of 0. jhrg 4/20/22
        d_bes_timeout = TheBESKeys::TheKeys()->read_int_key(BES_TIMEOUT_KEY, 0);
        VERBOSE(d_dhi_ptr->data[REQUEST_FROM] << "Set request timeout to " << d_bes_timeout << " seconds (from keys)." << endl);
    }
}
 
void BESInterface::clear_bes_timeout()
{
    d_bes_timeout = 0;
 
    // Clearing bes_timeout requires disabling the timeout in RequestServiceTimer::TheTimer()
    RequestServiceTimer::TheTimer()->disable_timeout();
}
 
int BESInterface::execute_request(const string &from)
{
    BESDEBUG("bes", "Entering: " << __PRETTY_FUNCTION__ << endl);
 
    if (!d_dhi_ptr) {
        throw BESInternalError("DataHandlerInterface can not be null", __FILE__, __LINE__);
    }
 
    BESStopWatch sw;
    if (BESDebug::IsSet(TIMING_LOG_KEY)) {
        // It would be great to have more info to put here, but that is buried in
        // BESXMLInterface::build_data_request_plan() where the XML document is
        // parsed. jhrg 11/9/17
        sw.start("BESInterface::execute_request", d_dhi_ptr->data[REQUEST_ID]);
    }
 
    // TODO These never change for the life of a BES, so maybe they can move out of
    //  code that runs for every request? jhrg 11/8/17
    d_dhi_ptr->set_output_stream(d_strm);
    d_dhi_ptr->data[REQUEST_FROM] = from;
 
    // TODO If this is only used for logging, it is not needed since the log has a copy
    //  of the BES PID. jhrg 11/13/17
    ostringstream ss;
    ss << getpid();
    d_dhi_ptr->data[SERVER_PID] = ss.str();
 
    // We split up the calls for the reason that if we catch an
    // exception during the initialization, building, execution, or response
    // transmit of the request then we can transmit the exception/error
    // information.
    int status = 0; // save the return status from exception_manager() and return that.
    try {
        VERBOSE(d_dhi_ptr->data[REQUEST_FROM] << " request received" << endl);
 
        // Initialize the transmitter for this interface instance to the BASIC
        // TRANSMITTER. This ensures that a simple response, such as an error,
        // can be sent back to the OLFS should that be needed.
        d_transmitter = BESReturnManager::TheManager()->find_transmitter(BASIC_TRANSMITTER);
        if (!d_transmitter)
            throw BESInternalError(string("Unable to find transmitter '") + BASIC_TRANSMITTER + "'", __FILE__, __LINE__);
 
        build_data_request_plan();
 
        set_bes_timeout();
 
        // Start the request service timer.  The value bes_timeout == 0 disables the timeout,
        // otherwise the timeout can be disabled by BESUtil::conditional_timeout_cancel()
        // used by the transmitters, transforms to disable request timeout as streaming begins.
        RequestServiceTimer::TheTimer()->start(std::chrono::seconds{d_bes_timeout});
        BESDEBUG("request_timer",prolog << RequestServiceTimer::TheTimer()->dump() << endl);
 
        // This method (execute_data_request_plan()) does two key things:
        // Calls the request handler to make a response object' (the C++
        // object that will hold the response) and then calls the transmitter
        // to actually send it or build and send it.
 
        // HK-474. The exception caused by the errant config file in the ticket is
        // thrown from inside SaxParserWrapper::rethrowException(). It will be caught
        // below. jhrg 11/12//19
        execute_data_request_plan();
 
        // clear the timeout
        clear_bes_timeout();
 
        d_dhi_ptr->executed = true;
    }
    catch (const BESError &e) {
        BESDEBUG("bes",  string(__PRETTY_FUNCTION__) +  " - Caught BESError. msg: " << e.get_message() << endl );
        status = handleException(e, *d_dhi_ptr);
    }
    catch (const bad_alloc &e) {
        stringstream msg;
        msg << __PRETTY_FUNCTION__ <<  " - BES out of memory. msg: " << e.what()  << endl;
        BESDEBUG("bes", msg.str() << endl );
        BESInternalFatalError ex(msg.str(), __FILE__, __LINE__);
        status = handleException(ex, *d_dhi_ptr);
    }
    catch (const exception &e) {
        stringstream msg;
        msg << __PRETTY_FUNCTION__ << " - Caught C++ Exception. msg: " << e.what() << endl;
        BESDEBUG("bes", msg.str() << endl );
        BESInternalError ex(msg.str(), __FILE__, __LINE__);
        status = handleException(ex, *d_dhi_ptr);
    }
    catch (...) {
        string msg =  string(__PRETTY_FUNCTION__) +  " - An unidentified exception has been thrown.";
        BESDEBUG("bes", msg << endl );
        BESInternalError ex(msg, __FILE__, __LINE__);
        status = handleException(ex, *d_dhi_ptr);
    }
 
    return status;
}
 
int BESInterface::finish(int status)
{
    if (d_dhi_ptr->error_info) {
        d_dhi_ptr->error_info->print(*d_strm /*cout*/);
        delete d_dhi_ptr->error_info;
        d_dhi_ptr->error_info = 0;
    }
 
    // if there is a problem with the rest of these steps then all we will
    // do is log it to the BES log file and not handle the exception with
    // the exception manager.
    try {
        log_status();
        end_request();
    }
    catch (BESError &ex) {
        ERROR_LOG("Problem logging status or running end of request cleanup: " << ex.get_message() << endl);
    }
    catch (...) {
        ERROR_LOG("Unknown problem logging status or running end of request cleanup" << endl);
    }
 
    return status;
}
 
void BESInterface::end_request()
{
    // now clean up any containers that were used in the request, release
    // the resource
    d_dhi_ptr->first_container();
    while (d_dhi_ptr->container) {
        d_dhi_ptr->container->release();
        d_dhi_ptr->next_container();
    }
}
 
void BESInterface::dump(ostream & strm) const
{
    strm << BESIndent::LMarg << "BESInterface::dump - (" << (void *) this << ")" << endl;
    BESIndent::Indent();
 
    strm << BESIndent::LMarg << "data handler interface:" << endl;
    BESIndent::Indent();
    d_dhi_ptr->dump(strm);
    BESIndent::UnIndent();
 
    if (d_transmitter) {
        strm << BESIndent::LMarg << "transmitter:" << endl;
        BESIndent::Indent();
        d_transmitter->dump(strm);
        BESIndent::UnIndent();
    }
    else {
        strm << BESIndent::LMarg << "transmitter: not set" << endl;
    }
 
    BESIndent::UnIndent();
}