This class defines a generic task object (coordinator or worker) for the multi-work distributed computations framework. More...

#include <mwtask.h>

Inheritance diagram for chomp::multiwork::mwTask:

Public Member Functions
	mwTask ()
	The default constructor. More...

virtual	~mwTask ()
	The destructor. More...

void	Port (int number)
	Sets the port number for the communication or 0 to use none. More...

int	Port () const
	Returns the current port number. More...

void	ControlNumber (unsigned int number)
	Sets the control number for identification. More...

unsigned int	ControlNumber () const
	Returns the currently set identification control number. More...

void	TimeOut (int seconds)
	Sets the network connection time-out interval in seconds. More...

int	TimeOut () const
	Returns the currently set network connection time-out interval. More...

int	LogFile (const char *filename)
	Begins logging detailed communication debug information to the given file. More...

void	LogFile (const mwTask &other)
	Uses another task's log file to log this task's information. More...

void	LogClose ()
	Closes the log file and adds a line with the time information unless this log file was borrowed from another task. More...

int	Add (const char *name, int port=-1)
	Adds an address to the list of computers to connect to at the beginning of working or coordinating. More...

int	Load (const char *filename)
	Loads computer addresses from the given file. More...

int	QuitWorkers ()
	Quits all the workers whose addresses were added with the 'Add' and 'Load' functions. More...

Static Protected Member Functions
static int	SendMessage (int fd, unsigned int ctrl, unsigned int code, const mwData &x)
	Sends a message with data to the given socket. More...

static int	RecvMessage (int fd, unsigned int &ctrl, unsigned int &code, mwData &x)
	Receives a message with data from the given socket. More...

Protected Attributes
std::ofstream *	logFile
	The debug log file stream. More...

std::vector< std::string >	computers
	A list of workers or coordinators to connect to at start-up. More...

std::vector< int >	ports
	A list of port numbers of workers to connect to at start-up. More...

Private Member Functions
	mwTask (const mwTask &)
	The copy constructor is forbidden. More...

mwTask &	operator= (const mwTask &)
	The assignment operator is forbidden. More...

Private Attributes
int	portnum
	The network communication port number. More...

unsigned int	ctrlnum
	The control number that is used to recognize a compatible worker or a compatible coordinator. More...

int	timeout
	The network communication time-out in seconds. More...

bool	logBorrowed
	Is this log file pointer borrowed from another task? More...

Detailed Description

This class defines a generic task object (coordinator or worker) for the multi-work distributed computations framework.

It is the common part of a worker task and a coordinator task, and contains some general settings that apply to both. Note that this class is inherited by the worker and the coordinator class in the virtual mode, which allows one to create a class that is both a worker and a coordinator at the same time (although this is not recommended in general).

Definition at line 98 of file mwtask.h.

Constructor & Destructor Documentation

◆ mwTask() [1/2]

chomp::multiwork::mwTask::mwTask ( )

inline

The default constructor.

Definition at line 219 of file mwtask.h.

                      :
        portnum (mwPORT),
        ctrlnum (mwCTRLNUM),
        timeout (mwTIMEOUT),
        logFile (0),
        logBorrowed (false)
{
        return;
} /* mwTask::mwTask */

◆ ~mwTask()

chomp::multiwork::mwTask::~mwTask ( )

inlinevirtual

The destructor.

Definition at line 304 of file mwtask.h.

{
        // close the log file if it was in use
        LogClose ();
 
        return;
} /* mwTask::~mwTask */

References LogClose().

◆ mwTask() [2/2]

chomp::multiwork::mwTask::mwTask ( const mwTask & )

inlineprivate

The copy constructor is forbidden.

Definition at line 210 of file mwtask.h.

210{}

Member Function Documentation

◆ Add()

int chomp::multiwork::mwTask::Add	(	const char *	name,
		int	port = `-1`
	)

inline

Adds an address to the list of computers to connect to at the beginning of working or coordinating.

The addresses must be in the form "computer.domain:port". If port is not defined then the default port number is used.

Definition at line 350 of file mwtask.h.

{
        // if the name is empty, ignore it
        if (!name || !*name)
                return mwError;
 
        // determine whether the name contains a colon and port number
        int pos = 1;
        while (name [pos])
                ++ pos;
        -- pos;
        while (pos && (name [pos] != ':') &&
                (name [pos] >= '0') && (name [pos] <= '9'))
        {
                -- pos;
        }
 
        // if the name contains colon and some digits after the colon...
        if (pos && (name [pos] == ':') && name [pos + 1])
        {
                // append the computer name and the chosen port number
                char *compname = new char [pos + 1];
                for (int i = 0; i < pos; ++ i)
                        compname [i] = name [i];
                compname [pos] = '\0';
                port = std::atoi (name + pos + 1);
                if (port <= 0)
                        return mwError;
                computers. push_back (std::string (compname));
                ports. push_back (port);
                delete [] compname;
        }
        else
        {
                // if the port number is not reasonable, use the default one
                if (port <= 0)
                        port = portnum;
                if (port <= 0)
                        return mwError;
                computers. push_back (std::string (name));
                ports. push_back (port);
        }
        return mwOk;
} /* mwTask::Add */

References computers, chomp::multiwork::mwError, chomp::multiwork::mwOk, portnum, and ports.

Referenced by Load().

◆ ControlNumber() [1/2]

unsigned int chomp::multiwork::mwTask::ControlNumber ( ) const

inline

Returns the currently set identification control number.

Definition at line 332 of file mwtask.h.

{
        return ctrlnum;
} /* mwTask::ControlNumber */

References ctrlnum.

Referenced by chomp::multiwork::mwCoordinator::RecvMessageC(), chomp::multiwork::mwWorker::RecvMessageW(), chomp::multiwork::mwCoordinator::SendMessageC(), and chomp::multiwork::mwWorker::SendMessageW().

◆ ControlNumber() [2/2]

void chomp::multiwork::mwTask::ControlNumber ( unsigned int number )

inline

Sets the control number for identification.

Definition at line 326 of file mwtask.h.

{
        ctrlnum = number;
        return;
} /* mwTask::ControlNumber */

References ctrlnum.

◆ Load()

int chomp::multiwork::mwTask::Load ( const char * filename )

inline

Loads computer addresses from the given file.

Returns the number of acquired addresses or mwError.

Definition at line 395 of file mwtask.h.

{
        std::ifstream f (filename);
        if (!f)
                return mwError;
 
        char buf [512];
        int counter = 0;
        while (1)
        {
                *buf = '\0';
                f. getline (buf, 512, '\n');
                if ((*buf == ';') || (*buf == '#') || (*buf == '/'))
                        continue;
                if (*buf)
                {
                        int result = this -> Add (buf, portnum);
                        if (result == mwOk)
                                ++ counter;
                }
                if (!f)
                        return counter;
        }
} /* mwTask::Load */

References Add(), chomp::multiwork::mwError, chomp::multiwork::mwOk, and portnum.

◆ LogClose()

void chomp::multiwork::mwTask::LogClose ( )

inline

Closes the log file and adds a line with the time information unless this log file was borrowed from another task.

Definition at line 231 of file mwtask.h.

{
        if (!logFile)
                return;
        if (logBorrowed)
        {
                logFile = 0;
                logBorrowed = false;
                return;
        }
        std::time_t stop_time;
        std::time (&stop_time);
        *logFile << "\nMultiWork log file closed on " <<
                std::asctime (std::localtime (&stop_time)) << "\n"
                "-----------------------------------------------------\n" <<
                std::endl;
        delete logFile;
        logFile = 0;
        return;
} /* mwTask::LogClose */

References logBorrowed, and logFile.

Referenced by LogFile(), and ~mwTask().

◆ LogFile() [1/2]

int chomp::multiwork::mwTask::LogFile ( const char * filename )

inline

Begins logging detailed communication debug information to the given file.

Returns mwOk on success, mwError if cannot open/create the file.

Definition at line 252 of file mwtask.h.

{
        // close the current log if in use
        if (logFile)
                LogClose ();
 
        // if no file name supplied, return now
        if (!filename || !*filename)
                return mwOk;
 
        // create a file stream variable
        logFile = new std::ofstream;
        if (!logFile)
                return mwError;
 
        // open the log file for appending
        logFile -> open (filename, std::ios::app);
 
        // write the current time to the log
        std::time_t start_time;
        std::time (&start_time);
        *logFile << "MultiWork log file opened on " <<
                std::asctime (std::localtime (&start_time)) << std::endl;
 
        // if unable to open the file or an error occurred, return mwError
        if (!*logFile)
        {
                delete logFile;
                return mwError;
        }
 
        return mwOk;
} /* mwTask::LogFile */

References LogClose(), logFile, chomp::multiwork::mwError, and chomp::multiwork::mwOk.

◆ LogFile() [2/2]

void chomp::multiwork::mwTask::LogFile ( const mwTask & other )

inline

Uses another task's log file to log this task's information.

Definition at line 286 of file mwtask.h.

{
        // close the current log if in use
        LogClose ();
 
        // if there is no other log file, do nothing
        if (!other. logFile)
                return;
 
        // borrow the log file pointer
        logBorrowed = true;
        logFile = other. logFile;
 
        return;
} /* mwTask::LogFile */

References logBorrowed, LogClose(), and logFile.

◆ operator=()

mwTask & chomp::multiwork::mwTask::operator= ( const mwTask & )

inlineprivate

The assignment operator is forbidden.

Definition at line 213 of file mwtask.h.

213{return *this;}

◆ Port() [1/2]

int chomp::multiwork::mwTask::Port ( ) const

inline

Returns the current port number.

Definition at line 321 of file mwtask.h.

{
        return portnum;
} /* mwTask::Port */

References portnum.

Referenced by chomp::multiwork::mwCoordinator::BeginListening(), chomp::multiwork::mwWorker::Work(), and chomp::multiwork::mwWorker::WorkOne().

◆ Port() [2/2]

void chomp::multiwork::mwTask::Port ( int number )

inline

Sets the port number for the communication or 0 to use none.

Definition at line 314 of file mwtask.h.

{
        if (number >= 0)
                portnum = static_cast<short int> (number);
        return;
} /* mwTask::Port */

References portnum.

◆ QuitWorkers()

int chomp::multiwork::mwTask::QuitWorkers ( )

inline

Quits all the workers whose addresses were added with the 'Add' and 'Load' functions.

Returns mwOk or mwError.

Definition at line 492 of file mwtask.h.

{
        // write to the log file what you are doing
        if (logFile)
                *logFile << "Turning workers off..." << std::endl;
        
        // try connecting to each worker and ask them to exit
        int counter = 0;
        for (unsigned int n = 0; n < computers. size (); ++ n)
        {
                // retrieve the computer name and port from the list
                const char *name = computers [n]. c_str ();
                int port = ports [n];
 
                // if no valid name or port number read, skip this item
                if (!*name || !port)
                        continue;
 
                // try connecting to the computer
                int fd = mwConnect (name, port);
 
                // if unsuccessful, make a note and take another one
                if (fd < 0)
                {
                        if (logFile)
                        {
                                *logFile << "Worker " << name << ":" <<
                                        port << " could not be contacted." <<
                                        std::endl;
                        }
                        continue;
                }
                
                // prepare the control code to send to the worker
                unsigned int code = mwByeMsg | mwDontKeepMsg;
 
                // send the 'Bye!' message to the worker and disconnect it
                mwData empty;
                int result = this -> SendMessage (fd, ctrlnum, code, empty);
                mwDisconnect (fd);
 
                // add an appropriate message to the log file
                if (result == mwOk)
                {
                        ++ counter;
                        if (logFile)
                        {
                                *logFile << "Worker " << name << ":" <<
                                        port << " exited successfully." <<
                                        std::endl;
                        }
                }
                else if (logFile)
                {
                        *logFile << "Error while sending the disconnect "
                                "message to " << name << ":" << port <<
                                "." << std::endl;
                }
        }
 
        // write to the log file how many workers were turned off
        if (logFile)
                *logFile << counter << " worker(s) have been shut down." <<
                        std::endl;
 
        return mwOk;
} /* mwTask::QuitWorkers */

References computers, ctrlnum, logFile, chomp::multiwork::mwByeMsg, chomp::multiwork::mwConnect(), chomp::multiwork::mwDisconnect(), chomp::multiwork::mwDontKeepMsg, chomp::multiwork::mwOk, ports, and SendMessage().

◆ RecvMessage()

int chomp::multiwork::mwTask::RecvMessage	(	int	fd,
		unsigned int &	ctrl,
		unsigned int &	code,
		mwData &	x
	)

inlinestaticprotected

Receives a message with data from the given socket.

Receives a message from the given socket.

Verifies the received control code if it is correct. Returns mwOk on success or mwError in the case of failure.

Returns mwOk, mwError or mwLost.

Definition at line 437 of file mwtask.h.

{
        // read the code and length of the message
        char buf00 [12];
        int result = mwRecvBytes (fd, buf00, 12);
        if (result < 0)
                return result;
        unsigned char *buf0 = reinterpret_cast<unsigned char *> (buf00);
 
        // extract the length of the message
        int len = (int) (buf0 [8]) << 24;
        len |= (int) (buf0 [9]) << 16;
        len |= (int) (buf0 [10]) << 8;
        len |= (int) (buf0 [11]);
        if (len < 0)
                return mwError;
 
        // extract the control code of the message
        ctrl = (int) (buf0 [0]) << 24;
        ctrl |= (int) (buf0 [1]) << 16;
        ctrl |= (int) (buf0 [2]) << 8;
        ctrl |= (int) (buf0 [3]);
 
        // extract the code of the message
        code = (int) (buf0 [4]) << 24;
        code |= (int) (buf0 [5]) << 16;
        code |= (int) (buf0 [6]) << 8;
        code |= (int) (buf0 [7]);
 
        // if the message length is zero, no more reading is necessary
        if (!len)
        {
                x. Reset ();
                return mwOk;
        }
 
        // prepare a memory buffer for the message
        char *buf = new char [len];
        if (!buf)
                return mwError;
 
        // read the message
        result = mwRecvBytes (fd, buf, len);
        if (result < 0)
        {
                delete [] buf;
                return result;
        }
 
        // transform the message to mw data
        x. Take (buf, len);
        return mwOk;
} /* RecvMessage */

References chomp::multiwork::mwError, chomp::multiwork::mwOk, and chomp::multiwork::mwRecvBytes().

Referenced by chomp::multiwork::mwCoordinator::RecvMessageC(), and chomp::multiwork::mwWorker::RecvMessageW().

◆ SendMessage()

int chomp::multiwork::mwTask::SendMessage	(	int	fd,
		unsigned int	ctrl,
		unsigned int	code,
		const mwData &	x
	)

inlinestaticprotected

Sends a message with data to the given socket.

Sends a message to the given socket.

The message includes a control number. Returns mwOk on success and mwError in the case of failure.

Returns mwOk, mwError or mwLost.

Definition at line 427 of file mwtask.h.

{
        mwData sending;
        sending << ctrl << code << x. Length () << x;
        return mwSendBytes (fd, sending. Buffer (), sending. Length ());
} /* SendMessage */

References chomp::multiwork::mwSendBytes().

Referenced by QuitWorkers(), chomp::multiwork::mwCoordinator::SendMessageC(), and chomp::multiwork::mwWorker::SendMessageW().

◆ TimeOut() [1/2]

int chomp::multiwork::mwTask::TimeOut ( ) const

inline

Returns the currently set network connection time-out interval.

Definition at line 343 of file mwtask.h.

{
        return timeout;
} /* mwTask::TimeOut */

References timeout.

Referenced by chomp::multiwork::mwCoordinator::RunLoop(), chomp::multiwork::mwWorker::Work(), and chomp::multiwork::mwWorker::WorkOne().

◆ TimeOut() [2/2]

void chomp::multiwork::mwTask::TimeOut ( int seconds )

inline

Sets the network connection time-out interval in seconds.

Definition at line 337 of file mwtask.h.

{
        timeout = seconds;
        return;
} /* mwTask::TimeOut */

References timeout.

Member Data Documentation

◆ computers

std::vector<std::string> chomp::multiwork::mwTask::computers

protected

A list of workers or coordinators to connect to at start-up.

Definition at line 201 of file mwtask.h.

Referenced by Add(), chomp::multiwork::mwCoordinator::ConnectWorkers(), QuitWorkers(), and chomp::multiwork::mwWorker::Work().

◆ ctrlnum

unsigned int chomp::multiwork::mwTask::ctrlnum

private

The control number that is used to recognize a compatible worker or a compatible coordinator.

Note: The worker sends its negation.

Definition at line 168 of file mwtask.h.

Referenced by ControlNumber(), and QuitWorkers().

◆ logBorrowed

bool chomp::multiwork::mwTask::logBorrowed

private

Is this log file pointer borrowed from another task?

Definition at line 181 of file mwtask.h.

Referenced by LogClose(), and LogFile().

◆ logFile

std::ofstream* chomp::multiwork::mwTask::logFile

protected

The debug log file stream.

Definition at line 177 of file mwtask.h.

◆ portnum

int chomp::multiwork::mwTask::portnum

private

The network communication port number.

Definition at line 164 of file mwtask.h.

Referenced by Add(), Load(), and Port().

◆ ports

std::vector<int> chomp::multiwork::mwTask::ports

protected

A list of port numbers of workers to connect to at start-up.

Definition at line 204 of file mwtask.h.

Referenced by Add(), chomp::multiwork::mwCoordinator::ConnectWorkers(), QuitWorkers(), and chomp::multiwork::mwWorker::Work().

◆ timeout

int chomp::multiwork::mwTask::timeout

private

The network communication time-out in seconds.

Definition at line 171 of file mwtask.h.

Referenced by TimeOut(), and chomp::multiwork::mwWorker::Work().

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

chomp/multiwork/mwtask.h

Public Member Functions

Static Protected Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ mwTask() [1/2]

◆ ~mwTask()

◆ mwTask() [2/2]

Member Function Documentation

◆ Add()

◆ ControlNumber() [1/2]

◆ ControlNumber() [2/2]

◆ Load()

◆ LogClose()

◆ LogFile() [1/2]

◆ LogFile() [2/2]

◆ operator=()

◆ Port() [1/2]

◆ Port() [2/2]

◆ QuitWorkers()

◆ RecvMessage()

◆ SendMessage()

◆ TimeOut() [1/2]

◆ TimeOut() [2/2]

Member Data Documentation

◆ computers

◆ ctrlnum

◆ logBorrowed

◆ logFile

◆ portnum

◆ ports

◆ timeout