Process Array Example
^^^^^^^^^^^^^^^^^^^^^

.. code-block:: bash

    # This module shows the basic pattern for running an array of
    # parallel tasks. array_writer_define_opts loops over a fixed set
    # of task identifiers and calls save_opt_list once per iteration,
    # so DeBasher schedules one array_writer task per call with its own
    # "-id" and "-outf" options. array_reader_define_opts mirrors the
    # same loop, reading each writer task's output through
    # define_opt_from_proc_task_out. The loop itself is written by hand
    # here: compare it with the following example, where the same
    # scenario is expressed through DeBasher's array option handler
    # convention instead.

    array_writer_document()
    {
        document_process "Executes an array of 4 tasks. Each task creates a file containing the task index."
    }

    array_writer_explain_opts()
    {
        # -c option
        local description="Sleep time in seconds"
        explain_opt "-c" "<int>" "$description"

        # -id option
        local description="id of writer"
        explain_opt "-id" "<int>" "$description"

        # -outf option
        local description="output file of writer"
        explain_opt "-outf" "<file>" "$description"
    }

    array_writer_identify_cmdline_opts()
    {
        opt_is_cmdline "-c"
    }

    array_writer_define_opts()
    {
        # Initialize variables
        local cmdline=$1
        local process_spec=$2
        local process_name=$3
        local process_outdir=$4
        local optlist=""

        # -c option
        define_cmdline_opt "$cmdline" "-c" optlist || return 1

        # Save option list so as to execute process four times
        for id in 0 1 2 3; do
            local specific_optlist=${optlist}
            define_opt "-id" $id specific_optlist || return 1
            define_opt "-outf" "${process_outdir}/${id}" specific_optlist || return 1
            save_opt_list specific_optlist
        done
    }

    array_writer()
    {
        # Initialize variables
        local sleep_time=$(read_opt_value_from_func_args "-c" "$@")
        local id=$(read_opt_value_from_func_args "-id" "$@")
        local outf=$(read_opt_value_from_func_args "-outf" "$@")

        # Sleep some time
        sleep ${sleep_time}

        # Create file
        echo $id > "${outf}"
    }

    array_writer_reset_outfiles()
    {
        # Initialize variables
        local outf=$(read_opt_value_from_func_args "-outf" "$@")

        # Remove output file
        if [ -f "${outf}" ]; then
            rm "${outf}"
        fi
    }

    array_reader_document()
    {
        document_process "Reads each array_writer task's output file and copies its content to the reader's own output file."
    }

    array_reader_explain_opts()
    {
        # -id option
        local description="id of reader"
        explain_opt "-id" "<int>" "$description"

        # -infile option
        local description="input file"
        explain_opt "-infile" "<file>" "$description"

        # -outdir option
        local description="output directory of reader"
        explain_opt "-outdir" "<dir>" "$description"
    }

    array_reader_identify_cmdline_opts()
    {
        :
    }

    array_reader_define_opts()
    {
        # Initialize variables
        local cmdline=$1
        local process_spec=$2
        local process_name=$3
        local process_outdir=$4
        local optlist=""

        # Save option list so as to execute process four times
        for id in 0 1 2 3; do
            local specific_optlist=${optlist}
            define_opt "-id" $id specific_optlist || return 1
            define_opt_from_proc_task_out "-infile" "array_writer" "${id}" "-outf" specific_optlist || return 1
            define_opt "-outdir" "${process_outdir}" specific_optlist || return 1
            save_opt_list specific_optlist
        done
    }

    array_reader()
    {
        # Initialize variables
        local id=$(read_opt_value_from_func_args "-id" "$@")
        local infile=$(read_opt_value_from_func_args "-infile" "$@")
        local outd=$(read_opt_value_from_func_args "-outdir" "$@")

        # Copy content of infile to auxiliary file
        cat "${infile}" > "${outd}"/${id}_aux

        # Copy content of infile to final file
        cat "${outd}"/${id}_aux > "${outd}"/${id}
    }

    array_reader_post()
    {
        logmsg "Cleaning directory..."

        # Initialize variables
        local id=$(read_opt_value_from_func_args "-id" "$@")
        local outd=$(read_opt_value_from_func_args "-outdir" "$@")

        # Remove auxiliary file
        rm "${outd}"/${id}_aux

        logmsg "Cleaning finished"
    }

    debasher_array_example_original_program()
    {
        add_debasher_process "array_writer" "cpus=1 mem=32 time=00:01:00,00:02:00 throttle=2"
        add_debasher_process "array_reader" "cpus=1 mem=32 time=00:01:00 throttle=4"
    }