Class: UI

Inherits:
Object
  • Object
show all
Defined in:
lib/ui.rb

Instance Method Summary collapse

Constructor Details

#initialize(config) ⇒ UI

Returns a new instance of UI.



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# File 'lib/ui.rb', line 6

def initialize(config)
	@config = config

    init_screen
    cbreak
    curs_set(0)

    # set keyboard input timeout - sneaky way to manage refresh rate
    Curses.timeout = @config[:refresh_rate]

    if can_change_color?
        start_color
        init_pair(0, COLOR_WHITE, COLOR_BLACK)
        init_pair(1, COLOR_WHITE, COLOR_BLUE)
        init_pair(2, COLOR_WHITE, COLOR_RED)
    end

    @stat_cols      = %w[ calls objsize req/sec bw(kbps) ]
    @stat_col_width = 10 
    @key_col_width  = 0

    @commands = {
        'Q' => "quit",
        'C' => "sort by calls",
        'S' => "sort by size",
        'R' => "sort by req/sec",
        'B' => "sort by bandwidth",
        'T' => "toggle sort order (asc|desc)"
    }
end

Instance Method Details

#done ⇒ Object 



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# File 'lib/ui.rb', line 169

def done
    nocbreak
    close_screen
end

#footer ⇒ Object 



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# File 'lib/ui.rb', line 49

def footer
    footer_text = @commands.map { |k,v| "#{k}:#{v}" }.join(' | ')
    setpos(lines-1, 0)
    attrset(color_pair(2))
    addstr(sprintf "%-#{cols}s", footer_text)
end

#header ⇒ Object 



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# File 'lib/ui.rb', line 37

def header
    # pad stat columns to @stat_col_width
    @stat_cols = @stat_cols.map { |c| sprintf("%#{@stat_col_width}s", c) }

    # key column width is whatever is left over
    @key_col_width = cols - (@stat_cols.length * @stat_col_width)

    attrset(color_pair(1))
    setpos(0,0)
    addstr(sprintf "%-#{@key_col_width}s%s", "memcache key", @stat_cols.join)
end

#input_handler ⇒ Object 



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# File 'lib/ui.rb', line 152

def input_handler
    # Curses.getch has a bug in 1.8.x causing non-blocking
    # calls to block reimplemented using IO.select
    if RUBY_VERSION =~ /^1.8/
  refresh_secs = @config[:refresh_rate].to_f / 1000 

        if IO.select([STDIN], nil, nil, refresh_secs)
            c = getch
            c.chr
        else
            nil
        end
    else
        getch
    end
end

#render_stats(sniffer, sort_mode, sort_order = :desc) ⇒ Object 



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# File 'lib/ui.rb', line 56

def render_stats(sniffer, sort_mode, sort_order = :desc)
    render_start_t = Time.now.to_f * 1000

    # subtract header + footer lines
    maxlines = lines - 3
    offset   = 1

    # calculate packet loss ratio
    if sniffer.metrics[:stats][:recv] > 0
        loss = sprintf("%5.2f", (sniffer.metrics[:stats][:drop].to_f / sniffer.metrics[:stats][:recv].to_f) * 100)
    else
        loss = 0
    end

    # construct and render footer stats line
    setpos(lines-2,0)
    attrset(color_pair(2))
    header_summary = sprintf "%-28s %-14s %-30s", 
        "sort mode: #{sort_mode.to_s} (#{sort_order.to_s})",
        "keys: #{sniffer.metrics[:calls].keys.count}",
        "packets (recv/dropped): #{sniffer.metrics[:stats][:recv]} / #{sniffer.metrics[:stats][:drop]} (#{loss}%)" 
    addstr(sprintf "%-#{cols}s", header_summary)

    # reset colours for main key display
    attrset(color_pair(0))

    top = []

    sniffer.semaphore.synchronize do 
        # we may have seen no packets received on the sniffer thread 
        return if sniffer.metrics[:start_time].nil?

        elapsed = Time.now.to_f - sniffer.metrics[:start_time]

        # iterate over all the keys in the metrics hash and calculate some values
        sniffer.metrics[:calls].each do |k,v|
                reqsec = v / elapsed

                # if req/sec is <= the discard threshold delete those keys from
                # the metrics hash - this is a hack to manage the size of the
                # metrics hash in high volume environments
                if reqsec <= @config[:discard_thresh]
                    sniffer.metrics[:calls].delete(k)
                    sniffer.metrics[:objsize].delete(k)
                    sniffer.metrics[:reqsec].delete(k)
                    sniffer.metrics[:bw].delete(k)
                else
                    sniffer.metrics[:reqsec][k]  = v / elapsed
                    sniffer.metrics[:bw][k]      = ((sniffer.metrics[:objsize][k] * sniffer.metrics[:reqsec][k]) * 8) / 1000
                end
        end

        top = sniffer.metrics[sort_mode].sort { |a,b| a[1] <=> b[1] }
    end

    unless sort_order == :asc
        top.reverse!
    end

    for i in 0..maxlines-1
        if i < top.length
            k = top[i][0]
            v = top[i][1]

            # if the key is too wide for the column truncate it and add an ellipsis
            if k.length > @key_col_width
                display_key = k[0..@key_col_width-4]
                display_key = "#{display_key}..."
            else
                display_key = k
            end
       
            # render each key
            line = sprintf "%-#{@key_col_width}s %9.d %9.d %9.2f %9.2f",
                             display_key,
                             sniffer.metrics[:calls][k],
                             sniffer.metrics[:objsize][k],
                             sniffer.metrics[:reqsec][k],
                             sniffer.metrics[:bw][k]
        else
            # we're not clearing the display between renders so erase past
            # keys with blank lines if there's < maxlines of results
            line = " "*cols
        end

        setpos(1+i, 0)
        addstr(line)
    end

    # print render time in status bar
    runtime = (Time.now.to_f * 1000) - render_start_t
    attrset(color_pair(2))
    setpos(lines-2, cols-18)
    addstr(sprintf "rt: %8.3f (ms)", runtime)
end