Re: How to persist text on the screen when the client exits?

Richard Neill <[email protected]> Tue, 01 Jan 2013 23:59:03 +0000

Newsgroups	gmane.comp.sysutils.lcdproc
Message-ID	<[email protected]>

Dear Eric,

Thanks for your quick reply.

I'm afraid that my simplified bash script
may have added confusion - I do know about the -t option for the client.
Also, I'd rather not respawn python every time - but in this case it's 
OK (the performance hit, while wasteful, is not actually an issue). The 
machine I'm monitoring is actually an ADSL router - it's job is just to 
run multilink ppp, and is rather overspecd,

So, I'm attaching my script, which may make things a bit clearer. This 
is launched from cron with "@reboot".

Anyway, it works fine, except that the screen is blank about half the time.

What I really want is to treat the LCD display like a simple character 
device, into which I can echo text. I appreciate the sophistication of 
the lcdproc architecture, with support for buttons, menus etc, but in 
this particular use-case, I don't need it.

Best wishes,

Richard

On 01/01/13 23:44, Eric Pooch wrote:
> You need to re-imagine your client rather than the change the server.
> Your client is spawning 4 processes every 2 seconds. This doesn't
> seem like a good idea.
>
> As a temporary fix, the -t option  for lcdproc_client.py will keep
> the connection open for the time you specify.  I would change your
> final sleep command to account for this.
>
> --Eric
>
> On Jan 1, 2013, at 3:27 PM, Richard Neill wrote:
>
>> Dear All,
>>
>> I've just joined this list, so please excuse me if I ask an obvious
>> question.
>>
>> I'm trying to get a server status monitor system working,
>> monitoring a set of parameters of my choice (the lcdproc defaults
>> aren't suitable for me here)
>>
>> So, I have LCDd running   (with a 20x2 picolcd), and found the text
>> client here:  http://lcdproc-client.sourceforge.net/
>>
>> I have a bash-script that sends strings to the client every few
>> seconds, and they display on the LCD as expected. A simplified
>> example:
>>
>> while : ; do hostname | lcdproc_client.py -f - sleep 1 date  |
>> lcdproc_client.py -f - sleep 1 done
>>
>>
>> This displays the hostname and the date, alternately, as I expect.
>>
>> BUT, between these, every time the python script exits, the system
>> keeps going back to either the LCDd default screen, or to blank
>> (the value of ServerScreen).
>>
>> How can I get LCDd to just leave the text on screen as it was,
>> until I explicitly overwrite it?
>>
>> Thanks very much,
>>
>> Richard
>>
>>
>> P.S. Might I suggest that a "--text" option to lcdproc i.e. "write
>> this line to screen, and exit" would be really useful in the
>> default distribution.
>>
>>
>> _______________________________________________ LCDproc mailing
>> list [email protected]
>> http://lists.omnipotent.net/mailman/listinfo/lcdproc
>
>

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lcd_status.sh (application/x-shellscript, 2.9 KB)

#!/bin/bash

cd `dirname $0`
LCD_CLIENT="./lcdproc_client.py"
DEBUG=false

#20 x 2 lines. Prototype messages
#12345678901234567890
#12345678901234567890

#tub: 18:22:31
#up:  4 days

#cpu:  0.01 0.02 0.05
#disk: 13% used

#8.8.8.8 is alive
#bbc.co.uk is alive

#RUN/stop: SSH DHCPD
#BIND SMTP NTP APACHE 

#pppd: call XXXXXX 
#pppd: call XXXXXX

#ppp0: xx.xx.xx.xx
#eth0: 192.168.0.2


#20 char x 2 line.  Too long and it gets truncated.
write_msg (){
	MSG="$1"
	[ "$DEBUG" == true ] && { echo "$MSG"; sleep 1 ;}
	echo -ne "$MSG" | $LCD_CLIENT -f - -t 2    #returns after 2 seconds.
}

screen_1(){
	#Hostname. Returns e.g.: "tub"
	hostname=$(hostname -s)

	#Time. Returns e.g.: "20:18:09"
	time=$(date '+%H:%M:%S')

	#Uptime. Returns e.g.: "up: 4 days"
	uptime=$(uptime | cut -d , -f 1 | grep -oE 'up.*' | sed 's/up/up: /')

	echo "$hostname: $time"$'\n'"$uptime"
}

screen_2(){
	#Loadavg. Returns e.g.: "0.01 0.02 0.05"
	loadavg=$(cat /proc/loadavg | cut -d ' ' -f 1-3)

	#Disk used percent. Returns e.g.: "14%"
	diskused=$(df -h | grep /dev/sda1 | grep -oE '..%')

	echo "cpu:  $loadavg"$'\n'"disk: $diskused used"
}

screen_3(){
	#Services. Returns e.g.: "RUN/stop: SSH DHCPD\nBIND SMTP NTP APACHE"  (where the service is captialised iff it is running.
	#NB "service postfix status" won't run as non-root. So pgrep master instead.
	services="RUN/stop: "
	if service ssh status             >/dev/null 2>&1; then services=$services"SSH "; else services=$services"ssh "; fi
	if service isc-dhcp-server status >/dev/null 2>&1 ; then services=$services"DHCPD "; else services=$services"dhcpd "; fi
	services=$services$'\n'
	if service bind9 status   >/dev/null 2>&1 ; then services=$services"BIND "; else services=$services"bind "; fi
	if pgrep [m]aster         >/dev/null 2>&1 ; then services=$services"SMTP "; else services=$services"smtp "; fi
	if service ntp status     >/dev/null 2>&1 ; then services=$services"NTP "; else services=$services"ntp "; fi
#	if service xdm status     >/dev/null 2>&1 ; then services=$services"XDM "; else services=$services"xdm "; fi
	if service apache2 status >/dev/null 2>&1 ; then services=$services"APACHE "; else services=$services"apache "; fi
	echo "$services"
}

screen_4(){
	#Fping. Returns e.g.:  "8.8.8.8 is alive\nbbc.co.uk is alive"
	fping=$(fping 8.8.8.8 bbc.co.uk)
	echo "$fping"
}

screen_5(){
	#PPPD status. Returns the pppd processes and what they are calling.  e.g.: "pppd: call xxxx\npppd: call xxxx"
	pppd=$(ps aux | grep [p]ppd | grep -oE '[p]ppd.*' | sed 's/dsl-provider-//g' | sed -s 's/updetach//' | sed 's/ /: /')
	echo "$pppd"
}

screen_6(){
	#IP addresses. Returns e.g.: "ppp0: xx.xx.xx.xx\neth0: 192.168.0.2"
	ips="ppp0: "$(ifconfig ppp0 | grep -oE 'inet addr:[0-9.]*' | cut -d : -f 2)$'\n'"eth0: "$(ifconfig eth0 | grep -oE 'inet addr:[0-9.]*' | cut -d : -f 2)$'\n'
	echo "$ips"
}

while : ; do

	write_msg "$(screen_1)"
	write_msg "$(screen_2)"
	write_msg "$(screen_3)"
	write_msg "$(screen_4)"
	write_msg "$(screen_5)"
	write_msg "$(screen_6)"

done