Getting memory used in /overlay partition as variable

Developer's Corner Scene Scripting
#1

Is there a way to get information about memory used in /overlay partition (where system files are stored) as a variable?
I want to run a scene when my memory will be filled above certain limit. I can see that information via “OScommand” section in Alt UI (df - h), but can make a variable which reads and stores such data?

In AltUI I can see amount of memory and percentage of space filled. In my case it can be any of these parameters, as I can refer to the percentage limit or to kB’s used (or left).

#2

This will pipe the result into a string that you can parse…

local p = io.popen "df -h"
local df = p:read "*a"
p: close()
#3

So here’s a function which does the business:

local function df()
    local format = "(%S+)%s+(%d+)%s+(%d+)%s+(%d+)[^/]+(/%S+)"
    local d = {}
    local p = io.popen "df"
    if p then
        local df = p:read "*a"
        p: close()
        local n = tonumber
        for f,b,u,a,m in df: gmatch(format) do
            d[#d+1] = {file=f, blocks=n(b), used=n(u), available=n(a), mounted=m}
        end
    end
    return d
end

and calling it on one of my Vera’s gives a structure line this

{
	 {
	 	 available = 0,
	 	 blocks = 4608,
	 	 file = "/dev/root",
	 	 mounted = "/rom",
	 	 used = 4608
	 },{
	 	 available = 24904,
	 	 blocks = 31240,
	 	 file = "tmpfs",
	 	 mounted = "/tmp",
	 	 used = 6336
	 },{
	 	 available = 512,
	 	 blocks = 512,
	 	 file = "tmpfs",
	 	 mounted = "/dev",
	 	 used = 0
	 },{
	 	 available = 7384,
	 	 blocks = 11264,
	 	 file = "/dev/mtdblock7",
	 	 mounted = "/overlay",
	 	 used = 3880
	 },{
	 	 available = 0,
	 	 blocks = 4480,
	 	 file = "/dev/mtdblock8",
	 	 mounted = "/mios",
	 	 used = 4480
	 }
}
#4

Thanks for the code, but how can I extract some of the results (lets say I want to have “used” value of "file = “/dev/mtdblock7” parameter)?
Is it possible?
Sorry for asking for direct result, but here my “lua programming” skills are definitely too small.

#5

Hmmm… perhaps you shouldn’t be doing this?

lets say I want to have "used" value of "file = "/dev/mtdblock7" parameter)

Easiest, then, simply to index the data by the “file” parameter and directly access the data:

local dfinfo = {}
for _, d in ipairs(df()) do dfinfo[d.file] = d end
local x = dfinfo ["/dev/mtdblock7"]

gives you a table ‘x’ that looks like this:

{
	 available = 42032,
	 blocks = 64456,
	 file = "/dev/mtdblock7",
	 mounted = "/boot",
	 used = 22424
}

so the answer you want is in x.used

#6

Most probably.
Unfortunately dealing with Vera forces me to learn new skills :confused:

#7

[quote=“akbooer, post:5, topic:199235”]Easiest, then, simply to index the data by the “file” parameter and directly access the data:

local dfinfo = {} for _, d in ipairs(df()) do dfinfo[d.file] = d end local x = dfinfo ["/dev/mtdblock7"] [/quote]

I’ve tried to run the code within test lua and got an error. What I’m doing wrong?

#8

You also included the code for the function defined earlier?

#9

No… :frowning:

OK, so the whole structure should be like this?

local function df()
    local format = "(%S+)%s+(%d+)%s+(%d+)%s+(%d+)[^/]+(/%S+)"
    local d = {}
    local p = io.popen "df"
    if p then
        local df = p:read "*a"
        p: close()
        local n = tonumber
        for f,b,u,a,m in df: gmatch(format) do
            d[#d+1] = {file=f, blocks=n(b), used=n(u), available=n(a), mounted=m}
        end
    end
    return d
end

local dfinfo = {}
for _, d in ipairs(df()) do dfinfo[d.file] = d end
local x = dfinfo ["/dev/mtdblock7"]

And then I can use variables as x.available or x.used, in a way like:

if (tonumber(x.available) < [desired limit of memory]) then....

?

Yes, it is definitely over my knowledge, I just don’t want to run clearing code or reboot controller every day, and looking for some smarter solution.

Edit: I’ve tested it, it works!
Thanks for your help!

#10

I modified your code and set to run as part of my daily routine.

local function getOverlayDiskSpace()
local function df()
local format = “(%S+)%s+(%d+)%s+(%d+)%s+(%d+)[^/]+(/%S+)”
local d = {}
local p = io.popen “df”
if p then
local df = p:read “*a”
p: close()
local n = tonumber
for f,b,u,a,m in df: gmatch(format) do
d[#d+1] = {file=f, blocks=n(b), used=n(u), available=n(a), mounted=m}
end
end
return d
end

local dfinfo = {}
for _, d in ipairs(df()) do dfinfo[d.mounted] = d end
local x = dfinfo ["/overlay"]
return (x.available / (x.available + x.used) * 100)

end

local d = getOverlayDiskSpace()
if (d<30) then – alert at 30%
sendAlert("Vera’s Overlay partition at " … tostring(round(d, 2)) … “%”)
end

It will alert you if the partitions is under 30% (we know it’s safe at 20% or more). I just changed to check for the /overlay mounted partition, since mine is mounted as /dev/mtdblock6 instead of /dev/mtdblock6, so I guess it may depend on your system, and I’m using a percentage value, since we know it’s what matters the most.
sendAlert function is my custom function sending alert to my Telegram bot.
I hope I’d be useful to anyone.