​How to retrieve text data (not png image) through api_jsonrpc.php ?

[beginer2Zabbix]

Hi Admin,

I need help.

I have a Zabbix server checking a computer running state. I can get the CPU data from browser like this by this URL
http://my-zabbix-server/chart.php?fr...amp;amp;to=now.....

(PS: below graph is not from my applicaiton, but has same layout)



My question is how to retrieve text data (in above png image) through api_jsonrpc.php ?
I need the the max value for business purpose.



I use Chrome to generate Powershell command to call Zabbix api_jsonrpc.php


Chrome command like this:

Invoke-WebRequest -Uri "http://ipaddress/chart.php?from=now-3d&to=now&itemids%5B0%5D=188888&......" -Headers @{
    "User-Agent"=Mozilla/5.0....."
    "Referer"="http://ipaddress/history.php?action=showgraph&itemids[]=1888888"
    ...
}​ 

I use Invoke-RestMethod instead

$from = (Get-Date).AddDays(-3).ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ")
$to = (Get-Date).ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ")
​
$jsonBodyData = @{
    jsonrpc = "2.0"
    method = "item.get"
    params = @{
        output = "extend"
        itemids = $itemId
        time_from = $from
        time_till = $from
        sortfield = "clock"
        sortorder = "ASC"
    }
    auth = $authToken
    id = 2
} | ConvertTo-Json
    
$returnData = Invoke-RestMethod -Uri $zabbixApiUrl -Method Post -Body $returnData -ContentType "application/json"​ 

But $returnData's result contains one record only, has prevvalue, and lastvalue, but no max value.
May I know how to get the max value, may thanks.

[PeterZielony]

Is it something you will have to run regularly? Or one off?
You could take it out from db itself based on itemid

if its regular requirement i would set calulated item for each period.

One calculated item daily with max value for "yesterday's" max, and then based on that daily more items calculated max for 2, 3, 7 days etc based on initial daily.

So zabbix backend dont have to calculate big data sets for each item but only for one daily and rest is based on few numbers from max each day. But you will have data with daily refresh for yesterday's data - more accurate and less impact on db/frontend with 1 day delay unless they need have last 24h one too - as a seperate calculated "last24h" along with yesterday's


Cpu, ram usage are items with a lot of metrics values... for 200 pcs and occasionally you can run into timeout situations when frontend is busy or even cripple web interface


you could then use api to get values but to be honest i rather take from db itself - it will be presented in table right away but drawback is to have list of itemids .. but with api you still need them either way. I would say database directly for big dataset and for so many items- but that's how I would do it

[beginer2Zabbix]

hi
I got progress about it.

I updated code like this:

$from = (((Get-Date).AddDays(-3).ToUniversalTime().ticks - (Get-Date "1970-01-01").ToUniversalTime().ticks)/10000000).toString().SubString(0, 10)
$to = (((Get-Date).ToUniversalTime().ticks - (Get-Date "1970-01-01").ToUniversalTime().ticks)/10000000).toString().SubString(0, 10)

$jsonBodyData = @{
    jsonrpc = "2.0"
    method = "history.get"
    params = @{
        output = "extend"
        history = 0
        itemids = $itemId
        time_from = $from
        time_till = $to
        sortfield = "clock"
        sortorder = "DESC"
        limit = 100
    }
    auth = $authToken
    id = 2
} | ConvertTo-Json
    
$returnData = Invoke-RestMethod -Uri $zabbixApiUrl -Method Post -Body $returnData -ContentType "application/json"​​ 

then , I received data like this:

result: [
...
    {
        itemid: "88887777"
        clock: 1702621309
        value: 34.4563
        ns: 775488818
     }
...
] 

but still no max data in resoponse.

[cyber]

Why do you expect it to return max value? Just because it is on the picture together with others? Doesn't work that way..

https://www.zabbix.com/documentation/current/en/manual/api/reference/history/get

Where in here do you see anything about returning max value?

The method allows to retrieve history data according to the given parameters.

It returns you a selection of values, based on your criteria. If you want max or min or avg... use those returned values and calculate it... There are sorting functions in PHP..

[beginer2Zabbix]

I updated code "trend.get"

$from = (((Get-Date).AddDays(-3).ToUniversalTime().ticks - (Get-Date "1970-01-01").ToUniversalTime().ticks)/10000000).toString().SubString(0, 10)
$to = (((Get-Date).ToUniversalTime().ticks - (Get-Date "1970-01-01").ToUniversalTime().ticks)/10000000).toString().SubString(0, 10)

$jsonBodyData = @{
    jsonrpc = "2.0"
    method = "trend.get"
    params = @{
        output = "extend"
        history = 0
        itemids = $itemId
        time_from = $from
        time_till = $to
        sortfield = "value_max"
        limit = 100
    }
    auth = $authToken
    id = 2
} | ConvertTo-Json
    
$returnData = Invoke-RestMethod -Uri $zabbixApiUrl -Method Post -Body $returnData -ContentType "application/json"​​  

$sortedData = $returnData.result | Sort-Object -Property value_max -Descending
Write-Host = $sortedData[0].value_max​ 

I can get the MAX VALUE!!!

Then I tried change time duration,
(Get-Date).AddDays(-1)....... can work as expect
(Get-Date).AddHours(-24)....... can work as expect
(Get-Date).AddHours(-12)....... can work as expect

(Get-Date).AddHours(-9)....... no data in result of API response, but I can get data from webpage. Does anyone advice me how to fetch data within 10 hours?

[cyber]

If any other "hour" works, then also 9 or 10 should work...

Trends are ok, but you should not rely on them for last hour as trend is a record of min/max/avg value for 1h period.. so it may not be accurate for current hour, which may affect whole result of you select for multiple hours...

[beginer2Zabbix]

Why do you expect it to return max value? Just because it is on the picture together with others? Doesn't work that way..

https://www.zabbix.com/documentation/current/en/manual/api/reference/history/get

Where in here do you see anything about returning max value?

It returns you a selection of values, based on your criteria. If you want max or min or avg... use those returned values and calculate it... There are sorting functions in PHP..

Hi cyber

thank you for your suggestion
.
The requirement is I need collect 200+ host's max cpu/memory for a specific period( 24Hours / 3Days / 1 week / 2 weeks ... ) , client need the max value only so far.
Client insist I should achieve the same result, my powershell script retrieved data(the value of max) should as same as web page.

Would you please help confirm how the Zabbix generate this graph?

history.get? (filter response result as you mentioned above?)
trend.get? (it works as expect, if the target period longer than 24H)
or use Calculated items ?

[PeterZielony]

Is it something you will have to run regularly? Or one off?
You could take it out from db itself based on itemid

if its regular requirement i would set calulated item for each period.

One calculated item daily with max value for "yesterday's" max, and then based on that daily more items calculated max for 2, 3, 7 days etc based on initial daily.

So zabbix backend dont have to calculate big data sets for each item but only for one daily and rest is based on few numbers from max each day. But you will have data with daily refresh for yesterday's data - more accurate and less impact on db/frontend with 1 day delay unless they need have last 24h one too - as a seperate calculated "last24h" along with yesterday's


Cpu, ram usage are items with a lot of metrics values... for 200 pcs and occasionally you can run into timeout situations when frontend is busy or even cripple web interface


you could then use api to get values but to be honest i rather take from db itself - it will be presented in table right away but drawback is to have list of itemids .. but with api you still need them either way. I would say database directly for big dataset and for so many items- but that's how I would do it

[beginer2Zabbix]

Is it something you will have to run regularly? Or one off?
You could take it out from db itself based on itemid

if its regular requirement i would set calulated item for each period.

One calculated item daily with max value for "yesterday's" max, and then based on that daily more items calculated max for 2, 3, 7 days etc based on initial daily.

So zabbix backend dont have to calculate big data sets for each item but only for one daily and rest is based on few numbers from max each day. But you will have data with daily refresh for yesterday's data - more accurate and less impact on db/frontend with 1 day delay unless they need have last 24h one too - as a seperate calculated "last24h" along with yesterday's


Cpu, ram usage are items with a lot of metrics values... for 200 pcs and occasionally you can run into timeout situations when frontend is busy or even cripple web interface


you could then use api to get values but to be honest i rather take from db itself - it will be presented in table right away but drawback is to have list of itemids .. but with api you still need them either way. I would say database directly for big dataset and for so many items- but that's how I would do it

Thank you for your guide.

This a maintenance work, client need max cpu/mem repors about 3 to 5 times a week. I have no permission to access database, no Java env, no Python env, thanks God I have Powershell 5.0(without any 3rd party lab) and a Zabbix guest account. look like I should retrieve all data(base on itemid) then filter the max value in my code.

[PeterZielony]

Strange.. you have do all that work for client and they won't give you required access?


You could bring arg about locking frontend using api for big datasets - this isn't just "give me one value" but heavy calculation per host - you have thousands of values for cpu itself and mem (and you need them all.. without limit = 100 ) - multiply this by 200 hosts - api isn't designed to run reports that heavy.

Either way - you should have at least few additional items containing max per item and per time scale- then your powershell would work better (and faster without locking frontend)... but with read-only access you can't modify templates?

And like cyber said - do not rely on trends for this.. data won't be accurately presented

[beginer2Zabbix]

Hi Guys

I did this work by history way. The workload on the server side is indeed very high when querying, but it is not to an unacceptable. Thank you