about

For script use language: Lua 5.1

Official lua documentation site

for developers

We use Golang library https://github.com/yuin/gopher-lua

A simple example. Comments in lua scripts have prefix --

script.lua

-- in the head of script you can define some meta-tags. 
-- See more in section 'meta-tags'
-- @cron 0 * * * *

-- store 1e9 to the variable sizeLimit  
local sizeLimit = 1000000000

-- add Log module
local log = require("log")
-- add Clickhouse datasource
local ch1 = require("datasource.clickhouse.ch1")

-- send query to the clickhouse datasource
local res, err = ch1.query("SELECT sum(bytes) AS size FROM system.parts WHERE active")
-- if an error occurred, print the error and exit
if err ~= nil then
    log.error("clickhouse 'ch1' query error: " .. err)
    return
end

-- get first item (first array element in Lua is 1, not 0!)
-- and get field size
local currentSize = res[1].size

if currentSize > sizeLimit then
    alert.error("clickhouse-disk-space", "Check disk space in Clickhouse cluster! Current busy: " .. tostring(currentSize))
else
    alert.success("clickhouse-disk-space", "Clickhouse disk space - ok")
end 

Naming

Script name builds by next pattern:

<provider type>.<provider name>.<name>

Where:

• provider type is string file, folder or postgres
• provider name is provider name from the config file

For folder and file providers file name will be take as script name. If suffix .lua is present, it will be trimmed.

Example:

config.yaml

scripts:
  folder:
    - name: scripts
      path: /opt/scripts
      mask: '*.lua'
  file:
    - name: demo1
      filename: /path/to/demo.lua

Script names:

folder.scripts.demo