etc/job_submit.lua.example

--[[
--Example job_submit.lua file for Slurm
--For more information check:
-- https://slurm.schedmd.com/job_submit_plugins.html
--For the list of available fields check:
-- src/plugins/job_submit/lua/job_submit_lua.c
--]]

log_prefix = 'slurm_job_submit'

function _find_in_str(str, arg)
	if str ~= nil then
		return string.find(str,arg)
	else
		return false
	end
end

function _log_user_and_debug(fmt, ...)
	--[[
	    Different messages logged to end user should be associated
	    unique return code, to make those properly displayed in case
	    of modification of array job.
  	--]]

	--[[ Implicit definition of arg was removed in Lua 5.2 --]]
	local arg = {...}

	--[[
	--  Returning a message to user from slurm_job_modify is supported
	--  since Slurm 23.02, using it in older versions will result in
	--  an error message in slurmctld logs.
	--  In older versions of Lua - prior to Lua 5.2 you may need to use
	--  unpack as a built-in instead of table.unpack
	]]--

	slurm.log_user(fmt, table.unpack(arg))
	slurm.log_debug(fmt, table.unpack(arg))
end


-- Do not allow interactive jobs longer than 4 hours except for certain users
function validate_interactive_job(job_desc, uid)
	if job_desc['script'] ~= nil then
		return slurm.SUCCESS -- no limit for batch jobs
	end
	if uid == 0 --[[ or uid == SpecialUser --]] then
		_log_user_and_debug("Interactive job allowed for uid: %u", uid)
	else
		local time_limit = job_desc['time_limit']
		if (time_limit == slurm.NO_VAL) then
			_log_user_and_debug("You must request a time limit within 4 hours for interactive jobs")
			return slurm.ESLURM_INVALID_TIME_LIMIT
		elseif (time_limit > (4 * 60)) then
			_log_user_and_debug("Interactive jobs for time longer than 4h forbidden")
			return slurm.ESLURM_INVALID_TIME_LIMIT
		end
	end
	return slurm.SUCCESS
end

function slurm_job_submit(job_desc, part_list, submit_uid)

	--[[
	   Don't block any activity from root.
	   This may make reproduction of user errors difficult
	--]]
	if submit_uid == 0 then
		return slurm.SUCCESS
	end

	local rc = validate_interactive_job(job_desc, submit_uid)
	if rc ~= slurm.SUCCESS then
		return rc
	end

	--[[
	-- Change partition to GPU if job requested any GPU
	-- depending on option used this may be visible in
	-- different job_desc field:
	-- --gres=gpu: -> tres_per_node
	-- --gpus-per-task -> tres_per_task
	-- --gpus-per-socket -> tres_per_socket
	-- --gpus -> tres_per_job
	--]]

	if _find_in_str(job_desc['tres_per_node'], "gpu") or
	   _find_in_str(job_desc['tres_per_task'], "gpu") or
	   _find_in_str(job_desc['tres_per_socket'], "gpu") or
	   _find_in_str(job_desc['tres_per_job'], "gpu") then
		job_desc.partition = 'gpu'
		_log_user_and_debug("%s: Set partition to: %s",
			            log_prefix,
				    job_desc.partition)
	end


	--[[ Forbid unlimited --mem if memory specified --]]
	if job_desc['min_mem_per_node'] ~= nil then
		if job_desc['min_mem_per_node'] == 0 then
			slurm.log_user("%s: --mem=0 is not allowed",
				       log_prefix);
			return slurm.ESLURM_ACCOUNTING_POLICY;
		end
	else
		--[[ Enforce --mem specification --]]
		if job_desc['min_mem_per_cpu'] == nil then
			_log_user_and_debug("%s: Neither --mem nor --mem-per-cpu specified",
				            log_prefix);
				return slurm.ESLURM_ACCOUNTING_POLICY;
		else
			if job_desc['min_mem_per_cpu'] == 0 then
				_log_user_and_debug("%s: --mem-per-cpu=0 is not allowed",
					            log_prefix);
				return slurm.ESLURM_ACCOUNTING_POLICY;
			end
		end
	end

       --[[ Forbid usage of MAINT job name --]]
	if job_desc['name'] == "MAINT" then
	       _log_user_and_debug("%s: JobName=MAINT reserved. Please use other name.",
			           log_prefix);
	       return slurm.ERROR
	end

	--[[
	-- If no default partition, set to the highest
	-- priority partition this user has access to
	--]]
	if job_desc['partition'] == nil then
		local new_partition = nil
		local top_priority  = -1
		local last_priority = -1
		local inx = 0
		for name, part in pairs(part_list) do
			slurm.log_debug2("%s: part name[%d]:%s",
				        log_prefix,
				        inx,
					part['name'])
			inx = inx + 1
			--[[
			-- Don't change partition if the default
			-- is defined in the slurm.conf
			--]]
			if part['flag_default'] ~= 0 then
				top_priority = -1
				break
			end

			if part['priority_job_factor'] ~= nil then
				slurm.log_debug3("%s: last priority is %d",
					        log_prefix,
						part['priority_job_factor'])
				last_priority = part['priority_job_factor']
				if last_priority > top_priority then
					top_priority = last_priority
					new_partition = part.name
				end
			end
		end

		if top_priority >= 0 then
			_log_user_and_debug("%s: setting default partition value: %s",
				            log_prefix,
					    new_partition)
			job_desc.partition = new_partition
		end
	end

	return slurm.SUCCESS
end

function  slurm_job_modify(job_desc, job_ptr, part_list, modify_uid)
	--[[
        --   While working on that it's important to understand that
        --   modification of a job array metarecord may differs from specific
        --   element modification. When job is not yet split to tasks it will
        --   be treated as one element.
        --]]


	--[[ Don't block/modify any update from root --]]
	if modify_uid == 0 then
		return slurm.SUCCESS
	end

	local rc = validate_interactive_job(job_desc, modify_uid)
	if rc ~= slurm.SUCCESS then
		return rc
	end

	--[[
	-- Forbid unlimited --mem in update
	-- for instance: scontrol update job=XX MinMemoryNode=0
	--]]
	if job_desc['min_mem_per_node'] ~= nil then
		if job_desc['min_mem_per_node'] == 0 then
			_log_user_and_debug("%s: Updating MinMemPerNode=0 is not allowed",
				            log_prefix)
			return slurm.ESLURM_ACCOUNTING_POLICY;
		end
	end
	if job_desc['min_mem_per_cpu'] ~= nil then
		if job_desc['min_mem_per_cpu'] == 0 then
			_log_user_and_debug("%s: Updating MinMemoryCPU=0 is not allowed",
				            log_prefix)
			return slurm.ESLURM_ACCOUNTING_POLICY;
		end
	end

       --[[ Forbid usage of MAINT job name --]]
	if job_desc['name'] == "MAINT" then
		_log_user_and_debug("%s: Updating JobName to MAINT is not allowed from non-root user",
			            log_prefix);
		--[[
		-- This will show 'Unspecified error' but use of
		-- slurm.log_user is limited to job_submit
		--]]
	       return slurm.ERROR
	end

	return slurm.SUCCESS
end