`module Host`

Per-host (system-wide) memory metrics. Use Host::Memory for total/used/free and swap; use Process::Metrics::Memory for per-process metrics.

Definitions

`Memory`

Struct for host memory snapshot. All sizes in bytes. Stored: total_size, used_size, swap_*, reclaimable_size. free_size and available_size are derived.

Implementation

Memory = Struct.new(:total_size, :used_size, :swap_total_size, :swap_used_size, :reclaimable_size) do
	def to_h
		super.merge(free_size: free_size, available_size: available_size)
	end
	
	alias as_json to_h
	
	def to_json(*arguments)
		as_json.to_json(*arguments)
	end
	
	# Complement of used: total_size - used_size. Same meaning on all platforms.
	def free_size
		total_size - used_size
	end
	
	# Memory that could be used: free_size plus reclaimable. Use this for "available" when reclaimable_size is set; otherwise equals free_size.
	def available_size
		free_size + (reclaimable_size || 0)
	end
	
	# Create a zero-initialized Host::Memory instance.
	# @returns [Memory]
	def self.zero
		self.new(0, 0, nil, nil, nil)
	end
	
	# Whether host memory capture is supported on this platform.
	# @returns [Boolean]
	def self.supported?
		false
	end
	
	# Capture current host memory. Implemented by Host::Memory::Linux or Host::Memory::Darwin (in host/memory/linux.rb, host/memory/darwin.rb).
	# @returns [Memory | Nil] A Host::Memory instance, or nil if not supported or capture failed.
	def self.capture
		return nil
	end
end

`def self.name`

System name from uname -a (kernel name, nodename, release, etc.). Returns nil if uname is not available.

Signature

returns　String, nil

Implementation

def self.name
	IO.popen(["uname", "-a"], "r", &:read)&.strip
rescue Errno::ENOENT
	nil
end