import time

from landscape.lib.monitor import CoverageMonitor
from landscape.lib.sysstats import MemoryStats

from landscape.accumulate import Accumulator
from landscape.monitor.plugin import MonitorPlugin


class MemoryInfo(MonitorPlugin):
"""Plugin captures information about free memory and free swap."""

persist_name = "memory-info"
scope = "memory"
# Prevent the Plugin base-class from scheduling looping calls.
run_interval = None

def __init__(self, interval=15, monitor_interval=60 * 60,
source_filename="/proc/meminfo", create_time=time.time):
self._interval = interval
self._monitor_interval = monitor_interval
self._source_filename = source_filename
self._memory_info = []
self._create_time = create_time

def register(self, registry):
super(MemoryInfo, self).register(registry)
self._accumulate = Accumulator(self._persist, self.registry.step_size)
self.registry.reactor.call_every(self._interval, self.run)
self._monitor = CoverageMonitor(self._interval, 0.8,
"memory/swap snapshot",
create_time=self._create_time)
self.registry.reactor.call_every(self._monitor_interval,
self._monitor.log)
self.registry.reactor.call_on("stop", self._monitor.log, priority=2000)
self.call_on_accepted("memory-info", self.send_message, True)

def create_message(self):
memory_info = self._memory_info
self._memory_info = []
return {"type": "memory-info", "memory-info": memory_info}

def send_message(self, urgent=False):
message = self.create_message()
if len(message["memory-info"]):
self.registry.broker.send_message(
message, self._session_id, urgent=urgent)

def exchange(self, urgent=False):
self.registry.broker.call_if_accepted("memory-info",
self.send_message, urgent)

def run(self):
self._monitor.ping()
new_timestamp = int(self._create_time())
memstats = MemoryStats(self._source_filename)
memory_step_data = self._accumulate(
new_timestamp, memstats.free_memory, "accumulate-memory")
swap_step_data = self._accumulate(
new_timestamp, memstats.free_swap, "accumulate-swap")

if memory_step_data and swap_step_data:
timestamp = memory_step_data[0]
free_memory = int(memory_step_data[1])
free_swap = int(swap_step_data[1])
self._memory_info.append((timestamp, free_memory, free_swap))