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Python Script to Upload Memcache Metrics to CloudWatch
import sys, time, subprocess, socket, telnetlib
from datetime import datetime
from collections import defaultdict
from boto.ec2.cloudwatch import CloudWatchConnection
MAPPINGS = {
# Memcached name: (AWS Name, AWS Metric Type, Calculation Method)
'uptime': ('Uptime', 'Count', 'gauge'),
'curr_connections': ('CurrConnections', 'Count', 'gauge'),
'cmd_get': ('CmdGet', 'Count', 'sampling'),
'cmd_set': ('CmdSet', 'Count', 'sampling'),
'cmd_flush': ('CmdFlush', 'Count', 'sampling'),
'cmd_touch': ('CmdTouch', 'Count', 'sampling'),
'get_hits': ('GetHits', 'Count', 'sampling'),
'get_misses': ('GetMisses', 'Count', 'sampling'),
'delete_hits': ('DeleteHits', 'Count', 'sampling'),
'delete_misses': ('DeleteMisses', 'Count', 'sampling'),
'incr_hits': ('IncrHits', 'Count', 'sampling'),
'incr_misses': ('IncrMisses', 'Count', 'sampling'),
'decr_hits': ('DecrHits', 'Count', 'sampling'),
'decr_misses': ('DecrMisses', 'Count', 'sampling'),
'cas_hits': ('CasHits', 'Count', 'sampling'),
'cas_misses': ('CasMisses', 'Count', 'sampling'),
'touch_hits': ('TouchHits', 'Count', 'sampling'),
'touch_misses': ('TouchMisses', 'Count', 'sampling'),
'bytes_read': ('BytesReadIntoMemcached', 'Bytes', 'sampling'),
'bytes_written': ('BytesWrittenOutFromMemcached', 'Bytes', 'sampling'),
'evictions': ('Evictions', 'Count', 'sampling'),
'bytes': ('BytesUsedForCacheItems', 'Bytes', 'gauge'),
'curr_items': ('CurrItems', 'Count', 'gauge')
}
# Stats not readable from Memcached 'stats' directly,
# we need to fetch or calculate these explicity
DERIVED_STATS = {
'new_connections': ('NewConnections', 'Count', 'sampling'),
'new_items': ('NewItems', 'Count', 'sampling'),
'cpu_util': ('CPUUtilization', 'Percent', 'gauge'),
'freeable_mem': ('FreeableMemory', 'Kilobytes', 'gauge'),
'network_in': ('NetworkBytesIn', 'Bytes', 'sampling'),
'network_out': ('NetworkBytesOut', 'Bytes', 'sampling'),
'swap_usage': ('SwapUsage', 'Kilobytes', 'gauge')
}
def client():
global _client
if _client is None:
_client = telnetlib.Telnet('127.0.0.1', '11211')
return _client
def command(client, cmd):
'Write a command to telnet and return the response'
client.write("%s\n" % cmd)
return client.read_until('END')
def get_stats():
c = client()
return command(c, 'stats')
def parse_stats(new_stats):
# Clear our parsed stats
parsed_stats = {}
# Parse the Memcached 'stats' output
for stat in new_stats.split('\n'):
if stat.startswith('STAT'):
stat = stat.split()
key = stat[1]
value = stat[2]
# Filter down to the keys we care about
if key in MAPPINGS.keys():
parsed_stats[key] = int(value)
return parsed_stats
def calculate_regular_stats(current_stats, old_stats):
calculated_stats = {}
for key in current_stats.keys():
# Check to see if we are a measurement where we
# are interested in the diff between pollings
if 'sampling' in MAPPINGS[key][2]:
diff = current_stats[key] - old_stats[key]
calculated_stats[key] = diff
# Otherwise this is a gauge and we just care about
# the value, not the difference
else:
calculated_stats[key] = current_stats[key]
return calculated_stats
def _calculate_new_connections(current_stats, old_stats):
# Not sure how amazon is calculating this
pass
def _calculate_new_items(current_stats, old_stats):
# Not sure how amazon is calculating this
pass
def _get_network_in(current_stats, old_stats):
# Not sure how amazon is calculating this
pass
def _get_network_out(current_stats, old_stats):
# Not sure how amazon is calculating this
pass
def _get_cpu_usage():
# Get the 3rd field of the ps aux command which should be CPU usage
# of the process as a percentage
command = "ps aux | grep '/usr/bin/memcached' | grep -v grep | awk '{print $3}'"
# Create our new process
proc = subprocess.Popen(command, shell=True, stderr=subprocess.PIPE, stdout=subprocess.PIPE)
# Filter the result
result = proc.stdout.readline().rstrip()
if result is not None:
return float(result)
else:
return 0.0
def _parse_memory():
mem_info = defaultdict(int)
# Get the systems memory info
command = "cat /proc/meminfo"
# Create our new process
proc = subprocess.Popen(command, shell=True, stderr=subprocess.PIPE, stdout=subprocess.PIPE)
# Parse through the lines gathering relevant information
for line in proc.stdout.readlines():
for word in ['SwapCached:', 'MemFree:', 'Cached:', 'Buffers:']:
if line.startswith(word):
# Pull out the value of the line and convert it to an int
value = int(line.split()[1])
if 'swap' in word.lower():
mem_info['swap_usage'] = value
else:
mem_info['freeable_mem'] += value
return mem_info
def calculate_derived_stats():
calculated_stats = {}
mem_info = _parse_memory()
calculated_stats.update(mem_info)
calculated_stats.update({ 'cpu_util': _get_cpu_usage() })
return calculated_stats
def compile_stats(old_stats):
final_stats = {}
global previous_stats
new_stats = get_stats()
current_stats = parse_stats(new_stats)
previous_stats = current_stats
final_stats.update(calculate_regular_stats(current_stats, old_stats))
final_stats.update(calculate_derived_stats())
return final_stats
def send_stats():
# Uncomfortable with the global here
global previous_stats
stats = compile_stats(previous_stats)
for key, value in stats.iteritems():
name = "{0}:{1}".format(hostname, key)
if key in MAPPINGS.keys():
unit = MAPPINGS[key][1]
elif key in DERIVED_STATS.keys():
unit = DERIVED_STATS[key][1]
else:
unit = "count"
print namespace, name, value, unit
conn.put_metric_data(namespace=namespace, name=name, value=float(value), unit=unit)
# We want to have these stats set to 0
_client = None
previous_stats = defaultdict(int)
conn = CloudWatchConnection()
namespace = "Memcached"
hostname = socket.gethostname()
while True:
if datetime.now().second == 0:
send_stats()
time.sleep(1)
@tootedom

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commented May 17, 2018

Hi @andrewgross

Thanks for this code. Quick question, what OOS license applies to this?

thanks
/dom

@andrewgross

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Owner Author

commented May 20, 2018

Hey /dom,

At the moment I do not have any license applied to this. You (or your company) are free to use it however you wish for whatever you wish.

@tootedom

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commented May 21, 2018

Thanks Andrew,

Much appreciated.
/dom

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