#!/usr/bin/env python

# graph operations-per-second from a set of storage servers.

# the OPERATION value should come from the following list:
#   allocate:   allocate_buckets, first step to upload an immutable file
#    write: write data to an immutable share
#    close: finish writing to an immutable share
#    cancel: abandon a partial immutable share
#   get: get_buckets, first step to download an immutable file
#    read: read data from an immutable share
#   writev: slot_testv_and_readv_and_writev, modify/create a directory
#   readv: read a directory (or mutable file)

# To use this, create a symlink from
# /etc/munin/plugins/tahoe_server_operations_OPERATION to this script. For
# example:

# ln -s /usr/share/munin/plugins/tahoe_server_operations_ \
#  /etc/munin/plugins/tahoe_server_operations_allocate

# Also, you will need to put a list of node statistics URLs in the plugin's
# environment, by adding a stanza like the following to a file in
# /etc/munin/plugin-conf.d/, such as /etc/munin/plugin-conf.d/tahoe_operations:
#
# [tahoe_server_operations*]
# env.url_storage1 http://localhost:9011/statistics?t=json
# env.url_storage2 http://localhost:9012/statistics?t=json
# env.url_storage3 http://localhost:9013/statistics?t=json
# env.url_storage4 http://localhost:9014/statistics?t=json

# of course, these URLs must match the webports you have configured into the
# storage nodes.

from __future__ import print_function

import os, sys
import urllib
import json

node_urls = []
for k,v in os.environ.items():
    if k.startswith("url_"):
        nodename = k[len("url_"):]
        node_urls.append( (nodename, v) )
node_urls.sort()

my_name = os.path.basename(sys.argv[0])
PREFIX = "tahoe_server_operations_"
assert my_name.startswith(PREFIX)
operation = my_name[len(PREFIX):]

configinfo = \
"""graph_title Tahoe Server '%(operation)s' Operations
graph_vlabel ops per second
graph_category tahoe
graph_info This graph shows how many '%(operation)s' operations take place on the storage server
""" % {'operation': operation}

for nodename, url in node_urls:
    configinfo += "%s.label %s\n" % (nodename, nodename)
    configinfo += "%s.type DERIVE\n" % (nodename,)
    configinfo += "%s.min 0\n" % (nodename,)
    configinfo += "%s.draw LINE2\n" % (nodename,)


if len(sys.argv) > 1:
    if sys.argv[1] == "config":
        print(configinfo.rstrip())
        sys.exit(0)

for nodename, url in node_urls:
    data = json.loads(urllib.urlopen(url).read())
    key = "storage_server.%s" % operation
    value = data["counters"][key]
    print("%s.value %s" % (nodename, value))