337 lines
11 KiB
Python
337 lines
11 KiB
Python
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import subprocess
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import re
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import io
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import os
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from tempfile import TemporaryFile
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from operator import xor, eq
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from functools import reduce
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from itertools import starmap
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import math
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class RRDIncompatibleException(Exception):
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"""
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Is raised when an RRD doesn't have the desired definition and cannot be
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upgraded to it.
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"""
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pass
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class RRDOutdatedException(Exception):
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"""
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Is raised when an RRD doesn't have the desired definition, but can be
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upgraded to it.
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"""
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pass
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if not hasattr(__builtins__, "FileNotFoundError"):
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class FileNotFoundError(Exception):
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pass
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class RRD:
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"""
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An RRD is a Round Robin Database, a database which forgets old data and
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aggregates multiple records into new ones.
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It contains multiple Data Sources (DS) which can be thought of as columns,
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and Round Robin Archives (RRA) which can be thought of as tables with the
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DS as columns and time-dependant rows.
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"""
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# rra[2].cdp_prep[0].value = 1,8583033333e+03
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_info_regex = re.compile("""
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(?P<section>[a-z_]+)
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\[ (?P<key>[a-zA-Z0-9_]+) \]
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\.
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(?P<name>[a-z_]+)
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\s*=\s*
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"? (?P<value>.*?) "?
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$""", re.X)
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_cached_info = None
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def _exec_rrdtool(self, cmd, *args, **kwargs):
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pargs = ["rrdtool", cmd, self.filename]
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for k,v in kwargs.items():
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pargs.extend(["--" + k, str(v)])
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pargs.extend(args)
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subprocess.check_output(pargs)
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def __init__(self, filename):
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self.filename = filename
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def ensureSanity(self, ds_list, rra_list, **kwargs):
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"""
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Create or upgrade the RRD file if necessary to contain all DS in
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ds_list. If it needs to be created, the RRAs in rra_list and any kwargs
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will be used for creation. Note that RRAs and options of an existing
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database are NOT modified!
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"""
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try:
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self.checkSanity(ds_list)
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except FileNotFoundError:
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self.create(ds_list, rra_list, **kwargs)
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except RRDOutdatedException:
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self.upgrade(ds_list)
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def checkSanity(self, ds_list=()):
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"""
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Check if the RRD file exists and contains (at least) the DS listed in
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ds_list.
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"""
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if not os.path.exists(self.filename):
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raise FileNotFoundError(self.filename)
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info = self.info()
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if set(ds_list) - set(info['ds'].values()) != set():
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for ds in ds_list:
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if ds.name in info['ds'] and ds.type != info['ds'][ds.name].type:
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raise RRDIncompatibleException("%s is %s but should be %s" % (ds.name, ds.type, info['ds'][ds.name].type))
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else:
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raise RRDOutdatedException()
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def upgrade(self, dss):
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"""
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Upgrade the DS definitions (!) of this RRD.
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(To update its values, use update())
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The list dss contains DSS objects to be updated or added. The
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parameters of a DS can be changed, but not its type. New DS are always
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added at the end in the order of their appearance in the list.
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This is done internally via an rrdtool dump -> rrdtool restore and
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modifying the dump on the fly.
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"""
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info = self.info()
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new_ds = list(info['ds'].values())
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new_ds.sort(key=lambda ds: ds.index)
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for ds in dss:
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if ds.name in info['ds']:
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old_ds = info['ds'][ds.name]
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if info['ds'][ds.name].type != ds.type:
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raise RuntimeError('Cannot convert existing DS "%s" from type "%s" to "%s"' %
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(ds.name, old_ds.type, ds.type))
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ds.index = old_ds.index
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new_ds[ds.index] = ds
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else:
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ds.index = len(new_ds)
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new_ds.append(ds)
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added_ds_num = len(new_ds) - len(info['ds'])
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dump = subprocess.Popen(
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["rrdtool", "dump", self.filename],
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stdout=subprocess.PIPE
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)
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restore = subprocess.Popen(
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["rrdtool", "restore", "-", self.filename + ".new"],
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stdin=subprocess.PIPE
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)
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echo = True
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ds_definitions = True
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for line in dump.stdout:
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if ds_definitions and b'<ds>' in line:
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echo = False
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if b'<!-- Round Robin Archives -->' in line:
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ds_definitions = False
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for ds in new_ds:
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restore.stdin.write(bytes("""
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<ds>
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<name> %s </name>
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<type> %s </type>
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<minimal_heartbeat>%i</minimal_heartbeat>
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<min>%s</min>
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<max>%s</max>
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<!-- PDP Status -->
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<last_ds>%s</last_ds>
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<value>%s</value>
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<unknown_sec> %i </unknown_sec>
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</ds>
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""" % (
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ds.name,
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ds.type,
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ds.args[0],
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ds.args[1],
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ds.args[2],
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ds.last_ds,
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ds.value,
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ds.unknown_sec)
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, "utf-8"))
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if b'</cdp_prep>' in line:
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restore.stdin.write(added_ds_num*b"""
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<ds>
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<primary_value> NaN </primary_value>
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<secondary_value> NaN </secondary_value>
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<value> NaN </value>
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<unknown_datapoints> 0 </unknown_datapoints>
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</ds>
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""")
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# echoing of input line
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if echo:
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restore.stdin.write(
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line.replace(
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b'</row>',
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(added_ds_num*b'<v>NaN</v>')+b'</row>'
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)
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)
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if ds_definitions and b'</ds>' in line:
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echo = True
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dump.stdout.close()
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restore.stdin.close()
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dump.wait()
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restore.wait()
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os.rename(self.filename + ".new", self.filename)
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self._cached_info = None
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def create(self, ds_list, rra_list, **kwargs):
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"""
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Create a new RRD file with the specified list of RRAs and DSs.
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Any kwargs are passed as --key=value to rrdtool create.
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"""
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self._exec_rrdtool(
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"create",
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*map(str, rra_list + ds_list),
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**kwargs
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)
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self._cached_info = None
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def update(self, V):
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"""
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Update the RRD with new values V.
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V can be either list or dict:
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* If it is a dict, its keys must be DS names in the RRD and it is
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ensured that the correct DS are updated with the correct values, by
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passing a "template" to rrdtool update (see man rrdupdate).
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* If it is a list, no template is generated and the order of the
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values in V must be the same as that of the DS in the RRD.
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"""
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try:
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args = ['N:' + ':'.join(map(str, V.values()))]
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kwargs = {'template': ':'.join(V.keys())}
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except AttributeError:
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args = ['N:' + ':'.join(map(str, V))]
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kwargs = {}
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self._exec_rrdtool("update", *args, **kwargs)
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self._cached_info = None
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def info(self):
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"""
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Return a dictionary with information about the RRD.
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See `man rrdinfo` for more details.
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"""
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if self._cached_info:
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return self._cached_info
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env = os.environ.copy()
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env["LC_ALL"] = "C"
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proc = subprocess.Popen(
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["rrdtool", "info", self.filename],
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stdout=subprocess.PIPE,
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env=env
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)
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out, err = proc.communicate()
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out = out.decode()
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info = {}
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for line in out.splitlines():
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base = info
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for match in self._info_regex.finditer(line):
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section, key, name, value = match.group("section", "key", "name", "value")
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if section and key:
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try:
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key = int(key)
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except ValueError:
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pass
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if section not in base:
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base[section] = {}
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if key not in base[section]:
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base[section][key] = {}
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base = base[section][key]
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if name and value:
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try:
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base[name] = int(value)
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except ValueError:
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try:
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base[name] = float(value)
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except:
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base[name] = value
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dss = {}
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for name, ds in info['ds'].items():
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ds_obj = DS(name, ds['type'], ds['minimal_heartbeat'], ds['min'], ds['max'])
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ds_obj.index = ds['index']
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ds_obj.last_ds = ds['last_ds']
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ds_obj.value = ds['value']
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ds_obj.unknown_sec = ds['unknown_sec']
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dss[name] = ds_obj
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info['ds'] = dss
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rras = []
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for rra in info['rra'].values():
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rras.append(RRA(rra['cf'], rra['xff'], rra['pdp_per_row'], rra['rows']))
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info['rra'] = rras
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self._cached_info = info
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return info
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class DS:
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"""
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DS stands for Data Source and represents one line of data points in a Round
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Robin Database (RRD).
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"""
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name = None
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type = None
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args = []
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index = -1
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last_ds = 'U'
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value = 0
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unknown_sec = 0
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def __init__(self, name, dst, *args):
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self.name = name
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self.type = dst
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self.args = args
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def __str__(self):
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return "DS:%s:%s:%s" % (
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self.name,
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self.type,
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":".join(map(str, self._nan_to_U_args()))
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)
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def __repr__(self):
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return "%s(%r, %r, %s)" % (
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self.__class__.__name__,
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self.name,
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self.type,
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", ".join(map(repr, self.args))
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)
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def __eq__(self, other):
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return all(starmap(eq, zip(self._compare_keys(), other._compare_keys())))
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def __hash__(self):
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return reduce(xor, map(hash, self._compare_keys()))
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def _nan_to_U_args(self):
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return tuple(
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'U' if type(arg) is float and math.isnan(arg)
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else arg
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for arg in self.args
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)
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def _compare_keys(self):
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return (self.name, self.type, self._nan_to_U_args())
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class RRA:
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def __init__(self, cf, *args):
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self.cf = cf
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self.args = args
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def __str__(self):
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return "RRA:%s:%s" % (self.cf, ":".join(map(str, self.args)))
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def __repr__(self):
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return "%s(%r, %s)" % (
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self.__class__.__name__,
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self.cf,
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", ".join(map(repr, self.args))
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)
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