Files
deb-python-taskflow/taskflow/examples/resume_vm_boot.py
Joshua Harlow d433a5323f Deprecate engine_conf and prefer engine instead
To avoid having one set of options coming from `engine_conf`
and another set of options coming from `kwargs` and another set
coming from `engine_conf` if it is a URI just start to shift
toward `engine_conf` being deprecated and `engine` being a string
type only (or a URI with additional query parameters) and having
any additional **kwargs that are provided just get merged into the
final engine options.

This adds a new helper function that handles all these various
options and adds in a keyword argument `engine` that will be shifted
to in a future version (in that future version we can also then
remove the `engine_conf` and just stick to a smaller set of option
mechanisms).

It also adjusts all examples to use this new and more easier to
understand format and adjusts tests, conductor interface to use
this new more easily understandable style of getting an engine.

Change-Id: Ic7617057338e0c63775cf38a24643cff6e454950
2014-10-18 13:28:27 -07:00

278 lines
9.2 KiB
Python

# -*- coding: utf-8 -*-
# Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import contextlib
import hashlib
import logging
import os
import random
import sys
import time
logging.basicConfig(level=logging.ERROR)
self_dir = os.path.abspath(os.path.dirname(__file__))
top_dir = os.path.abspath(os.path.join(os.path.dirname(__file__),
os.pardir,
os.pardir))
sys.path.insert(0, top_dir)
sys.path.insert(0, self_dir)
from taskflow import engines
from taskflow import exceptions as exc
from taskflow.openstack.common import uuidutils
from taskflow.patterns import graph_flow as gf
from taskflow.patterns import linear_flow as lf
from taskflow import task
from taskflow.utils import eventlet_utils as e_utils
from taskflow.utils import persistence_utils as p_utils
import example_utils as eu # noqa
# INTRO: This examples shows how a hierarchy of flows can be used to create a
# vm in a reliable & resumable manner using taskflow + a miniature version of
# what nova does while booting a vm.
@contextlib.contextmanager
def slow_down(how_long=0.5):
try:
yield how_long
finally:
if len(sys.argv) > 1:
# Only both to do this if user input provided.
print("** Ctrl-c me please!!! **")
time.sleep(how_long)
class PrintText(task.Task):
"""Just inserts some text print outs in a workflow."""
def __init__(self, print_what, no_slow=False):
content_hash = hashlib.md5(print_what.encode('utf-8')).hexdigest()[0:8]
super(PrintText, self).__init__(name="Print: %s" % (content_hash))
self._text = print_what
self._no_slow = no_slow
def execute(self):
if self._no_slow:
eu.print_wrapped(self._text)
else:
with slow_down():
eu.print_wrapped(self._text)
class DefineVMSpec(task.Task):
"""Defines a vm specification to be."""
def __init__(self, name):
super(DefineVMSpec, self).__init__(provides='vm_spec', name=name)
def execute(self):
return {
'type': 'kvm',
'disks': 2,
'vcpu': 1,
'ips': 1,
'volumes': 3,
}
class LocateImages(task.Task):
"""Locates where the vm images are."""
def __init__(self, name):
super(LocateImages, self).__init__(provides='image_locations',
name=name)
def execute(self, vm_spec):
image_locations = {}
for i in range(0, vm_spec['disks']):
url = "http://www.yahoo.com/images/%s" % (i)
image_locations[url] = "/tmp/%s.img" % (i)
return image_locations
class DownloadImages(task.Task):
"""Downloads all the vm images."""
def __init__(self, name):
super(DownloadImages, self).__init__(provides='download_paths',
name=name)
def execute(self, image_locations):
for src, loc in image_locations.items():
with slow_down(1):
print("Downloading from %s => %s" % (src, loc))
return sorted(image_locations.values())
class CreateNetworkTpl(task.Task):
"""Generates the network settings file to be placed in the images."""
SYSCONFIG_CONTENTS = """DEVICE=eth%s
BOOTPROTO=static
IPADDR=%s
ONBOOT=yes"""
def __init__(self, name):
super(CreateNetworkTpl, self).__init__(provides='network_settings',
name=name)
def execute(self, ips):
settings = []
for i, ip in enumerate(ips):
settings.append(self.SYSCONFIG_CONTENTS % (i, ip))
return settings
class AllocateIP(task.Task):
"""Allocates the ips for the given vm."""
def __init__(self, name):
super(AllocateIP, self).__init__(provides='ips', name=name)
def execute(self, vm_spec):
ips = []
for i in range(0, vm_spec.get('ips', 0)):
ips.append("192.168.0.%s" % (random.randint(1, 254)))
return ips
class WriteNetworkSettings(task.Task):
"""Writes all the network settings into the downloaded images."""
def execute(self, download_paths, network_settings):
for j, path in enumerate(download_paths):
with slow_down(1):
print("Mounting %s to /tmp/%s" % (path, j))
for i, setting in enumerate(network_settings):
filename = ("/tmp/etc/sysconfig/network-scripts/"
"ifcfg-eth%s" % (i))
with slow_down(1):
print("Writing to %s" % (filename))
print(setting)
class BootVM(task.Task):
"""Fires off the vm boot operation."""
def execute(self, vm_spec):
print("Starting vm!")
with slow_down(1):
print("Created: %s" % (vm_spec))
class AllocateVolumes(task.Task):
"""Allocates the volumes for the vm."""
def execute(self, vm_spec):
volumes = []
for i in range(0, vm_spec['volumes']):
with slow_down(1):
volumes.append("/dev/vda%s" % (i + 1))
print("Allocated volume %s" % volumes[-1])
return volumes
class FormatVolumes(task.Task):
"""Formats the volumes for the vm."""
def execute(self, volumes):
for v in volumes:
print("Formatting volume %s" % v)
with slow_down(1):
pass
print("Formatted volume %s" % v)
def create_flow():
# Setup the set of things to do (mini-nova).
flow = lf.Flow("root").add(
PrintText("Starting vm creation.", no_slow=True),
lf.Flow('vm-maker').add(
# First create a specification for the final vm to-be.
DefineVMSpec("define_spec"),
# This does all the image stuff.
gf.Flow("img-maker").add(
LocateImages("locate_images"),
DownloadImages("download_images"),
),
# This does all the network stuff.
gf.Flow("net-maker").add(
AllocateIP("get_my_ips"),
CreateNetworkTpl("fetch_net_settings"),
WriteNetworkSettings("write_net_settings"),
),
# This does all the volume stuff.
gf.Flow("volume-maker").add(
AllocateVolumes("allocate_my_volumes", provides='volumes'),
FormatVolumes("volume_formatter"),
),
# Finally boot it all.
BootVM("boot-it"),
),
# Ya it worked!
PrintText("Finished vm create.", no_slow=True),
PrintText("Instance is running!", no_slow=True))
return flow
eu.print_wrapped("Initializing")
# Setup the persistence & resumption layer.
with eu.get_backend() as backend:
try:
book_id, flow_id = sys.argv[2].split("+", 1)
if not uuidutils.is_uuid_like(book_id):
book_id = None
if not uuidutils.is_uuid_like(flow_id):
flow_id = None
except (IndexError, ValueError):
book_id = None
flow_id = None
# Set up how we want our engine to run, serial, parallel...
executor = None
if e_utils.EVENTLET_AVAILABLE:
executor = e_utils.GreenExecutor(5)
# Create/fetch a logbook that will track the workflows work.
book = None
flow_detail = None
if all([book_id, flow_id]):
with contextlib.closing(backend.get_connection()) as conn:
try:
book = conn.get_logbook(book_id)
flow_detail = book.find(flow_id)
except exc.NotFound:
pass
if book is None and flow_detail is None:
book = p_utils.temporary_log_book(backend)
engine = engines.load_from_factory(create_flow,
backend=backend, book=book,
engine='parallel',
executor=executor)
print("!! Your tracking id is: '%s+%s'" % (book.uuid,
engine.storage.flow_uuid))
print("!! Please submit this on later runs for tracking purposes")
else:
# Attempt to load from a previously partially completed flow.
engine = engines.load_from_detail(flow_detail, backend=backend,
engine='parallel', executor=executor)
# Make me my vm please!
eu.print_wrapped('Running')
engine.run()
# How to use.
#
# 1. $ python me.py "sqlite:////tmp/nova.db"
# 2. ctrl-c before this finishes
# 3. Find the tracking id (search for 'Your tracking id is')
# 4. $ python me.py "sqlite:////tmp/cinder.db" "$tracking_id"
# 5. Watch it pick up where it left off.
# 6. Profit!