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GeezerVison is showing github.com — cloudstack/python/lib/cloud_utils.py at main · NetApp/cloudstack Expand file tree/ Copy pathcloud_utils.pyMore file actions 681 lines (568 loc) · 22.9 KB / Copy pathcloud_utils.pyFile metadata and controls681 lines (568 loc) · 22.9 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 #!/usr/bin/env python3 # Licensed to the Apache Software Foundation (ASF) under one # or more contributor license agreements. See the NOTICE file # distributed with this work for additional information # regarding copyright ownership. The ASF licenses this file # to you 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. # -*- coding: utf-8 -*- """CloudStack Python utility library""" import sys, os, subprocess, errno, re, time, glob import urllib.request, urllib.error, urllib.parse import xml.dom.minidom import logging import socket # exit() error constants E_GENERIC= 1 E_NOKVM = 2 E_NODEFROUTE = 3 E_DHCP = 4 E_NOPERSISTENTNET = 5 E_NETRECONFIGFAILED = 6 E_VIRTRECONFIGFAILED = 7 E_FWRECONFIGFAILED = 8 E_AGENTRECONFIGFAILED = 9 E_AGENTFAILEDTOSTART = 10 E_NOFQDN = 11 E_SELINUXENABLED = 12 try: E_USAGE = os.EX_USAGE except AttributeError: E_USAGE = 64 E_NEEDSMANUALINTERVENTION = 13 E_INTERRUPTED = 14 E_SETUPFAILED = 15 E_UNHANDLEDEXCEPTION = 16 E_MISSINGDEP = 17 Unknown = 0 Fedora = 1 CentOS = 2 Ubuntu = 3 RHEL6 = 4 SUSE = 5 IPV4 = 4 IPV6 = 6 #=================== DISTRIBUTION DETECTION ================= if os.path.exists("/etc/fedora-release"): distro = Fedora elif os.path.exists("/etc/centos-release"): distro = CentOS elif os.path.exists("/etc/redhat-release"): version = open("/etc/redhat-release").readline() if version.find("Red Hat Enterprise Linux Server release 6") != -1: distro = RHEL6 elif version.find("CentOS") != -1: distro = CentOS else: distro = CentOS elif os.path.exists("/etc/legal") and "Ubuntu" in open("/etc/legal").read(-1): distro = Ubuntu elif os.path.exists("/etc/os-release") and "SUSE" in open("/etc/os-release").read(-1): distro = SUSE else: distro = Unknown logFileName=None # ================== LIBRARY UTILITY CODE============= def setLogFile(logFile): global logFileName logFileName=logFile def read_properties(propfile): if not hasattr(propfile,"read"): propfile = open(propfile) properties = propfile.read().splitlines() properties = [ s.strip() for s in properties ] properties = [ s for s in properties if s and not s.startswith("#") and not s.startswith(";") ] #[ logging.debug("Valid config file line: %s",s) for s in properties ] proppairs = [ s.split("=",1) for s in properties ] return dict(proppairs) def stderr(msgfmt,*args): """Print a message to stderr, optionally interpolating the arguments into it""" msgfmt += "\n" if logFileName != None: sys.stderr = open(logFileName, 'a+') if args: sys.stderr.write(msgfmt%args) else: sys.stderr.write(msgfmt) def exit(errno=E_GENERIC,message=None,*args): """Exit with an error status code, printing a message to stderr if specified""" if message: stderr(message,*args) sys.exit(errno) def resolve(host,port): return [ (x[4][0],len(x[4])+2) for x in socket.getaddrinfo(host,port,socket.AF_UNSPEC,socket.SOCK_STREAM, 0, socket.AI_PASSIVE) ] def resolves_to_ipv6(host,port): return resolve(host,port)[0][1] == IPV6 ###add this to Python 2.4, patching the subprocess module at runtime if hasattr(subprocess,"check_call"): from subprocess import CalledProcessError, check_call else: class CalledProcessError(Exception): def __init__(self, returncode, cmd): self.returncode = returncode ; self.cmd = cmd def __str__(self): return "Command '%s' returned non-zero exit status %d" % (self.cmd, self.returncode) subprocess.CalledProcessError = CalledProcessError def check_call(*popenargs, **kwargs): retcode = subprocess.call(*popenargs, **kwargs) cmd = kwargs.get("args") if cmd is None: cmd = popenargs[0] if retcode: raise subprocess.CalledProcessError(retcode, cmd) return retcode subprocess.check_call = check_call # python 2.4 does not have this try: any = any all = all except NameError: def any(sequence): for i in sequence: if i: return True return False def all(sequence): for i in sequence: if not i: return False return True class Command: """This class simulates a shell command""" def __init__(self,name,parent=None): self.__name = name self.__parent = parent def __getattr__(self,name): if name == "_print": name = "print" return Command(name,self) def __call__(self,*args,**kwargs): cmd = self.__get_recursive_name() + list(args) #print " ",cmd kwargs = dict(kwargs) if "stdout" not in kwargs: kwargs["stdout"] = subprocess.PIPE if "stderr" not in kwargs: kwargs["stderr"] = subprocess.PIPE popen = subprocess.Popen(cmd,**kwargs) m = popen.communicate() ret = popen.wait() if ret: e = CalledProcessError(ret,cmd) e.stdout,e.stderr = m raise e class CommandOutput: def __init__(self,stdout,stderr): self.stdout = stdout self.stderr = stderr return CommandOutput(*m) def __lt__(self,other): cmd = self.__get_recursive_name() #print " ",cmd,"<",other popen = subprocess.Popen(cmd,stdin=subprocess.PIPE,stdout=subprocess.PIPE,stderr=subprocess.PIPE) m = popen.communicate(other) ret = popen.wait() if ret: e = CalledProcessError(ret,cmd) e.stdout,e.stderr = m raise e class CommandOutput: def __init__(self,stdout,stderr): self.stdout = stdout self.stderr = stderr return CommandOutput(*m) def __get_recursive_name(self,sep=None): m = self l = [] while m is not None: l.append(m.__name) m = m.__parent l.reverse() if sep: return sep.join(l) else: return l def __str__(self): return '<Command %r>'%self.__get_recursive_name(sep=" ") def __repr__(self): return self.__str__() kvmok = Command("kvm-ok") getenforce = Command("/usr/sbin/getenforce") ip = Command("ip") service = Command("service") chkconfig = Command("chkconfig") updatercd = Command("update-rc.d") ufw = Command("ufw") iptables = Command("iptables") iptablessave = Command("iptables-save") augtool = Command("augtool") ifconfig = Command("ifconfig") ifdown = Command("ifdown") ifup = Command("ifup") uuidgen = Command("uuidgen") def is_service_running(servicename): try: o = service(servicename,"status") if distro is Ubuntu: # status in ubuntu does not signal service status via return code if "start/running" in o.stdout: return True return False else: # retcode 0, service running return True except CalledProcessError as e: # retcode nonzero, service not running return False def stop_service(servicename,force=False): # This function is idempotent. N number of calls have the same result as N+1 number of calls. if is_service_running(servicename) or force: service(servicename,"stop",stdout=None,stderr=None) def disable_service(servicename): # Stops AND disables the service stop_service(servicename) if distro is Ubuntu: updatercd("-f",servicename,"remove",stdout=None,stderr=None) else: chkconfig("--del",servicename,stdout=None,stderr=None) def start_service(servicename,force=False): # This function is idempotent unless force is True. N number of calls have the same result as N+1 number of calls. if not is_service_running(servicename) or force: service(servicename,"start",stdout=None,stderr=None) def enable_service(servicename,forcestart=False): # Stops AND disables the service if distro is Ubuntu: updatercd("-f",servicename,"remove",stdout=None,stderr=None) updatercd("-f",servicename,"start","2","3","4","5",".",stdout=None,stderr=None) else: chkconfig("--add",servicename,stdout=None,stderr=None) chkconfig("--level","345",servicename,"on",stdout=None,stderr=None) start_service(servicename,force=forcestart) def replace_line(f,startswith,stanza,always_add=False): lines = [ s.strip() for s in open(f).readlines() ] newlines = [] replaced = False for line in lines: if line.startswith(startswith): newlines.append(stanza) replaced = True else: newlines.append(line) if not replaced and always_add: newlines.append(stanza) newlines = [ s + '\n' for s in newlines ] open(f,"w").writelines(newlines) def replace_or_add_line(f,startswith,stanza): return replace_line(f,startswith,stanza,always_add=True) # ==================================== CHECK FUNCTIONS ========================== # If they return without exception, it's okay. If they raise a CheckFailed exception, that means a condition # (generallly one that needs administrator intervention) was detected. class CheckFailed(Exception): pass #check function def check_hostname(): """If the hostname is a non-fqdn, fail with CalledProcessError. Else return 0.""" try: check_call(["hostname",'--fqdn']) except CalledProcessError: raise CheckFailed("This machine does not have an FQDN (fully-qualified domain name) for a hostname") #check function def check_kvm(): if distro in (Fedora,CentOS,RHEL6,SUSE): if os.path.exists("/dev/kvm"): return True raise CheckFailed("KVM is not correctly installed on this system, or support for it is not enabled in the BIOS") else: try: kvmok() return True except CalledProcessError: raise CheckFailed("KVM is not correctly installed on this system, or support for it is not enabled in the BIOS") except OSError as e: if e.errno == errno.ENOENT: raise CheckFailed("KVM is not correctly installed on this system, or support for it is not enabled in the BIOS") raise return True raise AssertionError("check_kvm() should have never reached this part") def check_cgroups(): return glob.glob("/*/cpu.shares") #check function def check_selinux(): if distro not in [Fedora,CentOS,RHEL6,SUSE]: return # no selinux outside of those enforcing = False config_enforcing = False try: output = getenforce().stdout.decode('utf-8').strip() if "nforcing" in output: enforcing = True if any ( [ s.startswith("SELINUX=enforcing") for s in open("/etc/selinux/config").readlines() ] ): config_enforcing = True else: config_enforcing = False except (IOError,OSError) as e: if e.errno == 2: pass else: raise CheckFailed("An unknown error (%s) took place while checking for SELinux"%str(e)) if enforcing: raise CheckFailed('''SELinux is set to enforcing. There are two options: 1> Set it permissive in /etc/selinux/config, then reboot the machine. 2> Type 'setenforce Permissive' in commandline, after which you can run this program again. We strongly suggest you doing the option 1 that makes sure SELinux goes into permissive after system reboot.\n''') if config_enforcing: print("WARNING: We detected that your SELinux is not configured in permissive. to make sure cloudstack won't block by \ SELinux after system reboot, we strongly suggest you setting it in permissive in /etc/selinux/config, then reboot the machine.") def preflight_checks(do_check_kvm=True): if distro is Ubuntu: preflight_checks = [ (check_hostname,"Checking hostname"), ] else: preflight_checks = [ (check_hostname,"Checking hostname"), (check_selinux,"Checking if SELinux is disabled"), ] #preflight_checks.append( (check_cgroups,"Checking if the control groups /cgroup filesystem is mounted") ) if do_check_kvm: preflight_checks.append( (check_kvm,"Checking for KVM") ) return preflight_checks def backup_etc(targetdir): if not targetdir.endswith("/"): targetdir += "/" check_call( ["mkdir","-p",targetdir] ) rsynccall = ["rsync","-ax","--delete"] + ["/etc/",targetdir] check_call( rsynccall ) def restore_etc(targetdir): if not targetdir.endswith("/"): targetdir += "/" rsynccall = ["rsync","-ax","--delete"] + [targetdir,"/etc/"] check_call( rsynccall ) def remove_backup(targetdir): check_call( ["rm","-rf",targetdir] ) def list_zonespods(host): text = urllib.request.urlopen('http://%s:8096/client/api?command=listPods'%host).read(-1) dom = xml.dom.minidom.parseString(text) x = [ (zonename,podname) for pod in dom.childNodes[0].childNodes for podname in [ x.childNodes[0].wholeText for x in pod.childNodes if x.tagName == "name" ] for zonename in [ x.childNodes[0].wholeText for x in pod.childNodes if x.tagName == "zonename" ] ] return x def prompt_for_hostpods(zonespods): """Ask user to select one from those zonespods Returns (zone,pod) or None if the user made the default selection.""" while True: stderr("Type the number of the zone and pod combination this host belongs to (hit ENTER to skip this step)") print(" N) ZONE, POD") print("================") for n,(z,p) in enumerate(zonespods): print("%3d) %s, %s"%(n,z,p)) print("================") print("> ", end=' ') zoneandpod = input().strip() if not zoneandpod: # we go with default, do not touch anything, just break return None try: # if parsing fails as an int, just vomit and retry zoneandpod = int(zoneandpod) if zoneandpod >= len(zonespods) or zoneandpod < 0: raise ValueError("%s out of bounds"%zoneandpod) except ValueError as e: stderr(str(e)) continue # re-ask # oh yeah, the int represents an valid zone and pod index in the array return zonespods[zoneandpod] # this configures the agent def device_exist(devName): try: alreadysetup = False if distro in (Fedora,CentOS, RHEL6): alreadysetup = augtool._print("/files/etc/sysconfig/network-scripts/ifcfg-%s"%devName).stdout.strip() elif distro == SUSE: alreadysetup = augtool._print("/files/etc/sysconfig/network/ifcfg-%s"%devName).stdout.strip() elif distro == Ubuntu: alreadysetup = augtool.match("/files/etc/network/interfaces/iface",devName).stdout.strip() return alreadysetup except OSError as e: return False def setup_agent_config(configfile, host, zone, pod, cluster, guid, pubNic, prvNic): stderr("Examining Agent configuration") fn = configfile text = open(fn).read(-1) lines = [ s.strip() for s in text.splitlines() ] confopts = dict([ m.split("=",1) for m in lines if "=" in m and not m.startswith("#") ]) confposes = dict([ (m.split("=",1)[0],n) for n,m in enumerate(lines) if "=" in m and not m.startswith("#") ]) if guid != None: confopts['guid'] = guid else: if "guid" not in confopts: stderr("Generating GUID for this Agent") confopts['guid'] = uuidgen().stdout.strip() if host == None: try: host = confopts["host"] except KeyError: host = "localhost" stderr("Please enter the host name of the management server that this agent will connect to: (just hit ENTER to go with %s)",host) print("> ", end=' ') newhost = input().strip() if newhost: host = newhost confopts["host"] = host if pubNic != None and device_exist(pubNic): confopts["public.network.device"] = pubNic if prvNic == None or not device_exist(prvNic): confopts["private.network.device"] = pubNic if prvNic != None and device_exist(prvNic): confopts["private.network.device"] = prvNic if pubNic == None or not device_exist(pubNic): confopts["public.network.device"] = prvNic stderr("Querying %s for zones and pods",host) try: if zone == None or pod == None: x = list_zonespods(confopts['host']) zoneandpod = prompt_for_hostpods(x) if zoneandpod: confopts["zone"],confopts["pod"] = zoneandpod stderr("You selected zone %s pod %s",confopts["zone"],confopts["pod"]) else: stderr("Skipped -- using the previous zone %s pod %s",confopts["zone"],confopts["pod"]) else: confopts["zone"] = zone confopts["pod"] = pod confopts["cluster"] = cluster except (urllib.error.URLError,urllib.error.HTTPError) as e: stderr("Query failed: %s. Defaulting to zone %s pod %s",str(e),confopts["zone"],confopts["pod"]) for opt,val in list(confopts.items()): line = "=".join([opt,val]) if opt not in confposes: lines.append(line) else: lines[confposes[opt]] = line text = "\n".join(lines) open(fn,"w").write(text) def setup_consoleproxy_config(configfile, host, zone, pod): stderr("Examining Console Proxy configuration") fn = configfile text = open(fn).read(-1) lines = [ s.strip() for s in text.splitlines() ] confopts = dict([ m.split("=",1) for m in lines if "=" in m and not m.startswith("#") ]) confposes = dict([ (m.split("=",1)[0],n) for n,m in enumerate(lines) if "=" in m and not m.startswith("#") ]) if "guid" not in confopts: stderr("Generating GUID for this Console Proxy") confopts['guid'] = uuidgen().stdout.strip() if host == None: try: host = confopts["host"] except KeyError: host = "localhost" stderr("Please enter the host name of the management server that this console-proxy will connect to: (just hit ENTER to go with %s)",host) print("> ", end=' ') newhost = input().strip() if newhost: host = newhost confopts["host"] = host stderr("Querying %s for zones and pods",host) try: if zone == None or pod == None: x = list_zonespods(confopts['host']) zoneandpod = prompt_for_hostpods(x) if zoneandpod: confopts["zone"],confopts["pod"] = zoneandpod stderr("You selected zone %s pod %s",confopts["zone"],confopts["pod"]) else: stderr("Skipped -- using the previous zone %s pod %s",confopts["zone"],confopts["pod"]) else: confopts["zone"] = zone confopts["pod"] = pod except (urllib.error.URLError,urllib.error.HTTPError) as e: stderr("Query failed: %s. Defaulting to zone %s pod %s",str(e),confopts["zone"],confopts["pod"]) for opt,val in list(confopts.items()): line = "=".join([opt,val]) if opt not in confposes: lines.append(line) else: lines[confposes[opt]] = line text = "\n".join(lines) open(fn,"w").write(text) # =========================== DATABASE MIGRATION SUPPORT CODE =================== # Migrator, Migratee and Evolvers -- this is the generic infrastructure. class MigratorException(Exception): pass class NoMigrationPath(MigratorException): pass class NoMigrator(MigratorException): pass INITIAL_LEVEL = '-' class Migrator: """Migrator class. The migrator gets a list of Python objects, and discovers MigrationSteps in it. It then sorts the steps into a chain, based on the attributes from_level and to_level in each one of the steps. When the migrator's run(context) is called, the chain of steps is applied sequentially on the context supplied to run(), in the order of the chain of steps found at discovery time. See the documentation for the MigrationStep class for information on how that happens. """ def __init__(self,evolver_source): self.discover_evolvers(evolver_source) self.sort_evolvers() def discover_evolvers(self,source): self.evolvers = [] for val in source: if hasattr(val,"from_level") and hasattr(val,"to_level") and val.to_level: self.evolvers.append(val) def sort_evolvers(self): new = [] while self.evolvers: if not new: try: idx= [ i for i,s in enumerate(self.evolvers) if s.from_level == INITIAL_LEVEL ][0] # initial evolver except IndexError as e: raise IndexError("no initial evolver (from_level is None) could be found") else: try: idx= [ i for i,s in enumerate(self.evolvers) if new[-1].to_level == s.from_level ][0] except IndexError as e: raise IndexError("no evolver could be found to evolve from level %s"%new[-1].to_level) new.append(self.evolvers.pop(idx)) self.evolvers = new def get_evolver_chain(self): return [ (s.from_level, s.to_level, s) for s in self.evolvers ] def get_evolver_by_starting_level(self,level): try: return [ s for s in self.evolvers if s.from_level == level][0] except IndexError: raise NoMigrator("No evolver knows how to evolve the database from schema level %r"%level) def get_evolver_by_ending_level(self,level): try: return [ s for s in self.evolvers if s.to_level == level][0] except IndexError: raise NoMigrator("No evolver knows how to evolve the database to schema level %r"%level) def run(self, context, dryrun = False, starting_level = None, ending_level = None): """Runs each one of the steps in sequence, passing the migration context to each. At the end of the process, context.commit() is called to save the changes, or context.rollback() is called if dryrun = True. If starting_level is not specified, then the context.get_schema_level() is used to find out at what level the context is at. Then starting_level is set to that. If ending_level is not specified, then the evolvers will run till the end of the chain.""" assert dryrun is False # NOT IMPLEMENTED, prolly gonna implement by asking the context itself to remember its state starting_level = starting_level or context.get_schema_level() or self.evolvers[0].from_level ending_level = ending_level or self.evolvers[-1].to_level evolution_path = self.evolvers idx = evolution_path.index(self.get_evolver_by_starting_level(starting_level)) evolution_path = evolution_path[idx:] try: idx = evolution_path.index(self.get_evolver_by_ending_level(ending_level)) except ValueError: raise NoEvolutionPath("No evolution path from schema level %r to schema level %r" % \ (starting_level,ending_level)) evolution_path = evolution_path[:idx+1] logging.info("Starting migration on %s"%context) for ec in evolution_path: assert ec.from_level == context.get_schema_level() evolver = ec(context=context) logging.info("%s (from level %s to level %s)", evolver, evolver.from_level, evolver.to_level) #try: evolver.run() #except: #context.rollback() #raise context.set_schema_level(evolver.to_level) #context.commit() logging.info("%s is now at level %s",context,context.get_schema_level()) #if dryrun: # implement me with backup and restore #logging.info("Rolling back changes on %s",context) #context.rollback() #else: #logging.info("Committing changes on %s",context) #context.commit() logging.info("Migration finished") class MigrationStep: """Base MigrationStep class, aka evolver. You develop your own steps, and then pass a list of those steps to the Migrator instance that will run them in order. When the migrator runs, it will take the list of steps you gave, and, for each step: a) instantiate it, passing the context you gave to the migrator into the step's __init__(). b) run() the method in the migration step. As you can see, the default MigrationStep constructor makes the passed context available as self.context in the methods of your step. Each step has two member vars that determine in which order they are run, and if they need to run: - from_level = the schema level that the database should be at, before running the evolver The value None has special meaning here, it means the first evolver that should be run if the database does not have a schema level yet. - to_level = the schema level number that the database will be at after the evolver has run """ # Implement these attributes in your steps from_level = None to_level = None def __init__(self,context): self.context = context def run(self): raise NotImplementedError class MigrationContext: def __init__(self): pass def commit(self):raise NotImplementedError def rollback(self):raise NotImplementedError def get_schema_level(self):raise NotImplementedError def set_schema_level(self,l):raise NotImplementedError |
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