[3] | 1 | #!/usr/bin/env python |
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| 2 | # -*- coding: utf-8 -*- |
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| 3 | |
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| 4 | import shutil |
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| 5 | from StringIO import StringIO |
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| 6 | |
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| 7 | import migrate |
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| 8 | from migrate.versioning import exceptions, genmodel, schemadiff |
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| 9 | from migrate.versioning.base import operations |
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| 10 | from migrate.versioning.template import template |
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| 11 | from migrate.versioning.script import base |
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| 12 | from migrate.versioning.util import import_path, load_model, construct_engine |
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| 13 | |
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| 14 | class PythonScript(base.BaseScript): |
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| 15 | |
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| 16 | @classmethod |
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| 17 | def create(cls, path, **opts): |
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| 18 | """Create an empty migration script""" |
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| 19 | cls.require_notfound(path) |
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| 20 | |
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| 21 | # TODO: Use the default script template (defined in the template |
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| 22 | # module) for now, but we might want to allow people to specify a |
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| 23 | # different one later. |
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| 24 | template_file = None |
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| 25 | src = template.get_script(template_file) |
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| 26 | shutil.copy(src, path) |
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| 27 | |
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| 28 | @classmethod |
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| 29 | def make_update_script_for_model(cls, engine, oldmodel, |
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| 30 | model, repository, **opts): |
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| 31 | """Create a migration script""" |
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| 32 | |
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| 33 | # Compute differences. |
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| 34 | if isinstance(repository, basestring): |
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| 35 | # oh dear, an import cycle! |
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| 36 | from migrate.versioning.repository import Repository |
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| 37 | repository = Repository(repository) |
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| 38 | oldmodel = load_model(oldmodel) |
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| 39 | model = load_model(model) |
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| 40 | diff = schemadiff.getDiffOfModelAgainstModel( |
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| 41 | oldmodel, |
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| 42 | model, |
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| 43 | engine, |
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| 44 | excludeTables=[repository.version_table]) |
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| 45 | decls, upgradeCommands, downgradeCommands = \ |
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| 46 | genmodel.ModelGenerator(diff).toUpgradeDowngradePython() |
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| 47 | |
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| 48 | # Store differences into file. |
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| 49 | template_file = None |
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| 50 | src = template.get_script(template_file) |
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| 51 | contents = open(src).read() |
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| 52 | search = 'def upgrade():' |
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| 53 | contents = contents.replace(search, '\n\n'.join((decls, search)), 1) |
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| 54 | if upgradeCommands: |
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| 55 | contents = contents.replace(' pass', upgradeCommands, 1) |
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| 56 | if downgradeCommands: |
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| 57 | contents = contents.replace(' pass', downgradeCommands, 1) |
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| 58 | return contents |
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| 59 | |
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| 60 | @classmethod |
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| 61 | def verify_module(cls,path): |
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| 62 | """Ensure this is a valid script, or raise InvalidScriptError""" |
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| 63 | # Try to import and get the upgrade() func |
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| 64 | try: |
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| 65 | module=import_path(path) |
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| 66 | except: |
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| 67 | # If the script itself has errors, that's not our problem |
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| 68 | raise |
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| 69 | try: |
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| 70 | assert callable(module.upgrade) |
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| 71 | except Exception, e: |
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| 72 | raise exceptions.InvalidScriptError(path + ': %s' % str(e)) |
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| 73 | return module |
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| 74 | |
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| 75 | def preview_sql(self, url, step, **args): |
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| 76 | """Mock engine to store all executable calls in a string \ |
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| 77 | and execute the step""" |
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| 78 | buf = StringIO() |
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| 79 | args['engine_arg_strategy'] = 'mock' |
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| 80 | args['engine_arg_executor'] = lambda s, p='': buf.write(s + p) |
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| 81 | engine = construct_engine(url, **args) |
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| 82 | |
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| 83 | self.run(engine, step) |
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| 84 | |
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| 85 | return buf.getvalue() |
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| 86 | |
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| 87 | def run(self, engine, step): |
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| 88 | """Core method of Script file. \ |
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| 89 | Exectues update() or downgrade() function""" |
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| 90 | if step > 0: |
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| 91 | op = 'upgrade' |
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| 92 | elif step < 0: |
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| 93 | op = 'downgrade' |
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| 94 | else: |
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| 95 | raise exceptions.ScriptError("%d is not a valid step" % step) |
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| 96 | funcname = base.operations[op] |
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| 97 | |
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| 98 | migrate.migrate_engine = engine |
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| 99 | #migrate.run.migrate_engine = migrate.migrate_engine = engine |
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| 100 | func = self._func(funcname) |
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| 101 | func() |
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| 102 | migrate.migrate_engine = None |
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| 103 | #migrate.run.migrate_engine = migrate.migrate_engine = None |
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| 104 | |
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| 105 | @property |
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| 106 | def module(self): |
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| 107 | if not hasattr(self,'_module'): |
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| 108 | self._module = self.verify_module(self.path) |
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| 109 | return self._module |
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| 110 | |
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| 111 | def _func(self, funcname): |
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| 112 | fn = getattr(self.module, funcname, None) |
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| 113 | if not fn: |
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| 114 | msg = "The function %s is not defined in this script" |
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| 115 | raise exceptions.ScriptError(msg%funcname) |
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| 116 | return fn |
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