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authorMike Bayer <mike_mp@zzzcomputing.com>2017-05-22 14:08:55 -0400
committerMike Bayer <mike_mp@zzzcomputing.com>2017-05-22 15:51:07 -0400
commit9f0fb6c601829cb7c9f449d57e12e8b95dab51f5 (patch)
tree1201e89aa89fac39316ccfa87567a88b9667fa4c
parentda1bc9878b71f6f7b87e2fa7895e1631ae581609 (diff)
downloadsqlalchemy-9f0fb6c601829cb7c9f449d57e12e8b95dab51f5.tar.gz
Allow metadata.reflect() to recover from unreflectable tables
Added support for views that are unreflectable due to stale table definitions, when calling :meth:`.MetaData.reflect`; a warning is emitted for the table that cannot respond to ``DESCRIBE`` but the operation succeeds. The MySQL dialect now raises UnreflectableTableError which is in turn caught by MetaData.reflect(). Reflecting the view standalone raises this error directly. Change-Id: Id8005219d8e073c154cc84a873df911b4a6cf4d6 Fixes: #3871
-rw-r--r--doc/build/changelog/changelog_12.rst9
-rw-r--r--lib/sqlalchemy/dialects/mysql/base.py9
-rw-r--r--lib/sqlalchemy/exc.py8
-rw-r--r--lib/sqlalchemy/sql/schema.py5
-rw-r--r--lib/sqlalchemy/testing/assertions.py15
-rw-r--r--test/dialect/mysql/test_reflection.py31
-rw-r--r--test/engine/test_reflection.py31
7 files changed, 101 insertions, 7 deletions
diff --git a/doc/build/changelog/changelog_12.rst b/doc/build/changelog/changelog_12.rst
index 0f7b7b9af..a96436aaf 100644
--- a/doc/build/changelog/changelog_12.rst
+++ b/doc/build/changelog/changelog_12.rst
@@ -25,6 +25,15 @@
:ref:`change_3796`
+ .. change:: 3871
+ :tags: bug, mysql
+ :tickets: 3871
+
+ Added support for views that are unreflectable due to stale
+ table definitions, when calling :meth:`.MetaData.reflect`; a warning
+ is emitted for the table that cannot respond to ``DESCRIBE``,
+ but the operation succeeds.
+
.. change:: baked_opts
:tags: feature, ext
diff --git a/lib/sqlalchemy/dialects/mysql/base.py b/lib/sqlalchemy/dialects/mysql/base.py
index 21d325d0c..277ae5815 100644
--- a/lib/sqlalchemy/dialects/mysql/base.py
+++ b/lib/sqlalchemy/dialects/mysql/base.py
@@ -2052,8 +2052,14 @@ class MySQLDialect(default.DefaultDialect):
rp = connection.execution_options(
skip_user_error_events=True).execute(st)
except exc.DBAPIError as e:
- if self._extract_error_code(e.orig) == 1146:
+ code = self._extract_error_code(e.orig)
+ if code == 1146:
raise exc.NoSuchTableError(full_name)
+ elif code == 1356:
+ raise exc.UnreflectableTableError(
+ "Table or view named %s could not be "
+ "reflected: %s" % (full_name, e)
+ )
else:
raise
rows = self._compat_fetchall(rp, charset=charset)
@@ -2063,7 +2069,6 @@ class MySQLDialect(default.DefaultDialect):
return rows
-
class _DecodingRowProxy(object):
"""Return unicode-decoded values based on type inspection.
diff --git a/lib/sqlalchemy/exc.py b/lib/sqlalchemy/exc.py
index e8ba34ba4..3db3c1085 100644
--- a/lib/sqlalchemy/exc.py
+++ b/lib/sqlalchemy/exc.py
@@ -199,6 +199,14 @@ class NoSuchTableError(InvalidRequestError):
"""Table does not exist or is not visible to a connection."""
+class UnreflectableTableError(InvalidRequestError):
+ """Table exists but can't be reflectted for some reason.
+
+ .. versionadded:: 1.2
+
+ """
+
+
class UnboundExecutionError(InvalidRequestError):
"""SQL was attempted without a database connection to execute it on."""
diff --git a/lib/sqlalchemy/sql/schema.py b/lib/sqlalchemy/sql/schema.py
index 1cdc7b425..a9aee5883 100644
--- a/lib/sqlalchemy/sql/schema.py
+++ b/lib/sqlalchemy/sql/schema.py
@@ -3903,7 +3903,10 @@ class MetaData(SchemaItem):
name not in current]
for name in load:
- Table(name, self, **reflect_opts)
+ try:
+ Table(name, self, **reflect_opts)
+ except exc.UnreflectableTableError as uerr:
+ util.warn("Skipping table %s: %s" % (name, uerr))
def append_ddl_listener(self, event_name, listener):
"""Append a DDL event listener to this ``MetaData``.
diff --git a/lib/sqlalchemy/testing/assertions.py b/lib/sqlalchemy/testing/assertions.py
index 884556345..dfea33dc7 100644
--- a/lib/sqlalchemy/testing/assertions.py
+++ b/lib/sqlalchemy/testing/assertions.py
@@ -130,9 +130,16 @@ def _expect_warnings(exc_cls, messages, regex=True, assert_=True,
real_warn = warnings.warn
- def our_warn(msg, exception, *arg, **kw):
- if not issubclass(exception, exc_cls):
- return real_warn(msg, exception, *arg, **kw)
+ def our_warn(msg, *arg, **kw):
+ if isinstance(msg, exc_cls):
+ exception = msg
+ msg = str(exception)
+ elif arg:
+ exception = arg[0]
+ else:
+ exception = None
+ if not exception or not issubclass(exception, exc_cls):
+ return real_warn(msg, *arg, **kw)
if not filters:
return
@@ -143,7 +150,7 @@ def _expect_warnings(exc_cls, messages, regex=True, assert_=True,
seen.discard(filter_)
break
else:
- real_warn(msg, exception, *arg, **kw)
+ real_warn(msg, *arg, **kw)
with mock.patch("warnings.warn", our_warn):
yield
diff --git a/test/dialect/mysql/test_reflection.py b/test/dialect/mysql/test_reflection.py
index 9e122e680..dc088223d 100644
--- a/test/dialect/mysql/test_reflection.py
+++ b/test/dialect/mysql/test_reflection.py
@@ -7,11 +7,13 @@ from sqlalchemy import Column, Table, DDL, MetaData, TIMESTAMP, \
BigInteger
from sqlalchemy import event
from sqlalchemy import sql
+from sqlalchemy import exc
from sqlalchemy import inspect
from sqlalchemy.dialects.mysql import base as mysql
from sqlalchemy.dialects.mysql import reflection as _reflection
from sqlalchemy.testing import fixtures, AssertsExecutionResults
from sqlalchemy import testing
+from sqlalchemy.testing import assert_raises_message, expect_warnings
class TypeReflectionTest(fixtures.TestBase):
@@ -430,6 +432,35 @@ class ReflectionTest(fixtures.TestBase, AssertsExecutionResults):
[('a', mysql.INTEGER), ('b', mysql.VARCHAR)]
)
+ @testing.provide_metadata
+ def test_skip_not_describable(self):
+ @event.listens_for(self.metadata, "before_drop")
+ def cleanup(*arg, **kw):
+ with testing.db.connect() as conn:
+ conn.execute("DROP TABLE IF EXISTS test_t1")
+ conn.execute("DROP TABLE IF EXISTS test_t2")
+ conn.execute("DROP VIEW IF EXISTS test_v")
+
+ with testing.db.connect() as conn:
+ conn.execute("CREATE TABLE test_t1 (id INTEGER)")
+ conn.execute("CREATE TABLE test_t2 (id INTEGER)")
+ conn.execute("CREATE VIEW test_v AS SELECT id FROM test_t1" )
+ conn.execute("DROP TABLE test_t1")
+
+ m = MetaData()
+ with expect_warnings(
+ "Skipping .* Table or view named .?test_v.? could not be "
+ "reflected: .* references invalid table"
+ ):
+ m.reflect(views=True, bind=conn)
+ eq_(m.tables['test_t2'].name, "test_t2")
+
+ assert_raises_message(
+ exc.UnreflectableTableError,
+ "references invalid table",
+ Table, 'test_v', MetaData(), autoload_with=conn
+ )
+
@testing.exclude('mysql', '<', (5, 0, 0), 'no information_schema support')
def test_system_views(self):
dialect = testing.db.dialect
diff --git a/test/engine/test_reflection.py b/test/engine/test_reflection.py
index 9616c300d..80a804796 100644
--- a/test/engine/test_reflection.py
+++ b/test/engine/test_reflection.py
@@ -12,6 +12,8 @@ from sqlalchemy.testing import eq_, is_true, assert_raises, \
from sqlalchemy import testing
from sqlalchemy.util import ue
from sqlalchemy.testing import config
+from sqlalchemy.testing import mock
+from sqlalchemy.testing import expect_warnings
metadata, users = None, None
@@ -972,6 +974,35 @@ class ReflectionTest(fixtures.TestBase, ComparesTables):
m9.reflect()
self.assert_(not m9.tables)
+ @testing.provide_metadata
+ def test_reflect_all_unreflectable_table(self):
+ names = ['rt_%s' % name for name in ('a', 'b', 'c', 'd', 'e')]
+
+ for name in names:
+ Table(name, self.metadata,
+ Column('id', sa.Integer, primary_key=True))
+ self.metadata.create_all()
+
+ m = MetaData()
+
+ reflecttable = testing.db.dialect.reflecttable
+
+ def patched(conn, table, *arg, **kw):
+ if table.name == 'rt_c':
+ raise sa.exc.UnreflectableTableError("Can't reflect rt_c")
+ else:
+ return reflecttable(conn, table, *arg, **kw)
+
+ with mock.patch.object(testing.db.dialect, "reflecttable", patched):
+ with expect_warnings("Skipping table rt_c: Can't reflect rt_c"):
+ m.reflect(bind=testing.db)
+
+ assert_raises_message(
+ sa.exc.UnreflectableTableError,
+ "Can't reflect rt_c",
+ Table, 'rt_c', m, autoload_with=testing.db
+ )
+
def test_reflect_all_conn_closing(self):
m1 = MetaData()
c = testing.db.connect()