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Replace stop_replication with requirement for an exception.

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This commit is contained in:
Oleksandr Shulgin 2015-10-19 15:42:42 +02:00
parent 0435320f34
commit 4ab7cf0157
6 changed files with 51 additions and 51 deletions
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18
doc/src/extras.rst
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@ -348,9 +348,11 @@ The individual messages in the replication stream are presented by
`start_replication()` first.
When called, this method enters an endless loop, reading messages from
the server and passing them to ``consume()``. In order to make this
method break out of the loop and return, ``consume()`` can call
`stop_replication()` on the cursor or it can throw an exception.
the server and passing them to ``consume()``, then waiting for more
messages from the server. In order to make this method break out of
the loop and return, ``consume()`` can throw a `StopReplication`
exception (any unhandled exception will make it break out of the loop
as well).
If *decode* is set to `!True`, the messages read from the server are
converted according to the connection `~connection.encoding`. This
@ -398,13 +400,6 @@ The individual messages in the replication stream are presented by
load on network and the server. A possible strategy is to confirm
after every COMMIT message.
.. method:: stop_replication()
This method can be called on synchronous connection from the
``consume()`` callable in order to break out of the endless loop in
`consume_replication_stream()`. If called on asynchronous connection
or when replication is not in progress, this method raises an error.
.. method:: send_replication_feedback(write_lsn=0, flush_lsn=0, apply_lsn=0, reply=False)
:param write_lsn: a LSN position up to which the client has written the data locally
@ -506,10 +501,11 @@ The individual messages in the replication stream are presented by
if not sel[0]:
cur.send_replication_feedback()
.. index::
pair: Cursor; Replication
.. autoclass:: StopReplication
.. index::
single: Data types; Additional

12
lib/extras.py
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@ -500,6 +500,18 @@ class PhysicalReplicationConnection(ReplicationConnectionBase):
super(PhysicalReplicationConnection, self).__init__(*args, **kwargs)
class StopReplication(Exception):
"""
Exception used to break out of the endless loop in
`~ReplicationCursor.consume_replication_stream()`.
Subclass of `~exceptions.Exception`. Intentionally *not* inherited from
`~psycopg2.Error` as occurrence of this exception does not indicate an
error.
"""
pass
class ReplicationCursor(_cursor):
"""A cursor used for communication on the replication protocol."""

1
psycopg/cursor.h
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@ -75,7 +75,6 @@ struct cursorObject {
/* replication cursor attrs */
int repl_started:1; /* if replication is started */
int repl_stop:1; /* if client requested to stop replication */
int repl_consuming:1; /* if running the consume loop */
struct timeval repl_keepalive_interval; /* interval for keepalive messages in replication mode */
XLogRecPtr repl_write_lsn; /* LSN stats for replication feedback messages */

19
psycopg/cursor_type.c
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@ -1605,7 +1605,6 @@ psyco_curs_start_replication_expert(cursorObject *self, PyObject *args, PyObject
Dprintf("psyco_curs_start_replication_expert: %s", command);
self->copysize = 0;
self->repl_stop = 0;
self->repl_consuming = 0;
self->repl_write_lsn = InvalidXLogRecPtr;
@ -1626,21 +1625,6 @@ psyco_curs_start_replication_expert(cursorObject *self, PyObject *args, PyObject
return res;
}
#define psyco_curs_stop_replication_doc \
"stop_replication() -- Set flag to break out of the endless loop in consume_replication_stream()."
static PyObject *
psyco_curs_stop_replication(cursorObject *self)
{
EXC_IF_CURS_CLOSED(self);
EXC_IF_CURS_ASYNC(self, stop_replication);
EXC_IF_NOT_REPLICATING(self, stop_replication);
self->repl_stop = 1;
Py_RETURN_NONE;
}
#define psyco_curs_consume_replication_stream_doc \
"consume_replication_stream(consumer, keepalive_interval=10) -- Consume replication stream."
@ -1684,7 +1668,6 @@ psyco_curs_consume_replication_stream(cursorObject *self, PyObject *args, PyObje
}
self->repl_consuming = 0;
self->repl_stop = 0; /* who knows, what if we will be called again? */
return res;
}
@ -1992,8 +1975,6 @@ static struct PyMethodDef cursorObject_methods[] = {
METH_VARARGS|METH_KEYWORDS, psyco_curs_copy_expert_doc},
{"start_replication_expert", (PyCFunction)psyco_curs_start_replication_expert,
METH_VARARGS|METH_KEYWORDS, psyco_curs_start_replication_expert_doc},
{"stop_replication", (PyCFunction)psyco_curs_stop_replication,
METH_NOARGS, psyco_curs_stop_replication_doc},
{"consume_replication_stream", (PyCFunction)psyco_curs_consume_replication_stream,
METH_VARARGS|METH_KEYWORDS, psyco_curs_consume_replication_stream_doc},
{"read_replication_message", (PyCFunction)psyco_curs_read_replication_message,

7
psycopg/pqpath.c
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@ -1743,7 +1743,7 @@ pq_copy_both(cursorObject *curs, PyObject *consume, int decode, double keepalive
keep_intr.tv_sec = (int)keepalive_interval;
keep_intr.tv_usec = (keepalive_interval - keep_intr.tv_sec)*1.0e6;
while (!curs->repl_stop) {
while (1) {
msg = pq_read_replication_message(curs, decode);
if (!msg) {
goto exit;
@ -1803,11 +1803,6 @@ pq_copy_both(cursorObject *curs, PyObject *consume, int decode, double keepalive
goto exit;
}
Py_DECREF(tmp);
if (curs->repl_stop) {
Dprintf("pq_copy_both: repl_stop flag set by consume_func");
break;
}
}
}

45
tests/test_replication.py
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@ -25,6 +25,7 @@
import psycopg2
import psycopg2.extensions
from psycopg2.extras import PhysicalReplicationConnection, LogicalReplicationConnection
from psycopg2.extras import StopReplication
from testutils import unittest
from testutils import skip_before_postgres
@ -77,20 +78,6 @@ class ReplicationTest(ReplicationTestCase):
cur.execute("IDENTIFY_SYSTEM")
cur.fetchall()
@skip_before_postgres(9, 0)
def test_stop_replication_raises(self):
conn = self.repl_connect(connection_factory=PhysicalReplicationConnection)
if conn is None: return
cur = conn.cursor()
self.assertRaises(psycopg2.ProgrammingError, cur.stop_replication)
cur.start_replication()
cur.stop_replication() # doesn't raise now
def consume(msg):
pass
cur.consume_replication_stream(consume) # should return at once
@skip_before_postgres(9, 4) # slots require 9.4
def test_create_replication_slot(self):
conn = self.repl_connect(connection_factory=PhysicalReplicationConnection)
@ -115,6 +102,36 @@ class ReplicationTest(ReplicationTestCase):
self.create_replication_slot(cur, slot)
cur.start_replication(slot)
@skip_before_postgres(9, 4) # slots require 9.4
def test_stop_replication(self):
conn = self.repl_connect(connection_factory=LogicalReplicationConnection)
if conn is None: return
cur = conn.cursor()
slot = "test_slot1"
self.create_replication_slot(cur, slot, output_plugin='test_decoding')
self.make_replication_event()
cur.start_replication(slot)
def consume(msg):
raise StopReplication()
self.assertRaises(StopReplication, cur.consume_replication_stream, consume)
# generate an event for our replication stream
def make_replication_event(self):
conn = self.connect()
if conn is None: return
cur = conn.cursor()
try:
cur.execute("DROP TABLE dummy1")
except psycopg2.ProgrammingError:
conn.rollback()
cur.execute("CREATE TABLE dummy1()")
conn.commit()
class AsyncReplicationTest(ReplicationTestCase):
@skip_before_postgres(9, 4)