Support IPv6

[keisku]

Overview

This PR replaces manual socket creation with socket.create_connection() to support both IPv4 and IPv6 seamlessly, and updates the split_host_port() to support IPv6 address.

Motivation

IPv6 Support.

Previously, the code forced AF_INET for socket connections, making IPv6 usage either impossible or unreliable.

For example, empty response from client.stats().

python -c "import bmemcached; client = bmemcached.Client('2001:db8::2:11211', '', ''); print(client.stats())"
{'2001:db8::2:11211': {}}

By switching to socket.create_connection((self.host, self.port), self.socket_timeout), Python automatically selects the appropriate address family (IPv4 or IPv6).

Testing

Using docker-compose.

• https://docs.docker.com/engine/daemon/ipv6/
• https://docs.docker.com/compose/

services:
  memcached:
    container_name: memcached
    image: bitnami/memcached:latest
    environment:
    - MEMCACHED_LISTEN_ADDRESS=[::]
    ports:
      - "11211:11211"
    networks:
      - ip6net
networks:
  ip6net:
    enable_ipv6: true
    ipam:
      config:
        - subnet: 2001:db8::/64

docker inspect memcached | grep GlobalIPv6Address
            "GlobalIPv6Address": "",
                    "GlobalIPv6Address": "2001:db8::2",

Make a memcached client container image.

docker build --no-cache -t memcached-client --quiet -<<-EOD
FROM python:3.9
WORKDIR /src
RUN <<RUNEND
git clone --branch support-ipv6 --depth=1 https://github.com/keisku/python-binary-memcached.git
cd python-binary-memcached
pip install .
RUNEND
EOD

docker run --rm --network host memcached-client python -c "import bmemcached; client = bmemcached.Client('[2001:db8::2]', '', ''); print(client.stats()); client.disconnect_all()"
{'[2001:db8::2]': {'pid': b'1', 'uptime': b'61798', 'time': b'1736215951', 'version': b'1.6.34', 'libevent': b'2.1.12-stable', 'pointer_size': b'64', 'rusage_user': b'4.650069', 'rusage_system': b'1.189757', 'max_connections': b'1024', 'curr_connections': b'1', 'total_connections': b'7', 'rejected_connections': b'0', 'connection_structures': b'2', 'response_obj_oom': b'0', 'response_obj_count': b'1', 'response_obj_bytes': b'65536', 'read_buf_count': b'8', 'read_buf_bytes': b'131072', 'read_buf_bytes_free': b'49152', 'read_buf_oom': b'0', 'reserved_fds': b'20', 'cmd_get': b'0', 'cmd_set': b'0', 'cmd_flush': b'0', 'cmd_touch': b'0', 'cmd_meta': b'0', 'get_hits': b'0', 'get_misses': b'0', 'get_expired': b'0', 'get_flushed': b'0', 'delete_misses': b'0', 'delete_hits': b'0', 'incr_misses': b'0', 'incr_hits': b'0', 'decr_misses': b'0', 'decr_hits': b'0', 'cas_misses': b'0', 'cas_hits': b'0', 'cas_badval': b'0', 'touch_hits': b'0', 'touch_misses': b'0', 'store_too_large': b'0', 'store_no_memory': b'0', 'auth_cmds': b'0', 'auth_errors': b'0', 'bytes_read': b'144', 'bytes_written': b'18501', 'limit_maxbytes': b'67108864', 'accepting_conns': b'1', 'listen_disabled_num': b'0', 'time_in_listen_disabled_us': b'0', 'threads': b'4', 'conn_yields': b'0', 'hash_power_level': b'16', 'hash_bytes': b'524288', 'hash_is_expanding': b'0', 'slab_reassign_rescues': b'0', 'slab_reassign_chunk_rescues': b'0', 'slab_reassign_inline_reclaim': b'0', 'slab_reassign_busy_items': b'0', 'slab_reassign_busy_deletes': b'0', 'slab_reassign_busy_nomem': b'0', 'slab_reassign_running': b'0', 'slabs_moved': b'0', 'lru_crawler_running': b'0', 'lru_crawler_starts': b'45', 'lru_maintainer_juggles': b'61841', 'malloc_fails': b'0', 'log_worker_dropped': b'0', 'log_worker_written': b'0', 'log_watcher_skipped': b'0', 'log_watcher_sent': b'0', 'log_watchers': b'0', 'unexpected_napi_ids': b'0', 'round_robin_fallback': b'0', 'bytes': b'0', 'curr_items': b'0', 'total_items': b'0', 'slab_global_page_pool': b'0', 'expired_unfetched': b'0', 'evicted_unfetched': b'0', 'evicted_active': b'0', 'evictions': b'0', 'reclaimed': b'0', 'crawler_reclaimed': b'0', 'crawler_items_checked': b'0', 'lrutail_reflocked': b'0', 'moves_to_cold': b'0', 'moves_to_warm': b'0', 'moves_within_lru': b'0', 'direct_reclaims': b'0', 'lru_bumps_dropped': b'0'}}

docker run --rm --network host memcached-client python -c "import bmemcached; client = bmemcached.Client('[2001:db8::2]:11211', '', ''); print(client.stats()); client.disconnect_all()"
{'[2001:db8::2]:11211': {'pid': b'1', 'uptime': b'61811', 'time': b'1736215964', 'version': b'1.6.34', 'libevent': b'2.1.12-stable', 'pointer_size': b'64', 'rusage_user': b'4.651855', 'rusage_system': b'1.189757', 'max_connections': b'1024', 'curr_connections': b'1', 'total_connections': b'9', 'rejected_connections': b'0', 'connection_structures': b'2', 'response_obj_oom': b'0', 'response_obj_count': b'1', 'response_obj_bytes': b'65536', 'read_buf_count': b'8', 'read_buf_bytes': b'131072', 'read_buf_bytes_free': b'49152', 'read_buf_oom': b'0', 'reserved_fds': b'20', 'cmd_get': b'0', 'cmd_set': b'0', 'cmd_flush': b'0', 'cmd_touch': b'0', 'cmd_meta': b'0', 'get_hits': b'0', 'get_misses': b'0', 'get_expired': b'0', 'get_flushed': b'0', 'delete_misses': b'0', 'delete_hits': b'0', 'incr_misses': b'0', 'incr_hits': b'0', 'decr_misses': b'0', 'decr_hits': b'0', 'cas_misses': b'0', 'cas_hits': b'0', 'cas_badval': b'0', 'touch_hits': b'0', 'touch_misses': b'0', 'store_too_large': b'0', 'store_no_memory': b'0', 'auth_cmds': b'0', 'auth_errors': b'0', 'bytes_read': b'192', 'bytes_written': b'25911', 'limit_maxbytes': b'67108864', 'accepting_conns': b'1', 'listen_disabled_num': b'0', 'time_in_listen_disabled_us': b'0', 'threads': b'4', 'conn_yields': b'0', 'hash_power_level': b'16', 'hash_bytes': b'524288', 'hash_is_expanding': b'0', 'slab_reassign_rescues': b'0', 'slab_reassign_chunk_rescues': b'0', 'slab_reassign_inline_reclaim': b'0', 'slab_reassign_busy_items': b'0', 'slab_reassign_busy_deletes': b'0', 'slab_reassign_busy_nomem': b'0', 'slab_reassign_running': b'0', 'slabs_moved': b'0', 'lru_crawler_running': b'0', 'lru_crawler_starts': b'45', 'lru_maintainer_juggles': b'61855', 'malloc_fails': b'0', 'log_worker_dropped': b'0', 'log_worker_written': b'0', 'log_watcher_skipped': b'0', 'log_watcher_sent': b'0', 'log_watchers': b'0', 'unexpected_napi_ids': b'0', 'round_robin_fallback': b'0', 'bytes': b'0', 'curr_items': b'0', 'total_items': b'0', 'slab_global_page_pool': b'0', 'expired_unfetched': b'0', 'evicted_unfetched': b'0', 'evicted_active': b'0', 'evictions': b'0', 'reclaimed': b'0', 'crawler_reclaimed': b'0', 'crawler_items_checked': b'0', 'lrutail_reflocked': b'0', 'moves_to_cold': b'0', 'moves_to_warm': b'0', 'moves_within_lru': b'0', 'direct_reclaims': b'0', 'lru_bumps_dropped': b'0'}}

# Without brackets.
docker run --rm --network host memcached-client python -c "import bmemcached; client = bmemcached.Client('2001:db8::2', '', ''); print(client.stats()); client.disconnect_all()"
{'2001:db8::2': {'pid': b'1', 'uptime': b'61801', 'time': b'1736215954', 'version': b'1.6.34', 'libevent': b'2.1.12-stable', 'pointer_size': b'64', 'rusage_user': b'4.650573', 'rusage_system': b'1.189757', 'max_connections': b'1024', 'curr_connections': b'1', 'total_connections': b'8', 'rejected_connections': b'0', 'connection_structures': b'2', 'response_obj_oom': b'0', 'response_obj_count': b'1', 'response_obj_bytes': b'65536', 'read_buf_count': b'8', 'read_buf_bytes': b'131072', 'read_buf_bytes_free': b'49152', 'read_buf_oom': b'0', 'reserved_fds': b'20', 'cmd_get': b'0', 'cmd_set': b'0', 'cmd_flush': b'0', 'cmd_touch': b'0', 'cmd_meta': b'0', 'get_hits': b'0', 'get_misses': b'0', 'get_expired': b'0', 'get_flushed': b'0', 'delete_misses': b'0', 'delete_hits': b'0', 'incr_misses': b'0', 'incr_hits': b'0', 'decr_misses': b'0', 'decr_hits': b'0', 'cas_misses': b'0', 'cas_hits': b'0', 'cas_badval': b'0', 'touch_hits': b'0', 'touch_misses': b'0', 'store_too_large': b'0', 'store_no_memory': b'0', 'auth_cmds': b'0', 'auth_errors': b'0', 'bytes_read': b'168', 'bytes_written': b'22206', 'limit_maxbytes': b'67108864', 'accepting_conns': b'1', 'listen_disabled_num': b'0', 'time_in_listen_disabled_us': b'0', 'threads': b'4', 'conn_yields': b'0', 'hash_power_level': b'16', 'hash_bytes': b'524288', 'hash_is_expanding': b'0', 'slab_reassign_rescues': b'0', 'slab_reassign_chunk_rescues': b'0', 'slab_reassign_inline_reclaim': b'0', 'slab_reassign_busy_items': b'0', 'slab_reassign_busy_deletes': b'0', 'slab_reassign_busy_nomem': b'0', 'slab_reassign_running': b'0', 'slabs_moved': b'0', 'lru_crawler_running': b'0', 'lru_crawler_starts': b'45', 'lru_maintainer_juggles': b'61844', 'malloc_fails': b'0', 'log_worker_dropped': b'0', 'log_worker_written': b'0', 'log_watcher_skipped': b'0', 'log_watcher_sent': b'0', 'log_watchers': b'0', 'unexpected_napi_ids': b'0', 'round_robin_fallback': b'0', 'bytes': b'0', 'curr_items': b'0', 'total_items': b'0', 'slab_global_page_pool': b'0', 'expired_unfetched': b'0', 'evicted_unfetched': b'0', 'evicted_active': b'0', 'evictions': b'0', 'reclaimed': b'0', 'crawler_reclaimed': b'0', 'crawler_items_checked': b'0', 'lrutail_reflocked': b'0', 'moves_to_cold': b'0', 'moves_to_warm': b'0', 'moves_within_lru': b'0', 'direct_reclaims': b'0', 'lru_bumps_dropped': b'0'}}

Regression tests

services:
  memcached:
    container_name: memcached
    image: bitnami/memcached:latest

docker inspect memcached | grep IPAddress
            "SecondaryIPAddresses": null,
            "IPAddress": "",
                    "IPAddress": "172.20.0.2",

docker run --rm --network host memcached-client python -c "import bmemcached; client = bmemcached.Client('172.20.0.2:11211', '', ''); print(client.stats()); client.disconnect_all()"
{'172.20.0.2:11211': {'pid': b'1', 'uptime': b'29', 'time': b'1736216159', 'version': b'1.6.34', 'libevent': b'2.1.12-stable', 'pointer_size': b'64', 'rusage_user': b'0.036675', 'rusage_system': b'0.017052', 'max_connections': b'1024', 'curr_connections': b'2', 'total_connections': b'3', 'rejected_connections': b'0', 'connection_structures': b'3', 'response_obj_oom': b'0', 'response_obj_count': b'1', 'response_obj_bytes': b'16384', 'read_buf_count': b'2', 'read_buf_bytes': b'32768', 'read_buf_bytes_free': b'0', 'read_buf_oom': b'0', 'reserved_fds': b'20', 'cmd_get': b'0', 'cmd_set': b'0', 'cmd_flush': b'0', 'cmd_touch': b'0', 'cmd_meta': b'0', 'get_hits': b'0', 'get_misses': b'0', 'get_expired': b'0', 'get_flushed': b'0', 'delete_misses': b'0', 'delete_hits': b'0', 'incr_misses': b'0', 'incr_hits': b'0', 'decr_misses': b'0', 'decr_hits': b'0', 'cas_misses': b'0', 'cas_hits': b'0', 'cas_badval': b'0', 'touch_hits': b'0', 'touch_misses': b'0', 'store_too_large': b'0', 'store_no_memory': b'0', 'auth_cmds': b'0', 'auth_errors': b'0', 'bytes_read': b'24', 'bytes_written': b'0', 'limit_maxbytes': b'67108864', 'accepting_conns': b'1', 'listen_disabled_num': b'0', 'time_in_listen_disabled_us': b'0', 'threads': b'4', 'conn_yields': b'0', 'hash_power_level': b'16', 'hash_bytes': b'524288', 'hash_is_expanding': b'0', 'slab_reassign_rescues': b'0', 'slab_reassign_chunk_rescues': b'0', 'slab_reassign_inline_reclaim': b'0', 'slab_reassign_busy_items': b'0', 'slab_reassign_busy_deletes': b'0', 'slab_reassign_busy_nomem': b'0', 'slab_reassign_running': b'0', 'slabs_moved': b'0', 'lru_crawler_running': b'0', 'lru_crawler_starts': b'1', 'lru_maintainer_juggles': b'79', 'malloc_fails': b'0', 'log_worker_dropped': b'0', 'log_worker_written': b'0', 'log_watcher_skipped': b'0', 'log_watcher_sent': b'0', 'log_watchers': b'0', 'unexpected_napi_ids': b'0', 'round_robin_fallback': b'0', 'bytes': b'0', 'curr_items': b'0', 'total_items': b'0', 'slab_global_page_pool': b'0', 'expired_unfetched': b'0', 'evicted_unfetched': b'0', 'evicted_active': b'0', 'evictions': b'0', 'reclaimed': b'0', 'crawler_reclaimed': b'0', 'crawler_items_checked': b'0', 'lrutail_reflocked': b'0', 'moves_to_cold': b'0', 'moves_to_warm': b'0', 'moves_within_lru': b'0', 'direct_reclaims': b'0', 'lru_bumps_dropped': b'0'}}

docker run --rm --network host memcached-client python -c "import bmemcached; client = bmemcached.Client('172.20.0.2', '', ''); print(client.stats()); client.disconnect_all()"
{'172.20.0.2': {'pid': b'1', 'uptime': b'35', 'time': b'1736216165', 'version': b'1.6.34', 'libevent': b'2.1.12-stable', 'pointer_size': b'64', 'rusage_user': b'0.037426', 'rusage_system': b'0.017109', 'max_connections': b'1024', 'curr_connections': b'2', 'total_connections': b'4', 'rejected_connections': b'0', 'connection_structures': b'3', 'response_obj_oom': b'0', 'response_obj_count': b'1', 'response_obj_bytes': b'32768', 'read_buf_count': b'4', 'read_buf_bytes': b'65536', 'read_buf_bytes_free': b'16384', 'read_buf_oom': b'0', 'reserved_fds': b'20', 'cmd_get': b'0', 'cmd_set': b'0', 'cmd_flush': b'0', 'cmd_touch': b'0', 'cmd_meta': b'0', 'get_hits': b'0', 'get_misses': b'0', 'get_expired': b'0', 'get_flushed': b'0', 'delete_misses': b'0', 'delete_hits': b'0', 'incr_misses': b'0', 'incr_hits': b'0', 'decr_misses': b'0', 'decr_hits': b'0', 'cas_misses': b'0', 'cas_hits': b'0', 'cas_badval': b'0', 'touch_hits': b'0', 'touch_misses': b'0', 'store_too_large': b'0', 'store_no_memory': b'0', 'auth_cmds': b'0', 'auth_errors': b'0', 'bytes_read': b'48', 'bytes_written': b'3688', 'limit_maxbytes': b'67108864', 'accepting_conns': b'1', 'listen_disabled_num': b'0', 'time_in_listen_disabled_us': b'0', 'threads': b'4', 'conn_yields': b'0', 'hash_power_level': b'16', 'hash_bytes': b'524288', 'hash_is_expanding': b'0', 'slab_reassign_rescues': b'0', 'slab_reassign_chunk_rescues': b'0', 'slab_reassign_inline_reclaim': b'0', 'slab_reassign_busy_items': b'0', 'slab_reassign_busy_deletes': b'0', 'slab_reassign_busy_nomem': b'0', 'slab_reassign_running': b'0', 'slabs_moved': b'0', 'lru_crawler_running': b'0', 'lru_crawler_starts': b'1', 'lru_maintainer_juggles': b'84', 'malloc_fails': b'0', 'log_worker_dropped': b'0', 'log_worker_written': b'0', 'log_watcher_skipped': b'0', 'log_watcher_sent': b'0', 'log_watchers': b'0', 'unexpected_napi_ids': b'0', 'round_robin_fallback': b'0', 'bytes': b'0', 'curr_items': b'0', 'total_items': b'0', 'slab_global_page_pool': b'0', 'expired_unfetched': b'0', 'evicted_unfetched': b'0', 'evicted_active': b'0', 'evictions': b'0', 'reclaimed': b'0', 'crawler_reclaimed': b'0', 'crawler_items_checked': b'0', 'lrutail_reflocked': b'0', 'moves_to_cold': b'0', 'moves_to_warm': b'0', 'moves_within_lru': b'0', 'direct_reclaims': b'0', 'lru_bumps_dropped': b'0'}}

[jaysonsantos]

Let me just check with someone if it is ok to drop support for python2 and I'll review your pr, thanks for that!

[jaysonsantos]

Thank you so much for the help @keisku !