I would check the connection is going to the right server/database as well?
But past that, I can't help you - I'd try doing some things with plain
aioredis to see if you can replicate it there.
Andrew
On Fri, Mar 23, 2018 at 9:01 AM, 'Alex' via Django users <
django-users@googlegroups.com> wrote:
> Hi,
>
> I've used the redis-cli to get the contents of the key, and it has filled
> it properly, so the information is definitely in redis under that key. The
> issue seems to be that message = await connection.get(pers_key) always
> returns none. One thing I'm certain of is that it's in redis!
>
> Alex
>
> On Friday, 23 March 2018 15:58:37 UTC, Andrew Godwin wrote:
>>
>> It looks correct at first glance - I would insert a debugger there and
>> see what the Redis database contained manually at that point.
>>
>> Andrew
>>
>> On Fri, Mar 23, 2018 at 2:56 AM, 'Alex' via Django users <
>> django...@googlegroups.com> wrote:
>>
>>> I've been trying to add persistence to channel layers, such that each
>>> new consumer joining a group is sent the most recent message from that
>>> group, on connect. Below are my attempts. For some reason, the message in
>>> the highlighted line always seems to be of type 'None'. Am I going about
>>> this completely incorrectly? I'd be really grateful for any help.
>>>
>>>
>>> from channels_redis.core import RedisChannelLayer
>>> from channels.exceptions import ChannelFull
>>> import time
>>>
>>>
>>> class RedisChannelLayerGroupPersistence(RedisChannelLayer):
>>>
>>>
>>>
>>>
>>> async def group_send(self, group, message):
>>> """
>>> Sends a message to the entire group.
>>> """
>>> assert self.valid_group_name(group), "Group name not valid"
>>> # Retrieve list of all channel names
>>> key = self._group_key(group)
>>> pers_key = str(key) + "_PERS"
>>> async with self.connection(self.consistent_hash(group)) as
>>> connection:
>>> # Discard old channels based on group_expiry
>>> await connection.zremrangebyscore(key, min=0, max=int(time.
>>> time()) - self.group_expiry)
>>> # Return current lot
>>> channel_names = [
>>> x.decode("utf8") for x in
>>> await connection.zrange(key, 0, -1)
>>> ]
>>> # TODO: More efficient implementation (lua script per shard?)
>>> try:
>>> await connection.persist(pers_key)
>>> await connection.set(pers_key, str(message))
>>> print("TYPE = ================================================
>>> {}".format(type(str(message))))
>>>
>>>
>>> for channel in channel_names:
>>> try:
>>> await self.send(channel, message)
>>> except ChannelFull:
>>> pass
>>>
>>>
>>> async def group_add(self, group, channel):
>>>
>>>
>>> """
>>> Adds the channel name to a group.
>>> """
>>> # Check the inputs
>>> assert self.valid_group_name(group), "Group name not valid"
>>> assert self.valid_channel_name(channel), "Channel name not
>>> valid"
>>> # Get a connection to the right shard
>>> group_key = self._group_key(group)
>>> pers_key = str(group_key) + "_PERS"
>>> async with self.connection(self.consistent_hash(group)) as
>>> connection:
>>> message = await connection.get(pers_key) #ISSUE HERE
>>> ------------------ MESSAGE IS NONE
>>> # Add to group sorted set with creation time as timestamp
>>> await connection.zadd(
>>> group_key,
>>> time.time(),
>>> channel,
>>> )
>>> # Set expiration to be group_expiry, since everything in
>>> # it at this point is guaranteed to expire before that
>>> try:
>>> await self.send(channel, str(message))
>>> except ChannelFull:
>>> pass
>>>
>>>
>>>
>>>
>>> await connection.expire(group_key, self.group_expiry)
>>>
>>>
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