channnels -- communication with redis

Yuval Bachrach

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Jan 15, 2019, 4:32:23 PM1/15/19

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I fail to have django channels communication with redis running at docker container: I am running the channels tutorial and I get an error when just following the tutorial instructions.

I am quite new with Django (designed a simple site) and have no knowledge on redis nor docker

I am trying to lean channels using the tutorial: https://channels.readthedocs.io/en/latest/tutorial/

It uses redis over docker

At tutorial part 2 there is a test for “channel layer can communicate with Redis”.

I fails this test. I was looking over the web for solving this communication problem with no luck.

As I am not familiar with redis nor docker, I have hard time analyzing the reasons for the communication problems. I can see that redis is running inside a docker container.

$ docker ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS

NAMES

2bdabc272ec3 redis "docker-entrypoint.s…" About an hour ago Up About an hour 0.0.0.0:6379->6379/tcp

quizzical_panini

$ docker inspect quizzical_panini > redisimage.log

(YB: will paste the logfile at the end of this message)

python manage.py shell

import channels.layers

channel_layer = channels.layers.get_channel_layer()

from asgiref.sync import async_to_sync

async_to_sync(channel_layer.send)('test_channel', {'type': 'hello'})

Error begins with:

In [4]: async_to_sync(channel_layer.send)('test_channel', {'type': 'hello'})

---------------------------------------------------------------------------

ConnectionRefusedError Traceback (most recent call last)

<ipython-input-4-80e65666e9e2> in <module>

----> 1 async_to_sync(channel_layer.send)('test_channel', {'type': 'hello'})

A lot of other details. Ends up with:

504 # Jump to any except clause below.

--> 505 raise OSError(err, f'Connect call failed {address}')

506 except (BlockingIOError, InterruptedError):

507 # socket is still registered, the callback will be retried later

ConnectionRefusedError: [Errno 10061] Connect call failed ('127.0.0.1', 6379)

Some version details:

installing shell command:

$ docker run redis --version

Redis server v=5.0.3 sha=00000000:0 malloc=jemalloc-5.1.0 bits=64 build=9f27eb593282148b

$ pip install channels_redis

A lot of details: ends up with:

> Successfully installed channels-redis-2.3.3

$ python --version

Python 3.7.1

(note that it is a 32 bit python while docker requires 64 bits. I assumed it should not be the reason for the problems I do experience

>>>>>>>> redisimage.log generated by docker inspect as shown above <<<<<<

>>>>>>>> It is long. I can’t tell id/what is relevant

[

{

"Id": "2bdabc272ec364e6b34a40e253d089e48b73d55cddcade1d51b70c202aad6479",

"Created": "2019-01-15T14:02:36.679774957Z",

"Path": "docker-entrypoint.sh",

"Args": [

"redis-server"

],

"State": {

"Status": "running",

"Running": true,

"Paused": false,

"Restarting": false,

"OOMKilled": false,

"Dead": false,

"Pid": 8731,

"ExitCode": 0,

"Error": "",

"StartedAt": "2019-01-15T14:02:37.086931139Z",

"FinishedAt": "0001-01-01T00:00:00Z"

},

"Image": "sha256:5d2989ac9711b6c7a96dfca3110041d6259294f5ccd343491ecfffe3d14757cc",

"ResolvConfPath": "/mnt/sda1/var/lib/docker/containers/2bdabc272ec364e6b34a40e253d089e48b73d55cddcade1d51b70c202aad6479/resolv.conf",

"HostnamePath": "/mnt/sda1/var/lib/docker/containers/2bdabc272ec364e6b34a40e253d089e48b73d55cddcade1d51b70c202aad6479/hostname",

"HostsPath": "/mnt/sda1/var/lib/docker/containers/2bdabc272ec364e6b34a40e253d089e48b73d55cddcade1d51b70c202aad6479/hosts",

"LogPath": "/mnt/sda1/var/lib/docker/containers/2bdabc272ec364e6b34a40e253d089e48b73d55cddcade1d51b70c202aad6479/2bdabc272ec364e6b34a40e253d089e48b73d55cddcade1d51b70c202aad6479-json.log",

"Name": "/quizzical_panini",

"RestartCount": 0,

"Driver": "overlay2",

"Platform": "linux",

"MountLabel": "",

"ProcessLabel": "",

"AppArmorProfile": "",

"ExecIDs": null,

"HostConfig": {

"Binds": null,

"ContainerIDFile": "",

"LogConfig": {

"Type": "json-file",

"Config": {}

},

"NetworkMode": "default",

"PortBindings": {

"6379/tcp": [

{

"HostIp": "",

"HostPort": "6379"

}

]

},

"RestartPolicy": {

"Name": "no",

"MaximumRetryCount": 0

},

"AutoRemove": false,

"VolumeDriver": "",

"VolumesFrom": null,

"CapAdd": null,

"CapDrop": null,

"Dns": [],

"DnsOptions": [],

"DnsSearch": [],

"ExtraHosts": null,

"GroupAdd": null,

"IpcMode": "shareable",

"Cgroup": "",

"Links": null,

"OomScoreAdj": 0,

"PidMode": "",

"Privileged": false,

"PublishAllPorts": false,

"ReadonlyRootfs": false,

"SecurityOpt": null,

"UTSMode": "",

"UsernsMode": "",

"ShmSize": 67108864,

"Runtime": "runc",

"ConsoleSize": [

30,

129

],

"Isolation": "",

"CpuShares": 0,

"Memory": 0,

"NanoCpus": 0,

"CgroupParent": "",

"BlkioWeight": 0,

"BlkioWeightDevice": [],

"BlkioDeviceReadBps": null,

"BlkioDeviceWriteBps": null,

"BlkioDeviceReadIOps": null,

"BlkioDeviceWriteIOps": null,

"CpuPeriod": 0,

"CpuQuota": 0,

"CpuRealtimePeriod": 0,

"CpuRealtimeRuntime": 0,

"CpusetCpus": "",

"CpusetMems": "",

"Devices": [],

"DeviceCgroupRules": null,

"DiskQuota": 0,

"KernelMemory": 0,

"MemoryReservation": 0,

"MemorySwap": 0,

"MemorySwappiness": null,

"OomKillDisable": false,

"PidsLimit": 0,

"Ulimits": null,

"CpuCount": 0,

"CpuPercent": 0,

"IOMaximumIOps": 0,

"IOMaximumBandwidth": 0,

"MaskedPaths": [

"/proc/asound",

"/proc/acpi",

"/proc/kcore",

"/proc/keys",

"/proc/latency_stats",

"/proc/timer_list",

"/proc/timer_stats",

"/proc/sched_debug",

"/proc/scsi",

"/sys/firmware"

],

"ReadonlyPaths": [

"/proc/bus",

"/proc/fs",

"/proc/irq",

"/proc/sys",

"/proc/sysrq-trigger"

]

},

"GraphDriver": {

"Data": {

"LowerDir": "/mnt/sda1/var/lib/docker/overlay2/37ad581f24c8ec87f199192366c304f952ce27177477746a1d33875a1bd7d7c7-init/diff:/mnt/sda1/var/lib/docker/overlay2/c596b32c9a6bf4a75405f329338e49ff6167970587db8155633861147b0e6b8a/diff:/mnt/sda1/var/lib/docker/overlay2/6d489fac67dc1b566ea6afa79d458d979294142d7f35edd719081e5559d586c1/diff:/mnt/sda1/var/lib/docker/overlay2/5683f690ef322b4d9c02b1bec18880ddc76d48cfebb4a5454143c919dbd3cee8/diff:/mnt/sda1/var/lib/docker/overlay2/d8fd6e07474c264294c0064dda1af0f3c09d7ec35301b8eecacb4ee926a7215b/diff:/mnt/sda1/var/lib/docker/overlay2/cb37f96d8c4d6580faba935057636e928684d73ca58c53136a118918bddbb604/diff:/mnt/sda1/var/lib/docker/overlay2/df686dad04ba90e26a4bd48f64a9911f63547b205c7289d81fb55300aaacdbb4/diff",

"MergedDir": "/mnt/sda1/var/lib/docker/overlay2/37ad581f24c8ec87f199192366c304f952ce27177477746a1d33875a1bd7d7c7/merged",

"UpperDir": "/mnt/sda1/var/lib/docker/overlay2/37ad581f24c8ec87f199192366c304f952ce27177477746a1d33875a1bd7d7c7/diff",

"WorkDir": "/mnt/sda1/var/lib/docker/overlay2/37ad581f24c8ec87f199192366c304f952ce27177477746a1d33875a1bd7d7c7/work"

},

"Name": "overlay2"

},

"Mounts": [

{

"Type": "volume",

"Name": "aae85a2f1e19aedc87713b76fca072247d04632ef0c17c44e7dd44ad4e46219c",

"Source": "/mnt/sda1/var/lib/docker/volumes/aae85a2f1e19aedc87713b76fca072247d04632ef0c17c44e7dd44ad4e46219c/_data",

"Destination": "/data",

"Driver": "local",

"Mode": "",

"RW": true,

"Propagation": ""

}

],

"Config": {

"Hostname": "2bdabc272ec3",

"Domainname": "",

"User": "",

"AttachStdin": false,

"AttachStdout": false,

"AttachStderr": false,

"ExposedPorts": {

"6379/tcp": {}

},

"Tty": false,

"OpenStdin": false,

"StdinOnce": false,

"Env": [

"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",

"GOSU_VERSION=1.10",

"REDIS_VERSION=5.0.3",

"REDIS_DOWNLOAD_URL=http://download.redis.io/releases/redis-5.0.3.tar.gz",

"REDIS_DOWNLOAD_SHA=e290b4ddf817b26254a74d5d564095b11f9cd20d8f165459efa53eb63cd93e02"

],

"Cmd": [

"redis-server"

],

"ArgsEscaped": true,

"Image": "redis",

"Volumes": {

"/data": {}

},

"WorkingDir": "/data",

"Entrypoint": [

"docker-entrypoint.sh"

],

"OnBuild": null,

"Labels": {}

},

"NetworkSettings": {

"Bridge": "",

"SandboxID": "d45841da711498d7de27f9d6050c9b5a873e527cb683075277a9fb8621c1dd30",

"HairpinMode": false,

"LinkLocalIPv6Address": "",

"LinkLocalIPv6PrefixLen": 0,

"Ports": {

"6379/tcp": [

{

"HostIp": "0.0.0.0",

"HostPort": "6379"

}

]

},

"SandboxKey": "/var/run/docker/netns/d45841da7114",

"SecondaryIPAddresses": null,

"SecondaryIPv6Addresses": null,

"EndpointID": "11ad8c469ed5fc9d9ec1b796fe6853b91a8d61915a66f77763073f5f5535000f",

"Gateway": "172.17.0.1",

"GlobalIPv6Address": "",

"GlobalIPv6PrefixLen": 0,

"IPAddress": "172.17.0.2",

"IPPrefixLen": 16,

"IPv6Gateway": "",

"MacAddress": "02:42:ac:11:00:02",

"Networks": {

"bridge": {

"IPAMConfig": null,

"Links": null,

"Aliases": null,

"NetworkID": "354ba15e8a867d659da1a3093bd5ddb71df450b6dbb070edf492d980fdaf2c69",

"EndpointID": "11ad8c469ed5fc9d9ec1b796fe6853b91a8d61915a66f77763073f5f5535000f",

"Gateway": "172.17.0.1",

"IPAddress": "172.17.0.2",

"IPPrefixLen": 16,

"IPv6Gateway": "",

"GlobalIPv6Address": "",

"GlobalIPv6PrefixLen": 0,

"MacAddress": "02:42:ac:11:00:02",

"DriverOpts": null

}

]

--

Yuval B

PASCUAL Eric

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Jan 15, 2019, 4:38:43 PM1/15/19

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Hi,

How is configured your Docker stack exactly ? You should have several containers in it, at least one for the Redis server, another one for the Django app.

Do you use docker-compose to run the stack ? If yes, could you provide the YAML descriptor of the stack ?

Best

Eric

From: django...@googlegroups.com <django...@googlegroups.com> on behalf of Yuval Bachrach <yuval.b...@gmail.com>
Sent: Tuesday, January 15, 2019 5:31:18 PM
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Subject: channnels -- communication with redis

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Yuval Bachrach

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Jan 15, 2019, 4:51:01 PM1/15/19

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I did not configure anything, which is probably the problem..

I am following the tutorial. I just did what the tutorial instructed to do: So I have installed docker as instructed but haven't configured anything. The tutorial calls installing docker and does not state any action to take after installing....)

as I am not familiar with docker, could not tell if there is a need to configure anything to make django channels work. I still need to do whatever is required to make the tutorial work.Do I need to learn basics of docker first, or are there some simple things I can do to enable the environment and keep going with the channels tutorial?

To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/AM0P193MB030846511726FEDB5F8D35DD8C810%40AM0P193MB0308.EURP193.PROD.OUTLOOK.COM.

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Yuval B

Roger Gammans

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Jan 15, 2019, 5:32:47 PM1/15/19

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Hi Yuval

Are you using docker machine ? If so the redis server is on the docker machine's IP not on the localhost so you would need to update the docker host in the CHANNEL_LAYERS portion of settings.py.

You show a unix-like shell like for controlling docker; but the connect failed error looks very windowssy; so I'm not sure that the docker engine (daemon) and the python is running on the TCP stack (or kernel/VM) which you would need for the local host connection to work. Also it might be sensible to ensure the connection is being block by a local firewall if you have one.

It looks network/local environment related rather than something redis/docker specific. The error show the TCP connection (which you can test with telnet if you have it install) not be made between python and the redis deamon the most likely reason for that is a local firewall or a more complex environment.

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Roger Gammans <rgam...@gammascience.co.uk>
Gamma Science

Yuval Bachrach

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Jan 15, 2019, 6:31:43 PM1/15/19

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Thank you

I have installed docker on my PC and I run it locally.

At setting.py I have:

CHANNEL_LAYERS = {
    'default': {
        'BACKEND': 'channels_redis.core.RedisChannelLayer',
        'CONFIG': {
        # "hosts": [('172.17.0.1', 6379)],
        "hosts": [('127.0.0.1', 6379)],
        },
    },
}

I am running a windows os, With docker installation I got a "Docker Quickstart Terminal". This terminal looks like a unix shell - So I am using unix commands there. I run the docker commands on this shell (as you have seen) and also run the "python manage.py shell" on the same shell.

So I have the docker running on windows representing a unix shell... This is the exact configuration that is presented for this tutorial

The interface between the native windows stack and the docker which is unix oriented can be tricky but is supported officially by MSFT.

My windows version is "home"which may contribute to the problem I see (and is 64 bits, which is a requirement of docker. I have installed the 32 bit python, which I hope and assume is not the problem).

I have stopped "windows defender firewall" and executed the commands inside the python shell again: I still have the problem

You say: "It looks network/local environment related rather than something redis/docker specific" which I think is correct. Note, however, that when running runserver the comments I get are:

[Deprecation] chrome.loadTimes() is deprecated, instead use standardized API: nextHopProtocol in Navigation Timing 2. https://www.chromestatus.com/features/5637885046816768.

(anonymous) @ content.js:4

content.js:5 [Deprecation] chrome.loadTimes() is deprecated, instead use standardized API: nextHopProtocol in Navigation Timing 2. https://www.chromestatus.com/features/5637885046816768.

(anonymous) @ content.js:5

(index):28 Chat socket closed unexpectedly

chatSocket.onclose @ (index):28

Since the problem happens when firewall is inactivated, I am not sure what else I can do

Since redis is running inside a docker container, I am not sure how to test the connection with telnet (or ping): How do I test it?

To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/1547573530.1554.28.camel%40gammascience.co.uk.

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Yuval B

Yuval Bachrach

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Jan 16, 2019, 8:16:14 AM1/16/19

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(Tried to respond right after getting your response, however, I have my message in "sent items" but nothing more... I wonder if there is a filter I managed to hit having my response blocked... Si I will re-write:)

Thank you!

I have installed docker on my PC and I run it locally.

At setting.py I have:

CHANNEL_LAYERS = {
    'default': {
        'BACKEND': 'channels_redis.core.RedisChannelLayer',
        'CONFIG': {
        # "hosts": [('172.17.0.1', 6379)],
        "hosts": [('127.0.0.1', 6379)],
        },
    },
}

I am running a windows os,

With docker installation I got a "Docker Quickstart Terminal". This terminal looks like a unix shell (So I am using unix commands inside this shell)

This configuration is the exact configuration that is described at the channels tutorial
I run the docker commands in this shell (as you have seen)
As for "python manage.py shell" and running the set of commands causing the failure I have described: It happens both when I am running the python shell at this Docker terminal or a normal windows CMD

I am running "Microsoft Windows 10 home" 64 bits. The fact that it is the "home" version can be part of the problem I have, however, while 64 bit support is required (docker), there is no limitation as for "home".

- I also think that it is likely that I have a communication problem between the redis server running inside the docker container and the client outside but I can't tell fore sure ( "It looks network/local environment related rather than something redis/docker specific")

On Tue, Jan 15, 2019 at 7:32 PM Roger Gammans <rgam...@gammascience.co.uk> wrote:

To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/1547573530.1554.28.camel%40gammascience.co.uk.

For more options, visit https://groups.google.com/d/optout.

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Yuval B

Yuval Bachrach

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Jan 16, 2019, 9:22:18 AM1/16/19

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Trying one more time: I don't see my response at my inbox so others may not have it as well...

(Tried to respond right after getting your response, however, I have my message in "sent items" but nothing more... I wonder if there is a filter I managed to hit having my response blocked... Si I will re-write:)

Thank you!

I have installed docker on my PC and I run it locally.

At setting.py I have:

CHANNEL_LAYERS = {
    'default': {
        'BACKEND': 'channels_redis.core.RedisChannelLayer',
        'CONFIG': {
        # "hosts": [('172.17.0.1', 6379)],
        "hosts": [('127.0.0.1', 6379)],
        },
    },
}

I am running a windows os,
With docker installation I got a "Docker Quickstart Terminal". This terminal looks like a unix shell (So I am using unix commands inside this shell)

This configuration is the exact configuration that is described at the channels tutorial
I run the docker commands in this shell (as you have seen)
As for "python manage.py shell" and running the set of commands causing the failure I have described: It happens both when I am running the python shell at this Docker terminal or a normal windows CMD

I am running "Microsoft Windows 10 home" 64 bits. The fact that it is the "home" version can be part of the problem I have, however, while 64 bit support is required (docker), there is no limitation as for "home".

- I also think that it is likely that I have a communication problem between the redis server running inside the docker container and the client outside but I can't tell fore sure ( "It looks network/local environment related rather than something redis/docker specific")

To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/1547573530.1554.28.camel%40gammascience.co.uk.

For more options, visit https://groups.google.com/d/optout.

--

Yuval B

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