docker container.stats(stream=False) not found networks key-value in centos

I found i cannot find networks key-value in docker client stats

docker sdk for python = docker==4.1.0

centos7.5

centos version

# lsb_release -a
LSB Version:    :core-4.1-amd64:core-4.1-noarch
Distributor ID: CentOS
Description:    CentOS Linux release 7.5.1804 (Core) 
Release:        7.5.1804
Codename:       Core

centos docker version

# docker version
Client:
 Version:       17.12.1-ce
 API version:   1.35
 Go version:    go1.9.4
 Git commit:    7390fc6
 Built: Tue Feb 27 22:15:20 2018
 OS/Arch:       linux/amd64

Server:
 Engine:
  Version:      17.12.1-ce
  API version:  1.35 (minimum version 1.12)
  Go version:   go1.9.4
  Git commit:   7390fc6
  Built:        Tue Feb 27 22:17:54 2018
  OS/Arch:      linux/amd64
  Experimental: false

python code

docker sdk for python

import docker
client = docker.from_env()
stats = container.stats(stream=False)
print(stats)
print(str(list(stats['networks'].values())[0]['rx_bytes']))

stdout

{'read': '2020-03-30T13:22:01.786097801Z', 'preread': '2020-03-30T13:22:00.786132317Z', 
'pids_stats': {'current': 10}, 'blkio_stats': {'io_service_bytes_recursive': [], 'io_serviced_recursive': [], 
'io_queue_recursive': [], 'io_service_time_recursive': [], 'io_wait_time_recursive': [], 
'io_merged_recursive': [], 'io_time_recursive': [], 'sectors_recursive': []}, 'num_procs': 0, 'storage_stats': 
{}, 'cpu_stats': {'cpu_usage': {'total_usage': 1364516186, 'percpu_usage': [65757133, 62557842, 
66162812, 382085241, 167700841, 436523454, 119855237, 63873626], 'usage_in_kernelmode': 
400000000, 'usage_in_usermode': 850000000}, 'system_cpu_usage': 2370139470000000, 
'online_cpus': 8, 'throttling_data': {'periods': 0, 'throttled_periods': 0, 'throttled_time': 0}}, 
'precpu_stats': {'cpu_usage': {'total_usage': 1364424315, 'percpu_usage': [65665262, 62557842, 
66162812, 382085241, 167700841, 436523454, 119855237, 63873626], 'usage_in_kernelmode': 
400000000, 'usage_in_usermode': 850000000}, 'system_cpu_usage': 2370131490000000, 
'online_cpus': 8, 'throttling_data': {'periods': 0, 'throttled_periods': 0, 'throttled_time': 0}}, 
'memory_stats': {'usage': 75448320, 'max_usage': 76050432, 'stats': {'active_anon': 75448320, 
'active_file': 0, 'cache': 0, 'dirty': 0, 'hierarchical_memory_limit': 9223372036854771712, 
'hierarchical_memsw_limit': 9223372036854771712, 'inactive_anon': 0, 'inactive_file': 0, 'mapped_file':
 0, 'pgfault': 28619, 'pgmajfault': 0, 'pgpgin': 20295, 'pgpgout': 8518, 'rss': 75448320, 'rss_huge': 
27262976, 'total_active_anon': 75448320, 'total_active_file': 0, 'total_cache': 0, 'total_dirty': 0, 
'total_inactive_anon': 0, 'total_inactive_file': 0, 'total_mapped_file': 0, 'total_pgfault': 28619, 
'total_pgmajfault': 0, 'total_pgpgin': 20295, 'total_pgpgout': 8518, 'total_rss': 75448320, 
'total_rss_huge': 27262976, 'total_unevictable': 0, 'total_writeback': 0, 'unevictable': 0, 'writeback': 0}, 
'limit': 66312925184}, 'name': '/xxxx', 'id': 
'xxxx'}

ERROR:collect_data:'networks'

But When I run it in ubuntu

ubuntu18.04

ubuntu version

# lsb_release -a
LSB Version:    core-9.20170808ubuntu1-noarch:security-9.20170808ubuntu1-noarch
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.3 LTS
Release:        18.04
Codename:       bionic

ubuntu docker version

# docker version
Client:
 Version:           18.09.7
 API version:       1.39
 Go version:        go1.10.1
 Git commit:        2d0083d
 Built:             Fri Aug 16 14:20:06 2019
 OS/Arch:           linux/amd64
 Experimental:      false

Server:
 Engine:
  Version:          18.09.7
  API version:      1.39 (minimum version 1.12)
  Go version:       go1.10.1
  Git commit:       2d0083d
  Built:            Wed Aug 14 19:41:23 2019
  OS/Arch:          linux/amd64
  Experimental:     false

python code

docker sdk for python

import docker
client = docker.from_env()
stats = container.stats(stream=False)
print(stats)
print(str(list(stats['networks'].values())[0]['rx_bytes']))

stdout

{'read': '2020-03-30T13:07:01.094199037Z', 'preread': '2020-03-30T13:07:00.093103158Z', 
'pids_stats': {'current': 7}, 'blkio_stats': {'io_service_bytes_recursive': [{'major': 252, 'minor': 0, 'op': 
'Read', 'value': 0}, {'major': 252, 'minor': 0, 'op': 'Write', 'value': 385507328}, {'major': 252, 'minor': 0, 
'op': 'Sync', 'value': 241664}, {'major': 252, 'minor': 0, 'op': 'Async', 'value': 385265664}, {'major': 252, 
'minor': 0, 'op': 'Total', 'value': 385507328}], 'io_serviced_recursive': [{'major': 252, 'minor': 0, 'op': 
'Read', 'value': 0}, {'major': 252, 'minor': 0, 'op': 'Write', 'value': 11678}, {'major': 252, 'minor': 0, 'op': 
'Sync', 'value': 1334}, {'major': 252, 'minor': 0, 'op': 'Async', 'value': 10344}, {'major': 252, 'minor': 0, 
'op': 'Total', 'value': 11678}], 'io_queue_recursive': [], 'io_service_time_recursive': [], 
'io_wait_time_recursive': [], 'io_merged_recursive': [], 'io_time_recursive': [], 'sectors_recursive': []}, 
'num_procs': 0, 'storage_stats': {}, 'cpu_stats': {'cpu_usage': {'total_usage': 9756934763, 
'percpu_usage': [666952634, 478812429, 671823468, 485544816, 614203641, 552001733, 
581142364, 532484924, 575376052, 553035730, 577174864, 534464066, 666433643, 896704712, 
649666882, 721112805], 'usage_in_kernelmode': 5720000000, 'usage_in_usermode': 3040000000}, 
'system_cpu_usage': 135329085230000000, 'online_cpus': 16, 'throttling_data': {'periods': 0, 
'throttled_periods': 0, 'throttled_time': 0}}, 'precpu_stats': {'cpu_usage': {'total_usage': 9756934763, 
'percpu_usage': [666952634, 478812429, 671823468, 485544816, 614203641, 552001733, 
581142364, 532484924, 575376052, 553035730, 577174864, 534464066, 666433643, 896704712, 
649666882, 721112805], 'usage_in_kernelmode': 5720000000, 'usage_in_usermode': 3040000000}, 
'system_cpu_usage': 135329069510000000, 'online_cpus': 16, 'throttling_data': {'periods': 0, 
'throttled_periods': 0, 'throttled_time': 0}}, 'memory_stats': {'usage': 80257024, 'max_usage': 
82989056, 'stats': {'active_anon': 6430720, 'active_file': 9003008, 'cache': 62849024, 'dirty': 0, 
'hierarchical_memory_limit': 9223372036854771712, 'hierarchical_memsw_limit': 0, 'inactive_anon': 
9228288, 'inactive_file': 41926656, 'mapped_file': 11341824, 'pgfault': 1095805, 'pgmajfault': 0, 
'pgpgin': 635702, 'pgpgout': 619445, 'rss': 3739648, 'rss_huge': 0, 'total_active_anon': 6430720, 
'total_active_file': 9003008, 'total_cache': 62849024, 'total_dirty': 0, 'total_inactive_anon': 9228288,
 'total_inactive_file': 41926656, 'total_mapped_file': 11341824, 'total_pgfault': 1095805, 
'total_pgmajfault': 0, 'total_pgpgin': 635702, 'total_pgpgout': 619445, 'total_rss': 3739648, 
'total_rss_huge': 0, 'total_unevictable': 0, 'total_writeback': 0, 'unevictable': 0, 'writeback': 0}, 'limit': 
65419714560}, 'name': '/xxxx', 'id': 
'xxxx', 'networks': {'eth0':
 {'rx_bytes': 4950, 'rx_packets': 115, 'rx_errors': 0, 'rx_dropped': 0, 'tx_bytes': 0, 'tx_packets': 0, 
'tx_errors': 0, 'tx_dropped': 0}}}

4950

Is it because the docker SDK for python 4.1.0 on centos7.5 and docker 17.12 does not support getting the networks parameter?

Start by reproducing container.stats(stream=False) against the CentOS Docker Engine 17.12.1 and the Ubuntu Docker Engine 18.09.7, comparing the returned dictionaries. Read the Docker Engine stats API behavior for these versions and determine whether the missing networks field is expected. Done means the version-dependent behavior is explained and the issue is resolved with a documented limitation or appropriate SDK change.