[question] how to use container's `exec_run` with stream enabled?

[343i]

Hi,

I'm trying to convert following snippet of my code that is using docker-py to for exec_run to stream the result:

docker:

• code:

 exit_code, response = ubuntu_container.exec_run(cmd='apt-get install -y git docker.io neofetch', stream=True)
 
 for line in response:
     print(line.decode('utf-8').strip())

• output:

Reading package lists...

Building dependency tree...
Reading state information...

docker.io is already the newest version (26.1.3-0ubuntu1).
neofetch is already the newest version (7.1.0-4).
Suggested packages:
  gettext-base git-daemon-run | git-daemon-sysvinit git-doc git-email git-gui
  gitk gitweb git-cvs git-mediawiki git-svn
The following NEW packages will be installed:
git
0 upgraded, 1 newly installed, 0 to remove and 2 not upgraded.
Need to get 4045 kB of archives.
After this operation, 24.0 MB of additional disk space will be used.
Get:1 http://ports.ubuntu.com/ubuntu-ports oracular/main arm64 git arm64 1:2.45.2-1ubuntu1 [4045 kB]
debconf: delaying package configuration, since apt-utils is not installed
Fetched 4045 kB in 4s (914 kB/s)
Selecting previously unselected package git.

podman:

• code:

 exit_code, response = ubuntu_container.exec_run(cmd='apt-get install -y git docker.io neofetch', stream=True)
 
 for line in response:
     print(line) # changed as line.decode('utf-8').strip() throws AttributeError: 'int' object has no attribute 'decode'

• output:

1
0
0
0
0
0
0
59
72
105
116
58
49
32
104

moreover the numbers that are returned in output are returned all at once in end, not in stream fashion,

I assume I'm doing this wrong by trying to force the docker way, can someone share sample code that is to be followed for stream responses

[inknos]

Hey, thanks this is worth investigating. I can't reproduce it with this code here.

from podman import PodmanClient

client = PodmanClient()
c = client.containers.create('ubuntu:latest', command=['sleep', '1000'], detach=True)
c.start()

exit_code response = c.exec_run(cmd='apt-get install -y git', stream=True)
for line in response:
     print(line.decode('utf-8').strip())

Output

Reading package lists...

Building dependency tree...
Reading state information...

E: Unable to locate package git

can you share more details of your reproducer? also, some versions will help me investigating the issue

• podman version
• podman-py version
• python version
• os

[inknos]

hey @343i , did you have the chance to investigate on it?

[ChMcg]

@inknos Hi, I have a relevant question about handling return codes when using exec_run with stream=True.

Since the response is streamed, the return code is always None. Is this the intended behavior by design of the Podman API, or is there a workaround to retrieve the exit code?

[inknos]

Since the response is streamed, the return code is always None. Is this the intended behavior by design of the Podman API, or is there a workaround to retrieve the exit code?

@ChMcg , yes, you are not getting the exit code with stream. It's documented here.

[inknos]

closing, can't reproduce and no updates. feel free to reopen if you hit the issue and I'll help you investigating :)