Crash when processing Docker's "hello world"

[armijnhemel]

I tried to generate a report for Docker's hello world image, but tern crashed:

$ ./tern report -i docker.io/hello-world:latest
2018-11-07 20:44:35,758 - DEBUG - tern - Starting...
2018-11-07 20:44:35,759 - DEBUG - container - Running command: sudo docker ps
2018-11-07 20:44:35,787 - DEBUG - report - Setting up...
2018-11-07 20:44:35,788 - DEBUG - container - Running command: sudo docker images docker.io/hello-world:latest
2018-11-07 20:44:35,817 - DEBUG - container - Running command: sudo docker save docker.io/hello-world:latest
2018-11-07 20:44:35,853 - WARNING - report - Cannot retrieve full image metadata
2018-11-07 20:44:35,853 - DEBUG - report - Teardown...
2018-11-07 20:44:35,853 - DEBUG - rootfs - Running command: sudo rm -rf temp/mergedir
Traceback (most recent call last):
File "./tern", line 91, in
main(args)
File "./tern", line 47, in main
report.execute_docker_image(args)
File "/home/armijn/git/tern/report/report.py", line 402, in execute_docker_image
teardown()
File "/home/armijn/git/tern/report/report.py", line 75, in teardown
rootfs.clean_up()
File "/home/armijn/git/tern/utils/rootfs.py", line 163, in clean_up
root_command(remove, mergedir_path)
File "/home/armijn/git/tern/utils/rootfs.py", line 57, in root_command
raise subprocess.CalledProcessError(1, cmd=full_cmd, output=error)
subprocess.CalledProcessError: Command '['sudo', 'rm', '-rf', 'temp/mergedir']' returned non-zero exit status 1.

This is with 61f3a67

[nishakm]

2018-11-07 20:44:35,788 - DEBUG - container - Running command: sudo docker images docker.io/hello-world:latest
2018-11-07 20:44:35,817 - DEBUG - container - Running command: sudo docker save docker.io/hello-world:latest
2018-11-07 20:44:35,853 - WARNING - report - Cannot retrieve full image metadata

Looks like there was an error in running docker save docker.io/hello-world:latest

[nishakm]

I tried it locally and I am getting a different error:

2018-11-07 12:31:41,261 - DEBUG - tern - Starting...
2018-11-07 12:31:41,268 - DEBUG - container - Running command: docker ps
2018-11-07 12:31:41,344 - DEBUG - report - Setting up...
2018-11-07 12:31:45,410 - DEBUG - container - Running command: docker images docker.io/hello-world:latest
2018-11-07 12:31:45,478 - DEBUG - container - Running command: docker save docker.io/hello-world:latest
[sudo] password for nisha: 
2018-11-07 12:31:51,953 - DEBUG - rootfs - Running command: sudo mount -o bind temp/f22789aafb439644ab76948424a0c1b64f328cecde82c95edad3813aaadbe077/contents temp/mergedir
2018-11-07 12:31:52,019 - WARNING - command_lib - No listing for key . Consider adding this listing to command_lib/base.yml.

2018-11-07 12:31:52,020 - WARNING - report - No shell listing in command library. Using default shell
Traceback (most recent call last):
  File "./tern", line 91, in <module>
    main(args)
  File "./tern", line 47, in main
    report.execute_docker_image(args)
  File "/home/nisha/tern3.7/tern/report/report.py", line 393, in execute_docker_image
    analyze_docker_image(full_image)
  File "/home/nisha/tern3.7/tern/report/report.py", line 176, in analyze_docker_image
    binary, default_shell=constants.shell)
KeyError: 'binary'

So several issues:

1. Tern doesn't know what the baseOS for this image is. But it doesn't exit gracefully if it cannot find it.
2. It needs to check if all the set-up directories for mount exists before removing them

[armijnhemel]

This is indeed the case:

$ docker save docker.io/hello-world:latest -o /tmp/backup
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.26/images/get?names=docker.io%2Fhello-world%3Alatest: dial unix /var/run/docker.sock: connect: permission denied

So the error message would not be what I had expected.

[armijnhemel]

So several issues:

1. Tern doesn't know what the baseOS for this image is. But it doesn't exit gracefully if it cannot find it.

2. It needs to check if all the set-up directories for mount exists before removing them

This is the standard "hello world" from Docker: https://hub.docker.com/_/hello-world/

[nishakm]

Docker's hello-world container consists of only 1 executable file hello. This file has no information on version, license or project url. So unknown filesystem is probably a better warning for this content. Furthermore, Docker's hello-world container is only used for checking if Docker is installed properly on your machine and nothing else. So I don't think it makes any sense adding hello to the command library.
The two issues stated above are still valid. Thanks for testing this out @armijnhemel!

[nishakm]

Fixed in issues #120 and #121