Stop using assert in validate_config.py

[micahflee]

Status

Ready for review

Description of Changes

Fixes #683.

Here's how to reproduce the TOB-SDW-024 bug:

In sd-dev switch to the main branch in securedrop-workstation. In dom0, run make clone.

One of the checks in validate_config.py is that self.config["vmsizes"]["sd_log"] is an integer. So, in dom0, edit /usr/share/securedrop-workstation-dom0-config/config.json and make sd_log a string instead, like this:

{
    "submission_key_fpr": "65A1B5FF195B56353CC63DFFCC40EF1228271441",
    "hidserv": {
        "hostname": "pmlfte7wii27fi5ioyjwzbgdmjk2i5nx2gd6v3rk5bym7rattnvm36ad.onion",
        "key": "NDN4MWTGFCCJMJWXISZDN2RO3DZJKMVRBGIFCNYN2RKX4VDGKJTQ"
    },
    "environment": "dev",
    "vmsizes": {
        "sd_app": 10,
        "sd_log": "5"
    }
}

In dom0, change to ~/securedrop-workstation and run this to validate the config:

python3 files/sdw-admin.py --validate

It should fail:

[user@dom0 securedrop-workstation]$ python3 files/sdw-admin.py --validate
Validating...Traceback (most recent call last):
  File "/home/user/securedrop-workstation/files/sdw-admin.py", line 221, in <module>
    main()
  File "/home/user/securedrop-workstation/files/sdw-admin.py", line 172, in main
    validate_config(SCRIPTS_PATH)
  File "/home/user/securedrop-workstation/files/sdw-admin.py", line 108, in validate_config
    validator = SDWConfigValidator(path)  # noqa: F841
                ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/securedrop-workstation/files/validate_config.py", line 41, in __init__
    self.validate_existing_size()
  File "/home/user/securedrop-workstation/files/validate_config.py", line 132, in validate_existing_size
    assert isinstance(
AssertionError: Private volume size of sd-log must be an integer value.

Now run it with the -OO flag:

python3 -OO files/sdw-admin.py --validate

It will pass when really it should fail -- this is the bug:

[user@dom0 securedrop-workstation]$ python3 -OO files/sdw-admin.py --validate
Validating...OK

Now, switch to this PR's branch and run make clone in dom0. This time when you run it with the -OO flag, it will fail validation like it should:

[user@dom0 securedrop-workstation]$ python3 -OO files/sdw-admin.py --validate
Validating...Traceback (most recent call last):
  File "/home/user/securedrop-workstation/files/sdw-admin.py", line 108, in validate_config
    validator = SDWConfigValidator(path)  # noqa: F841
                ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/securedrop-workstation/files/validate_config.py", line 41, in __init__
    self.validate_existing_size()
  File "/home/user/securedrop-workstation/files/validate_config.py", line 151, in validate_existing_size
    raise ValidationError("Private volume size of sd-log must be an integer value.")
validate_config.ValidationError: Private volume size of sd-log must be an integer value.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/user/securedrop-workstation/files/sdw-admin.py", line 221, in <module>
    main()
  File "/home/user/securedrop-workstation/files/sdw-admin.py", line 172, in main
    validate_config(SCRIPTS_PATH)
  File "/home/user/securedrop-workstation/files/sdw-admin.py", line 110, in validate_config
    raise SDWAdminException("Error while validating configuration")
SDWAdminException: Error while validating configuration

[zenmonkeykstop]

Test plan and CI passes, visual review also good.