Pyinfra: Don't hide fact failure due to no sudo password/etc

[wookayin]

I don't know why such a basic function doesn't work and is not pretty usable.

pyinfra v0.16.2

pyinfra -v @local tt.py

tt.py:

from pyinfra import host


SUDO = True

assert host.fact.linux_name is not None

Outcome:

--> Loading config...
--> Loading inventory...

--> Connecting to hosts...
    [@local] Connected

--> Preparing operations...
    Loading: tt.py
    Loaded fact linux_distribution
--> An unexpected exception occurred:

  File "tt.py", line 6, in <module>
    assert host.fact.linux_name is not None
AssrtionError

[FooBarQuaxx]

Which Linux Distribution the above run host has?

[wookayin]

It is Ubuntu 20.04. But other than linux_name, every other attributes are None as well. Like host_names, etc.

[wookayin]

@FooBarQuaxx @Fizzadar Looks like this is a bug. This is because of the line SUDO = True; without this line it works correctly. Or when --sudo is passed. I can also reproduce in the latest master 1.0.dev1.

[FooBarQuaxx]

@wookayin yes a verbose run of pyinfra -vv --debug @local tt.py gives something similar to this:

...
[pyinfra.api.connectors.local] --> Running command on localhost: sudo -H -n sh -c 'cat /etc/*-release'
[@local] >>> sudo -H -n sh -c 'cat /etc/*-release'
[@local] sudo: a password is required
...

Edit: With a regular use, I don't thing you needed a SUDO run for all types of invocations.

[wookayin]

I see, thanks! This is because all sudo commands fail. Could we have better error handling in gathering facts? Throwing error should be more intuitive than having facts being None.

[FooBarQuaxx]

Your point was brought up before here and here

[Fizzadar]

So this is a bit more involved - v1 implements fact failure, but only where we don't expect facts to fail (ie deb_packages is expected to fail on some systems, so we return the default).

I agree when sudo password request is in the output pyinfra should make it explicitly obvious why the fact failed (and the need to pass use_sudo_password=True. Slightly related: https://github.com/Fizzadar/pyinfra/issues/359

Currently planning to properly review the facts api for v1.1.

[Fizzadar]

This is now covered by https://github.com/Fizzadar/pyinfra/commit/d8e97d36243be8d78a29e419afb33abad38332b5, which will print out the sudo password required error.

[pylang]

FYI: one of the examples doesn't work.

examples/docker_ce,py fails quietly - the command runs but nothing is executed. It seems host.fact.linux becomes None and skips the conditional block containing the commands.

Bypassing that, another problem: an error is thrown at the second apt.packages command, requiring a password, but none was asked. I tried the following but nothing works:

> pyinfra @local /path/to/docker_ce.py 
> pyinfra @local /path/to/docker_ce.py use_sudo_password=true
> pyinfra @local /path/to/docker_ce.py --use_sudo_password

A third issue: later host.fact.command("apt-key list") complains that no such fact exists.

UPDATE: the second issue regarding passwords was somewhat resolved adding use_sudo_password=True into the appropriate operation function (in code, not the terminal). See also more insight on env vars in config.py.

apt.key, isn't adding new gpgs when apt-key list is called.

Can confirm other facts are returning None, e.g. linux_id and code_name

The other issues remain.

[Fizzadar]

Nice spot @pylang! I've added https://github.com/Fizzadar/pyinfra/issues/408 to track this.