'`toolbox enter`' | message "Error: container <container_name> not found"

[Ricky-Tigg]

• toolbox v. 0.3
• host: Fedora 44

Description

Hello. The non-existence of a container corresponding to the host's Linux distribution and version is a valid state. Therefore, reporting this state as an error is inappropriate.

Steps to reproduce the behaviour

1. Run 'toolbox create -y --release 45'.
2. Ensure that the container fedora-toolbox-44 does not exist.

$ toolbox list -c
[...]  CONTAINER NAME     [...]  STATUS   [...]
[...]  fedora-toolbox-45  [...]  created  [...]

3. See the error message.

$ toolbox enter
Error: container fedora-toolbox-44 not found
Entering container fedora-toolbox-45 instead.
Use the 'create' command to create a different Toolbx.
Run 'toolbox --help' for usage

Expected behaviour

A message in output such as "Container fedora-toolbox-44 not found/does not exist." would be appropriate.

[debarshiray]

This is intentional. See this issue and this commit.

Pedantically speaking, toolbox create or enter without any options are meant to create and enter the default container (ie., the one matching the host's distribution and release). So the matching create and enter commands would be:

$ toolbox --assumeyes create --release 45
...
$ toobox enter fedora-toolbox-45  # or toolbox enter --release 45

The behaviour you are seeing is meant to make things easier for those with just one non-default container. There's a decent chance that they want to use the one they have, and if they don't then they know what's going on. If there were multiple non-default containers and no default container, then enter will error out if no container is explicitly specified, because it becomes harder for it to guess the container.

I suppose the Error: prefix can be changed to Warning: . I don't remember if there was a good reason to use Error: other than for consistency with other such messages.

[Ricky-Tigg]

Possible behaviors associated with 'toolbox enter' when invoked alone

note: When "container fedora-toolbox-44 not found" is part of the output message, the accompanying "Run 'toolbox --help' for usage." is omitted.

case 1 | The default container does not exist

• No other container exists

No Toolbx containers found. Create now? [y/N] N
A container can be created later with the 'create' command.

The interactive proposal for creating the default container is certainly well thought out because the behavior seems natural.

I note that "No Toolbox containers found. Create now? [y/N]" is not interpreted by the program as an error or even a warning, which is good, because the introduction of such mentions would lead the user to an interpretation according to which they are trying to execute an inappropriate command, which is obviously not the case.

Suggestion

This, which would inform the user, so that the created container, thus the distribution, and its release do not come as a surprise?

No Toolbox containers found. Create default container matching host now? [y/N]

• Only one other container exists

Error: container fedora-toolbox-44 not found
Entering container fedora-toolbox-45 instead.
Use the 'create' command to create a different Toolbx.

Entry performed into the other existing container.

Suggestion

Similar to the previous behavior, it would certainly be wise to give the user the opportunity to choose, via an interactive interface, to create the default container.

Default container fedora-toolbox-44 not found.
Select what you want to do.
1) [Enter] Create default container matching host now?
2) Enter container fedora-toolbox-45.
3) Quit/Do nothing.
Choice [1-3]: <answer>
Use the 'create' command to create a different Toolbox.

• Several other containers exist

Error: container fedora-toolbox-44 not found
Use the '--container' option to select a Toolbx.

No entry performed into any of the existing containers, no interactive proposal which is good.

case 2 | The default container exists

Entry performed into the default container. That is certainly well thought out because the behavior seems natural.

[debarshiray]

Possible behaviors associated with 'toolbox enter' when invoked alone

note: When "container fedora-toolbox-44 not found" is part of the output message, the accompanying "Run 'toolbox --help' for usage." is omitted.

case 1 | The default container does not exist

* No other container exists

No Toolbx containers found. Create now? [y/N] N
A container can be created later with the 'create' command.

The interactive proposal for creating the default container is certainly well thought out because the behavior seems natural.

I note that "No Toolbox containers found. Create now? [y/N]" is not interpreted by the program as an error or even a warning, which is good, because the introduction of such mentions would lead the user to an interpretation according to which they are trying to execute an inappropriate command, which is obviously not the case.

Suggestion

This, which would inform the user, so that the created container, thus the distribution, and its release do not come as a surprise?

No Toolbox containers found. Create default container matching host now? [y/N]

Interesting. In most cases, it shouldn't come as a surprise. If the user chooses to create a container, this is what happens:

$ toolbox enter
No Toolbx containers found. Create now? [y/N] y
Image required to create Toolbx container.
Download registry.fedoraproject.org/fedora-toolbox:42 (369.4MB)? [y/N]:

A new user will very likely not have the image downloaded, and they will be immediately shown its name, which clearly shows the distribution and release.

This has significant overlaps with the create command, which helps with consistency and documentation:

$ toolbox create
Image required to create Toolbx container.
Download registry.fedoraproject.org/fedora-toolbox:42 (369.4MB)? [y/N]:

However, I see a problem if the user already has the image, because this is what happens:

$ toolbox enter
No Toolbx containers found. Create now? [y/N] y
⬢ $

I believe we should show a message about the container that was just created. For example:

$ toolbox create
Created container: fedora-toolbox-42
Enter with: toolbox enter

* Only one other container exists

Error: container fedora-toolbox-44 not found
Entering container fedora-toolbox-45 instead.
Use the 'create' command to create a different Toolbx.

Entry performed into the other existing container.

Suggestion

Similar to the previous behavior, it would certainly be wise to give the user the opportunity to choose, via an interactive interface, to create the default container.

Default container fedora-toolbox-44 not found.
Select what you want to do.
1) [Enter] Create default container matching host now?
2) Enter container fedora-toolbox-45.
3) Quit/Do nothing.
Choice [1-3]: <answer>
Use the 'create' command to create a different Toolbox.

I don't want to offer a confirmation prompt because it will negate the point of this. See the motivation in the original issue.

The use-case is when a person has one single container which isn't the default, and they want to use it again and again. In such a case, typing a longer command (ie., toolbox enter CONTAINER) becomes onerous. Being able to type a shorter command (ie., toolbox enter) helps with that.

A confirmation prompt introduces a hurdle before the user can get to their container. Instead, we could have continued to demand that the user always type out the name of the container, which shell completion can help with.

The overall goal is to make the commands as self-documenting and convenient as possible.

In this case with enter, we need to show some message to the user because it isn't immediately or trivially obvious which container they are in. It can happen that a user mistakenly ends up in the wrong container and doesn't realize until later, which can be frustrating.

If the user doesn't want to use the only (non-default) container that's there, then all they have to do is exit the container (with ctrl+d or exit) and try again. Chances are very high that they will create a different container, and once they do that this scenario ceases to exist. The confirmation prompt will reduce the key strokes in this one-off event at the cost of adding a hurdle to repeated use of the only container.

That said, we can tweak the message that's currently shown.

* Several other containers exist

Error: container fedora-toolbox-44 not found
Use the '--container' option to select a Toolbx.

Re-reading the original issue, I am reminded of the request to list the existing containers.

Back then, toolbox(1) was written in POSIX shell. The limited programming environment and facilities stopped me from adding it. It should be easier to do with the Go implementation of toolbox(1) that we have now.