Provide notification on availability of new plugin version

[nvvalchev]

What's the user value of this feature request? As a cf CLI user, I could install a CLI plugin and then use the plugin provided commands. However, at some point of time the plugin provider could release a newer plugin version. There is currently no convenient (automated) way that I would be notified of the availability of plugin update, so I might run the older version for a long time before updating. The only possibility is that I look into the community plugins repo from time to time or look carefully in the cf-dev mailing list.

Who is the functionality for? The feature would be used by cf CLI users, and especially the ones consuming third-party plugins.

How often will this functionality be used by the user? The feature would be used on each execution of a cf CLI plugin. The plugin infrastructure logic might check for the existence of newer plugin version and propose a plugin update or just issue a warning or info message.

Who else is affected by the change? This would not be a breaking change. Even the performance impact might not be big as the CLI infrastructure might keep a cache of the available versions of the installed plugins and update this cache only from time to time, but not on each cf CLI plugin execution.

Is your feature request related to a problem? Please describe. We are developing a server-side application, extending the CF Controller API. The server-side application is exposed to the cf users via a CLI plugin. We tend to evolve rapidly the server-side and the CLI via new features and performance improvements. Therefore, we would like to notify automatically our users for new CLI plugin versions.

Describe the solution you'd like

1. A cf CLI user installs a plugin X with v1 from repository Y. The repository Y might or might not be added to the cf CLI via "cf add-plugin-repo"
2. The plugin X provider releases a newer version of plugin X (v2) and uploads it to repository Y.
3. A cf CLI user having already installed plugin X v1, executes a cf plugin X command.
4. The user is notified via INFO message that a newer version (v2) of plugin X exists, whereas the currently installed version is an old one. No automatic update to newer version is envisioned.

Describe alternatives you've considered None.

Additional context None.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/163692119

The labels on this github issue will be updated when the story is started.

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed.

[gururajsh]

Thank you for your submission. If this issue is still relevant with the latest CLI v8, please open a new ticket with the necessary information mentioned in our issue template.