CLI should indicate that a newer version is available

[bmarkons]

This is based on one customer question how to verify if latest version is being used.

We could print some warning message if there is new version available.

[markoa]

Changed the title slightly.

Support team received a number of tickets about orphan SSH sessions and had to refund credits for these cause users are not aware of the latest CLI.

What's good enough IMO:

• Implement sem upgrade.
• Once a day check availability of new version (on any command user runs).
• If a newer version is available, add a colorful message at the end of every command's output advising to run sem upgrade.

[shiroyasha]

We have to keep in mind that this has some negative implications as well, especially this part:

* If a newer version is available, add a colorful message at the end of every command's output advising to run `sem upgrade`.

This behavior is present in gcloud, and every time you want to automate something, you need to keep in mind that sometimes the output of the command has undesired side-effect output.

---

I'm not against the idea, but I would keep an open eye for these edge cases, and made sure that the semaphore CLI offers a pleasant experience for automation (scripting) as well.

[shiroyasha]

From the perspective of scriptability, I would maybe even prefer this flow:

If you have an old CLI:

$ sem get projects
[error] Unsupported client version.

Upgrade your client to the latest version with `sem upgrade`

(exit status 1)

The reason for this is when I am scripting it is easier to foresee that the command flat-out fails than for it to return something unexpected silently without breaking.

Consider the following example, where I want to extract only projects names with a simple awk

$ sem get projects | awk '{ print $1 }' 

It is easier to handle exit 1, then to handle a Notice: your CLI is outdated message at the end of the projects table.