added installation method config to skip install

[DEvil0000]

skipping installation as a option

[paulfantom]

Installation is already split into install.yml file and we have proper ansible tags in place, so what is the benefit of having this as a variable?

Also this role is intended to be a management tool for a full lifecycle of prometheus application and this includes day 1 and day 2 operations.

[DEvil0000]

We do the installation a different way with some other mechanism so we want to skip all installation related things and just configure the software with ansible. This is not too uncommen when looking at other roles.
There however might be other similar cases where you would not want or need the installation to be done e.g. when running the software in a container you would just want the configuration part to be done.

[paulfantom]

We do the installation a different way

just configure the software with ansible

So you want to literally copy prometheus config file and rules because this is what is left after you disable installation (as you can see in https://github.com/cloudalchemy/ansible-prometheus/blob/master/tasks/configure.yml), in such case why use this role at all? The main benefits of using this role are automated lifecycle of prometheus binary and secure by default systemd service file if you disable those, then everything else can be easily accomplished with one simple execution of copy or template module.

e.g. when running the software in a container

If you run in a container, then after changing configuration file prometheus needs to be reloaded, so you need to reload container. In such case this role doesn't support it and never will, so why going through the hassle of downloading a role which you are using in a way that can be accomplished with simpler methods?

[DEvil0000]

Yes, I only need the configure part (and the systemd file part as long as parts of the config are command line parameters) but does it hurt in any way if installation can get skipped?
In my understanding of open source software it is better to improve a existing project and add a (in this case small) feature/improvement then writing about the same solution again.
If you don't want this in your role feel free to close the PR.

[smutel]

Please consider this feature which is apparently needed by more than one person.

[paulfantom]

After some thought let's implement this.

@DEvil0000 Could you rebase?

[paulfantom]

Let's switch this to boolen like prometheus_skip_install and set it to false by default.

Also please add a not that this is exclusive with prometheus_binaries_local_dir and prometheus_version

[smutel]

@paulfantom, contact me if @DEvil0000 does not respond to your request

[DEvil0000]

I feel like I did ;)

[smutel]

It's mean that you will not update this MR anymore ?

[DEvil0000]

excuse me if I was not clear. I updated it and requested a new review before your comment as you can see in its history.
So what do you think is missing?

[smutel]

OK. Thanks.  @paulfantom, is-it ok for you ?

[paulfantom]

Thanks 👍