Please provide purge maintainer scriptlet

[gebi]

Hi,

please support purge for the remove maintainer scripts.

The reason is that in debian the useful distinction exists between removing a package and purging it.
The core of that being, that remove does remove the software but NEVER touches the data, as data being useless and at risk of exposure when some package config is deleted (eg. the user) removing the package configuration is a separate step.

I understand that it's rarely needed in the cloud with stateless containers, but for stateful deployments it's crucial and by no way "fine-grained" as described in the generated set of maintainer scripts.

It also makes it easier/possible to generate debian packages with fpm which behave more in line with traditionally created debian packages AND reducing the probability of errors like #kibana/6262 in the kibana debian package which removes and re-adds it's own user on package upgrade.

fpm postrm purge scriptlet:

elif [ "${1}" = "purge" -a -z "${2}" ]
then
    # like "on remove", but executes after dpkg deletes config files
    # 'apt-get purge' runs 'on remove' section, then this section.
    # Maybe we ignore this; it seems really fine-grained.
    # There is no equivalent in RPM or ARCH. A debian-specific argument
    # might perhaps be used here, but most people
    # probably don't need it.
    dummy
elif [ "${1}" = "upgrade" ]

[jordansissel]

For this: elastic/kibana#6262

Seems like the problem described in the above kibana issue is less about apt-get purge and more about two things:

• Don't do user management on package upgrades
• A service needs to be stopped in order to upgrade.

The patch elastic/kibana#7308 seems to add these things for Kibana.

I'm of the opinion that packages should never manage users or services, but I understand that opinions can differ on this :)

I don't think purge is related to these problem, especially considering RPM has no concept of 'purge'.

I'm open to having fpm make it easier to set a specific purge script, but as stated in this comment, I am not seeing a link between purge and the problem reported in Kibana.

[gebi]

Yea, even just the option to set a purge script would be very helpful!

Would it be possible to add this?

[jordansissel]

Definitely possible. Areas that would get code would be possibly the scripts in https://github.com/jordansissel/fpm/tree/master/templates/deb and adding a new option to the deb package to let you set the script to run on purge.