Add support for reading hosts/subnets from a file

[urhot]

This pull requests adds new argument to allow reading the hosts/subnets from a file.

This is sort of a duplicate of another pull request #42, but with a different approach. I leave it up to the author to decide if he wants to go forward with either of these.

Usage

New parameter: --routes-file <filename> or -f <filename>

For example:

vpn-slice --routes-file=/home/bob/.vpn-routes

The routes file should have one host per line, with optional comments:

# This is a comment
192.0.2.1
# Another comment
test1.example.com # one more comment
test2.example.com

To be considered

• Are the argument names good? Is it acceptable to dedicate -f for this feature?

Differences to the implementation in #42

• The provided file is not called a "config file", but just a list of hosts
• Does not use fromfile_prefix_chars, but instead a simple custom parser that knows how to handle comments

[nstp11]

Hi all, is there any update on this case?
Will we add this enhancement?

Regards

[oliveirarleo]

Hi guys.
I see the repo is being maintained. Any reason to not adopt this? in my case the routes grew so much the command cannot be run anymore.

[marmitar]

FileType might be better for handling file as arguments, like this one:

Suggested change

	p.add_argument('-f', '--routes-file', default=None, type=file_path_param, help='Path to List of VPN-internal hostnames, subnets (e.g. 192.168.0.0/24), or aliases (e.g. host1=192.168.1.2) to add to routing and /etc/hosts.')
	p.add_argument('-f', '--routes-file', default=None, type=argparse.FileType('r'), help='Path to List of VPN-internal hostnames, subnets (e.g. 192.168.0.0/24), or aliases (e.g. host1=192.168.1.2) to add to routing and /etc/hosts.')

[marmitar]

No need to read the entire file in memory beforehand, you can just iterate over the lines like this:

Suggested change

	lines = [x.strip() for x in f.readlines()]
	for line in lines:
	for line in f:
	line = line.strip()

[marmitar]

Redundant strip:

Suggested change

	if not len(line.strip()):
	if not line:

[marmitar]

Redundant strip:

Suggested change

	if line.strip().startswith('#'):
	if line.startswith('#'):

[fclante]

I see this has been approved, but not merged. Any prognosis?

[desaster]

There are some valid suggestions by @marmitar, however I have not gotten around to updating this PR. Partly because I don't currently use vpn-slice myself.