cli: add sopel-config {list,init,get}

[Exirel]

Replace #1465

The sopel-config is a CLI tool to:

• list existing configuration file from Sopel's homedir
• init a new configuration file in Sopel's homedir
• get a value from a section.option of Sopel's configuration

It could do much more, but I'll leave it here for now, since @dgw is quite busy.

Note: sopel-config list could replace sopel --list, and sopel-config init could replace sopel --wizard in the end. That requires more thought.

[dgw]

I haven't gone very far into this, but I did find it odd that there's no argument to list configs from a non-default homedir. Have you just not built that yet or did you specifically leave it out for some reason?

[Exirel]

I left it out because IIRC sopel start does not allow to use a different homedir: all you can do is to provide a configuration file. At the moment, Sopel is pretty strict about where its configuration file should be, and it lets you use another configuration file if you provide an absolute path or if you provide a relative path to the current directory. This can be seen by using the configuration wizard.

I don't really like it, but the bot isn't very good at managing that at the moment. Even though I think it's a very valid concern to have.

[dgw]

I smell a future enhancement, then. For this PR I'll ignore that omission, since it's out of scope to do anything about it here.

[dgw]

Well, the code looks all kinds of sensible.

I'll load it up and test the CLI a bit Soon™, but until then I left the usual crop of line notes nitpicking docstrings. 😉

[Exirel]

Push changes without rebase, since everything will be squashed into one commit in the end.

[dgw]

That makes it easy to see what you did, so :D

I was playing with the documentation and I tried making this change:

diff --git a/sopel/cli/config.py b/sopel/cli/config.py
index c8a2d29e..13462539 100644
--- a/sopel/cli/config.py
+++ b/sopel/cli/config.py
@@ -62,8 +62,7 @@ def build_parser():
 def handle_list(options):
     """Display a list of configuration available from Sopel's homedir
 
-    :param options: parsed arguments
-    :type options: ``argparse.Namespace``
+    :param argparse.Namespace options: parsed arguments
 
     This command displays an unordered list of config names from Sopel's
     default homedir, without their extensions::
@@ -92,8 +91,7 @@ def handle_list(options):
 def handle_init(options):
     """Use config wizard to initialize a new configuration file for the bot
 
-    :param options: parsed arguments
-    :type options: ``argparse.Namespace``
+    :param argparse.Namespace options: parsed arguments
 
     .. note::
 

Doing it that way makes Sphinx auto-link to the Python documentation for argparse.Namespace, which is nice. It also makes use of the fact that :param: takes a type inline, and eliminates excess lines.

It's not useful right now (because Sphinx isn't documenting anything in sopel.cli—that needs fixing too, in a separate PR), but in playing with the output I like this better.

(sopel.cli.run also outputs a not-so-nice docstring header because it still has that copyright bit in it, and Sphinx autodoc pulls the whole thing in… Again, separate PR for actually putting the whole cli submodule into the docs.)

[dgw]

Approving, because my last comment isn't really that important.

[Exirel]

@dgw rebased, squashed, Travis's happy, everything's good now!

[dgw]

Today's the day, @Exirel: You can start working on the next phase of this CLI. 😁