Make it so that most options in the config are optional, and commented out in
the generated config.
The reasons this is a good thing are as follows:
* If we decide that we should change the default for an option, we can do so,
and only those admins that have deliberately chosen to override that option
will be stuck on the old setting.
* It moves us towards a point where we can get rid of the super-surprising
feature of synapse where the default settings for the config come from the
generated yaml.
* It makes setting up a test config for unit testing an order of magnitude
easier (see forthcoming PR).
* It makes the generated config more consistent, and hopefully easier for users
to understand.
The general idea here is that config examples should just have a hash and no
extraneous whitespace, both to make it easier for people who don't understand
yaml, and to make the examples stand out from the comments.
Broadly three things here:
* disable W504 which seems a bit whacko
* remove a bunch of `as e` expressions from exception handlers that don't use
them
* use `r""` for strings which include backslashes
Also, we don't use pep8 any more, so we can get rid of the duplicate config
there.
The added addresses are expected to be local or loopback addresses and
shouldn't be spidered for previews.
Signed-off-by: Felix Schäfer <felix@thegcat.net>
Always set the config key with an empty list, even if a list isn't specified.
This means that the codepaths are the same for both the empty list and
for a missing key. Since the behaviour is the same for both cases this
makes the code somewhat easier to reason about.
Add url_preview_ip_range_blacklist to let admins specify internal IP ranges that must not be spidered.
Add url_preview_url_blacklist to let admins specify URL patterns that must not be spidered.
Implement a custom SpiderEndpoint and associated support classes to implement url_preview_ip_range_blacklist
Add commentary and generally address PR feedback
SYN-287
This requires that HS owners either opt in or out of stats reporting.
When --generate-config is passed, --report-stats must be specified
If an already-generated config is used, and doesn't have the
report_stats key, it is requested to be set.
