We do this by creating one more layer of indirection.
First we reach some generic vhost handling matrix.DOMAIN.
A bunch of override rules are added there (capturing traffic to send to
ma1sd, etc). nginx-status and similar generic things also live there.
We then proxy to the homeserver on some other vhost (only Synapse being
available right now, but repointing this to Dendrite or other will be
possible in the future).
Then that homeserver-specific vhost does its thing to proxy to the
homeserver. It may or may not use workers, etc.
Without matrix-corporal, the flow is now:
1. matrix.DOMAIN (matrix-nginx-proxy/matrix-domain.conf)
2. matrix-nginx-proxy/matrix-synapse.conf
3. matrix-synapse
With matrix-corporal enabled, it becomes:
1. matrix.DOMAIN (matrix-nginx-proxy/matrix-domain.conf)
2. matrix-corporal
3. matrix-nginx-proxy/matrix-synapse.conf
4. matrix-synapse
(matrix-corporal gets injected at step 2).
Not sure if it breaks with them or not, but no other directive
uses quotes and the nginx docs show examples without quotes,
so we're being consistent with all of that.
The different configurations are now all lower case, for consistent
naming.
`matrix_nginx_proxy_ssl_config` is now called
`matrix_nginx_proxy_ssl_preset`. The different options for "modern",
"intermediate" and "old" are stored in the main.yml file, instead of
being hardcoded in the configuration files. This will improve the
maintainability of the code.
The "custom" preset was removed. Now if one of the variables is set, it
will use it instead of the preset. This will allow to mix and match more
easily, for example using all the intermediate options but only
supporting TLSv1.2. This will also provide better backward
compatibility.
A new variable called `matrix_nginx_proxy_ssl_config` is created for
configuring how the nginx proxy configures SSL. Also a new configuration
validation option and other auxiliary variables are created.
A new variable configuration called `matrix_nginx_proxy_ssl_config` is
created. This allow to set the SSL configuration easily using the
default options proposed by Mozilla. The default configuration is set to
"Intermediate", removing the weak ciphers used in the old
configurations.
The new variable can also be set to "Custom" for a more granular control.
This allows to set another three variables called:
- `matrix_nginx_proxy_ssl_protocols`,
- `matrix_nginx_proxy_ssl_prefer_server_ciphers`
- `matrix_nginx_proxy_ssl_ciphers`
Also a new task is added to validate the SSL configuration variable.
