Cleaning hooks after the certificate has been retrieved is a mistake
since a failure somewhere in the process will prevent all called hook to
be cleaned. With the current implementation, only the currently failed
hook is left without being cleaned.
Sometimes, you want hooks to use different parameters depending on the
certificate. In order to achieve this, it is now now possible to
configure environment variables at certificate scope.
Thanks to this, the default hooks have been rewrote in order to use
cover more use cases.
Orders and authorization can both contain an error which can, for
example, help an user to fix a broken hook. It is therefore very useful
to display it.
Plus, when pooling one of those objects, having an error does not mean
we should stop pooling since the error may be temporary.
At some point, someone may add new domains to an existing certificate.
In such case, this certificate should be renewed as soon as possible
instead of upon expiration.
If a configuration field has a typo in its name, the configuration
should show an error message instead of silently ignoring this field,
which could create unwanted behavior.
If someone used the example the way it was defined, file-access issues
may arise. This new example add two new hooks to fix it. The example
should now work in most environment although the path may need to be
adapted.
Documentation is a crucial point for every project, and the most
effective and traditional way to document a program is to write man
page. Here, the mdoc is used because it is simple.
Because the documentation is quite different from the project itself,
the man pages and others helpful files are distributed under a different
license. For this usage, the GNU All-Permissive License is adequate.
https://www.gnu.org/prep/maintain/html_node/License-Notices-for-Other-Files.html
man 7 groff_mdoc
The previous system was too limited when it comes to flexibility using
hooks. This limitation came from the false idea that, for a given
certificate, all challenges must be validated with the same method. In
order to prove that false, domains in a certificate can now make use of
any challenge type available.
In order to be more flexible, hooks are now given a type and are defined
in the same registry (instead of 6). Each one will be called when
considered relevant based on its type.
Sometimes, it is not possible to use certificates signed by a known
certificate authority. Hence, in order to prevent a TLS error, it is
required to explicitly add a new trusted root certificate.
This is the case with Pebble, which provides the certificate.
https://github.com/letsencrypt/pebble#avoiding-client-https-errors