Eliminates a bajillion nil checks and footguns
(except in tests, which bypass exported APIs, but that is expected)
Most recent #207
Logging can still be disabled via zap.NewNop(), if necessary.
(But disabling logging in CertMagic is a really bad idea.)
This allows for user-loaded certificates to be associated with arbitrary
values such as user-provided IDs or categories. This can be useful if
multiple certificates satisfy a ClientHello but if a specific one still
needs to be chosen. See for example:
https://github.com/mholt/caddy/issues/2588
This is a breaking API change since we need to expose a tags parameter
to the caching functions, but we're not 1.0 yet so we will try this
API change and see how it goes.
* Significant refactor
This refactoring expands the capabilities of the library for advanced
use cases, as well as improving the overall architecture, including
possible memory leak fixes if used over a long period with many certs
loaded into memory. This refactor enables using different configs
depending on the certificate.
The public API has changed slightly, however, and arguably it is
slightly less convenient/elegant. I have never quite found the perfect
design for this package, and this certainly isn't it, but I think it's
better than what we had before.
There is still work to be done, but this is a good step forward. I've
decoupled Storage from Cache, and made it easier and more correct for
Configs (and Storage values) to be short-lived. Cache is the only value
that should be long-lived.
Note that CertMagic no longer automatically takes care of storage (i.e.
it used to delete old OCSP staples, but now it doesn't). The functions
to do this are still there and even exported, and now we expect the
application to call the cleanup functions when it wants to.
* Fix little oopsies
* Create Manager abstraction so obtain/renew isn't limited to ACME
