Before, Caddy couldn't support graceful (zero-downtime) restarts when the reloaded Caddyfile had a host in it that was elligible for a LE certificate because the port was already in use. This commit makes it possible to do zero-downtime reloads and issue certificates for new hosts that need it. Supports only http-01 challenge at this time.
OCSP stapling is improved in that it updates before the expiration time when the validity window has shifted forward. See 30c949085c. Before it only used to update when the status changed.
This commit also sets the user agent for Let's Encrypt requests with a string containing "Caddy".
By separating scheme and port at the parser, we are able to set the port appropriately and also keep the semantics of the scheme being specified by the user later on. The parser also stores an address' original input. Also, the config refactor makes it possible to partially load a config - valuable for determining which ones will need Let's Encrypt integration turned on during a restart.
Made a faulty assumption that virualhosts could share acme proxy handlers; turns out they can't without fumbling up the middleware configuration (middleware chains overlap and cross over into other virtualhosts)!
Hosts which are eligible for automatic HTTPS have default port "https" but other hosts (wildcards, loopback, etc.) have the default port 2015. The default host of empty string should be more IPv6-compatible.
It no longer uses regular expressions.
It supports both the Unix `{$ENV_VAR}` _and_ the Windows `{%ENV_VAR%}`
syntax.
Added test for both Unix and Windows env. syntax.
Added a -grace flag to customize graceful shutdown period, fixed bugs related to closing file descriptors (and dup'ed fds), improved healthcheck signaling to parent, fixed a race condition with the graceful listener, etc. These improvements mainly provide better support for frequent reloading or unusual use cases of Start and Stop after a Restart (POSIX systems). This forum thread was valuable help in debugging: https://forum.golangbridge.org/t/bind-address-already-in-use-even-after-listener-closed/1510?u=matt
