Some programs (Node.js, supervisor, etc.) open a stdin pipe by default and don't use it, causing Caddy to block. It is their error, but we have to try to accommodate unfortunately. To fix this more universally, parent must explicitly set -conf to "stdin" to read from pipe.
The error channel used when starting all the servers must be buffered so that, even if there are no errors at startup, the returns that insert into the error channel will not be blocked, since after startup, nobody is reading that channel anymore.
The base path being optional in the Caddyfile is convenient when you just want the whole site to be markdown-enabled. The other change is to always generate links... this is because an index page for markdown files may not be statically generated, but it should still show links. Commit 09341fc was a regression, and this fixes it.
Previously, if a listener fails to bind (for example), there was a race in caddy.go between unblocking the startup waitgroup and returning the error and putting it into errChan. Now, an error is returned directly into errChan and the closing of the startup waitgroup is defered until after that return takes place.
Log file can also be stdout or stderr. Log output is disabled by default now, which makes it more feasible to add more log statements to trace program flow in debugging situations.
Fixed bug where manually specifying port 443 disabled TLS (whoops); otherHostHasScheme was the culprit, since it would return true even if it was the same config that had that scheme.
Also, an error at startup (if not a restart) is now fatal, rather than keeping a half-alive zombie server.
By chaining in a middleware handler and using newly exposed hooks from the acme package, we're able to proxy ACME requests on port 443 to the ACME client listening on a different port.
