caddy: Add OnRestartFailed callback (#2262)

* Add callback OnRestartFailed to caddy.Controller

* markdown: Fix 500 error (#2266)

* Addressed the comments

* Update paths for filebrowser plugins

* httpserver: update minify ordering (#2273)

* Bump required version of golang to 1.10 in README.md (#2267)

Adding TLS client cert placeholders #2217 uses features of go
v1.10.  Update README requirements accordingly.

* Update CI to use Go 1.11

* caddytls: gofmt (Go 1.11) (#2241)

* Ensure assets path exists before writing UUID file

* Adding {when_unix_ms} requests placeholder (unix timestamp with a milliseconds precision) (#2260)

* update to quic-go v0.10.0 (#2288)

quic-go now vendors all of its dependencies, so we don't need to vendor
them here.

Created by running:
gvt delete github.com/lucas-clemente/quic-go
gvt delete github.com/bifurcation/mint
gvt delete github.com/lucas-clemente/aes12
gvt delete github.com/lucas-clemente/fnv128a
gvt delete github.com/lucas-clemente/quic-go-certificates
gvt delete github.com/aead/chacha20
gvt delete github.com/hashicorp/golang-lru
gvt fetch -tag v0.10.0-no-integrationtests github.com/lucas-clemente/quic-go

* fastcgi: Add default timeouts (#2265)

Default fastcgi timeout is 60 seconds
Add tests

* Fix AppVeyor builds (#2289)

* Attempting to fix AppVeyor builds

* Trying again, 2015 image this time

* Use Appveyor's Go 1.11 stack

* Restore GOPATH\bin to PATH and delete old image config

* Add gcc to path manually

* Addressed the comments

* Fix broken link to sourcegraph in README (#2285)

* Fix deadlock, ensure instances mutex unlocked (#2296)

it's a stupid mistake

* proxy: Use DualStack=true in defaultDialer (#2305)

* ci: get golint tool from `golang.org/x/lint/golint` (#2324)

* templates: TLSVersion (#2323)

* new template action: TLS protocol version

* new template action: use caddytls.GetSupportedProtocolName

Avoids code duplication by reusing existing method to get TLS protocol
version used on connection. Also adds tests

* Don't return error on onRestartFail. Only log it.

controller.go

@@ -86,6 +86,12 @@ func (c *Controller) OnRestart(fn func() error) {
 	c.instance.onRestart = append(c.instance.onRestart, fn)
 }
 
+// OnRestartFailed adds fn to the list of callback functions to execute
+// if the server failed to restart.
+func (c *Controller) OnRestartFailed(fn func() error) {
+	c.instance.onRestartFailed = append(c.instance.onRestartFailed, fn)
+}
+
 // OnShutdown adds fn to the list of callback functions to execute
 // when the server is about to be shut down (including restarts).
 func (c *Controller) OnShutdown(fn func() error) {