OnFirstStartup and OnFinalShutdown callbacks added

OnStartup and OnShutdown callbacks now run as part of restarts, too.
The startup and shutdown directives only run their commands NOT as part
of restarts, as before. Some middleware that use OnStartup may need to
switch to OnFirstStartup and implement OnFinalShutdown to do any cleanup
as needed.

caddy.go

@@ -73,10 +73,12 @@ type Instance struct {
 	// servers is the list of servers with their listeners.
 	servers []serverListener
 
-	// these are callbacks to execute when certain events happen
-	onStartup  []func() error
-	onRestart  []func() error
-	onShutdown []func() error
+	// these callbacks execute when certain events occur
+	onFirstStartup  []func() error // starting, not as part of a restart
+	onStartup       []func() error // starting, even as part of a restart
+	onRestart       []func() error // before restart commences
+	onShutdown      []func() error // stopping, even as part of a restart
+	onFinalShutdown []func() error // stopping, not as part of a restart
 }
 
 // Stop stops all servers contained in i. It does NOT
@@ -104,10 +106,11 @@ func (i *Instance) Stop() error {
 	return nil
 }
 
-// shutdownCallbacks executes all the shutdown callbacks of i.
-// An error returned from one does not stop execution of the rest.
-// All the errors will be returned.
-func (i *Instance) shutdownCallbacks() []error {
+// ShutdownCallbacks executes all the shutdown callbacks of i,
+// including ones that are scheduled only for the final shutdown
+// of i. An error returned from one does not stop execution of
+// the rest. All the non-nil errors will be returned.
+func (i *Instance) ShutdownCallbacks() []error {
 	var errs []error
 	for _, shutdownFunc := range i.onShutdown {
 		err := shutdownFunc()
@@ -115,6 +118,12 @@ func (i *Instance) shutdownCallbacks() []error {
 			errs = append(errs, err)
 		}
 	}
+	for _, finalShutdownFunc := range i.onFinalShutdown {
+		err := finalShutdownFunc()
+		if err != nil {
+			errs = append(errs, err)
+		}
+	}
 	return errs
 }
 
@@ -159,6 +168,12 @@ func (i *Instance) Restart(newCaddyfile Input) (*Instance, error) {
 	}
 
 	// success! stop the old instance
+	for _, shutdownFunc := range i.onShutdown {
+		err := shutdownFunc()
+		if err != nil {
+			return i, err
+		}
+	}
 	i.Stop()
 
 	log.Println("[INFO] Reloading complete")
@@ -409,6 +424,15 @@ func startWithListenerFds(cdyfile Input, inst *Instance, restartFds map[string]r
 		return err
 	}
 
+	// run startup callbacks
+	if restartFds == nil {
+		for _, firstStartupFunc := range inst.onFirstStartup {
+			err := firstStartupFunc()
+			if err != nil {
+				return err
+			}
+		}
+	}
 	for _, startupFunc := range inst.onStartup {
 		err := startupFunc()
 		if err != nil {

caddyhttp/errors/errors.go

@@ -29,7 +29,8 @@ type ErrorHandler struct {
 	LogFile    string
 	Log        *log.Logger
 	LogRoller  *httpserver.LogRoller
-	Debug      bool // if true, errors are written out to client rather than to a log
+	Debug      bool     // if true, errors are written out to client rather than to a log
+	file       *os.File // a log file to close when done
 }
 
 func (h ErrorHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {

caddyhttp/errors/setup.go

@@ -49,11 +49,10 @@ func setup(c *caddy.Controller) error {
 			}
 			if handler.LogRoller != nil {
 				file.Close()
-
 				handler.LogRoller.Filename = handler.LogFile
-
 				writer = handler.LogRoller.GetLogWriter()
 			} else {
+				handler.file = file
 				writer = file
 			}
 		}
@@ -62,6 +61,14 @@ func setup(c *caddy.Controller) error {
 		return nil
 	})
 
+	// When server stops, close any open log file
+	c.OnShutdown(func() error {
+		if handler.file != nil {
+			handler.file.Close()
+		}
+		return nil
+	})
+
 	httpserver.GetConfig(c).AddMiddleware(func(next httpserver.Handler) httpserver.Handler {
 		handler.Next = next
 		return handler

caddyhttp/log/log.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log"
 	"net/http"
+	"os"
 
 	"github.com/mholt/caddy"
 	"github.com/mholt/caddy/caddyhttp/httpserver"
@@ -67,6 +68,7 @@ type Rule struct {
 	Format     string
 	Log        *log.Logger
 	Roller     *httpserver.LogRoller
+	file       *os.File // if logging to a file that needs to be closed
 }
 
 const (

caddyhttp/log/setup.go

@@ -43,6 +43,7 @@ func setup(c *caddy.Controller) error {
 					rules[i].Roller.Filename = rules[i].OutputFile
 					writer = rules[i].Roller.GetLogWriter()
 				} else {
+					rules[i].file = file
 					writer = file
 				}
 			}
@@ -53,6 +54,16 @@ func setup(c *caddy.Controller) error {
 		return nil
 	})
 
+	// When server stops, close any open log files
+	c.OnShutdown(func() error {
+		for _, rule := range rules {
+			if rule.file != nil {
+				rule.file.Close()
+			}
+		}
+		return nil
+	})
+
 	httpserver.GetConfig(c).AddMiddleware(func(next httpserver.Handler) httpserver.Handler {
 		return Logger{Next: next, Rules: rules, ErrorFunc: httpserver.DefaultErrorFunc}
 	})

controller.go

@@ -54,8 +54,14 @@ func (c *Controller) ServerType() string {
 	return c.instance.serverType
 }
 
+// OnFirstStartup adds fn to the list of callback functions to execute
+// when the server is about to be started NOT as part of a restart.
+func (c *Controller) OnFirstStartup(fn func() error) {
+	c.instance.onFirstStartup = append(c.instance.onFirstStartup, fn)
+}
+
 // OnStartup adds fn to the list of callback functions to execute
-// when the server is about to be started.
+// when the server is about to be started (including restarts).
 func (c *Controller) OnStartup(fn func() error) {
 	c.instance.onStartup = append(c.instance.onStartup, fn)
 }
@@ -67,11 +73,17 @@ func (c *Controller) OnRestart(fn func() error) {
 }
 
 // OnShutdown adds fn to the list of callback functions to execute
-// when the server is about to be shut down..
+// when the server is about to be shut down (including restarts).
 func (c *Controller) OnShutdown(fn func() error) {
 	c.instance.onShutdown = append(c.instance.onShutdown, fn)
 }
 
+// OnFinalShutdown adds fn to the list of callback functions to execute
+// when the server is about to be shut down NOT as part of a restart.
+func (c *Controller) OnFinalShutdown(fn func() error) {
+	c.instance.onFinalShutdown = append(c.instance.onFinalShutdown, fn)
+}
+
 // Context gets the context associated with the instance associated with c.
 func (c *Controller) Context() Context {
 	return c.instance.context

sigtrap.go

@@ -72,7 +72,7 @@ func allShutdownCallbacks() []error {
 	var errs []error
 	instancesMu.Lock()
 	for _, inst := range instances {
-		errs = append(errs, inst.shutdownCallbacks()...)
+		errs = append(errs, inst.ShutdownCallbacks()...)
 	}
 	instancesMu.Unlock()
 	return errs

startupshutdown/startupshutdown.go

@@ -15,12 +15,12 @@ func init() {
 
 // Startup registers a startup callback to execute during server start.
 func Startup(c *caddy.Controller) error {
-	return registerCallback(c, c.OnStartup)
+	return registerCallback(c, c.OnFirstStartup)
 }
 
 // Shutdown registers a shutdown callback to execute during server stop.
 func Shutdown(c *caddy.Controller) error {
-	return registerCallback(c, c.OnShutdown)
+	return registerCallback(c, c.OnFinalShutdown)
 }
 
 // registerCallback registers a callback function to execute by