Add a cli parameter to -validate a Caddyfile. Issue #1328 (#1344)

* Allow -validate flag to validate caddyfile and return

* Ensure logging without -log flag

* Changes to validate seperatly to Starup func

* Removed change to Start signature.  Created function to ValidateCaddyfile

* comment and tidyup

* ValidateandExecuteDirectives with justValidate option

* remove debugging code

* Tidy up comments

* additional parameter added to calls to mustLogFataf

* ValidateAndExecuteDirectives needs to only return err

caddy.go

@@ -432,31 +432,7 @@ func startWithListenerFds(cdyfile Input, inst *Instance, restartFds map[string]r
 		cdyfile = CaddyfileInput{}
 	}
 
-	stypeName := cdyfile.ServerType()
-
-	stype, err := getServerType(stypeName)
-	if err != nil {
-		return err
-	}
-
-	inst.caddyfileInput = cdyfile
-
-	sblocks, err := loadServerBlocks(stypeName, cdyfile.Path(), bytes.NewReader(cdyfile.Body()))
-	if err != nil {
-		return err
-	}
-
-	inst.context = stype.NewContext()
-	if inst.context == nil {
-		return fmt.Errorf("server type %s produced a nil Context", stypeName)
-	}
-
-	sblocks, err = inst.context.InspectServerBlocks(cdyfile.Path(), sblocks)
-	if err != nil {
-		return err
-	}
-
-	err = executeDirectives(inst, cdyfile.Path(), stype.Directives(), sblocks)
+	err := ValidateAndExecuteDirectives(cdyfile, inst, false)
 	if err != nil {
 		return err
 	}
@@ -516,9 +492,48 @@ func startWithListenerFds(cdyfile Input, inst *Instance, restartFds map[string]r
 	return nil
 }
 
-func executeDirectives(inst *Instance, filename string,
-	directives []string, sblocks []caddyfile.ServerBlock) error {
+func ValidateAndExecuteDirectives(cdyfile Input, inst *Instance, justValidate bool) error {
+
+	// If parsing only inst will be nil, create an instance for this function call only.
+	if justValidate {
+		inst = &Instance{serverType: cdyfile.ServerType(), wg: new(sync.WaitGroup)}
+	}
 
+	stypeName := cdyfile.ServerType()
+
+	stype, err := getServerType(stypeName)
+	if err != nil {
+		return err
+	}
+
+	inst.caddyfileInput = cdyfile
+
+	sblocks, err := loadServerBlocks(stypeName, cdyfile.Path(), bytes.NewReader(cdyfile.Body()))
+	if err != nil {
+		return err
+	}
+
+	inst.context = stype.NewContext()
+	if inst.context == nil {
+		return fmt.Errorf("server type %s produced a nil Context", stypeName)
+	}
+
+	sblocks, err = inst.context.InspectServerBlocks(cdyfile.Path(), sblocks)
+	if err != nil {
+		return err
+	}
+
+	err = executeDirectives(inst, cdyfile.Path(), stype.Directives(), sblocks, justValidate)
+	if err != nil {
+		return err
+	}
+
+	return nil
+
+}
+
+func executeDirectives(inst *Instance, filename string,
+	directives []string, sblocks []caddyfile.ServerBlock, justValidate bool) error {
 	// map of server block ID to map of directive name to whatever.
 	storages := make(map[int]map[string]interface{})
 
@@ -568,6 +583,7 @@ func executeDirectives(inst *Instance, filename string,
 			}
 		}
 
+		if !justValidate {
 			// See if there are any callbacks to execute after this directive
 			if allCallbacks, ok := parsingCallbacks[inst.serverType]; ok {
 				callbacks := allCallbacks[dir]
@@ -578,6 +594,7 @@ func executeDirectives(inst *Instance, filename string,
 				}
 			}
 		}
+	}
 
 	return nil
 }

caddy/caddymain/run.go

@@ -40,6 +40,7 @@ func init() {
 	flag.StringVar(&revoke, "revoke", "", "Hostname for which to revoke the certificate")
 	flag.StringVar(&serverType, "type", "http", "Type of server to run")
 	flag.BoolVar(&version, "version", false, "Show version")
+	flag.BoolVar(&validate, "validate", false, "Parse the Caddyfile but do not start the server")
 
 	caddy.RegisterCaddyfileLoader("flag", caddy.LoaderFunc(confLoader))
 	caddy.SetDefaultCaddyfileLoader("default", caddy.LoaderFunc(defaultLoader))
@@ -74,7 +75,7 @@ func Run() {
 	if revoke != "" {
 		err := caddytls.Revoke(revoke)
 		if err != nil {
-			mustLogFatalf(err.Error())
+			mustLogFatalf("%v", err.Error())
 		}
 		fmt.Printf("Revoked certificate for %s\n", revoke)
 		os.Exit(0)
@@ -94,19 +95,29 @@ func Run() {
 	// Set CPU cap
 	err := setCPU(cpu)
 	if err != nil {
-		mustLogFatalf(err.Error())
+		mustLogFatalf("%v", err.Error())
 	}
 
 	// Get Caddyfile input
-	caddyfile, err := caddy.LoadCaddyfile(serverType)
+	caddyfileinput, err := caddy.LoadCaddyfile(serverType)
 	if err != nil {
-		mustLogFatalf(err.Error())
+		mustLogFatalf("%v", err.Error())
+	}
+
+	if validate {
+		justValidate := true
+		err := caddy.ValidateAndExecuteDirectives(caddyfileinput, nil, justValidate)
+		if err != nil {
+			mustLogFatalf("%v", err.Error())
+		}
+		log.Println("[INFO] Caddyfile Valid")
+		os.Exit(0)
 	}
 
 	// Start your engines
-	instance, err := caddy.Start(caddyfile)
+	instance, err := caddy.Start(caddyfileinput)
 	if err != nil {
-		mustLogFatalf(err.Error())
+		mustLogFatalf("%v", err.Error())
 	}
 
 	// Twiddle your thumbs
@@ -226,6 +237,7 @@ var (
 	revoke     string
 	version    bool
 	plugins    bool
+	validate   bool
 )
 
 // Build information obtained with the help of -ldflags