log: allow additional prefix/suffix with predefined format

Signed-off-by: Tw <tw19881113@gmail.com>

caddyhttp/log/setup.go

 package log
 
 import (
+	"strings"
+
 	"github.com/mholt/caddy"
 	"github.com/mholt/caddy/caddyhttp/httpserver"
 )
@@ -75,14 +77,8 @@ func logParse(c *caddy.Controller) ([]*Rule, error) {
 			format := DefaultLogFormat
 
 			if len(args) > 2 {
-				switch args[2] {
-				case "{common}":
-					format = CommonLogFormat
-				case "{combined}":
-					format = CombinedLogFormat
-				default:
-					format = args[2]
-				}
+				format = strings.Replace(args[2], "{common}", CommonLogFormat, -1)
+				format = strings.Replace(format, "{combined}", CombinedLogFormat, -1)
 			}
 
 			rules = appendEntry(rules, args[0], &Entry{

caddyhttp/log/setup_test.go

@@ -124,6 +124,16 @@ func TestLogParse(t *testing.T) {
 				Format: CommonLogFormat,
 			}},
 		}}},
+		{`log /myapi log.txt "prefix {common} suffix"`, false, []Rule{{
+			PathScope: "/myapi",
+			Entries: []*Entry{{
+				Log: &httpserver.Logger{
+					Output: "log.txt",
+					Roller: httpserver.DefaultLogRoller(),
+				},
+				Format: "prefix " + CommonLogFormat + " suffix",
+			}},
+		}}},
 		{`log /test accesslog.txt {combined}`, false, []Rule{{
 			PathScope: "/test",
 			Entries: []*Entry{{
@@ -134,6 +144,16 @@ func TestLogParse(t *testing.T) {
 				Format: CombinedLogFormat,
 			}},
 		}}},
+		{`log /test accesslog.txt "prefix {combined} suffix"`, false, []Rule{{
+			PathScope: "/test",
+			Entries: []*Entry{{
+				Log: &httpserver.Logger{
+					Output: "accesslog.txt",
+					Roller: httpserver.DefaultLogRoller(),
+				},
+				Format: "prefix " + CombinedLogFormat + " suffix",
+			}},
+		}}},
 		{`log /api1 log.txt
 		  log /api2 accesslog.txt {combined}`, false, []Rule{{
 			PathScope: "/api1",