httpcaddyfile: Allow hostname override for log directive

caddyconfig/httpcaddyfile/builtins.go

@@ -789,6 +789,7 @@ func parseInvoke(h Helper) (caddyhttp.MiddlewareHandler, error) {
 // parseLog parses the log directive. Syntax:
 //
 //	log {
+//	    hostname <hostname>
 //	    output <writer_module> ...
 //	    format <encoder_module> ...
 //	    level  <level>
@@ -842,8 +843,22 @@ func parseLogHelper(h Helper, globalLogNames map[string]struct{}) ([]ConfigValue
 
 		cl := new(caddy.CustomLog)
 
+		// allow overriding the current site block's hostnames for this logger;
+		// this is useful for setting up loggers per subdomain in a site block
+		// with a wildcard domain
+		customHostname := ""
+
 		for h.NextBlock(0) {
 			switch h.Val() {
+			case "hostname":
+				if parseAsGlobalOption {
+					return nil, h.Err("hostname is not allowed in the log global options")
+				}
+				if !h.NextArg() {
+					return nil, h.ArgErr()
+				}
+				customHostname = h.Val()
+
 			case "output":
 				if !h.NextArg() {
 					return nil, h.ArgErr()
@@ -902,18 +917,16 @@ func parseLogHelper(h Helper, globalLogNames map[string]struct{}) ([]ConfigValue
 				}
 
 			case "include":
-				// This configuration is only allowed in the global options
 				if !parseAsGlobalOption {
-					return nil, h.ArgErr()
+					return nil, h.Err("include is not allowed in the log directive")
 				}
 				for h.NextArg() {
 					cl.Include = append(cl.Include, h.Val())
 				}
 
 			case "exclude":
-				// This configuration is only allowed in the global options
 				if !parseAsGlobalOption {
-					return nil, h.ArgErr()
+					return nil, h.Err("exclude is not allowed in the log directive")
 				}
 				for h.NextArg() {
 					cl.Exclude = append(cl.Exclude, h.Val())
@@ -925,6 +938,8 @@ func parseLogHelper(h Helper, globalLogNames map[string]struct{}) ([]ConfigValue
 		}
 
 		var val namedCustomLog
+		val.hostname = customHostname
+
 		// Skip handling of empty logging configs
 		if !reflect.DeepEqual(cl, new(caddy.CustomLog)) {
 			if parseAsGlobalOption {

caddyconfig/httpcaddyfile/httptype.go

@@ -770,17 +770,25 @@ func (st *ServerType) serversFromPairings(
 			sblockLogHosts := sblock.hostsFromKeys(true)
 			for _, cval := range sblock.pile["custom_log"] {
 				ncl := cval.Value.(namedCustomLog)
-				if sblock.hasHostCatchAllKey() {
+				if sblock.hasHostCatchAllKey() && ncl.hostname == "" {
 					// all requests for hosts not able to be listed should use
 					// this log because it's a catch-all-hosts server block
 					srv.Logs.DefaultLoggerName = ncl.name
 				} else {
-					// map each host to the user's desired logger name
-					for _, h := range sblockLogHosts {
+					if ncl.hostname != "" {
+						// if the logger overrides the host, map that to the logger name;
 						if srv.Logs.LoggerNames == nil {
 							srv.Logs.LoggerNames = make(map[string]string)
 						}
-						srv.Logs.LoggerNames[h] = ncl.name
+						srv.Logs.LoggerNames[ncl.hostname] = ncl.name
+					} else {
+						// otherwise, map each host to the logger name
+						for _, h := range sblockLogHosts {
+							if srv.Logs.LoggerNames == nil {
+								srv.Logs.LoggerNames = make(map[string]string)
+							}
+							srv.Logs.LoggerNames[h] = ncl.name
+						}
 					}
 				}
 			}
@@ -1564,8 +1572,9 @@ func (c counter) nextGroup() string {
 }
 
 type namedCustomLog struct {
-	name string
-	log  *caddy.CustomLog
+	name     string
+	hostname string
+	log      *caddy.CustomLog
 }
 
 // sbAddrAssociation is a mapping from a list of

caddytest/integration/caddyfile_adapt/log_override_hostname.txt

@@ -0,0 +1,70 @@
+*.example.com {
+    log {
+        hostname foo.example.com
+        output file /foo.txt
+    }
+    log {
+        hostname bar.example.com
+        output file /bar.txt
+    }
+}
+----------
+{
+	"logging": {
+		"logs": {
+			"default": {
+				"exclude": [
+					"http.log.access.log0",
+					"http.log.access.log1"
+				]
+			},
+			"log0": {
+				"writer": {
+					"filename": "/foo.txt",
+					"output": "file"
+				},
+				"include": [
+					"http.log.access.log0"
+				]
+			},
+			"log1": {
+				"writer": {
+					"filename": "/bar.txt",
+					"output": "file"
+				},
+				"include": [
+					"http.log.access.log1"
+				]
+			}
+		}
+	},
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":443"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"*.example.com"
+									]
+								}
+							],
+							"terminal": true
+						}
+					],
+					"logs": {
+						"logger_names": {
+							"bar.example.com": "log1",
+							"foo.example.com": "log0"
+						}
+					}
+				}
+			}
+		}
+	}
+}