logging: Add support for additional logger filters other than hostname (#6082)

Co-authored-by: Francis Lavoie <[email protected]>

3 files changed, 33 insertions, 5 deletions

diff --git a/caddyconfig/httpcaddyfile/builtins.go b/caddyconfig/httpcaddyfile/builtins.go
index 27ab0a182..35a08ef27 100644
--- a/caddyconfig/httpcaddyfile/builtins.go
+++ b/caddyconfig/httpcaddyfile/builtins.go
@@ -51,6 +51,7 @@ func init() {
 	RegisterDirective("log", parseLog)
 	RegisterHandlerDirective("skip_log", parseLogSkip)
 	RegisterHandlerDirective("log_skip", parseLogSkip)
+	RegisterHandlerDirective("log_name", parseLogName)
 }
 
 // parseBind parses the bind directive. Syntax:
@@ -914,7 +915,7 @@ func parseLogHelper(h Helper, globalLogNames map[string]struct{}) ([]ConfigValue
 	// this is useful for setting up loggers per subdomain in a site block
 	// with a wildcard domain
 	customHostnames := []string{}
-
+	noHostname := false
 	for h.NextBlock(0) {
 		switch h.Val() {
 		case "hostnames":
@@ -1000,6 +1001,12 @@ func parseLogHelper(h Helper, globalLogNames map[string]struct{}) ([]ConfigValue
 				cl.Exclude = append(cl.Exclude, h.Val())
 			}
 
+		case "no_hostname":
+			if h.NextArg() {
+				return nil, h.ArgErr()
+			}
+			noHostname = true
+
 		default:
 			return nil, h.Errf("unrecognized subdirective: %s", h.Val())
 		}
@@ -1007,7 +1014,7 @@ func parseLogHelper(h Helper, globalLogNames map[string]struct{}) ([]ConfigValue
 
 	var val namedCustomLog
 	val.hostnames = customHostnames
-
+	val.noHostname = noHostname
 	isEmptyConfig := reflect.DeepEqual(cl, new(caddy.CustomLog))
 
 	// Skip handling of empty logging configs
@@ -1058,3 +1065,13 @@ func parseLogSkip(h Helper) (caddyhttp.MiddlewareHandler, error) {
 	}
 	return caddyhttp.VarsMiddleware{"log_skip": true}, nil
 }
+
+// parseLogName parses the log_name directive. Syntax:
+//
+//	log_name <names...>
+func parseLogName(h Helper) (caddyhttp.MiddlewareHandler, error) {
+	h.Next() // consume directive name
+	return caddyhttp.VarsMiddleware{
+		caddyhttp.AccessLoggerNameVarKey: h.RemainingArgs(),
+	}, nil
+}
diff --git a/caddyconfig/httpcaddyfile/directives.go b/caddyconfig/httpcaddyfile/directives.go
index 172594218..3e688ebcf 100644
--- a/caddyconfig/httpcaddyfile/directives.go
+++ b/caddyconfig/httpcaddyfile/directives.go
@@ -53,6 +53,7 @@ var defaultDirectiveOrder = []string{
 	"log_append",
 	"skip_log", // TODO: deprecated, renamed to log_skip
 	"log_skip",
+	"log_name",
 
 	"header",
 	"copy_response_headers", // only in reverse_proxy's handle_response
diff --git a/caddyconfig/httpcaddyfile/httptype.go b/caddyconfig/httpcaddyfile/httptype.go
index 8e7d21fa0..a8a2ae5b3 100644
--- a/caddyconfig/httpcaddyfile/httptype.go
+++ b/caddyconfig/httpcaddyfile/httptype.go
@@ -797,6 +797,15 @@ func (st *ServerType) serversFromPairings(
 			sblockLogHosts := sblock.hostsFromKeys(true)
 			for _, cval := range sblock.pile["custom_log"] {
 				ncl := cval.Value.(namedCustomLog)
+
+				// if `no_hostname` is set, then this logger will not
+				// be associated with any of the site block's hostnames,
+				// and only be usable via the `log_name` directive
+				// or the `access_logger_names` variable
+				if ncl.noHostname {
+					continue
+				}
+
 				if sblock.hasHostCatchAllKey() && len(ncl.hostnames) == 0 {
 					// all requests for hosts not able to be listed should use
 					// this log because it's a catch-all-hosts server block
@@ -1598,9 +1607,10 @@ func (c counter) nextGroup() string {
 }
 
 type namedCustomLog struct {
-	name      string
-	hostnames []string
-	log       *caddy.CustomLog
+	name       string
+	hostnames  []string
+	log        *caddy.CustomLog
+	noHostname bool
 }
 
 // sbAddrAssociation is a mapping from a list of