Logging: add support for additional logger filters other than hostname

caddyconfig/httpcaddyfile/builtins.go

@@ -915,7 +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{}
-
+	noLoggerNames := false
 	for h.NextBlock(0) {
 		switch h.Val() {
 		case "hostnames":
@@ -1001,14 +1001,20 @@ 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()
+			}
+			noLoggerNames = true
+
 		default:
 			return nil, h.Errf("unrecognized subdirective: %s", h.Val())
 		}
 	}
 
 	var val namedCustomLog
 	val.hostnames = customHostnames
-
+	val.noLoggerNames = noLoggerNames
 	isEmptyConfig := reflect.DeepEqual(cl, new(caddy.CustomLog))
 
 	// Skip handling of empty logging configs

caddyconfig/httpcaddyfile/httptype.go

@@ -797,6 +797,9 @@ func (st *ServerType) serversFromPairings(
 			sblockLogHosts := sblock.hostsFromKeys(true)
 			for _, cval := range sblock.pile["custom_log"] {
 				ncl := cval.Value.(namedCustomLog)
+				if ncl.noLoggerNames {
+					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
@@ -1591,9 +1594,10 @@ func (c counter) nextGroup() string {
 }
 
 type namedCustomLog struct {
-	name      string
-	hostnames []string
-	log       *caddy.CustomLog
+	name          string
+	hostnames     []string
+	log           *caddy.CustomLog
+	noLoggerNames bool
 }
 
 // sbAddrAssociation is a mapping from a list of

caddytest/integration/caddyfile_adapt/log_filter_with_header.txt

@@ -0,0 +1,129 @@
+localhost {
+	log {
+		output file ./caddy.access.log
+	}
+	log health_check_log {
+		output file ./caddy.access.health.log
+		no_hostname
+	}
+	@healthCheck `header_regexp('User-Agent', '^some-regexp$') || path('/healthz*')`
+	handle @healthCheck {
+		vars access_logger_name health_check_log
+		respond "Healthy"
+	}
+
+	handle {
+		respond "Hello World"
+	}
+}
+----------
+{
+	"logging": {
+		"logs": {
+			"default": {
+				"exclude": [
+					"http.log.access.health_check_log",
+					"http.log.access.log0"
+				]
+			},
+			"health_check_log": {
+				"writer": {
+					"filename": "./caddy.access.health.log",
+					"output": "file"
+				},
+				"include": [
+					"http.log.access.health_check_log"
+				]
+			},
+			"log0": {
+				"writer": {
+					"filename": "./caddy.access.log",
+					"output": "file"
+				},
+				"include": [
+					"http.log.access.log0"
+				]
+			}
+		}
+	},
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":443"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"localhost"
+									]
+								}
+							],
+							"handle": [
+								{
+									"handler": "subroute",
+									"routes": [
+										{
+											"group": "group2",
+											"handle": [
+												{
+													"handler": "subroute",
+													"routes": [
+														{
+															"handle": [
+																{
+																	"access_logger_name": "health_check_log",
+																	"handler": "vars"
+																},
+																{
+																	"body": "Healthy",
+																	"handler": "static_response"
+																}
+															]
+														}
+													]
+												}
+											],
+											"match": [
+												{
+													"expression": "header_regexp('User-Agent', '^some-regexp$') || path('/healthz*')"
+												}
+											]
+										},
+										{
+											"group": "group2",
+											"handle": [
+												{
+													"handler": "subroute",
+													"routes": [
+														{
+															"handle": [
+																{
+																	"body": "Hello World",
+																	"handler": "static_response"
+																}
+															]
+														}
+													]
+												}
+											]
+										}
+									]
+								}
+							],
+							"terminal": true
+						}
+					],
+					"logs": {
+						"logger_names": {
+							"localhost": "log0"
+						}
+					}
+				}
+			}
+		}
+	}
+}

modules/caddyhttp/logging.go

@@ -211,4 +211,7 @@ const (
 
 	// For adding additional fields to the access logs
 	ExtraLogFieldsCtxKey caddy.CtxKey = "extra_log_fields"
+
+	// Variable name used to indicate the logger to be used
+	AccessLoggerNameVarKey string = "access_logger_name"
 )