v2: 'log' directive for Caddyfile, and debug mode (#3052)

* httpcaddyfile: Begin implementing log directive, and debug mode

For now, debug mode just sets the log level for all logs to DEBUG
(unless a level is specified explicitly).

* httpcaddyfile: Finish 'log' directive

Also rename StringEncoder -> SingleFieldEncoder

* Fix minor bug in replacer (when vals are empty)

2 files changed, 177 insertions, 0 deletions

diff --git a/caddyconfig/httpcaddyfile/builtins.go b/caddyconfig/httpcaddyfile/builtins.go
index 8cfca18..43e184e 100644
--- a/caddyconfig/httpcaddyfile/builtins.go
+++ b/caddyconfig/httpcaddyfile/builtins.go
@@ -24,8 +24,10 @@ import (
 
 	"github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/caddy/v2/caddyconfig"
+	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
 	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
 	"github.com/caddyserver/caddy/v2/modules/caddytls"
+	"go.uber.org/zap/zapcore"
 )
 
 func init() {
@@ -37,6 +39,7 @@ func init() {
 	RegisterHandlerDirective("route", parseRoute)
 	RegisterHandlerDirective("handle", parseSegmentAsSubroute)
 	RegisterDirective("handle_errors", parseHandleErrors)
+	RegisterDirective("log", parseLog)
 }
 
 // parseBind parses the bind directive. Syntax:
@@ -426,9 +429,116 @@ func parseHandleErrors(h Helper) ([]ConfigValue, error) {
 	}, nil
 }
 
+// parseLog parses the log directive. Syntax:
+//
+//     log {
+//         output <writer_module> ...
+//         format <encoder_module> ...
+//         level  <level>
+//     }
+//
+func parseLog(h Helper) ([]ConfigValue, error) {
+	var configValues []ConfigValue
+	for h.Next() {
+		cl := new(caddy.CustomLog)
+
+		for h.NextBlock(0) {
+			switch h.Val() {
+			case "output":
+				if !h.NextArg() {
+					return nil, h.ArgErr()
+				}
+				moduleName := h.Val()
+
+				// can't use the usual caddyfile.Unmarshaler flow with the
+				// standard writers because they are in the caddy package
+				// (because they are the default) and implementing that
+				// interface there would unfortunately create circular import
+				var wo caddy.WriterOpener
+				switch moduleName {
+				case "stdout":
+					wo = caddy.StdoutWriter{}
+				case "stderr":
+					wo = caddy.StderrWriter{}
+				case "discard":
+					wo = caddy.DiscardWriter{}
+				default:
+					mod, err := caddy.GetModule("caddy.logging.writers." + moduleName)
+					if err != nil {
+						return nil, h.Errf("getting log writer module named '%s': %v", moduleName, err)
+					}
+					unm, ok := mod.New().(caddyfile.Unmarshaler)
+					if !ok {
+						return nil, h.Errf("log writer module '%s' is not a Caddyfile unmarshaler", mod)
+					}
+					err = unm.UnmarshalCaddyfile(h.NewFromNextSegment())
+					if err != nil {
+						return nil, err
+					}
+					wo, ok = unm.(caddy.WriterOpener)
+					if !ok {
+						return nil, h.Errf("module %s is not a WriterOpener", mod)
+					}
+				}
+				cl.WriterRaw = caddyconfig.JSONModuleObject(wo, "output", moduleName, h.warnings)
+
+			case "format":
+				if !h.NextArg() {
+					return nil, h.ArgErr()
+				}
+				moduleName := h.Val()
+				mod, err := caddy.GetModule("caddy.logging.encoders." + moduleName)
+				if err != nil {
+					return nil, h.Errf("getting log encoder module named '%s': %v", moduleName, err)
+				}
+				unm, ok := mod.New().(caddyfile.Unmarshaler)
+				if !ok {
+					return nil, h.Errf("log encoder module '%s' is not a Caddyfile unmarshaler", mod)
+				}
+				err = unm.UnmarshalCaddyfile(h.NewFromNextSegment())
+				if err != nil {
+					return nil, err
+				}
+				enc, ok := unm.(zapcore.Encoder)
+				if !ok {
+					return nil, h.Errf("module %s is not a zapcore.Encoder", mod)
+				}
+				cl.EncoderRaw = caddyconfig.JSONModuleObject(enc, "format", moduleName, h.warnings)
+
+			case "level":
+				if !h.NextArg() {
+					return nil, h.ArgErr()
+				}
+				cl.Level = h.Val()
+				if h.NextArg() {
+					return nil, h.ArgErr()
+				}
+
+			default:
+				return nil, h.Errf("unrecognized subdirective: %s", h.Val())
+			}
+		}
+
+		var val namedCustomLog
+		if !reflect.DeepEqual(cl, new(caddy.CustomLog)) {
+			cl.Include = []string{"http.log.access"}
+			val.name = fmt.Sprintf("log%d", logCounter)
+			val.log = cl
+			logCounter++
+		}
+		configValues = append(configValues, ConfigValue{
+			Class: "custom_log",
+			Value: val,
+		})
+	}
+	return configValues, nil
+}
+
 // tlsCertTags maps certificate filenames to their tag.
 // This is used to remember which tag is used for each
 // certificate files, since we need to avoid loading
 // the same certificate files more than once, overwriting
 // previous tags
 var tlsCertTags = make(map[string]string)
+
+var logCounter int
diff --git a/caddyconfig/httpcaddyfile/httptype.go b/caddyconfig/httpcaddyfile/httptype.go
index d4c2bb6..e3fcdd2 100644
--- a/caddyconfig/httpcaddyfile/httptype.go
+++ b/caddyconfig/httpcaddyfile/httptype.go
@@ -282,6 +282,35 @@ func (st ServerType) Setup(originalServerBlocks []caddyfile.ServerBlock,
 		}
 	}
 
+	// extract any custom logs, and enforce configured levels
+	var customLogs []namedCustomLog
+	var hasDefaultLog bool
+	for _, sb := range serverBlocks {
+		for _, clVal := range sb.pile["custom_log"] {
+			ncl := clVal.Value.(namedCustomLog)
+			if ncl.name == "" {
+				continue
+			}
+			if ncl.name == "default" {
+				hasDefaultLog = true
+			}
+			if _, ok := options["debug"]; ok && ncl.log.Level == "" {
+				ncl.log.Level = "DEBUG"
+			}
+			customLogs = append(customLogs, ncl)
+		}
+	}
+	if !hasDefaultLog {
+		// if the default log was not customized, ensure we
+		// configure it with any applicable options
+		if _, ok := options["debug"]; ok {
+			customLogs = append(customLogs, namedCustomLog{
+				name: "default",
+				log:  &caddy.CustomLog{Level: "DEBUG"},
+			})
+		}
+	}
+
 	// annnd the top-level config, then we're done!
 	cfg := &caddy.Config{AppsRaw: make(caddy.ModuleMap)}
 	if !reflect.DeepEqual(httpApp, caddyhttp.App{}) {
@@ -299,6 +328,18 @@ func (st ServerType) Setup(originalServerBlocks []caddyfile.ServerBlock,
 	if adminConfig, ok := options["admin"].(string); ok && adminConfig != "" {
 		cfg.Admin = &caddy.AdminConfig{Listen: adminConfig}
 	}
+	if len(customLogs) > 0 {
+		if cfg.Logging == nil {
+			cfg.Logging = &caddy.Logging{
+				Logs: make(map[string]*caddy.CustomLog),
+			}
+		}
+		for _, ncl := range customLogs {
+			if ncl.name != "" {
+				cfg.Logging.Logs[ncl.name] = ncl.log
+			}
+		}
+	}
 
 	return cfg, warnings, nil
 }
@@ -335,6 +376,8 @@ func (ServerType) evaluateGlobalOptionsBlock(serverBlocks []serverBlock, options
 			val, err = parseOptEmail(disp)
 		case "admin":
 			val, err = parseOptAdmin(disp)
+		case "debug":
+			options["debug"] = true
 		default:
 			return nil, fmt.Errorf("unrecognized parameter name: %s", dir)
 		}
@@ -506,6 +549,25 @@ func (st *ServerType) serversFromPairings(
 					srv.Errors.Routes = appendSubrouteToRouteList(srv.Errors.Routes, sr, matcherSetsEnc, p, warnings)
 				}
 			}
+
+			// add log associations
+			for _, cval := range sblock.pile["custom_log"] {
+				ncl := cval.Value.(namedCustomLog)
+				if srv.Logs == nil {
+					srv.Logs = &caddyhttp.ServerLogConfig{
+						LoggerNames: make(map[string]string),
+					}
+				}
+				hosts, err := st.hostsFromServerBlockKeys(sblock.block)
+				if err != nil {
+					return nil, err
+				}
+				for _, h := range hosts {
+					if ncl.name != "" {
+						srv.Logs.LoggerNames[h] = ncl.name
+					}
+				}
+			}
 		}
 
 		// a catch-all TLS conn policy is necessary to ensure TLS can
@@ -940,6 +1002,11 @@ type matcherSetAndTokens struct {
 	tokens     []caddyfile.Token
 }
 
+type namedCustomLog struct {
+	name string
+	log  *caddy.CustomLog
+}
+
 // sbAddrAssocation is a mapping from a list of
 // addresses to a list of server blocks that are
 // served on those addresses.