From 0407672a23b72ea9bab9b89d92014c2db286b18d Mon Sep 17 00:00:00 2001
From: Daniel Ponte <amigan@gmail.com>
Date: Thu, 17 Oct 2024 10:00:23 -0400
Subject: [PATCH] Improve logging. TODO: Switch to slog.

---
 .gitignore                   |   1 +
 config.sample.yaml           |   7 +++
 pkg/gordio/config/config.go  |  16 +++--
 pkg/gordio/server/logging.go | 110 +++++++++++++++++++++++++++++++++++
 pkg/gordio/server/server.go  |   7 +++
 5 files changed, 136 insertions(+), 5 deletions(-)
 create mode 100644 pkg/gordio/server/logging.go

diff --git a/.gitignore b/.gitignore
index 9115ebc..a37f180 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ client/calls/
 /gordio
 /calls
 Session.vim
+*.log
diff --git a/config.sample.yaml b/config.sample.yaml
index b98b24a..dc4b2b1 100644
--- a/config.sample.yaml
+++ b/config.sample.yaml
@@ -14,3 +14,10 @@ auth:
     "localhost": true
 listen: ':3050'
 public: true
+log:
+  # level logs at or above the specified level
+  # levels are trace, debug, info, warn, error, fatal, panic
+  # an entry without a file: property indicates stderr
+  - level: debug
+  - level: error
+    file: error.log
diff --git a/pkg/gordio/config/config.go b/pkg/gordio/config/config.go
index c8f0a8b..a33c4ef 100644
--- a/pkg/gordio/config/config.go
+++ b/pkg/gordio/config/config.go
@@ -9,11 +9,12 @@ import (
 )
 
 type Config struct {
-	DB     DB     `yaml:"db"`
-	CORS   CORS   `yaml:"cors"`
-	Auth   Auth   `yaml:"auth"`
-	Listen string `yaml:"listen"`
-	Public bool   `yaml:"public"`
+	DB     DB       `yaml:"db"`
+	CORS   CORS     `yaml:"cors"`
+	Auth   Auth     `yaml:"auth"`
+	Log    []Logger `yaml:"log"`
+	Listen string   `yaml:"listen"`
+	Public bool     `yaml:"public"`
 
 	configPath string
 }
@@ -33,6 +34,11 @@ type DB struct {
 	Driver  string `yaml:"driver"`
 }
 
+type Logger struct {
+	File   *string `yaml:"file"`
+	Level  *string `yaml:"level"`
+}
+
 func New(cmd *cobra.Command) *Config {
 	c := &Config{}
 	cmd.PersistentFlags().StringVarP(&c.configPath, "config", "c", "config.yaml", "configuration file")
diff --git a/pkg/gordio/server/logging.go b/pkg/gordio/server/logging.go
new file mode 100644
index 0000000..03d9930
--- /dev/null
+++ b/pkg/gordio/server/logging.go
@@ -0,0 +1,110 @@
+package server
+
+import (
+	"io"
+	"io/fs"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"dynatron.me/x/stillbox/pkg/gordio/config"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+const (
+	LOGPERM fs.FileMode = 0600
+)
+
+type Logger struct {
+	console io.Writer
+	writers []io.Writer
+	hup chan os.Signal
+}
+
+func NewLogger(cfg *config.Config) (*Logger, error) {
+	l := &Logger{
+		console: &zerolog.ConsoleWriter{Out: os.Stderr},
+	}
+	l.hup = make(chan os.Signal, 1)
+	go func() {
+		for sig := range l.hup {
+			log.Logger = log.Output(l.console)
+			log.Info().Msgf("received %s, closing and reopening logfiles", sig)
+			l.Close()
+			err := l.OpenLogs(cfg)
+			if err != nil {
+				log.Error().Err(err).Msg("error reopening logs")
+				continue
+			}
+
+			log.Logger = log.Output(zerolog.MultiLevelWriter(l.writers...))
+		}
+	}()
+
+	signal.Notify(l.hup, syscall.SIGHUP)
+
+	err := l.OpenLogs(cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	log.Logger = log.Output(zerolog.MultiLevelWriter(l.writers...))
+
+	return l, nil
+}
+
+func (l *Logger) Close() {
+	for _, lg := range l.writers {
+		if _, isConsole := lg.(*zerolog.ConsoleWriter); isConsole {
+			continue
+		}
+
+		if cl, isCloser := lg.(io.Closer); isCloser {
+			err := cl.Close()
+			if err != nil {
+				log.Error().Err(err).Msg("closing writer")
+			}
+		}
+	}
+
+	l.writers = nil
+}
+
+func (l *Logger) OpenLogs(cfg *config.Config) error {
+	l.writers = make([]io.Writer, 0, len(cfg.Log))
+	for _, lc := range cfg.Log {
+		level := zerolog.TraceLevel
+		if lc.Level != nil {
+			var err error
+
+			level, err = zerolog.ParseLevel(*lc.Level)
+			if err != nil {
+				return err
+			}
+		}
+
+		w := &zerolog.FilteredLevelWriter{
+			Level: level,
+		}
+
+		switch lc.File {
+		case nil:
+			w.Writer = &zerolog.LevelWriterAdapter{Writer: l.console}
+		default:
+			f, err := os.OpenFile(*lc.File, os.O_WRONLY|os.O_CREATE, LOGPERM)
+			if err != nil {
+				return err
+			}
+
+			w.Writer = &zerolog.LevelWriterAdapter{
+				Writer: f,
+			}
+		}
+
+		l.writers = append(l.writers, w)
+	}
+
+	return nil
+}
diff --git a/pkg/gordio/server/server.go b/pkg/gordio/server/server.go
index e51fa6c..aace9c0 100644
--- a/pkg/gordio/server/server.go
+++ b/pkg/gordio/server/server.go
@@ -23,9 +23,15 @@ type Server struct {
 	sources sources.Sources
 	sinks   sinks.Sinks
 	nex     *nexus.Nexus
+	logger  *Logger
 }
 
 func New(cfg *config.Config) (*Server, error) {
+	logger, err := NewLogger(cfg)
+	if err != nil {
+		return nil, err
+	}
+
 	db, err := database.NewClient(cfg.DB)
 	if err != nil {
 		return nil, err
@@ -39,6 +45,7 @@ func New(cfg *config.Config) (*Server, error) {
 		db:   db,
 		r:    r,
 		nex:  nexus.New(),
+		logger: logger,
 	}
 
 	srv.sinks.Register("database", sinks.NewDatabaseSink(srv.db), true)