go: partially rework how slogging works

app/app.go

@@ -7,11 +7,13 @@ import (
 	"git.dotya.ml/mirre-mt/pcmt/ent"
 	"git.dotya.ml/mirre-mt/pcmt/slogging"
 	"github.com/labstack/echo/v4"
+	"golang.org/x/exp/slog"
 )
 
 type App struct {
 	e             *echo.Echo
-	logger        *slogging.Logger
+	slogger       *slogging.Logger
+	logger        slogging.Logger
 	initialised   bool
 	embeds        Embeds
 	templatesPath string
@@ -34,7 +36,11 @@ func (a *App) Init(s *settings.Settings, logger *slogging.Logger, dbclient *ent.
 		e := echo.New()
 
 		a.e = e
-		a.logger = logger
+		a.slogger = logger
+		a.logger = *a.slogger
+		a.logger.Logger = a.logger.Logger.With(
+			slog.Group("pcmt extra", slog.String("module", "app")),
+		)
 
 		a.setting = s
 
@@ -76,20 +82,20 @@ func (a *App) E() *echo.Echo {
 	return a.e
 }
 
-// Logger returns app's logger instance.
+// Logger returns app's pointer to the global logger instance.
 func (a *App) Logger() *slogging.Logger {
-	return a.logger
+	return a.slogger
 }
 
 // PrintConfiguration outputs relevant settings of the application to console.
 func (a *App) PrintConfiguration() {
 	if a.setting != nil {
 		if a.setting.IsLive() {
-			a.Logger().Debug("app config: live mode enabled")
+			a.Logger().Debug("live mode enabled")
 		}
 
 		if a.setting.IsDevel() {
-			a.Logger().Debug("app config: devel mode enabled - make sure that browser-sync is running")
+			a.Logger().Debug("devel mode enabled - make sure that browser-sync is running")
 		}
 
 		return
@@ -112,9 +118,6 @@ func (a *App) SetEmbeds(templates, assets embed.FS) {
 // setDevel puts the app in devel mode, which loads a browser-sync script in
 // templates and expects browser-sync running.
 func (a *App) setDevel() {
-	a.Logger().Info("enabling debug logging for Echo")
+	a.Logger().Debug("enabling debug logging for Echo")
 	a.e.Debug = true
-
-	a.logger = slogging.SetLevel(slogging.LevelDebug)
-	a.Logger().Debug("enabled debug logging for the default logger")
 }

app/settings/settings.go

@@ -3,6 +3,7 @@ package settings
 import (
 	"git.dotya.ml/mirre-mt/pcmt/config"
 	"git.dotya.ml/mirre-mt/pcmt/slogging"
+	"golang.org/x/exp/slog"
 )
 
 type Settings struct {
@@ -31,10 +32,13 @@ func New() *Settings {
 // the settings struct. Order of preference for values is (from higher to
 // lower) as follows: flag -> Env var -> configuration file.
 func (s *Settings) Consolidate(conf *config.Config, host *string, port *int, devel *bool, version string) {
-	log := slogging.GetLogger()
+	log := *slogging.GetLogger() // have a local copy.
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "app/settings")),
+	)
 
 	log.Debug("starting to consolidate settings")
-	log.Debug("parsing config")
+	log.Debug("parsing config values")
 
 	s.SetHost(conf.Host)
 	s.SetPort(conf.Port)

config/config.go

@@ -9,6 +9,7 @@ import (
 
 	"git.dotya.ml/mirre-mt/pcmt/slogging"
 	"github.com/philandstuff/dhall-golang/v6"
+	"golang.org/x/exp/slog"
 )
 
 type session struct {
@@ -30,35 +31,66 @@ type Config struct {
 	}
 }
 
+var log slogging.Logger
+
 func LoadConfig(conf string, isPath bool) (*Config, error) {
 	var config Config
 
 	var err error
 
-	if isPath {
-		slogging.GetLogger().Debug("config from file")
+	slogger := slogging.GetLogger()
+	// initialise if not already initialised.
+	if slogger == nil {
+		slogger = slogging.Init(true)
+	}
+
+	// have a local copy.
+	log = *slogger
+	// add attr to all statements made with the local copy.
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "config")),
+	)
+
+	switch {
+	case isPath:
+		log.Debug("config from file")
 
 		err = dhall.UnmarshalFile(conf, &config)
-	} else {
-		slogging.GetLogger().Debug("config raw from cmdline")
+	case !isPath:
+		log.Debug("config raw from cmdline")
 
 		err = dhall.Unmarshal([]byte(conf), &config)
 	}
 
-	if err != nil {
-		return nil, err
+	if !config.Logger.Json {
+		slogger = slogging.Init(false)
+		log.Logger = slogger.Logger.With(
+			slog.Group("pcmt extra", slog.String("module", "config")),
+		)
 	}
 
 	if config.DevelMode {
-		_ = slogging.SetLevel(slogging.LevelDebug)
+		log.Debug("set DEBUG level based on config value")
 
-		slogging.GetLogger().Debugf("parsed config: %+v", config)
+		slogger = slogging.SetLevel(slogging.LevelDebug)
+		log.Logger = slogger.Logger.With(
+			slog.Group("pcmt extra", slog.String("module", "config")),
+		)
+
+		log.Debugf("parsed config: %+v", config)
 
 		if dhallCmdExists() {
 			_ = prettyPrintConfig(conf, isPath)
 		}
 	}
 
+	// only return now, one we had a chance to print the loaded config (as
+	// would be the case if the config adhered to the schema but our type
+	// definition above didn't - "don't know how to decode <nil> into ...")
+	if err != nil {
+		return nil, err
+	}
+
 	return &config, nil
 }
 
@@ -75,7 +107,7 @@ func prettyPrintConfig(conf string, isPath bool) error {
 
 	output, err := cmd.CombinedOutput()
 	if err != nil {
-		slogging.GetLogger().Debug("could not pretty-print config", "error", err)
+		log.Debug("could not pretty-print config", "error", err)
 		return err
 	}
 
@@ -93,7 +125,7 @@ func dhallCmdExists() bool {
 	defer cancel()
 
 	if err := exec.CommandContext(ctx, "/bin/sh", "-c", "command -v dhall").Run(); err != nil {
-		slogging.GetLogger().Debug("no command dhall")
+		log.Debug("no command dhall")
 		return false
 	}
 

handlers/config.go

@@ -5,17 +5,23 @@ import (
 
 	"git.dotya.ml/mirre-mt/pcmt/app/settings"
 	"git.dotya.ml/mirre-mt/pcmt/slogging"
+	"golang.org/x/exp/slog"
 )
 
 var (
 	setting  *settings.Settings
 	appver   string
-	log      *slogging.Logger
+	slogger  *slogging.Logger
+	log      slogging.Logger
 	tmplPath string
 )
 
 func InitHandlers(s *settings.Settings, tmpls fs.FS) {
-	log = slogging.GetLogger()
+	slogger = slogging.GetLogger()
+	log = *slogger // have a local copy.
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "handlers")),
+	)
 
 	setting = s
 

handlers/handlers.go

@@ -232,7 +232,7 @@ func SignupPost(client *ent.Client) echo.HandlerFunc {
 			return c.Redirect(http.StatusSeeOther, "/signup")
 		}
 
-		ctx := context.WithValue(context.Background(), moduser.CtxKey{}, log)
+		ctx := context.WithValue(context.Background(), moduser.CtxKey{}, slogger)
 
 		exists, err := moduser.Exists(ctx, client, username, email)
 		if err != nil {
@@ -339,7 +339,7 @@ func Home(client *ent.Client) echo.HandlerFunc {
 
 		var u moduser.User
 
-		ctx := context.WithValue(context.Background(), moduser.CtxKey{}, log)
+		ctx := context.WithValue(context.Background(), moduser.CtxKey{}, slogger)
 		if usr, err := moduser.QueryUser(ctx, client, username); err == nil && usr != nil {
 			c.Logger().Debug("got usr: ", usr.Username)
 			c.Logger().Debug("admin? ", usr.IsAdmin)

handlers/signin.go

@@ -64,7 +64,7 @@ func SigninPost(client *ent.Client) echo.HandlerFunc {
 			return c.Redirect(http.StatusFound, "/signin")
 		}
 
-		ctx := context.WithValue(context.Background(), moduser.CtxKey{}, log)
+		ctx := context.WithValue(context.Background(), moduser.CtxKey{}, slogger)
 		if usr, err := moduser.QueryUser(ctx, client, username); err == nil {
 			log.Info("queried user:", &usr.ID)
 

modules/db/db.go

@@ -6,6 +6,7 @@ import (
 	"git.dotya.ml/mirre-mt/pcmt/ent"
 	"git.dotya.ml/mirre-mt/pcmt/ent/migrate"
 	"git.dotya.ml/mirre-mt/pcmt/slogging"
+	"golang.org/x/exp/slog"
 )
 
 // CtxKey serves as a key to context values for this package.
@@ -13,7 +14,12 @@ type CtxKey struct{}
 
 // DropAll deletes an re-creates the whole db.
 func DropAll(ctx context.Context, client *ent.Client) error {
-	log := ctx.Value(CtxKey{}).(*slogging.Logger)
+	slogger := ctx.Value(CtxKey{}).(*slogging.Logger)
+	log := *slogger
+
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "modules/db")),
+	)
 
 	err := client.Schema.
 		Create(
@@ -31,7 +37,13 @@ func DropAll(ctx context.Context, client *ent.Client) error {
 
 // IsSetUp deletes the whole db.
 func IsSetUp(ctx context.Context, client *ent.Client) (bool, error) {
-	log := ctx.Value(CtxKey{}).(*slogging.Logger)
+	slogger := ctx.Value(CtxKey{}).(*slogging.Logger)
+	log := *slogger
+
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "modules/db")),
+	)
+
 	is, err := client.Setup.
 		Query().
 		Only(ctx)

modules/user/user.go

@@ -11,6 +11,7 @@ import (
 	passwd "git.dotya.ml/mirre-mt/pcmt/modules/password"
 	"git.dotya.ml/mirre-mt/pcmt/slogging"
 	"github.com/google/uuid"
+	"golang.org/x/exp/slog"
 )
 
 type User struct {
@@ -25,7 +26,12 @@ type User struct {
 
 // CreateUser adds a user entry to the database.
 func CreateUser(ctx context.Context, client *ent.Client, email, username, password string) (*ent.User, error) {
-	log := ctx.Value(CtxKey{}).(*slogging.Logger)
+	slogger := ctx.Value(CtxKey{}).(*slogging.Logger)
+	log := *slogger
+
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "modules/user")),
+	)
 
 	digest, err := passwd.GetHash(password)
 	if err != nil {
@@ -60,7 +66,12 @@ func CreateUser(ctx context.Context, client *ent.Client, email, username, passwo
 }
 
 func QueryUser(ctx context.Context, client *ent.Client, username string) (*ent.User, error) {
-	log := ctx.Value(CtxKey{}).(*slogging.Logger)
+	slogger := ctx.Value(CtxKey{}).(*slogging.Logger)
+	log := *slogger
+
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "modules/user")),
+	)
 
 	u, err := client.User.
 		Query().
@@ -84,7 +95,12 @@ func QueryUser(ctx context.Context, client *ent.Client, username string) (*ent.U
 // Exists determines whether the username OR email in question was previously
 // used to register a user.
 func Exists(ctx context.Context, client *ent.Client, username, email string) (bool, error) {
-	log := ctx.Value(CtxKey{}).(*slogging.Logger)
+	slogger := ctx.Value(CtxKey{}).(*slogging.Logger)
+	log := *slogger
+
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "modules/user")),
+	)
 
 	usernameExists, err := UsernameExists(ctx, client, username)
 	if err != nil {
@@ -120,8 +136,13 @@ func Exists(ctx context.Context, client *ent.Client, username, email string) (bo
 // UsernameExists queries the database to check whether the username is
 // available or taken, returns a bool and an error, which will be nil unless
 // the error is one of IsNot{Found,Singular}.
-func UsernameExists(ctx context.Context, client *ent.Client, username string) (bool, error) {
-	log := ctx.Value(CtxKey{}).(*slogging.Logger)
+func UsernameExists(ctx context.Context, client *ent.Client, username string) (bool, error) { //nolint:dupl
+	slogger := ctx.Value(CtxKey{}).(*slogging.Logger)
+	log := *slogger
+
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "modules/user")),
+	)
 
 	usr, err := client.User.
 		Query().
@@ -155,8 +176,13 @@ func UsernameExists(ctx context.Context, client *ent.Client, username string) (b
 // EmailExists queries the database to check whether the email was already
 // used; returns a bool and an error, which will be nil unless the error is not
 // one of IsNot{Found,Singular}.
-func EmailExists(ctx context.Context, client *ent.Client, email string) (bool, error) {
-	log := ctx.Value(CtxKey{}).(*slogging.Logger)
+func EmailExists(ctx context.Context, client *ent.Client, email string) (bool, error) { //nolint:dupl
+	slogger := ctx.Value(CtxKey{}).(*slogging.Logger)
+	log := *slogger
+
+	log.Logger = log.Logger.With(
+		slog.Group("pcmt extra", slog.String("module", "modules/user")),
+	)
 
 	usr, err := client.User.
 		Query().

run.go

@@ -11,6 +11,7 @@ import (
 	"syscall"
 	"time"
 
+	"golang.org/x/exp/slog"
 	// pure go postgres driver.
 	_ "github.com/lib/pq"
 	// ent pure go sqlite3 driver instead of "github.com/mattn/go-sqlite3".
@@ -61,7 +62,10 @@ var (
 	devel            = flag.Bool("devel", false, "Run the application in dev mode, connect to a local browser-sync instance for hot-reloading")
 	license          = flag.Bool("license", false, "Print licensing information and exit")
 	version          = "dev"
-	log              *slogging.Logger
+	// the global logger.
+	slogger *slogging.Logger
+	// local logger instance.
+	log slogging.Logger
 )
 
 func run() error {
@@ -74,8 +78,6 @@ func run() error {
 
 	printHeader()
 
-	log = slogging.Init(true)
-
 	// TODO: allow different configuration formats (toml, ni)
 	// TODO: rename main.go to pcmt.go
 	// TODO: add .golangci-lint
@@ -87,8 +89,7 @@ func run() error {
 
 	conf, err := config.LoadConfig(*configFlag, *configIsPathFlag)
 	if err != nil {
-		log.Errorf("error loading config file '%s', bailing", *configFlag)
-		return err
+		return fmt.Errorf("couldn't load config file '%s', full err: %w", *configFlag, err)
 	}
 
 	setting := settings.New()
@@ -97,6 +98,13 @@ func run() error {
 		conf, host, port, devel, version,
 	)
 
+	slogger = slogging.GetLogger() // init is performed in the config package.
+	log = *slogger                 // local copy.
+	log.Logger = log.Logger.With(
+		// local attrs.
+		slog.Group("pcmt extra", slog.String("module", "run")),
+	)
+
 	// expected connstring form for "github.com/xiaoqidun/entps":
 	// "file:ent?mode=memory&cache=shared&_fk=1"
 	// and for the postgres driver "github.com/lib/pq":
@@ -117,7 +125,7 @@ func run() error {
 	}
 	defer db.Close()
 
-	ctx := context.WithValue(context.Background(), moddb.CtxKey{}, log)
+	ctx := context.WithValue(context.Background(), moddb.CtxKey{}, slogger)
 
 	log.Info("making sure that the db is set up")
 
@@ -136,7 +144,7 @@ func run() error {
 
 	a := &app.App{}
 
-	err = a.Init(setting, log, db)
+	err = a.Init(setting, slogger, db)
 	if err != nil {
 		return err
 	}

slogging/log.go

@@ -37,6 +37,8 @@ func Init(jsonHandler bool) *Logger {
 		logger = &Logger{slog.New(opts.NewTextHandler(os.Stderr))}
 	}
 
+	slog.SetDefault(logger.Logger)
+
 	logger.Info("slog logger initialised")
 
 	return logger
@@ -70,6 +72,8 @@ func SetLevel(level int) *Logger {
 		logger = &Logger{slog.New(opts.NewTextHandler(os.Stderr))}
 	}
 
+	slog.SetDefault(logger.Logger)
+
 	return logger
 }