diff --git a/server/ctrladmin/ctrl.go b/server/ctrladmin/ctrl.go
index 1d542e4..f5557ce 100644
--- a/server/ctrladmin/ctrl.go
+++ b/server/ctrladmin/ctrl.go
@@ -236,6 +236,7 @@ type Flash struct {
 	Type    FlashType
 }
 
+//nolint:gochecknoinits
 func init() {
 	gob.Register(&Flash{})
 }
diff --git a/server/ctrladmin/handlers.go b/server/ctrladmin/handlers.go
index 999dc53..ce11fb8 100644
--- a/server/ctrladmin/handlers.go
+++ b/server/ctrladmin/handlers.go
@@ -82,7 +82,7 @@ func (c *Controller) ServeHome(r *http.Request) *Response {
 	c.DB.
 		Where("user_id=?", user.ID).
 		Find(&data.TranscodePreferences)
-	for profile := range encode.Profiles {
+	for profile := range encode.Profiles() {
 		data.TranscodeProfiles = append(data.TranscodeProfiles, profile)
 	}
 	//
diff --git a/server/ctrlsubsonic/handlers_raw.go b/server/ctrlsubsonic/handlers_raw.go
index 18fdc2d..fcb9893 100644
--- a/server/ctrlsubsonic/handlers_raw.go
+++ b/server/ctrlsubsonic/handlers_raw.go
@@ -72,7 +72,7 @@ func serveTrackRaw(w http.ResponseWriter, r *http.Request, opts serveTrackOption
 }
 
 func serveTrackEncode(w http.ResponseWriter, r *http.Request, opts serveTrackOptions) {
-	profile := encode.Profiles[opts.pref.Profile]
+	profile := encode.Profiles()[opts.pref.Profile]
 	bitrate := encode.GetBitrate(opts.maxBitrate, profile)
 	trackPath := path.Join(opts.musicPath, opts.track.RelPath())
 	cacheKey := encode.CacheKey(trackPath, opts.pref.Profile, bitrate)
diff --git a/server/ctrlsubsonic/spec/spec.go b/server/ctrlsubsonic/spec/spec.go
index 7b8c93b..d652bb5 100644
--- a/server/ctrlsubsonic/spec/spec.go
+++ b/server/ctrlsubsonic/spec/spec.go
@@ -7,7 +7,7 @@ import (
 	"go.senan.xyz/gonic/version"
 )
 
-var (
+const (
 	apiVersion = "1.9.0"
 	xmlns      = "http://subsonic.org/restapi"
 )
diff --git a/server/db/db.go b/server/db/db.go
index 634f30c..f710400 100644
--- a/server/db/db.go
+++ b/server/db/db.go
@@ -31,9 +31,8 @@ func wrapMigrations(migrs ...gormigrate.Migration) []*gormigrate.Migration {
 	return ret
 }
 
-var (
-	dbMaxOpenConns = 1
-	dbOptions      = url.Values{
+func defaultOptions() url.Values {
+	return url.Values{
 		// with this, multiple connections share a single data and schema cache.
 		// see https://www.sqlite.org/sharedcache.html
 		"cache": {"shared"},
@@ -43,7 +42,7 @@ var (
 		"_journal_mode": {"WAL"},
 		"_foreign_keys": {"true"},
 	}
-)
+}
 
 type DB struct {
 	*gorm.DB
@@ -55,13 +54,13 @@ func New(path string) (*DB, error) {
 		Scheme: "file",
 		Opaque: path,
 	}
-	url.RawQuery = dbOptions.Encode()
+	url.RawQuery = defaultOptions().Encode()
 	db, err := gorm.Open("sqlite3", url.String())
 	if err != nil {
 		return nil, fmt.Errorf("with gorm: %w", err)
 	}
 	db.SetLogger(log.New(os.Stdout, "gorm ", 0))
-	db.DB().SetMaxOpenConns(dbMaxOpenConns)
+	db.DB().SetMaxOpenConns(1)
 	migrOptions := &gormigrate.Options{
 		TableName:      "migrations",
 		IDColumnName:   "id",
@@ -69,13 +68,13 @@ func New(path string) (*DB, error) {
 		UseTransaction: false,
 	}
 	migr := gormigrate.New(db, migrOptions, wrapMigrations(
-		migrationInitSchema,
-		migrationCreateInitUser,
-		migrationMergePlaylist,
-		migrationCreateTranscode,
-		migrationAddGenre,
-		migrationUpdateTranscodePrefIDX,
-		migrationAddAlbumIDX,
+		migrateInitSchema(),
+		migrateCreateInitUser(),
+		migrateMergePlaylist(),
+		migrateCreateTranscode(),
+		migrateAddGenre(),
+		migrateUpdateTranscodePrefIDX(),
+		migrateAddAlbumIDX(),
 	))
 	if err = migr.Migrate(); err != nil {
 		return nil, fmt.Errorf("migrating to latest version: %w", err)
diff --git a/server/db/migrations.go b/server/db/migrations.go
index b777777..609762c 100644
--- a/server/db/migrations.go
+++ b/server/db/migrations.go
@@ -9,55 +9,58 @@ import (
 
 // $ date '+%Y%m%d%H%M'
 
-// not really a migration
-var migrationInitSchema = gormigrate.Migration{
-	ID: "202002192100",
-	Migrate: func(tx *gorm.DB) error {
-		return tx.AutoMigrate(
-			Artist{},
-			Track{},
-			User{},
-			Setting{},
-			Play{},
-			Album{},
-			Playlist{},
-			PlayQueue{},
-		).
-			Error
-	},
+func migrateInitSchema() gormigrate.Migration {
+	return gormigrate.Migration{
+		ID: "202002192100",
+		Migrate: func(tx *gorm.DB) error {
+			return tx.AutoMigrate(
+				Artist{},
+				Track{},
+				User{},
+				Setting{},
+				Play{},
+				Album{},
+				Playlist{},
+				PlayQueue{},
+			).
+				Error
+		},
+	}
 }
 
-// not really a migration
-var migrationCreateInitUser = gormigrate.Migration{
-	ID: "202002192019",
-	Migrate: func(tx *gorm.DB) error {
-		const (
-			initUsername = "admin"
-			initPassword = "admin"
-		)
-		err := tx.
-			Where("name=?", initUsername).
-			First(&User{}).
-			Error
-		if !gorm.IsRecordNotFoundError(err) {
-			return nil
-		}
-		return tx.Create(&User{
-			Name:     initUsername,
-			Password: initPassword,
-			IsAdmin:  true,
-		}).
-			Error
-	},
+func migrateCreateInitUser() gormigrate.Migration {
+	return gormigrate.Migration{
+		ID: "202002192019",
+		Migrate: func(tx *gorm.DB) error {
+			const (
+				initUsername = "admin"
+				initPassword = "admin"
+			)
+			err := tx.
+				Where("name=?", initUsername).
+				First(&User{}).
+				Error
+			if !gorm.IsRecordNotFoundError(err) {
+				return nil
+			}
+			return tx.Create(&User{
+				Name:     initUsername,
+				Password: initPassword,
+				IsAdmin:  true,
+			}).
+				Error
+		},
+	}
 }
 
-var migrationMergePlaylist = gormigrate.Migration{
-	ID: "202002192222",
-	Migrate: func(tx *gorm.DB) error {
-		if !tx.HasTable("playlist_items") {
-			return nil
-		}
-		return tx.Exec(`
+func migrateMergePlaylist() gormigrate.Migration {
+	return gormigrate.Migration{
+		ID: "202002192222",
+		Migrate: func(tx *gorm.DB) error {
+			if !tx.HasTable("playlist_items") {
+				return nil
+			}
+			return tx.Exec(`
 			UPDATE playlists
 			SET items=( SELECT group_concat(track_id) FROM (
 				SELECT track_id
@@ -66,78 +69,87 @@ var migrationMergePlaylist = gormigrate.Migration{
 				ORDER BY created_at
 			) );
 			DROP TABLE playlist_items;`,
-		).
-			Error
-	},
+			).
+				Error
+		},
+	}
 }
 
-var migrationCreateTranscode = gormigrate.Migration{
-	ID: "202003111222",
-	Migrate: func(tx *gorm.DB) error {
-		return tx.AutoMigrate(
-			TranscodePreference{},
-		).
-			Error
-	},
+func migrateCreateTranscode() gormigrate.Migration {
+	return gormigrate.Migration{
+		ID: "202003111222",
+		Migrate: func(tx *gorm.DB) error {
+			return tx.AutoMigrate(
+				TranscodePreference{},
+			).
+				Error
+		},
+	}
 }
 
-var migrationAddGenre = gormigrate.Migration{
-	ID: "202003121330",
-	Migrate: func(tx *gorm.DB) error {
-		return tx.AutoMigrate(
-			Genre{},
-			Album{},
-			Track{},
-		).
-			Error
-	},
+func migrateAddGenre() gormigrate.Migration {
+	return gormigrate.Migration{
+		ID: "202003121330",
+		Migrate: func(tx *gorm.DB) error {
+			return tx.AutoMigrate(
+				Genre{},
+				Album{},
+				Track{},
+			).
+				Error
+		},
+	}
 }
 
-var migrationUpdateTranscodePrefIDX = gormigrate.Migration{
-	ID: "202003241509",
-	Migrate: func(tx *gorm.DB) error {
-		var hasIDX int
-		tx.
-			Select("1").
-			Table("sqlite_master").
-			Where("type = ?", "index").
-			Where("name = ?", "idx_user_id_client").
-			Count(&hasIDX)
-		if hasIDX == 1 {
-			// index already exists
-			return nil
-		}
-		step := tx.Exec(`
+func migrateUpdateTranscodePrefIDX() gormigrate.Migration {
+	return gormigrate.Migration{
+		ID: "202003241509",
+		Migrate: func(tx *gorm.DB) error {
+			var hasIDX int
+			tx.
+				Select("1").
+				Table("sqlite_master").
+				Where("type = ?", "index").
+				Where("name = ?", "idx_user_id_client").
+				Count(&hasIDX)
+			if hasIDX == 1 {
+				// index already exists
+				return nil
+			}
+			step := tx.Exec(`
 			ALTER TABLE transcode_preferences RENAME TO transcode_preferences_orig;
 		`)
-		if err := step.Error; err != nil {
-			return fmt.Errorf("step rename: %w", err)
-		}
-		step = tx.AutoMigrate(
-			TranscodePreference{},
-		)
-		if err := step.Error; err != nil {
-			return fmt.Errorf("step create: %w", err)
-		}
-		step = tx.Exec(`
+			if err := step.Error; err != nil {
+				return fmt.Errorf("step rename: %w", err)
+			}
+			step = tx.AutoMigrate(
+				TranscodePreference{},
+			)
+			if err := step.Error; err != nil {
+				return fmt.Errorf("step create: %w", err)
+			}
+			step = tx.Exec(`
 			INSERT INTO transcode_preferences (user_id, client, profile)
 				SELECT user_id, client, profile
 				FROM transcode_preferences_orig;
 			DROP TABLE transcode_preferences_orig;
 		`)
-		if err := step.Error; err != nil {
-			return fmt.Errorf("step copy: %w", err)
-		}
-		return nil
-	},
+			if err := step.Error; err != nil {
+				return fmt.Errorf("step copy: %w", err)
+			}
+			return nil
+		},
+	}
 }
 
-var migrationAddAlbumIDX = gormigrate.Migration{
-	ID: "202004302006",
-	Migrate: func(tx *gorm.DB) error {
-		return tx.AutoMigrate(
-			Album{},
-		).
-			Error
-	},
+func migrateAddAlbumIDX() gormigrate.Migration {
+	return gormigrate.Migration{
+		ID: "202004302006",
+		Migrate: func(tx *gorm.DB) error {
+			return tx.AutoMigrate(
+				Album{},
+			).
+				Error
+		},
+	}
 }
diff --git a/server/db/model.go b/server/db/model.go
index b613bf3..16db3fe 100644
--- a/server/db/model.go
+++ b/server/db/model.go
@@ -94,8 +94,8 @@ func (t *Track) Ext() string {
 }
 
 func (t *Track) MIME() string {
-	ext := t.Ext()
-	return mime.Types[ext]
+	v, _ := mime.FromExtension(t.Ext())
+	return v
 }
 
 func (t *Track) RelPath() string {
diff --git a/server/encode/encode.go b/server/encode/encode.go
index bad408e..6c1023d 100644
--- a/server/encode/encode.go
+++ b/server/encode/encode.go
@@ -13,6 +13,10 @@ import (
 	"github.com/cespare/xxhash"
 )
 
+const (
+	buffLen = 4096
+)
+
 type Profile struct {
 	Format        string
 	Bitrate       int
@@ -20,15 +24,14 @@ type Profile struct {
 	forceRG       bool
 }
 
-var (
-	Profiles = map[string]*Profile{
+func Profiles() map[string]Profile {
+	return map[string]Profile{
 		"mp3":     {"mp3", 128, []string{"-c:a", "libmp3lame"}, false},
 		"mp3_rg":  {"mp3", 128, []string{"-c:a", "libmp3lame"}, true},
 		"opus":    {"opus", 96, []string{"-c:a", "libopus", "-vbr", "constrained"}, false},
 		"opus_rg": {"opus", 96, []string{"-c:a", "libopus", "-vbr", "constrained"}, true},
 	}
-	bufLen = 4096
-)
+}
 
 // copy command output to http response body using io.copy (simpler, but may increase ttfb)
 //nolint:deadcode,unused
@@ -45,7 +48,7 @@ func copyCmdOutput(out, cache io.Writer, pipeReader io.Reader) {
 // copy command output to http response manually with a buffer (should reduce ttfb)
 //nolint:deadcode,unused
 func writeCmdOutput(out, cache io.Writer, pipeReader io.ReadCloser) {
-	buffer := make([]byte, bufLen)
+	buffer := make([]byte, buffLen)
 	for {
 		n, err := pipeReader.Read(buffer)
 		if err != nil {
@@ -70,7 +73,7 @@ func writeCmdOutput(out, cache io.Writer, pipeReader io.ReadCloser) {
 }
 
 // pre-format the ffmpeg command with needed options
-func ffmpegCommand(filePath string, profile *Profile, bitrate string) *exec.Cmd {
+func ffmpegCommand(filePath string, profile Profile, bitrate string) *exec.Cmd {
 	args := []string{
 		"-v", "0",
 		"-i", filePath,
@@ -94,7 +97,7 @@ func ffmpegCommand(filePath string, profile *Profile, bitrate string) *exec.Cmd
 	return exec.Command("/usr/bin/ffmpeg", args...) //nolint:gosec
 }
 
-func Encode(out io.Writer, trackPath, cachePath string, profile *Profile, bitrate string) error {
+func Encode(out io.Writer, trackPath, cachePath string, profile Profile, bitrate string) error {
 	// prepare the command and file descriptors
 	cmd := ffmpegCommand(trackPath, profile, bitrate)
 	pipeReader, pipeWriter := io.Pipe()
@@ -126,13 +129,13 @@ func Encode(out io.Writer, trackPath, cachePath string, profile *Profile, bitrat
 
 // CacheKey generates the filename for the new transcode save
 func CacheKey(sourcePath string, profile, bitrate string) string {
-	format := Profiles[profile].Format
+	format := Profiles()[profile].Format
 	hash := xxhash.Sum64String(sourcePath)
 	return fmt.Sprintf("%x-%s-%s.%s", hash, profile, bitrate, format)
 }
 
 // GetBitrate checks if the client forces bitrate lower than set in profile
-func GetBitrate(clientBitrate int, profile *Profile) string {
+func GetBitrate(clientBitrate int, profile Profile) string {
 	bitrate := profile.Bitrate
 	if clientBitrate != 0 && clientBitrate < bitrate {
 		bitrate = clientBitrate
diff --git a/server/lastfm/lastfm.go b/server/lastfm/lastfm.go
index 809f2b5..f80b3b1 100644
--- a/server/lastfm/lastfm.go
+++ b/server/lastfm/lastfm.go
@@ -10,16 +10,15 @@ import (
 	"net/url"
 	"sort"
 	"strconv"
-	"time"
 
 	"go.senan.xyz/gonic/server/db"
 )
 
-var (
+const (
 	baseURL = "https://ws.audioscrobbler.com/2.0/"
-	client  = &http.Client{
-		Timeout: 10 * time.Second,
-	}
+)
+
+var (
 	ErrLastFM = errors.New("last.fm error")
 )
 
@@ -27,7 +26,7 @@ var (
 
 func getParamSignature(params url.Values, secret string) string {
 	// the parameters must be in order before hashing
-	paramKeys := make([]string, 0)
+	paramKeys := make([]string, 0, len(params))
 	for k := range params {
 		paramKeys = append(paramKeys, k)
 	}
@@ -45,7 +44,7 @@ func getParamSignature(params url.Values, secret string) string {
 func makeRequest(method string, params url.Values) (LastFM, error) {
 	req, _ := http.NewRequest(method, baseURL, nil)
 	req.URL.RawQuery = params.Encode()
-	resp, err := client.Do(req)
+	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return LastFM{}, fmt.Errorf("get: %w", err)
 	}
diff --git a/server/mime/mime.go b/server/mime/mime.go
index 7a5fd4d..63c8f93 100644
--- a/server/mime/mime.go
+++ b/server/mime/mime.go
@@ -1,11 +1,18 @@
 package mime
 
-var Types = map[string]string{
-	"mp3":  "audio/mpeg",
-	"flac": "audio/x-flac",
-	"aac":  "audio/x-aac",
-	"m4a":  "audio/m4a",
-	"m4b":  "audio/m4b",
-	"ogg":  "audio/ogg",
-	"opus": "audio/ogg",
+// this package is at such a high level in the hierarchy because
+// it's used by both `server/db` and `server/scanner`
+
+func FromExtension(ext string) (string, bool) {
+	types := map[string]string{
+		"mp3":  "audio/mpeg",
+		"flac": "audio/x-flac",
+		"aac":  "audio/x-aac",
+		"m4a":  "audio/m4a",
+		"m4b":  "audio/m4b",
+		"ogg":  "audio/ogg",
+		"opus": "audio/ogg",
+	}
+	v, ok := types[ext]
+	return v, ok
 }
diff --git a/server/scanner/scanner.go b/server/scanner/scanner.go
index cfc1919..2ae5536 100644
--- a/server/scanner/scanner.go
+++ b/server/scanner/scanner.go
@@ -44,7 +44,7 @@ func decoded(in string) string {
 
 // isScanning acts as an atomic boolean semaphore. we don't
 // want to have more than one scan going on at a time
-var isScanning int32
+var isScanning int32 //nolint:gochecknoglobals
 
 func IsScanning() bool {
 	return atomic.LoadInt32(&isScanning) == 1
@@ -224,19 +224,23 @@ type item struct {
 	stat      os.FileInfo
 }
 
-var coverFilenames = map[string]struct{}{
-	"cover.png":   {},
-	"cover.jpg":   {},
-	"cover.jpeg":  {},
-	"folder.png":  {},
-	"folder.jpg":  {},
-	"folder.jpeg": {},
-	"album.png":   {},
-	"album.jpg":   {},
-	"album.jpeg":  {},
-	"front.png":   {},
-	"front.jpg":   {},
-	"front.jpeg":  {},
+func isCover(filename string) bool {
+	known := map[string]struct{}{
+		"cover.png":   {},
+		"cover.jpg":   {},
+		"cover.jpeg":  {},
+		"folder.png":  {},
+		"folder.jpg":  {},
+		"folder.jpeg": {},
+		"album.png":   {},
+		"album.jpg":   {},
+		"album.jpeg":  {},
+		"front.png":   {},
+		"front.jpg":   {},
+		"front.jpeg":  {},
+	}
+	_, ok := known[filename]
+	return ok
 }
 
 // ## begin callbacks
@@ -267,8 +271,8 @@ func (s *Scanner) callbackItem(fullPath string, info *godirwalk.Dirent) error {
 	if isDir {
 		return s.handleFolder(it)
 	}
-	lowerFilename := strings.ToLower(filename)
-	if _, ok := coverFilenames[lowerFilename]; ok {
+	filenameLow := strings.ToLower(filename)
+	if isCover(filenameLow) {
 		s.curCover = filename
 		return nil
 	}
@@ -276,7 +280,7 @@ func (s *Scanner) callbackItem(fullPath string, info *godirwalk.Dirent) error {
 	if ext == "" {
 		return nil
 	}
-	if _, ok := mime.Types[ext[1:]]; ok {
+	if _, ok := mime.FromExtension(ext[1:]); ok {
 		return s.handleTrack(it)
 	}
 	return nil