Remove unnecessary code after dskit log.Interface has been dereleased (#10434)

This PR removes unnecessary code used to convert the dereleased `dslog.Interface` (see https://github.com/grafana/dskit/pull/359) into `go-kit.Logger`.
Additionally, it modifies the signature and implementation of `pkg/util/log/log.go`'s `InitLogger` as follows:

- previous signature 
  ```
  InitLogger(*server.Config, prometheus.Registerer, bool, bool)
  ```
  has been replaced with 
  ```
InitLogger(*server.Config, prometheus.Registerer, bool, bool) log.Logger
  ```
Namely, the new `InitLogger` initialises the global logger and returns
it.
- the new implementation initializes the global logger, but it does not override the default logger for the server. This is now done by the callers of `InitLogger`. Previously, it was done inside `InitLogger` for convenience, since the types of the 2 loggers were not the same.

Signed-off-by: Yuri Nikolic <durica.nikolic@grafana.com>

clients/cmd/docker-driver/main.go

@@ -12,7 +12,6 @@ import (
 	dslog "github.com/grafana/dskit/log"
 	"github.com/prometheus/common/version"
 
-	"github.com/grafana/loki/pkg/util"
 	_ "github.com/grafana/loki/pkg/util/build"
 	util_log "github.com/grafana/loki/pkg/util/log"
 )
@@ -54,7 +53,7 @@ func main() {
 func newLogger(lvl dslog.Level) log.Logger {
 	// plugin logs must be stdout to appear.
 	logger := log.NewLogfmtLogger(log.NewSyncWriter(os.Stdout))
-	logger = level.NewFilter(logger, util.LogFilter(lvl.String()))
+	logger = level.NewFilter(logger, lvl.Option)
 	logger = log.With(logger, "ts", log.DefaultTimestampUTC)
 	logger = log.With(logger, "caller", log.Caller(3))
 	return logger

clients/cmd/fluent-bit/loki.go

@@ -20,8 +20,6 @@ import (
 	"github.com/grafana/loki/clients/pkg/promtail/api"
 	"github.com/grafana/loki/clients/pkg/promtail/client"
 
-	"github.com/grafana/loki/pkg/util"
-
 	"github.com/grafana/loki/pkg/logproto"
 )
 
@@ -270,7 +268,7 @@ func (l *loki) createLine(records map[string]interface{}, f format) (string, err
 
 func newLogger(logLevel dslog.Level) log.Logger {
 	logger := log.NewLogfmtLogger(log.NewSyncWriter(os.Stderr))
-	logger = level.NewFilter(logger, util.LogFilter(logLevel.String()))
+	logger = level.NewFilter(logger, logLevel.Option)
 	logger = log.With(logger, "caller", log.Caller(3))
 	return logger
 }

clients/cmd/promtail/main.go

@@ -106,7 +106,8 @@ func main() {
 		fmt.Println("Invalid log level")
 		exit(1)
 	}
-	util_log.InitLogger(&config.Config.ServerConfig.Config, prometheus.DefaultRegisterer, true, false)
+	serverCfg := &config.Config.ServerConfig.Config
+	serverCfg.Log = util_log.InitLogger(serverCfg, prometheus.DefaultRegisterer, true, false)
 
 	// Use Stderr instead of files for the klog.
 	klog.SetOutput(os.Stderr)

clients/pkg/promtail/targets/lokipush/pushtarget.go

@@ -79,7 +79,8 @@ func (t *PushTarget) run() error {
 
 	// The logger registers a metric which will cause a duplicate registry panic unless we provide an empty registry
 	// The metric created is for counting log lines and isn't likely to be missed.
-	util_log.InitLogger(&t.config.Server, prometheus.NewRegistry(), true, false)
+	serverCfg := &t.config.Server
+	serverCfg.Log = util_log.InitLogger(serverCfg, prometheus.NewRegistry(), true, false)
 
 	srv, err := server.New(t.config.Server)
 	if err != nil {

cmd/loki/main.go

@@ -48,7 +48,8 @@ func main() {
 		level.Error(util_log.Logger).Log("msg", "invalid log level")
 		exit(1)
 	}
-	util_log.InitLogger(&config.Server, prometheus.DefaultRegisterer, config.UseBufferedLogger, config.UseSyncLogger)
+	serverCfg := &config.Server
+	serverCfg.Log = util_log.InitLogger(serverCfg, prometheus.DefaultRegisterer, config.UseBufferedLogger, config.UseSyncLogger)
 
 	// Validate the config once both the config file has been loaded
 	// and CLI flags parsed.

pkg/util/log.go

@@ -72,21 +72,3 @@ func (l LogAdapter) Printf(format string, v ...interface{}) {
 func (l LogAdapter) Println(v ...interface{}) {
 	level.Info(l).Log("msg", fmt.Sprint(v...))
 }
-
-// LogFilter translates a log level into a go-kit/log level filter.
-//
-// TODO(dannyk): remove once weaveworks/common updates to go-kit/log, we can then revert to using Level.Gokit
-func LogFilter(l string) level.Option {
-	switch l {
-	case "debug":
-		return level.AllowDebug()
-	case "info":
-		return level.AllowInfo()
-	case "warn":
-		return level.AllowWarn()
-	case "error":
-		return level.AllowError()
-	default:
-		return level.AllowAll()
-	}
-}

pkg/util/log/log.go

@@ -28,14 +28,13 @@ var (
 	plogger *prometheusLogger
 )
 
-// InitLogger initialises the global gokit logger (util_log.Logger) and overrides the
-// default logger for the server.
-func InitLogger(cfg *server.Config, reg prometheus.Registerer, buffered bool, sync bool) {
-	l := newPrometheusLogger(cfg.LogLevel, cfg.LogFormat, reg, buffered, sync)
-
+// InitLogger initialises the global gokit logger (util_log.Logger) and returns that logger.
+func InitLogger(cfg *server.Config, reg prometheus.Registerer, buffered bool, sync bool) log.Logger {
+	logger := newPrometheusLogger(cfg.LogLevel, cfg.LogFormat, reg, buffered, sync)
 	// when using util_log.Logger, skip 3 stack frames.
-	Logger = log.With(l, "caller", log.Caller(3))
-	cfg.Log = Logger
+	Logger = log.With(logger, "caller", log.Caller(3))
+
+	return Logger
 }
 
 type Flusher interface {
@@ -92,7 +91,7 @@ func LevelHandler(currentLogLevel *dslog.Level) http.HandlerFunc {
 					Status:  "failed",
 				}
 			} else {
-				plogger.Set(levelFilter(logLevel))
+				plogger.Set(currentLogLevel.Option)
 
 				msg := fmt.Sprintf("Log level set to %s", logLevel)
 				level.Info(Logger).Log("msg", msg)
@@ -159,7 +158,7 @@ func newPrometheusLogger(l dslog.Level, format string, reg prometheus.Registerer
 	}
 
 	baseLogger := dslog.NewGoKitWithWriter(format, writer)
-	logger := level.NewFilter(baseLogger, levelFilter(l.String()))
+	logger := level.NewFilter(baseLogger, l.Option)
 
 	plogger = &prometheusLogger{
 		baseLogger:          baseLogger,
@@ -224,19 +223,3 @@ func CheckFatal(location string, err error, logger log.Logger) {
 	}
 	os.Exit(1)
 }
-
-// TODO: remove once weaveworks/common updates to go-kit/log, we can then revert to using Level.Gokit
-func levelFilter(l string) level.Option {
-	switch l {
-	case "debug":
-		return level.AllowDebug()
-	case "info":
-		return level.AllowInfo()
-	case "warn":
-		return level.AllowWarn()
-	case "error":
-		return level.AllowError()
-	default:
-		return level.AllowAll()
-	}
-}

tools/tsdb/index-analyzer/main.go

@@ -90,7 +90,8 @@ func setup() (loki.Config, string, error) {
 	}
 
 	c.Config.StorageConfig.TSDBShipperConfig.Mode = indexshipper.ModeReadOnly
-	util_log.InitLogger(&c.Server, prometheus.DefaultRegisterer, c.UseBufferedLogger, c.UseSyncLogger)
+	serverCfg := &c.Server
+	serverCfg.Log = util_log.InitLogger(serverCfg, prometheus.DefaultRegisterer, c.UseBufferedLogger, c.UseSyncLogger)
 
 	c.Config.StorageConfig.TSDBShipperConfig.ActiveIndexDirectory = filepath.Join(dir, "tsdb-active")
 	c.Config.StorageConfig.TSDBShipperConfig.CacheLocation = filepath.Join(dir, "tsdb-cache")

tools/tsdb/migrate-versions/main.go

@@ -298,7 +298,8 @@ func setup() loki.Config {
 		os.Exit(1)
 	}
 
-	util_log.InitLogger(&c.Server, prometheus.DefaultRegisterer, c.UseBufferedLogger, c.UseSyncLogger)
+	serverCfg := &c.Server
+	serverCfg.Log = util_log.InitLogger(serverCfg, prometheus.DefaultRegisterer, c.UseBufferedLogger, c.UseSyncLogger)
 
 	if err := c.Validate(); err != nil {
 		level.Error(util_log.Logger).Log("msg", "validating config", "err", err.Error())