feat(cmd/node): add logs cmd to dynamically change the log level (#2601)

## Overview
Added cmds that allow to change log level during runtime

## Checklist

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- [ ] New and updated code has appropriate documentation
- [ ] New and updated code has new and/or updated testing
- [ ] Required CI checks are passing
- [ ] Visual proof for any user facing features like CLI or
documentation updates
- [ ] Linked issues closed with keywords

cmd/celestia/logs.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/spf13/cobra"
+
+	"github.com/celestiaorg/celestia-node/cmd"
+)
+
+var logCmd = &cobra.Command{
+	Use:  cmd.LogLevelFlag,
+	Args: cobra.ExactArgs(1),
+	Short: "Allows to set log level for all modules to " +
+		"`DEBUG, INFO, WARN, ERROR, DPANIC, PANIC, FATAL and their lower-case forms`",
+
+	RunE: func(c *cobra.Command, args []string) error {
+		client, err := rpcClient(c.Context())
+		if err != nil {
+			return err
+		}
+		return client.Node.LogLevelSet(c.Context(), "*", args[0])
+	},
+}
+
+var logModuleCmd = &cobra.Command{
+	Use:   cmd.LogLevelModuleFlag,
+	Args:  cobra.MinimumNArgs(1),
+	Short: "Allows to set log level for a particular module in format <module>:<level>",
+	RunE: func(c *cobra.Command, args []string) error {
+		client, err := rpcClient(c.Context())
+		if err != nil {
+			return err
+		}
+		for _, ll := range args {
+			params := strings.Split(ll, ":")
+			if len(params) != 2 {
+				return fmt.Errorf("cmd: %s arg must be in form <module>:<level>,"+
+					"e.g. pubsub:debug", cmd.LogLevelModuleFlag)
+			}
+			if err = client.Node.LogLevelSet(c.Context(), params[0], params[1]); err != nil {
+				return err
+			}
+		}
+		return nil
+	},
+}

cmd/celestia/rpc.go

@@ -60,6 +60,7 @@ func init() {
 		false,
 		"Print JSON-RPC request along with the response",
 	)
+	rpcCmd.AddCommand(logCmd, logModuleCmd)
 	rpcCmd.AddCommand(blobCmd)
 	rootCmd.AddCommand(rpcCmd)
 }

cmd/flags_misc.go

@@ -20,8 +20,8 @@ import (
 )
 
 var (
-	logLevelFlag        = "log.level"
-	logLevelModuleFlag  = "log.level.module"
+	LogLevelFlag        = "log.level"
+	LogLevelModuleFlag  = "log.level.module"
 	pprofFlag           = "pprof"
 	tracingFlag         = "tracing"
 	tracingEndpointFlag = "tracing.endpoint"
@@ -40,14 +40,14 @@ func MiscFlags() *flag.FlagSet {
 	flags := &flag.FlagSet{}
 
 	flags.String(
-		logLevelFlag,
+		LogLevelFlag,
 		"INFO",
 		`DEBUG, INFO, WARN, ERROR, DPANIC, PANIC, FATAL
 and their lower-case forms`,
 	)
 
 	flags.StringSlice(
-		logLevelModuleFlag,
+		LogLevelModuleFlag,
 		nil,
 		"<module>:<level>, e.g. pubsub:debug",
 	)
@@ -123,24 +123,24 @@ and their lower-case forms`,
 
 // ParseMiscFlags parses miscellaneous flags from the given cmd and applies values to Env.
 func ParseMiscFlags(ctx context.Context, cmd *cobra.Command) (context.Context, error) {
-	logLevel := cmd.Flag(logLevelFlag).Value.String()
+	logLevel := cmd.Flag(LogLevelFlag).Value.String()
 	if logLevel != "" {
 		level, err := logging.LevelFromString(logLevel)
 		if err != nil {
-			return ctx, fmt.Errorf("cmd: while parsing '%s': %w", logLevelFlag, err)
+			return ctx, fmt.Errorf("cmd: while parsing '%s': %w", LogLevelFlag, err)
 		}
 
 		logs.SetAllLoggers(level)
 	}
 
-	logModules, err := cmd.Flags().GetStringSlice(logLevelModuleFlag)
+	logModules, err := cmd.Flags().GetStringSlice(LogLevelModuleFlag)
 	if err != nil {
 		panic(err)
 	}
 	for _, ll := range logModules {
 		params := strings.Split(ll, ":")
 		if len(params) != 2 {
-			return ctx, fmt.Errorf("cmd: %s arg must be in form <module>:<level>, e.g. pubsub:debug", logLevelModuleFlag)
+			return ctx, fmt.Errorf("cmd: %s arg must be in form <module>:<level>, e.g. pubsub:debug", LogLevelModuleFlag)
 		}
 
 		err := logging.SetLogLevel(params[0], params[1])