Add endpoints to provide ability to modify logging verbosity (#16111)

* add func to set level for specific logger

* add endpoints to modify log level

* initialize base logger with IndependentLevels

* test to ensure other loggers remain unchanged

* add DELETE loggers endpoints to revert back to config

* add API docs page

* add changelog entry

* remove extraneous line

* add log level field to Core struct

* add godoc for getLogLevel

* add some loggers to c.allLoggers

command/server.go

@@ -460,8 +460,9 @@ func (c *ServerCommand) runRecoveryMode() int {
 	}
 
 	c.logger = hclog.NewInterceptLogger(&hclog.LoggerOptions{
-		Output: c.gatedWriter,
-		Level:  level,
+		Output:            c.gatedWriter,
+		Level:             level,
+		IndependentLevels: true,
 		// Note that if logFormat is either unspecified or standard, then
 		// the resulting logger's format will be standard.
 		JSONFormat: logFormat == logging.JSONFormat,
@@ -592,6 +593,7 @@ func (c *ServerCommand) runRecoveryMode() int {
 		Physical:     backend,
 		StorageType:  config.Storage.Type,
 		Seal:         barrierSeal,
+		LogLevel:     logLevelString,
 		Logger:       c.logger,
 		DisableMlock: config.DisableMlock,
 		RecoveryMode: c.flagRecovery,
@@ -1116,14 +1118,16 @@ func (c *ServerCommand) Run(args []string) int {
 
 	if c.flagDevThreeNode || c.flagDevFourCluster {
 		c.logger = hclog.NewInterceptLogger(&hclog.LoggerOptions{
-			Mutex:  &sync.Mutex{},
-			Output: c.gatedWriter,
-			Level:  hclog.Trace,
+			Mutex:             &sync.Mutex{},
+			Output:            c.gatedWriter,
+			Level:             hclog.Trace,
+			IndependentLevels: true,
 		})
 	} else {
 		c.logger = hclog.NewInterceptLogger(&hclog.LoggerOptions{
-			Output: c.gatedWriter,
-			Level:  level,
+			Output:            c.gatedWriter,
+			Level:             level,
+			IndependentLevels: true,
 			// Note that if logFormat is either unspecified or standard, then
 			// the resulting logger's format will be standard.
 			JSONFormat: logFormat == logging.JSONFormat,