refactor(dlv): replace custom logger func with structured logger

- Before this commit, logging relied on a custom logger function that lacked structured logging,
  leading to inconsistent logging patterns and limited flexibility.
- After this commit, a structured `logger.Logger` is used, improving log consistency, flexibility,
  and integration with the existing logging framework.

Author: gfouillet

cmd/jujud-controller/main_debug.go

@@ -24,7 +24,7 @@ func main() {
 
 	// Start the delve runner against a socket.
 	debugMain := dlv.NewDlvRunner(
-		dlv.WithLoggerFunc(logger.Infof),
+		dlv.WithLogger(logger.Child("dlv")),
 		dlv.Headless(),
 		dlv.NoWait(),
 		dlv.WithApiVersion(2),

cmd/jujud/main_debug.go

@@ -24,7 +24,7 @@ func main() {
 
 	// Start the delve runner against a socket.
 	debugMain := dlv.NewDlvRunner(
-		dlv.WithLoggerFunc(logger.Infof),
+		dlv.WithLogger(logger.Child("dlv")),
 		dlv.Headless(),
 		dlv.NoWait(),
 		dlv.WithApiVersion(2),

internal/dlv/delve.go

@@ -4,7 +4,6 @@
 package dlv
 
 import (
-	"fmt"
 	"os"
 
 	"github.com/go-delve/delve/cmd/dlv/cmds"
@@ -36,8 +35,8 @@ func NewDlvRunner(opts ...Option) func(main MainWithArgs) MainWithArgs {
 			return main
 		}
 		if err := os.Setenv(envNoDebug, "1"); err != nil {
-			logger.Printf("Failed to set env %q: %v", envNoDebug, err)
-			logger.Printf("Starting without debug mode...")
+			logger.Warningf("Failed to set env %q: %v", envNoDebug, err)
+			logger.Warningf("Starting without debug mode...")
 			return main
 		}
 
@@ -55,21 +54,16 @@ func NewDlvRunner(opts ...Option) func(main MainWithArgs) MainWithArgs {
 			// socket
 			config.runSidecars()
 
-			logger.Printf("Starting dlv with %v", dlvArgs)
-			logger.Printf("Running in debug mode")
-			defer logger.Printf("dlv has stopped")
+			logger.Infof("Starting dlv with %v", dlvArgs)
+			logger.Infof("Running in debug mode")
+			defer logger.Infof("dlv has stopped")
 
 			// Execute delve
 			if err := dlvCmd.Execute(); err != nil {
-				fmt.Printf("Failed to run dlv: %v\n", err)
+				logger.Errorf("Failed to run dlv: %v\n", err)
 				return 1
 			}
 			return 0
 		}
 	}
 }
-
-// logger allows to inject the way logs will be handled by wrapped program.
-type logger interface {
-	Printf(format string, v ...interface{})
-}

internal/dlv/options.go

@@ -12,13 +12,16 @@ import (
 
 	"github.com/juju/clock"
 	"github.com/juju/retry"
+
+	"github.com/juju/juju/core/logger"
+	internallogger "github.com/juju/juju/internal/logger"
 )
 
 // Config is a type that represents a map of configuration options where the key is a string and the value can be any type.
 // They are passed to Delve as command line option.
 type Config struct {
-	// definedLogger allows injecting a custom logger implementation to handle logging for the wrapped program.
-	definedLogger logger
+	// definedLogger allows injecting the logger to dlv instance
+	definedLogger logger.Logger
 
 	// dlvArgs contains a map of command line arguments for the Delve debugger, which would typically be added to the
 	// command in the form `--[key]=[value]`
@@ -50,14 +53,10 @@ func With(key string, value ...any) Option {
 	}
 }
 
-// LoggerFunc is a type that defines a function signature for logging messages formatted according to a format specifier.
-type LoggerFunc func(format string, v ...interface{})
-
-// WithLoggerFunc allows setting a custom LoggerFunc for logging.
-// It returns an Option that configures a Config instance to use the provided LoggerFunc for logging.
-func WithLoggerFunc(logger LoggerFunc) Option {
+// WithLogger sets a custom logger to be used in the configuration.
+func WithLogger(logger logger.Logger) Option {
 	return func(o *Config) {
-		o.definedLogger = loggerWrapper{logf: logger}
+		o.definedLogger = logger
 	}
 }
 
@@ -138,30 +137,14 @@ func tryFixPermission(path string) error {
 	})
 }
 
-// logger returns the logger implementation to use, defaulting to the predefined defaultLogger if none is specified.
-func (config *Config) logger() logger {
+// logger returns the logger implementation to use, defaulting to noop
+func (config *Config) logger() logger.Logger {
 	if config.definedLogger == nil {
-		return defaultLogger
+		return internallogger.Noop()
 	}
 	return config.definedLogger
 }
 
-// loggerWrapper wraps a LoggerFunc to conform with the logger interface.
-type loggerWrapper struct {
-	logf LoggerFunc
-}
-
-// Printf logs a formatted message using a specified format and variadic arguments.
-func (l loggerWrapper) Printf(format string, v ...interface{}) {
-	l.logf(format, v...)
-}
-
-// defaultLogger is the default logger implementing the logger interface, using fmt.Printf to log formatted messages.
-var defaultLogger = loggerWrapper{func(format string, v ...interface{}) {
-	fmt.Printf(format, v...)
-	fmt.Println()
-}}
-
 // apply sets multiple configuration options on a Config instance.
 func (o *Config) apply(opts ...Option) {
 	for _, opt := range opts {