The given code defines a simple logger implementation in Go...

August 31, 2025 at 02:10 AM

package logger

import (
	"context"
	"log"
	"os"
)

type Logger struct {
	debug *log.Logger
	info  *log.Logger
	warn  *log.Logger
	error *log.Logger
}

func NewLogger() *Logger {
	return &Logger{
		debug: log.New(os.Stdout, "DEBUG: ", log.LstdFlags),
		info:  log.New(os.Stdout, "INFO: ", log.LstdFlags),
		warn:  log.New(os.Stdout, "WARN: ", log.LstdFlags),
		error: log.New(os.Stdout, "ERROR: ", log.LstdFlags),
	}
}

func (l *Logger) Debug(ctx context.Context, v ...interface{}) {
	l.debug.Println(v...)
}
func (l *Logger) Info(ctx context.Context, v ...interface{}) {
	l.info.Println(v...)
}
func (l *Logger) Warn(v ...interface{}) {
	l.warn.Println(v...)
}
func (l *Logger) Error(v ...interface{}) {
	l.error.Println(v...)
}

cannot use "Server started on %s" (constant of type string) as context.Context value in argument to log.Info: string does not implement context.Context (missing method Deadline)

The given code defines a simple logger implementation in Go with support for different logging levels: DEBUG, INFO, WARN, and ERROR.

Structure and Functions:

Logger struct:
- Represents the logger with fields for the different log levels (debug, info, warn, error), each of which is a pointer to a log.Logger instance.
NewLogger function:
- This is a constructor function for creating and returning a new Logger instance.
- For each log level (debug, info, warn, error), it initializes a log.Logger that writes output to os.Stdout with a specific prefix (DEBUG:, INFO:, etc.) and includes a timestamp via the log.LstdFlags option.
Logging methods (Debug, Info, Warn, and Error):
- These are methods of the Logger struct intended for logging messages at respective log levels.
- They accept variadic arguments (v ...interface{}) to allow flexible formatting and log the message using the corresponding log.Logger.
Context Parameter in Debug/Info:
- The Debug and Info methods expect a context.Context as the first argument, but it is not currently used in the implementation.
- The presence of this context.Context parameter suggests that these methods may, in the future, leverage the context for tasks such as passing information between function calls or adding metadata to logs.
Error in Usage:
- The error in the final line indicates incorrect usage of the Info method:
```
cannot use "Server started on %s" (constant of type string) as context.Context value in argument to log.Info: string does not implement context.Context (missing method Deadline)
```
- This occurs because the Info method's signature requires the first parameter to be of type context.Context, but a string ("Server started on %s") was passed instead.
- To fix this, you should provide a valid context.Context as the first argument when calling Info, e.g., logger.Info(context.Background(), "Server started on %s", port).

Example Usage:

package main

import (
	"context"
	"log"
	"os"
)

func main() {
	logger := NewLogger()

	// Correct usage with a context
	ctx := context.Background()
	logger.Info(ctx, "Server started on port %d", 8080)

	// Calling other log methods
	logger.Debug(ctx, "Debugging information")
	logger.Warn("This is a warning")
	logger.Error("An error occurred")
}

Key Points:

The code provides a clean logger abstraction for handling multiple log levels (Debug, Info, Warn, Error).
The Debug and Info methods require a valid context.Context argument, making them more suited for future extensibility regarding context-aware logging.
The provided error results from a mismatch in expected argument types when invoking the Info method.

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