xps_logger

xps_logger is a utility designed to provide logging functionality to aid in the development of eXpServer. It includes a logger() function that enables logging messages at different levels and supports colored output depending on the error level.

Source files

The xps_logger.h and xps_logger.c files can be dropped into your existing C project and compiled along with it.

expserver/src/utils/xps_logger.h

#ifndef XPS_LOGGER_H
#define XPS_LOGGER_H

#include "../xps.h"

// Basic text colors
#define BLACK_TEXT "\x1b[30m"
#define RED_TEXT "\x1b[31m"
#define GREEN_TEXT "\x1b[32m"
#define YELLOW_TEXT "\x1b[33m"
#define BLUE_TEXT "\x1b[34m"
#define MAGENTA_TEXT "\x1b[35m"
#define CYAN_TEXT "\x1b[36m"
#define WHITE_TEXT "\x1b[37m"

// Extended text colors (256 colors)
#define EXTENDED_TEXT(x) "\x1b[38;5;" #x "m"

// Basic background colors
#define BLACK_BG "\x1b[40m"
#define RED_BG "\x1b[41m"
#define GREEN_BG "\x1b[42m"
#define YELLOW_BG "\x1b[43m"
#define BLUE_BG "\x1b[44m"
#define MAGENTA_BG "\x1b[45m"
#define CYAN_BG "\x1b[46m"
#define WHITE_BG "\x1b[47m"

// Extended background colors (256 colors)
#define EXTENDED_BG(x) "\x1b[48;5;" #x "m"

#define RESET_COLOR "\x1b[0m"

#define BOLD_START "\033[1m"
#define BOLD_END "\033[0m"

typedef enum { LOG_ERROR, LOG_INFO, LOG_DEBUG, LOG_WARNING, LOG_HTTP } xps_log_level_t;

void logger(xps_log_level_t level, const char *function_name, const char *format_string, ...);

#endif

expserver/src/utils/xps_logger.c

#include "../xps.h"

void logger(xps_log_level_t level, const char *function_name, const char *format_string, ...) {
  char *XPS_DEBUG = getenv("XPS_DEBUG");

  if ((XPS_DEBUG == NULL || strcmp(XPS_DEBUG, "1") != 0) && level == LOG_DEBUG)
    return;

  const char *log_level_strings[] = {"ERROR", "INFO", "DEBUG", "WARNING", "HTTP"};
  const char *log_level_colors[] = {RED_BG, BLUE_BG, MAGENTA_TEXT, YELLOW_BG, GREEN_BG};

  va_list args;
  va_start(args, format_string);

  printf("%s" BOLD_START " %s " BOLD_END RESET_COLOR " " GREEN_TEXT "%s" RESET_COLOR " : ",
         log_level_colors[level], log_level_strings[level], function_name);
  vprintf(format_string, args);
  printf("\n");

  fflush(stdout);

  va_end(args);
}

Usage

To log messages, you can use the logger() function provided by the module. Here's a basic example:

void logger(xps_log_level_t level, const char *function_name, const char *format_string, ...);

• level: Log level of the message of type xps_log_level_t
• function_name: Name of the function logging the message
• format_string: Format string for the message
• Additional arguments can be passed similar to printf format

Environment Variable for Debugging

Logging behavior can be controlled using the XPS_DEBUG environment variable. Log messages of level DEBUG will be printed on the terminal only when XPS_DEBUG env var is set to “1”.

export XPS_DEBUG=1

You can unset it using the following command:

unset XPS_DEBUG

Examples

Examples of logging errors of different levels:

// ERROR
logger(LOG_ERROR, "xps_loop_create()", "epoll_create1() failed");

// INFO
logger(LOG_INFO, "listener_connection_handler()", "new connection");

// DEBUG
logger(LOG_DEBUG, "listener_connection_handler()", "make_socket_non_blocking() failed");

// WARNING
logger(LOG_WARNING, "sigint_handler()", "SIGINT received");

// HTTP
logger(LOG_HTTP, "xps_http()", "%s %s", http_req->method, http_req->path);

Error levels

xps_logger provides predefined error levels with corresponding colors:

Level	Color
ERROR	RED_BG
INFO	BLUE_BG
DEBUG	MAGENTA_TEXT
WARNING	YELLOW_BG
HTTP	GREEN_BG

Extendibility

Users can extend xps_logger further by altering xps_logger.h and xps_logger.c to include additional logging error levels or alter existing ones.