core: dprint - support for structured logging

- enable formatting the logging output with different functions

src/core/dprint.c

@@ -1,5 +1,5 @@
 /*
- * debug print 
+ * debug print
  *
  * Copyright (C) 2001-2003 FhG Fokus
  *
@@ -15,8 +15,8 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
- * You should have received a copy of the GNU General Public License 
- * along with this program; if not, write to the Free Software 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 /*!
@@ -27,11 +27,11 @@
  */
 
 
- 
+
 #include "globals.h"
 #include "dprint.h"
 #include "pvar.h"
- 
+
 #include <stdarg.h>
 #include <stdio.h>
 #include <strings.h>
@@ -51,7 +51,7 @@ void km_log_func_set(km_log_f f)
 
 #ifndef NO_SIG_DEBUG
 /* signal protection: !=0 when LOG/DBG/... are printing */
-volatile int dprint_crit = 0; 
+volatile int dprint_crit = 0;
 #endif
 
 static char* str_fac[]={"LOG_AUTH","LOG_CRON","LOG_DAEMON",
@@ -63,7 +63,7 @@ static char* str_fac[]={"LOG_AUTH","LOG_CRON","LOG_DAEMON",
 			"LOG_AUTHPRIV","LOG_FTP","LOG_SYSLOG",
 #endif
 			0};
-			
+
 static int int_fac[]={LOG_AUTH ,  LOG_CRON , LOG_DAEMON ,
 		      LOG_KERN , LOG_LOCAL0 , LOG_LOCAL1 ,
 		      LOG_LOCAL2 , LOG_LOCAL3 , LOG_LOCAL4 , LOG_LOCAL5 ,
@@ -479,3 +479,39 @@ void log_prefix_set(sip_msg_t *msg)
 		return;
 	log_prefix_val = &log_prefix_str;
 }
+
+/* structured logging */
+
+ksr_slog_f _ksr_slog_func = NULL;
+
+void ksr_slog_json(ksr_logdata_t *kld, const char *format, ...)
+{
+	va_list arglist;
+#define KSR_SLOG_MAX_SIZE 32*1024
+	char obuf[KSR_SLOG_MAX_SIZE];
+	int n;
+
+	n = 0;
+	va_start(arglist, format);
+	n += vsnprintf(obuf + n, KSR_SLOG_MAX_SIZE - n, format, arglist);
+	va_end(arglist);
+
+	if (unlikely(log_stderr)) {
+		if (unlikely(log_color)) dprint_color(kld->v_level);
+		fprintf(stderr,
+				"{ \"level\": \"%s\", \"module\": \"%s\", \"file\": \"%s\", \"line\": %d, \"function\": \"%s\", \"message\": \"%.*s\" }\n",
+				kld->v_lname, kld->v_mname, kld->v_fname, kld->v_fline, kld->v_func, n, obuf);
+		if (unlikely(log_color)) dprint_color_reset();
+	} else {
+		_km_log_func(kld->v_facility,
+				"{  \"level\": \"%s\", \"module\": \"%s\", \"file\": \"%s\", \"line\": %d, \"function\": \"%s\", \"message\": \"%.*s\" }\n",
+				kld->v_lname, kld->v_mname, kld->v_fname, kld->v_fline, kld->v_func, n, obuf);
+	}
+}
+
+void ksr_slog_init(char *ename)
+{
+	if(ename && (strlen(ename)==4) && (strcasecmp(ename, "json")==0)) {
+		_ksr_slog_func = &ksr_slog_json;
+	}
+}

src/core/dprint.h

@@ -13,8 +13,8 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
- * You should have received a copy of the GNU General Public License 
- * along with this program; if not, write to the Free Software 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
@@ -106,6 +106,28 @@
 #define LOG2SYSLOG_LEVEL(level) \
 	(log_level_info[(level) - (L_ALERT)].syslog_level)
 
+/**
+ * data fileds used for structured logging
+ */
+typedef struct ksr_logdata {
+	/* next field are automatically set by log macro */
+	int v_facility;
+	int v_level;
+	char *v_lname;
+	const char *v_fname;
+	int v_fline;
+	const char *v_mname;
+	const char *v_func;
+	const char *v_locinfo;
+	/* next field are __not__ automatically set by log macro */
+	int v_pid;
+	int v_pidx;
+} ksr_logdata_t;
+
+typedef void (*ksr_slog_f)(ksr_logdata_t*, const char*, ...);
+void ksr_slog_init(char *ename);
+
+extern ksr_slog_f _ksr_slog_func;
 
 /** @brief my_pid(), process_no are from pt.h but we cannot \#include it here
    because of circular dependencies */
@@ -259,23 +281,39 @@ void log_prefix_init(void);
 					int __llevel; \
 					__llevel = ((level)<L_ALERT)?L_ALERT:(((level)>L_DBG)?L_DBG:level); \
 					DPRINT_CRIT_ENTER; \
-					if (unlikely(log_stderr)) { \
-						if (unlikely(log_color)) dprint_color(__llevel); \
-						fprintf(stderr, "%2d(%d) %s: %.*s%s" _FUNC_FMT_ fmt, \
+					if (_ksr_slog_func) { /* structured logging */ \
+						ksr_logdata_t __kld = {0}; \
+						__kld.v_facility = LOG2SYSLOG_LEVEL(__llevel) | \
+							   (((facility) != DEFAULT_FACILITY) ? \
+								(facility) : \
+								get_debug_facility(LOG_MNAME, LOG_MNAME_LEN)); \
+						__kld.v_level = __llevel; \
+						__kld.v_lname = (lname)?(lname):LOG_LEVEL2NAME(__llevel); \
+						__kld.v_fname = __FILE__; \
+						__kld.v_fline = __LINE__; \
+						__kld.v_mname = LOG_MNAME; \
+						__kld.v_func = _FUNC_NAME_; \
+						__kld.v_locinfo = prefix; \
+						_ksr_slog_func(&__kld, fmt, ## args); \
+					} else { /* classic logging */ \
+						if (unlikely(log_stderr)) { \
+							if (unlikely(log_color)) dprint_color(__llevel); \
+							fprintf(stderr, "%2d(%d) %s: %.*s%s" _FUNC_FMT_ fmt, \
 								process_no, my_pid(), \
 								(lname)?(lname):LOG_LEVEL2NAME(__llevel), \
 								LOGV_PREFIX_LEN, LOGV_PREFIX_STR, \
-								(prefix), _FUNC_NAME_, ## args);\
-						if (unlikely(log_color)) dprint_color_reset(); \
-					} else { \
-						_km_log_func(LOG2SYSLOG_LEVEL(__llevel) |\
+								(prefix), _FUNC_NAME_, ## args); \
+							if (unlikely(log_color)) dprint_color_reset(); \
+						} else { \
+							_km_log_func(LOG2SYSLOG_LEVEL(__llevel) | \
 							   (((facility) != DEFAULT_FACILITY) ? \
 								(facility) : \
 								get_debug_facility(LOG_MNAME, LOG_MNAME_LEN)), \
-								"%s: %.*s%s" _FUNC_FMT_ fmt,\
-								(lname)?(lname):LOG_LEVEL2NAME(__llevel),\
+								"%s: %.*s%s" _FUNC_FMT_ fmt, \
+								(lname)?(lname):LOG_LEVEL2NAME(__llevel), \
 								LOGV_PREFIX_LEN, LOGV_PREFIX_STR, \
 								(prefix), _FUNC_NAME_, ## args); \
+						} \
 					} \
 					DPRINT_CRIT_EXIT; \
 				} \