3 /* log - a generic logging facility in the spirit of log4j */
5 /* Copyright (c) 2003, 2004 Martin Quinson. All rights reserved. */
7 /* This program is free software; you can redistribute it and/or modify it
8 * under the terms of the license (GNU LGPL) which comes with this package. */
13 #include "xbt_modinter.h"
16 #include "xbt/sysdep.h"
18 #include "xbt/error.h"
19 #include "xbt/dynar.h"
22 /** \defgroup XBT_log Logging support.
23 * \brief A generic logging facility in the spirit of log4j
25 * This section describes the API to the log functions used
26 * everywhere in this project.
30 This is an adaptation of the log4c project, which is dead upstream, and
31 which I was given the permission to fork under the LGPL licence by the
32 authors. log4c itself was loosely based on the Apache project's Log4J,
33 Log4CC, etc. project. Because C is not object oriented, a lot had to change.
35 There is 3 main concepts: category, priority and appender. These three
36 concepts work together to enable developers to log messages according to
37 message type and priority, and to control at runtime how these messages are
38 formatted and where they are reported.
40 <h3>Category hierarchy</h3>
42 The first and foremost advantage of any logging API over plain printf()
43 resides in its ability to disable certain log statements while allowing
44 others to print unhindered. This capability assumes that the logging space,
45 that is, the space of all possible logging statements, is categorized
46 according to some developer-chosen criteria.
48 This observation led to choosing category as the central concept of the
49 system. Every category is declared by providing a name and an optional
50 parent. If no parent is explicitly named, the root category, LOG_ROOT_CAT is
51 the category's parent.
53 A category is created by a macro call at the top level of a file. A
54 category can be created with any one of the following macros:
56 - \ref XBT_LOG_NEW_CATEGORY(MyCat); Create a new root
57 - \ref XBT_LOG_NEW_SUBCATEGORY(MyCat, ParentCat);
58 Create a new category being child of the category ParentCat
59 - \ref XBT_LOG_NEW_DEFAULT_CATEGORY(MyCat);
60 Like XBT_LOG_NEW_CATEGORY, but the new category is the default one
62 - \ref XBT_LOG_NEW_DEFAULT_SUBCATEGORY(MyCat, ParentCat);
63 Like XBT_LOG_NEW_SUBCATEGORY, but the new category is the default one
66 The parent cat can be defined in the same file or in another file (in
67 which case you want to use the \ref XBT_LOG_EXTERNAL_CATEGORY macro to make
68 it visible in the current file), but each category may have only one
71 Typically, there will be a Category for each module and sub-module, so you
72 can independently control logging for each module.
76 A category may be assigned a threshold priorty. The set of priorites are
77 defined by the \ref e_xbt_log_priority_t enum. All logging request under
78 this priority will be discarded.
80 If a given category is not assigned a threshold priority, then it inherits
81 one from its closest ancestor with an assigned threshold. To ensure that all
82 categories can eventually inherit a threshold, the root category always has
83 an assigned threshold priority.
85 Logging requests are made by invoking a logging macro on a category. All of
86 the macros have a printf-style format string followed by arguments. If you
87 compile with the -Wall option, gcc will warn you for unmatched arguments, ie
88 when you pass a pointer to a string where an integer was specified by the
89 format. This is usualy a good idea.
91 Because most C compilers do not support vararg macros, there is a version of
92 the macro for any number of arguments from 0 to 6. The macro name ends with
93 the total number of arguments.
95 Here is an example of the most basic type of macro. This is a logging
96 request with priority <i>warning</i>.
98 <code>CLOG5(MyCat, gras_log_priority_warning, "Values are: %d and '%s'", 5,
101 A logging request is said to be enabled if its priority is higher than or
102 equal to the threshold priority of its category. Otherwise, the request is
103 said to be disabled. A category without an assigned priority will inherit
104 one from the hierarchy.
106 It is possible to use any non-negative integer as a priority. If, as in the
107 example, one of the standard priorites is used, then there is a convenience
108 macro that is typically used instead. For example, the above example is
109 equivalent to the shorter:
111 <code>CWARN4(MyCat, "Values are: %d and '%s'", 5, "oops");</code>
113 <h3>Default category</h3>
115 If \ref XBT_LOG_NEW_DEFAULT_SUBCATEGORY(MyCat, Parent) or
116 \ref XBT_LOG_NEW_DEFAULT_CATEGORY(MyCat) is used to create the
117 category, then the even shorter form can be used:
119 <code>WARN3("Values are: %d and '%s'", 5, "oops");</code>
121 Only one default category can be created per file, though multiple
122 non-defaults can be created and used.
126 Here is a more complete example:
131 / * create a category and a default subcategory * /
132 XBT_LOG_NEW_CATEGORY(VSS);
133 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(SA, VSS);
136 / * Now set the parent's priority. (the string would typcially be a runtime option) * /
137 xbt_log_control_set("SA.thresh=3");
139 / * This request is enabled, because WARNING >= INFO. * /
140 CWARN2(VSS, "Low fuel level.");
142 / * This request is disabled, because DEBUG < INFO. * /
143 CDEBUG2(VSS, "Starting search for nearest gas station.");
145 / * The default category SA inherits its priority from VSS. Thus,
146 the following request is enabled because INFO >= INFO. * /
147 INFO1("Located nearest gas station.");
149 / * This request is disabled, because DEBUG < INFO. * /
150 DEBUG1("Exiting gas station search");
154 <h3>Configuration</h3>
155 Configuration is typically done during program initialization by invoking
156 the xbt_log_control_set() method. The control string passed to it typically
157 comes from the command line. Look at the documentation for that function for
158 the format of the control string.
160 Any SimGrid program can furthermore be configured at run time by passing a
161 --xbt-log argument on the command line (--gras-log, --msg-log and
162 --surf-log are synonyms). You can provide several of those arguments to
163 change the setting of several categories.
167 Clever design insures efficiency. Except for the first invocation, a
168 disabled logging request requires an a single comparison of a static
169 variable to a constant.
171 There is also compile time constant, \ref XBT_LOG_STATIC_THRESHOLD, which
172 causes all logging requests with a lower priority to be optimized to 0 cost
173 by the compiler. By setting it to gras_log_priority_infinite, all logging
174 requests are statically disabled and cost nothing. Released executables
175 might be compiled with
176 \verbatim-DXBT_LOG_STATIC_THRESHOLD=gras_log_priority_infinite\endverbatim
178 Compiling with the \verbatim-DNLOG\endverbatim option disables all logging
179 requests at compilation time while the \verbatim-DNDEBUG\endverbatim disables
180 the requests of priority below INFO.
184 Each category has an optional appender. An appender is a pointer to a
185 structure which starts with a pointer to a doAppend() function. DoAppend()
186 prints a message to a log.
188 When a category is passed a message by one of the logging macros, the
189 category performs the following actions:
191 - if the category has an appender, the message is passed to the
192 appender's doAppend() function,
193 - if 'willLogToParent' is true for the category, the message is passed
194 to the category's parent.
196 By default, only the root category have an appender, and 'willLogToParent'
197 is true for any other category. This situation causes all messages to be
198 logged by the root category's appender.
200 The default appender function currently prints to stderr, and no other one
201 exist, even if more would be needed, like the one able to send the logs to a
202 remote dedicated server, or other ones offering different output formats.
203 This is on our TODO list for quite a while now, but your help would be
206 <h3>Misc and Caveats</h3>
208 - Do not use any of the macros that start with '_'.
209 - Log4J has a 'rolling file appender' which you can select with a run-time
210 option and specify the max file size. This would be a nice default for
211 non-kernel applications.
212 - Careful, category names are global variables.
219 Dans gras, tu ne te contente pas d'écrire des choses à l'écran, mais tu
220 écris sur un sujet particulier (notion de canal) des choses d'une gravité
221 particulière. Il y a 7 niveaux de gravité.
222 trace: tracer les entrées dans une fonction, retour de fonction
223 (famille de macros XBT_IN/XBT_OUT)
224 debug: pour t'aider à mettre au point le module, potentiellement tres bavard
225 verbose: quelques infos succintes sur les internals du module
226 info: niveau normal, ton de la conversation
227 warning: problème potentiel, mais auquel on a su faire face
228 error: problème qui t'as empêché de faire ton job
229 critical: juste avant de mourir
231 Quand on compile avec -DNDEBUG (par défaut dans le paquet Debian), tout ce
232 qui est '>= verbose' est supprimé au moment de la compilation. Retiré du
235 Ensuite, tu écris dans un canal particulier. Tous les canaux sont rangés en
236 arbre. Il faudrait faire un ptit script qui fouille les sources à la
237 recherche des macros XBT_LOG_NEW_* utilisées pour créer des canaux. Le
238 dernier argument de ces macros est ignoré dans le source. Il est destiné à
239 être la documentation de la chose en une ligne. En gros, ca fait:
260 +--raw_trp (Je devrais tuer ce module, un jour)
266 Et ensuite les utilisateurs peuvent choisir le niveau de gravité qui les
267 interresse sur tel ou tel sujet.
269 Toute la mécanique de logging repose sur des variables statiques dont le nom
270 dépend du nom du canal.
271 => attention aux conflits de nom de canal
272 => il faut une macro XBT_LOG dans chaque fichier où tu fais des logs.
274 XBT_LOG_NEW_CATEGORY: nouveau canal sous "root". Rare, donc.
275 XBT_LOG_NEW_SUBCATEGORY: nouveau canal dont on précise le père.
276 XBT_LOG_DEFAULT_CATEGORY: indique quel est le canal par défaut dans ce fichier
277 XBT_LOG_NEW_DEFAULT_CATEGORY: Crèe un canal et l'utilise par défaut
278 XBT_LOG_NEW_DEFAULT_SUBCATEGORY: devine
279 XBT_LOG_EXTERNAL_CATEGORY: quand tu veux utiliser par défaut un canal créé
280 dans un autre fichier.
282 Une fois que ton canal est créé, tu l'utilise avec les macros LOG, DEBUG,
283 VERB, WARN, ERROR et CRITICAL. Il faut que tu donne le nombre d'arguments
284 après le nom de macro. Exemple: LOG2("My name is %s %s","Martin","Quinson")
285 Si tu veux préciser explicitement le canal où écrire, ajoute un C devant le
286 nom de la macro. Exemple: CCRITICAL0(module, "Cannot initialize GRAS")
288 Toutes ces macros (enfin, ce en quoi elles se réécrivent) vérifient leurs
289 arguments comme printf le fait lorsqu'on compile avec gcc.
290 LOG1("name: %d","toto"); donne un warning, et donc une erreur en mode
293 Enfin, tu peux tester si un canal est ouvert à une priorité donnée (pour
294 préparer plus de débug, par exemple. Dans le parseur, je fais du pretty
295 printing sur ce qu'il faut parser dans ce cas).
296 XBT_LOG_ISENABLED(catName, priority) Le second argument doit être une valeur
297 de e_xbt_log_priority_t (log.h). Par exemple: xbt_log_priority_verbose
299 Voila sur comment mettre des logs dans ton code. N'hesite pas à faire pleins
300 de canaux différents pour des aspects différents de ton code. En
301 particulier, dans les dict, j'ai un canal pour l'ajout, le retrait, le
302 netoyage du code après suppression et ainsi de suite. De cette façon, je
303 peux choisir qui m'interresse.
306 Pour utiliser les logs, tu déjà faire, non ? Tu colle sur la ligne de
307 commande un ou plusieurs arguments de la forme
308 --gras-log="<réglage> [<reglage>+]" (ou sans " si t'as pas d'espace)
309 chaque réglage étant de la forme:
310 <canal>.thres=<priorité>
311 Les différents réglages sont lus de gauche à droite.
312 "root.thres=debug root.thres=critical" ferme tout, normalement.
318 e_xbt_log_priority_t thresh;
319 } s_xbt_log_setting_t,*xbt_log_setting_t;
321 static xbt_dynar_t xbt_log_settings=NULL;
322 static void _free_setting(void *s) {
323 xbt_log_setting_t set=(xbt_log_setting_t)s;
325 xbt_free(set->catname);
326 /* xbt_free(set); FIXME: uncommenting this leads to segfault when more than one chunk is passed as gras-log */
330 const char *xbt_log_priority_names[8] = {
341 s_xbt_log_category_t _XBT_LOGV(XBT_LOG_ROOT_CAT) = {
343 "root", xbt_log_priority_uninitialized, 0,
347 XBT_LOG_NEW_SUBCATEGORY(xbt,XBT_LOG_ROOT_CAT,"All XBT categories (simgrid toolbox)");
348 XBT_LOG_NEW_SUBCATEGORY(surf,XBT_LOG_ROOT_CAT,"All SURF categories");
349 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(log,xbt,"Loggings from the logging mecanism itself");
351 void xbt_log_init(int *argc,char **argv, const char *defaultlog) {
356 /* Set logs and init log submodule */
357 for (i=1; i<*argc; i++) {
358 if (!strncmp(argv[i],"--gras-log=",strlen("--gras-log=")) ||
359 !strncmp(argv[i],"--surf-log=",strlen("--surf-log=")) ||
360 !strncmp(argv[i],"--msg-log=",strlen("--msg-log=")) ||
361 !strncmp(argv[i],"--xbt-log=",strlen("--xbt-log="))) {
363 opt=strchr(argv[i],'=');
365 xbt_log_control_set(opt);
366 DEBUG1("Did apply '%s' as log setting",opt);
367 /*remove this from argv*/
368 for (j=i+1; j<*argc; j++) {
373 i--; /* compensate effect of next loop incrementation */
376 if (!found && defaultlog) {
377 xbt_log_control_set(defaultlog);
381 void xbt_log_exit(void) {
382 VERB0("Exiting log");
383 xbt_dynar_free(&xbt_log_settings);
387 static void _apply_control(xbt_log_category_t cat) {
389 xbt_log_setting_t setting=NULL;
392 if (!xbt_log_settings)
395 xbt_assert0(cat,"NULL category");
396 xbt_assert(cat->name);
398 xbt_dynar_foreach(xbt_log_settings,cursor,setting) {
399 xbt_assert0(setting,"Damnit, NULL cat in the list");
400 xbt_assert1(setting->catname,"NULL setting(=%p)->catname",(void*)setting);
402 if (!strcmp(setting->catname,cat->name)) {
405 xbt_log_threshold_set(cat, setting->thresh);
406 xbt_dynar_cursor_rm(xbt_log_settings,&cursor);
408 if (cat->threshold <= xbt_log_priority_verbose) {
409 s_xbt_log_event_t _log_ev =
410 {cat,xbt_log_priority_verbose,__FILE__,_XBT_GNUC_FUNCTION,__LINE__};
411 _xbt_log_event_log(&_log_ev,
412 "Apply settings for category '%s': set threshold to %s (=%d)",
414 xbt_log_priority_names[cat->threshold], cat->threshold);
418 if (!found && cat->threshold <= xbt_log_priority_verbose) {
419 s_xbt_log_event_t _log_ev =
420 {cat,xbt_log_priority_verbose,__FILE__,_XBT_GNUC_FUNCTION,__LINE__};
421 _xbt_log_event_log(&_log_ev,
422 "Category '%s': inherited threshold = %s (=%d)",
424 xbt_log_priority_names[cat->threshold], cat->threshold);
429 void _xbt_log_event_log( xbt_log_event_t ev, const char *fmt, ...) {
430 xbt_log_category_t cat = ev->cat;
431 va_start(ev->ap, fmt);
433 xbt_log_appender_t appender = cat->appender;
434 if (appender != NULL) {
435 appender->do_append(appender, ev, fmt);
437 if (!cat->willLogToParent)
445 static void _cat_init(xbt_log_category_t category) {
446 if (category == &_XBT_LOGV(XBT_LOG_ROOT_CAT)) {
447 category->threshold = xbt_log_priority_info;
448 category->appender = xbt_log_default_appender;
450 xbt_log_parent_set(category, category->parent);
452 _apply_control(category);
456 * This gets called the first time a category is referenced and performs the
458 * Also resets threshold to inherited!
460 int _xbt_log_cat_init(e_xbt_log_priority_t priority,
461 xbt_log_category_t category) {
465 return priority >= category->threshold;
468 void xbt_log_parent_set(xbt_log_category_t cat,
469 xbt_log_category_t parent) {
471 xbt_assert0(cat,"NULL category to be given a parent");
472 xbt_assert1(parent,"The parent category of %s is NULL",cat->name);
474 /* unlink from current parent */
475 if (cat->threshold != xbt_log_priority_uninitialized) {
476 xbt_log_category_t* cpp = &parent->firstChild;
477 while(*cpp != cat && *cpp != NULL) {
478 cpp = &(*cpp)->nextSibling;
480 xbt_assert(*cpp == cat);
481 *cpp = cat->nextSibling;
485 cat->parent = parent;
486 cat->nextSibling = parent->firstChild;
487 parent->firstChild = cat;
489 /* Make sure parent is initialized */
490 if (parent->threshold == xbt_log_priority_uninitialized) {
495 cat->threshold = parent->threshold;
496 cat->isThreshInherited = 1;
497 } /* log_setParent */
499 static void _set_inherited_thresholds(xbt_log_category_t cat) {
500 xbt_log_category_t child = cat->firstChild;
501 for( ; child != NULL; child = child->nextSibling) {
502 if (child->isThreshInherited) {
503 if (cat != &_XBT_LOGV(log))
504 VERB3("Set category threshold of %s to %s (=%d)",
505 child->name,xbt_log_priority_names[cat->threshold],cat->threshold);
506 child->threshold = cat->threshold;
507 _set_inherited_thresholds(child);
512 void xbt_log_threshold_set(xbt_log_category_t cat,
513 e_xbt_log_priority_t threshold) {
514 cat->threshold = threshold;
515 cat->isThreshInherited = 0;
516 _set_inherited_thresholds(cat);
519 static void _xbt_log_parse_setting(const char* control_string,
520 xbt_log_setting_t set) {
521 const char *name, *dot, *eq;
524 if (!*control_string)
526 DEBUG1("Parse log setting '%s'",control_string);
528 control_string += strspn(control_string, " ");
529 name = control_string;
530 control_string += strcspn(control_string, ".= ");
531 dot = control_string;
532 control_string += strcspn(control_string, "= ");
534 control_string += strcspn(control_string, " ");
536 xbt_assert1(*dot == '.' && *eq == '=',
537 "Invalid control string '%s'",control_string);
539 if (!strncmp(dot + 1, "thresh", min(eq - dot - 1,strlen("thresh")))) {
541 char *neweq=xbt_strdup(eq+1);
544 while (*(++p) != '\0') {
545 if (*p >= 'a' && *p <= 'z') {
550 DEBUG1("New priority name = %s",neweq);
551 for (i=0; i<xbt_log_priority_infinite-1; i++) {
552 if (!strncmp(xbt_log_priority_names[i],neweq,p-eq)) {
553 DEBUG1("This is priority %d",i);
557 if (i<xbt_log_priority_infinite-1) {
560 xbt_assert1(FALSE,"Unknown priority name: %s",eq+1);
565 snprintf(buff,min(512,eq - dot - 1),"%s",dot+1);
566 xbt_assert1(FALSE,"Unknown setting of the log category: %s",buff);
568 set->catname=(char*)xbt_malloc(dot - name+1);
570 strncpy(set->catname,name,dot-name);
571 set->catname[dot-name]='\0'; /* Just in case */
572 DEBUG1("This is for cat '%s'", set->catname);
575 static xbt_error_t _xbt_log_cat_searchsub(xbt_log_category_t cat,char *name,
576 /*OUT*/xbt_log_category_t*whereto) {
578 xbt_log_category_t child;
580 if (!strcmp(cat->name,name)) {
584 for(child=cat->firstChild ; child != NULL; child = child->nextSibling) {
585 errcode=_xbt_log_cat_searchsub(child,name,whereto);
586 if (errcode==no_error)
589 return mismatch_error;
592 static void _cleanup_double_spaces(char *s) {
615 if (e ^ !isspace(*p))
626 * \param control_string What to parse
628 * Typically passed a command-line argument. The string has the syntax:
630 * ( [category] "." [keyword] "=" value (" ")... )...
632 * where [category] is one the category names and keyword is one of the
635 * thresh value is an integer priority level. Sets the category's
636 * threshold priority.
639 * This routine may only be called once and that must be before any other
640 * logging command! Typically, this is done from main().
642 void xbt_log_control_set(const char* control_string) {
644 xbt_log_setting_t set;
649 DEBUG1("Parse log settings '%s'",control_string);
650 if (control_string == NULL)
652 if (xbt_log_settings == NULL)
653 xbt_log_settings = xbt_dynar_new(sizeof(xbt_log_setting_t),
656 set = xbt_new(s_xbt_log_setting_t,1);
657 cs=xbt_strdup(control_string);
659 _cleanup_double_spaces(cs);
662 xbt_log_category_t cat;
672 _xbt_log_parse_setting(p,set);
674 errcode = _xbt_log_cat_searchsub(&_XBT_LOGV(root),set->catname,&cat);
675 if (errcode == mismatch_error) {
676 DEBUG0("Store for further application");
677 DEBUG1("push %p to the settings",(void*)set);
678 xbt_dynar_push(xbt_log_settings,&set);
679 /* malloc in advance the next slot */
680 set = xbt_new(s_xbt_log_setting_t,1);
682 DEBUG0("Apply directly");
683 xbt_free(set->catname);
684 xbt_log_threshold_set(cat,set->thresh);
691 void xbt_log_appender_set(xbt_log_category_t cat, xbt_log_appender_t app) {