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.
28 \section log_overview Overview
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 \section log_cat Category hierarchy
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.
74 For a list of all existing categories, please refer to the \ref XBT_log_cats section.
76 \section log_pri Priority
78 A category may be assigned a threshold priorty. The set of priorites are
79 defined by the \ref e_xbt_log_priority_t enum. All logging request under
80 this priority will be discarded.
82 If a given category is not assigned a threshold priority, then it inherits
83 one from its closest ancestor with an assigned threshold. To ensure that all
84 categories can eventually inherit a threshold, the root category always has
85 an assigned threshold priority.
87 Logging requests are made by invoking a logging macro on a category. All of
88 the macros have a printf-style format string followed by arguments. If you
89 compile with the -Wall option, gcc will warn you for unmatched arguments, ie
90 when you pass a pointer to a string where an integer was specified by the
91 format. This is usualy a good idea.
93 Because most C compilers do not support vararg macros, there is a version of
94 the macro for any number of arguments from 0 to 6. The macro name ends with
95 the total number of arguments.
97 Here is an example of the most basic type of macro. This is a logging
98 request with priority <i>warning</i>.
100 <code>CLOG5(MyCat, gras_log_priority_warning, "Values are: %d and '%s'", 5,
103 A logging request is said to be enabled if its priority is higher than or
104 equal to the threshold priority of its category. Otherwise, the request is
105 said to be disabled. A category without an assigned priority will inherit
106 one from the hierarchy.
108 It is possible to use any non-negative integer as a priority. If, as in the
109 example, one of the standard priorites is used, then there is a convenience
110 macro that is typically used instead. For example, the above example is
111 equivalent to the shorter:
113 <code>CWARN4(MyCat, "Values are: %d and '%s'", 5, "oops");</code>
115 \subsection log_subcat Using a default category
117 If \ref XBT_LOG_NEW_DEFAULT_SUBCATEGORY(MyCat, Parent) or
118 \ref XBT_LOG_NEW_DEFAULT_CATEGORY(MyCat) is used to create the
119 category, then the even shorter form can be used:
121 <code>WARN3("Values are: %d and '%s'", 5, "oops");</code>
123 Only one default category can be created per file, though multiple
124 non-defaults can be created and used.
126 \section log_example Example
128 Here is a more complete example:
133 / * create a category and a default subcategory * /
134 XBT_LOG_NEW_CATEGORY(VSS);
135 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(SA, VSS);
138 / * Now set the parent's priority. (the string would typcially be a runtime option) * /
139 xbt_log_control_set("SA.thresh=3");
141 / * This request is enabled, because WARNING >= INFO. * /
142 CWARN2(VSS, "Low fuel level.");
144 / * This request is disabled, because DEBUG < INFO. * /
145 CDEBUG2(VSS, "Starting search for nearest gas station.");
147 / * The default category SA inherits its priority from VSS. Thus,
148 the following request is enabled because INFO >= INFO. * /
149 INFO1("Located nearest gas station.");
151 / * This request is disabled, because DEBUG < INFO. * /
152 DEBUG1("Exiting gas station search");
156 \section log_conf Configuration
157 Configuration is typically done during program initialization by invoking
158 the xbt_log_control_set() method. The control string passed to it typically
159 comes from the command line. Look at the documentation for that function for
160 the format of the control string.
162 Any SimGrid program can furthermore be configured at run time by passing a
163 --xbt-log argument on the command line (--gras-log, --msg-log and
164 --surf-log are synonyms). You can provide several of those arguments to
165 change the setting of several categories.
167 \section log_perf Performance
169 Clever design insures efficiency. Except for the first invocation, a
170 disabled logging request requires an a single comparison of a static
171 variable to a constant.
173 There is also compile time constant, \ref XBT_LOG_STATIC_THRESHOLD, which
174 causes all logging requests with a lower priority to be optimized to 0 cost
175 by the compiler. By setting it to gras_log_priority_infinite, all logging
176 requests are statically disabled and cost nothing. Released executables
177 might be compiled with
178 \verbatim-DXBT_LOG_STATIC_THRESHOLD=gras_log_priority_infinite\endverbatim
180 Compiling with the \verbatim-DNLOG\endverbatim option disables all logging
181 requests at compilation time while the \verbatim-DNDEBUG\endverbatim disables
182 the requests of priority below INFO.
184 \section log_app Appenders
186 Each category has an optional appender. An appender is a pointer to a
187 structure which starts with a pointer to a doAppend() function. DoAppend()
188 prints a message to a log.
190 When a category is passed a message by one of the logging macros, the
191 category performs the following actions:
193 - if the category has an appender, the message is passed to the
194 appender's doAppend() function,
195 - if 'willLogToParent' is true for the category, the message is passed
196 to the category's parent.
198 By default, only the root category have an appender, and 'willLogToParent'
199 is true for any other category. This situation causes all messages to be
200 logged by the root category's appender.
202 The default appender function currently prints to stderr, and no other one
203 exist, even if more would be needed, like the one able to send the logs to a
204 remote dedicated server, or other ones offering different output formats.
205 This is on our TODO list for quite a while now, but your help would be
208 \section log_misc Misc and Caveats
210 - Do not use any of the macros that start with '_'.
211 - Log4J has a 'rolling file appender' which you can select with a run-time
212 option and specify the max file size. This would be a nice default for
213 non-kernel applications.
214 - Careful, category names are global variables.
221 Dans gras, tu ne te contente pas d'écrire des choses à l'écran, mais tu
222 écris sur un sujet particulier (notion de canal) des choses d'une gravité
223 particulière. Il y a 7 niveaux de gravité.
224 trace: tracer les entrées dans une fonction, retour de fonction
225 (famille de macros XBT_IN/XBT_OUT)
226 debug: pour t'aider à mettre au point le module, potentiellement tres bavard
227 verbose: quelques infos succintes sur les internals du module
228 info: niveau normal, ton de la conversation
229 warning: problème potentiel, mais auquel on a su faire face
230 error: problème qui t'as empêché de faire ton job
231 critical: juste avant de mourir
233 Quand on compile avec -DNDEBUG (par défaut dans le paquet Debian), tout ce
234 qui est '>= verbose' est supprimé au moment de la compilation. Retiré du
237 Ensuite, tu écris dans un canal particulier. Tous les canaux sont rangés en
238 arbre. Il faudrait faire un ptit script qui fouille les sources à la
239 recherche des macros XBT_LOG_NEW_* utilisées pour créer des canaux. Le
240 dernier argument de ces macros est ignoré dans le source. Il est destiné à
241 être la documentation de la chose en une ligne. En gros, ca fait:
262 +--raw_trp (Je devrais tuer ce module, un jour)
268 Et ensuite les utilisateurs peuvent choisir le niveau de gravité qui les
269 interresse sur tel ou tel sujet.
271 Toute la mécanique de logging repose sur des variables statiques dont le nom
272 dépend du nom du canal.
273 => attention aux conflits de nom de canal
274 => il faut une macro XBT_LOG dans chaque fichier où tu fais des logs.
276 XBT_LOG_NEW_CATEGORY: nouveau canal sous "root". Rare, donc.
277 XBT_LOG_NEW_SUBCATEGORY: nouveau canal dont on précise le père.
278 XBT_LOG_DEFAULT_CATEGORY: indique quel est le canal par défaut dans ce fichier
279 XBT_LOG_NEW_DEFAULT_CATEGORY: Crèe un canal et l'utilise par défaut
280 XBT_LOG_NEW_DEFAULT_SUBCATEGORY: devine
281 XBT_LOG_EXTERNAL_CATEGORY: quand tu veux utiliser par défaut un canal créé
282 dans un autre fichier.
284 Une fois que ton canal est créé, tu l'utilise avec les macros LOG, DEBUG,
285 VERB, WARN, ERROR et CRITICAL. Il faut que tu donne le nombre d'arguments
286 après le nom de macro. Exemple: LOG2("My name is %s %s","Martin","Quinson")
287 Si tu veux préciser explicitement le canal où écrire, ajoute un C devant le
288 nom de la macro. Exemple: CCRITICAL0(module, "Cannot initialize GRAS")
290 Toutes ces macros (enfin, ce en quoi elles se réécrivent) vérifient leurs
291 arguments comme printf le fait lorsqu'on compile avec gcc.
292 LOG1("name: %d","toto"); donne un warning, et donc une erreur en mode
295 Enfin, tu peux tester si un canal est ouvert à une priorité donnée (pour
296 préparer plus de débug, par exemple. Dans le parseur, je fais du pretty
297 printing sur ce qu'il faut parser dans ce cas).
298 XBT_LOG_ISENABLED(catName, priority) Le second argument doit être une valeur
299 de e_xbt_log_priority_t (log.h). Par exemple: xbt_log_priority_verbose
301 Voila sur comment mettre des logs dans ton code. N'hesite pas à faire pleins
302 de canaux différents pour des aspects différents de ton code. En
303 particulier, dans les dict, j'ai un canal pour l'ajout, le retrait, le
304 netoyage du code après suppression et ainsi de suite. De cette façon, je
305 peux choisir qui m'interresse.
308 Pour utiliser les logs, tu déjà faire, non ? Tu colle sur la ligne de
309 commande un ou plusieurs arguments de la forme
310 --gras-log="<réglage> [<reglage>+]" (ou sans " si t'as pas d'espace)
311 chaque réglage étant de la forme:
312 <canal>.thres=<priorité>
313 Les différents réglages sont lus de gauche à droite.
314 "root.thres=debug root.thres=critical" ferme tout, normalement.
320 e_xbt_log_priority_t thresh;
321 } s_xbt_log_setting_t,*xbt_log_setting_t;
323 static xbt_dynar_t xbt_log_settings=NULL;
324 static void _free_setting(void *s) {
325 xbt_log_setting_t set=(xbt_log_setting_t)s;
327 xbt_free(set->catname);
328 /* xbt_free(set); FIXME: uncommenting this leads to segfault when more than one chunk is passed as gras-log */
332 const char *xbt_log_priority_names[8] = {
343 s_xbt_log_category_t _XBT_LOGV(XBT_LOG_ROOT_CAT) = {
345 "root", xbt_log_priority_uninitialized, 0,
349 XBT_LOG_NEW_CATEGORY(xbt,"All XBT categories (simgrid toolbox)");
350 XBT_LOG_NEW_CATEGORY(surf,"All SURF categories");
351 XBT_LOG_NEW_CATEGORY(msg,"All MSG categories");
352 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(log,xbt,"Loggings from the logging mecanism itself");
354 void xbt_log_init(int *argc,char **argv, const char *defaultlog) {
359 /* Set logs and init log submodule */
360 for (i=1; i<*argc; i++) {
361 if (!strncmp(argv[i],"--gras-log=",strlen("--gras-log=")) ||
362 !strncmp(argv[i],"--surf-log=",strlen("--surf-log=")) ||
363 !strncmp(argv[i],"--msg-log=",strlen("--msg-log=")) ||
364 !strncmp(argv[i],"--xbt-log=",strlen("--xbt-log="))) {
366 opt=strchr(argv[i],'=');
368 xbt_log_control_set(opt);
369 DEBUG1("Did apply '%s' as log setting",opt);
370 /*remove this from argv*/
371 for (j=i+1; j<*argc; j++) {
376 i--; /* compensate effect of next loop incrementation */
379 if (!found && defaultlog) {
380 xbt_log_control_set(defaultlog);
384 void xbt_log_exit(void) {
385 VERB0("Exiting log");
386 xbt_dynar_free(&xbt_log_settings);
390 static void _apply_control(xbt_log_category_t cat) {
392 xbt_log_setting_t setting=NULL;
395 if (!xbt_log_settings)
398 xbt_assert0(cat,"NULL category");
399 xbt_assert(cat->name);
401 xbt_dynar_foreach(xbt_log_settings,cursor,setting) {
402 xbt_assert0(setting,"Damnit, NULL cat in the list");
403 xbt_assert1(setting->catname,"NULL setting(=%p)->catname",(void*)setting);
405 if (!strcmp(setting->catname,cat->name)) {
408 xbt_log_threshold_set(cat, setting->thresh);
409 xbt_dynar_cursor_rm(xbt_log_settings,&cursor);
411 if (cat->threshold <= xbt_log_priority_verbose) {
412 s_xbt_log_event_t _log_ev =
413 {cat,xbt_log_priority_verbose,__FILE__,_XBT_GNUC_FUNCTION,__LINE__};
414 _xbt_log_event_log(&_log_ev,
415 "Apply settings for category '%s': set threshold to %s (=%d)",
417 xbt_log_priority_names[cat->threshold], cat->threshold);
421 if (!found && cat->threshold <= xbt_log_priority_verbose) {
422 s_xbt_log_event_t _log_ev =
423 {cat,xbt_log_priority_verbose,__FILE__,_XBT_GNUC_FUNCTION,__LINE__};
424 _xbt_log_event_log(&_log_ev,
425 "Category '%s': inherited threshold = %s (=%d)",
427 xbt_log_priority_names[cat->threshold], cat->threshold);
432 void _xbt_log_event_log( xbt_log_event_t ev, const char *fmt, ...) {
433 xbt_log_category_t cat = ev->cat;
434 va_start(ev->ap, fmt);
436 xbt_log_appender_t appender = cat->appender;
437 if (appender != NULL) {
438 appender->do_append(appender, ev, fmt);
440 if (!cat->willLogToParent)
448 static void _cat_init(xbt_log_category_t category) {
449 if (category == &_XBT_LOGV(XBT_LOG_ROOT_CAT)) {
450 category->threshold = xbt_log_priority_info;
451 category->appender = xbt_log_default_appender;
453 xbt_log_parent_set(category, category->parent);
455 _apply_control(category);
459 * This gets called the first time a category is referenced and performs the
461 * Also resets threshold to inherited!
463 int _xbt_log_cat_init(e_xbt_log_priority_t priority,
464 xbt_log_category_t category) {
468 return priority >= category->threshold;
471 void xbt_log_parent_set(xbt_log_category_t cat,
472 xbt_log_category_t parent) {
474 xbt_assert0(cat,"NULL category to be given a parent");
475 xbt_assert1(parent,"The parent category of %s is NULL",cat->name);
477 /* unlink from current parent */
478 if (cat->threshold != xbt_log_priority_uninitialized) {
479 xbt_log_category_t* cpp = &parent->firstChild;
480 while(*cpp != cat && *cpp != NULL) {
481 cpp = &(*cpp)->nextSibling;
483 xbt_assert(*cpp == cat);
484 *cpp = cat->nextSibling;
488 cat->parent = parent;
489 cat->nextSibling = parent->firstChild;
490 parent->firstChild = cat;
492 /* Make sure parent is initialized */
493 if (parent->threshold == xbt_log_priority_uninitialized) {
498 cat->threshold = parent->threshold;
499 cat->isThreshInherited = 1;
500 } /* log_setParent */
502 static void _set_inherited_thresholds(xbt_log_category_t cat) {
503 xbt_log_category_t child = cat->firstChild;
504 for( ; child != NULL; child = child->nextSibling) {
505 if (child->isThreshInherited) {
506 if (cat != &_XBT_LOGV(log))
507 VERB3("Set category threshold of %s to %s (=%d)",
508 child->name,xbt_log_priority_names[cat->threshold],cat->threshold);
509 child->threshold = cat->threshold;
510 _set_inherited_thresholds(child);
515 void xbt_log_threshold_set(xbt_log_category_t cat,
516 e_xbt_log_priority_t threshold) {
517 cat->threshold = threshold;
518 cat->isThreshInherited = 0;
519 _set_inherited_thresholds(cat);
522 static void _xbt_log_parse_setting(const char* control_string,
523 xbt_log_setting_t set) {
524 const char *name, *dot, *eq;
527 if (!*control_string)
529 DEBUG1("Parse log setting '%s'",control_string);
531 control_string += strspn(control_string, " ");
532 name = control_string;
533 control_string += strcspn(control_string, ".= ");
534 dot = control_string;
535 control_string += strcspn(control_string, "= ");
537 control_string += strcspn(control_string, " ");
539 xbt_assert1(*dot == '.' && *eq == '=',
540 "Invalid control string '%s'",control_string);
542 if (!strncmp(dot + 1, "thresh", min(eq - dot - 1,strlen("thresh")))) {
544 char *neweq=xbt_strdup(eq+1);
547 while (*(++p) != '\0') {
548 if (*p >= 'a' && *p <= 'z') {
553 DEBUG1("New priority name = %s",neweq);
554 for (i=0; i<xbt_log_priority_infinite-1; i++) {
555 if (!strncmp(xbt_log_priority_names[i],neweq,p-eq)) {
556 DEBUG1("This is priority %d",i);
560 if (i<xbt_log_priority_infinite-1) {
563 xbt_assert1(FALSE,"Unknown priority name: %s",eq+1);
568 snprintf(buff,min(512,eq - dot - 1),"%s",dot+1);
569 xbt_assert1(FALSE,"Unknown setting of the log category: %s",buff);
571 set->catname=(char*)xbt_malloc(dot - name+1);
573 strncpy(set->catname,name,dot-name);
574 set->catname[dot-name]='\0'; /* Just in case */
575 DEBUG1("This is for cat '%s'", set->catname);
578 static xbt_error_t _xbt_log_cat_searchsub(xbt_log_category_t cat,char *name,
579 /*OUT*/xbt_log_category_t*whereto) {
581 xbt_log_category_t child;
583 if (!strcmp(cat->name,name)) {
587 for(child=cat->firstChild ; child != NULL; child = child->nextSibling) {
588 errcode=_xbt_log_cat_searchsub(child,name,whereto);
589 if (errcode==no_error)
592 return mismatch_error;
595 static void _cleanup_double_spaces(char *s) {
618 if (e ^ !isspace(*p))
629 * \param control_string What to parse
631 * Typically passed a command-line argument. The string has the syntax:
633 * ( [category] "." [keyword] "=" value (" ")... )...
635 * where [category] is one the category names and keyword is one of the
638 * thresh value is an integer priority level. Sets the category's
639 * threshold priority.
642 * This routine may only be called once and that must be before any other
643 * logging command! Typically, this is done from main().
645 void xbt_log_control_set(const char* control_string) {
647 xbt_log_setting_t set;
652 DEBUG1("Parse log settings '%s'",control_string);
653 if (control_string == NULL)
655 if (xbt_log_settings == NULL)
656 xbt_log_settings = xbt_dynar_new(sizeof(xbt_log_setting_t),
659 set = xbt_new(s_xbt_log_setting_t,1);
660 cs=xbt_strdup(control_string);
662 _cleanup_double_spaces(cs);
665 xbt_log_category_t cat;
675 _xbt_log_parse_setting(p,set);
677 errcode = _xbt_log_cat_searchsub(&_XBT_LOGV(root),set->catname,&cat);
678 if (errcode == mismatch_error) {
679 DEBUG0("Store for further application");
680 DEBUG1("push %p to the settings",(void*)set);
681 xbt_dynar_push(xbt_log_settings,&set);
682 /* malloc in advance the next slot */
683 set = xbt_new(s_xbt_log_setting_t,1);
685 DEBUG0("Apply directly");
686 xbt_free(set->catname);
687 xbt_log_threshold_set(cat,set->thresh);
694 void xbt_log_appender_set(xbt_log_category_t cat, xbt_log_appender_t app) {