src/core/store_json.c

   1 /*
   2  * SysDB - src/core/store_json.c
   3  * Copyright (C) 2013-2015 Sebastian 'tokkee' Harl <sh@tokkee.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  16  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  17  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  18  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
  19  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 /*
  29  * This module implements JSON support.
  30  */
  31
  32 #if HAVE_CONFIG_H
  33 #       include "config.h"
  34 #endif /* HAVE_CONFIG_H */
  35
  36 #include "sysdb.h"
  37 #include "core/store-private.h"
  38 #include "utils/error.h"
  39
  40 #include <assert.h>
  41
  42 #include <ctype.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45
  46 /*
  47  * private data types
  48  */
  49
  50 struct sdb_store_json_formatter {
  51         sdb_object_t super;
  52
  53         /* The string buffer to write to */
  54         sdb_strbuf_t *buf;
  55
  56         /* The context describes the state of the formatter through
  57          * the path pointing to the current object */
  58         int context[8];
  59         size_t current;
  60
  61         int type;
  62         int flags;
  63 };
  64 #define F(obj) ((sdb_store_json_formatter_t *)(obj))
  65
  66 static int
  67 formatter_init(sdb_object_t *obj, va_list ap)
  68 {
  69         sdb_store_json_formatter_t *f = F(obj);
  70
  71         f->buf = va_arg(ap, sdb_strbuf_t *);
  72         if (! f->buf)
  73                 return -1;
  74
  75         f->type = va_arg(ap, int);
  76         if ((f->type != SDB_HOST) && (f->type != SDB_SERVICE) && (f->type != SDB_METRIC))
  77                 return -1;
  78
  79         f->flags = va_arg(ap, int);
  80
  81         f->context[0] = 0;
  82         f->current = 0;
  83         return 0;
  84 } /* formatter_init */
  85
  86 static sdb_type_t formatter_type = {
  87         /* size = */ sizeof(sdb_store_json_formatter_t),
  88         /* init = */ formatter_init,
  89         /* destroy = */ NULL,
  90 };
  91
  92 /* A generic representation of a stored object. */
  93 typedef struct {
  94         /* identifier */
  95         int type;
  96         const char *name;
  97
  98         /* attribute value (optional) */
  99         sdb_data_t *value;
 100
 101         /* metric's timeseries (optional)
 102          * -1: unset
 103          *  0: false
 104          *  1: true */
 105         int timeseries;
 106
 107         /* generic meta-data */
 108         sdb_time_t last_update;
 109         sdb_time_t interval;
 110         size_t backends_num;
 111         const char * const *backends;
 112 } obj_t;
 113
 114 /*
 115  * private helper functions
 116  */
 117
 118 static void
 119 escape_string(const char *src, char *dest)
 120 {
 121         size_t i = 1;
 122         dest[0] = '"';
 123         for ( ; *src; ++src) {
 124                 char c = *src;
 125                 if ((c == '"') || (c == '\\') || iscntrl((int)c)) {
 126                         dest[i] = '\\';
 127                         ++i;
 128                 }
 129                 switch (c) {
 130                         case '\a': dest[i] = 'a'; break;
 131                         case '\b': dest[i] = 'b'; break;
 132                         case '\t': dest[i] = 't'; break;
 133                         case '\n': dest[i] = 'n'; break;
 134                         case '\v': dest[i] = 'v'; break;
 135                         case '\f': dest[i] = 'f'; break;
 136                         case '\r': dest[i] = 'r'; break;
 137                         default: dest[i] = c; break;
 138                 }
 139                 ++i;
 140         }
 141         dest[i] = '"';
 142         dest[i + 1] = '\0';
 143 } /* escape_string */
 144
 145 /* handle_new_object takes care of all maintenance logic related to adding a
 146  * new object. That is, it manages context information and emit the prefix and
 147  * suffix of an object. */
 148 static int
 149 handle_new_object(sdb_store_json_formatter_t *f, int type)
 150 {
 151         /* first top-level object */
 152         if (! f->context[0]) {
 153                 if ((type != f->type) && (type != SDB_HOST)) {
 154                         sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
 155                                         "as the first element during %s JSON serialization",
 156                                         SDB_STORE_TYPE_TO_NAME(type),
 157                                         SDB_STORE_TYPE_TO_NAME(f->type));
 158                         return -1;
 159                 }
 160                 if (f->flags & SDB_WANT_ARRAY)
 161                         sdb_strbuf_append(f->buf, "[");
 162                 assert(f->current == 0);
 163                 f->context[f->current] = type;
 164                 return 0;
 165         }
 166
 167         if ((f->context[f->current] != SDB_HOST)
 168                         && (type != SDB_ATTRIBUTE)) {
 169                 /* new entry of the same type or a parent object;
 170                  * rewind to the right state */
 171                 while ((f->current > 0)
 172                                 && (f->context[f->current] != type)) {
 173                         sdb_strbuf_append(f->buf, "}]");
 174                         --f->current;
 175                 }
 176         }
 177
 178         if (type == f->context[f->current]) {
 179                 /* new entry of the same type */
 180                 sdb_strbuf_append(f->buf, "},");
 181         }
 182         else if ((f->context[f->current] == SDB_HOST)
 183                         || (type == SDB_ATTRIBUTE)) {
 184                 assert(type != SDB_HOST);
 185                 /* all object types may be children of a host;
 186                  * attributes may be children of any type */
 187                 sdb_strbuf_append(f->buf, ", \"%ss\": [",
 188                                 SDB_STORE_TYPE_TO_NAME(type));
 189                 ++f->current;
 190         }
 191         else {
 192                 sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
 193                                 "on level %zu during JSON serialization",
 194                                 SDB_STORE_TYPE_TO_NAME(type), f->current);
 195                 return -1;
 196         }
 197
 198         assert(f->current < SDB_STATIC_ARRAY_LEN(f->context));
 199         f->context[f->current] = type;
 200         return 0;
 201 } /* handle_new_object */
 202
 203 static int
 204 json_emit(sdb_store_json_formatter_t *f, obj_t *obj)
 205 {
 206         char time_str[64];
 207         char interval_str[64];
 208         char name[2 * strlen(obj->name) + 3];
 209         size_t i;
 210
 211         assert(f && obj);
 212
 213         handle_new_object(f, obj->type);
 214
 215         escape_string(obj->name, name);
 216         sdb_strbuf_append(f->buf, "{\"name\": %s, ", name);
 217         if ((obj->type == SDB_ATTRIBUTE) && (obj->value)) {
 218                 char tmp[sdb_data_strlen(obj->value) + 1];
 219                 char val[2 * sizeof(tmp) + 3];
 220                 if (! sdb_data_format(obj->value, tmp, sizeof(tmp),
 221                                         SDB_DOUBLE_QUOTED))
 222                         snprintf(tmp, sizeof(tmp), "<error>");
 223
 224                 if (tmp[0] == '"') {
 225                         /* a string; escape_string handles quoting */
 226                         tmp[strlen(tmp) - 1] = '\0';
 227                         escape_string(tmp + 1, val);
 228                         sdb_strbuf_append(f->buf, "\"value\": %s, ", val);
 229                 }
 230                 else
 231                         sdb_strbuf_append(f->buf, "\"value\": %s, ", tmp);
 232         }
 233         else if ((obj->type == SDB_METRIC) && (obj->timeseries >= 0)) {
 234                 if (obj->timeseries)
 235                         sdb_strbuf_append(f->buf, "\"timeseries\": true, ");
 236                 else
 237                         sdb_strbuf_append(f->buf, "\"timeseries\": false, ");
 238         }
 239
 240         /* TODO: make time and interval formats configurable */
 241         if (! sdb_strftime(time_str, sizeof(time_str), obj->last_update))
 242                 snprintf(time_str, sizeof(time_str), "<error>");
 243         time_str[sizeof(time_str) - 1] = '\0';
 244
 245         if (! sdb_strfinterval(interval_str, sizeof(interval_str),
 246                                 obj->interval))
 247                 snprintf(interval_str, sizeof(interval_str), "<error>");
 248         interval_str[sizeof(interval_str) - 1] = '\0';
 249
 250         sdb_strbuf_append(f->buf, "\"last_update\": \"%s\", "
 251                         "\"update_interval\": \"%s\", \"backends\": [",
 252                         time_str, interval_str);
 253
 254         for (i = 0; i < obj->backends_num; ++i) {
 255                 sdb_strbuf_append(f->buf, "\"%s\"", obj->backends[i]);
 256                 if (i < obj->backends_num - 1)
 257                         sdb_strbuf_append(f->buf, ",");
 258         }
 259         sdb_strbuf_append(f->buf, "]");
 260         return 0;
 261 } /* json_emit */
 262
 263 static int
 264 emit_host(sdb_store_host_t *host, sdb_object_t *user_data)
 265 {
 266         sdb_store_json_formatter_t *f = F(user_data);
 267
 268         if ((! host) || (! user_data))
 269                 return -1;
 270
 271         {
 272                 obj_t o = {
 273                         SDB_HOST,
 274                         host->name,
 275
 276                         /* value */ NULL,
 277                         /* timeseries */ -1,
 278
 279                         host->last_update,
 280                         host->interval,
 281                         host->backends_num,
 282                         (const char * const *)host->backends,
 283                 };
 284
 285                 return json_emit(f, &o);
 286         }
 287 } /* emit_host */
 288
 289 static int
 290 emit_service(sdb_store_service_t *service, sdb_object_t *user_data)
 291 {
 292         sdb_store_json_formatter_t *f = F(user_data);
 293
 294         if ((! service) || (! user_data))
 295                 return -1;
 296
 297         {
 298                 obj_t o = {
 299                         SDB_SERVICE,
 300                         service->name,
 301
 302                         /* value */ NULL,
 303                         /* timeseries */ -1,
 304
 305                         service->last_update,
 306                         service->interval,
 307                         service->backends_num,
 308                         (const char * const *)service->backends,
 309                 };
 310
 311                 return json_emit(f, &o);
 312         }
 313 } /* emit_service */
 314
 315 static int
 316 emit_metric(sdb_store_metric_t *metric, sdb_object_t *user_data)
 317 {
 318         sdb_store_json_formatter_t *f = F(user_data);
 319
 320         if ((! metric) || (! user_data))
 321                 return -1;
 322
 323         {
 324                 obj_t o = {
 325                         SDB_METRIC,
 326                         metric->name,
 327
 328                         /* value */ NULL,
 329                         /* timeseries */ metric->store.type != NULL,
 330
 331                         metric->last_update,
 332                         metric->interval,
 333                         metric->backends_num,
 334                         (const char * const *)metric->backends,
 335                 };
 336
 337                 return json_emit(f, &o);
 338         }
 339 } /* emit_metric */
 340
 341 static int
 342 emit_attribute(sdb_store_attribute_t *attr, sdb_object_t *user_data)
 343 {
 344         sdb_store_json_formatter_t *f = F(user_data);
 345
 346         if ((! attr) || (! user_data))
 347                 return -1;
 348
 349         {
 350                 obj_t o = {
 351                         SDB_ATTRIBUTE,
 352                         attr->key,
 353
 354                         /* value */ &attr->value,
 355                         /* timeseries */ -1,
 356
 357                         attr->last_update,
 358                         attr->interval,
 359                         attr->backends_num,
 360                         (const char * const *)attr->backends,
 361                 };
 362
 363                 return json_emit(f, &o);
 364         }
 365 } /* emit_attribute */
 366
 367 /*
 368  * public API
 369  */
 370
 371 sdb_store_writer_t sdb_store_json_writer = {
 372         emit_host, emit_service, emit_metric, emit_attribute,
 373 };
 374
 375 sdb_store_json_formatter_t *
 376 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags)
 377 {
 378         return F(sdb_object_create("json-formatter", formatter_type,
 379                                 buf, type, flags));
 380 } /* sdb_store_json_formatter */
 381
 382 /* TODO: Move sdb_store_emit* somewhere else. */
 383
 384 int
 385 sdb_store_emit(sdb_store_obj_t *obj, sdb_store_writer_t *w, sdb_object_t *wd)
 386 {
 387         if ((! obj) || (! w)
 388                         || (! w->store_host) || (! w->store_service)
 389                         || (! w->store_metric) || (! w->store_attribute))
 390                 return -1;
 391
 392         switch (obj->type) {
 393         case SDB_HOST:
 394                 {
 395                         sdb_store_host_t host = {
 396                                 obj->_name,
 397                                 obj->last_update,
 398                                 obj->interval,
 399                                 (const char * const *)obj->backends,
 400                                 obj->backends_num,
 401                         };
 402                         return w->store_host(&host, wd);
 403                 }
 404         case SDB_SERVICE:
 405                 {
 406                         sdb_store_service_t service = {
 407                                 obj->parent ? obj->parent->_name : NULL,
 408                                 obj->_name,
 409                                 obj->last_update,
 410                                 obj->interval,
 411                                 (const char * const *)obj->backends,
 412                                 obj->backends_num,
 413                         };
 414                         return w->store_service(&service, wd);
 415                 }
 416         case SDB_METRIC:
 417                 {
 418                         sdb_store_metric_t metric = {
 419                                 obj->parent ? obj->parent->_name : NULL,
 420                                 obj->_name,
 421                                 {
 422                                         METRIC(obj)->store.type,
 423                                         METRIC(obj)->store.id,
 424                                 },
 425                                 obj->last_update,
 426                                 obj->interval,
 427                                 (const char * const *)obj->backends,
 428                                 obj->backends_num,
 429                         };
 430                         return w->store_metric(&metric, wd);
 431                 }
 432         case SDB_ATTRIBUTE:
 433                 {
 434                         sdb_store_attribute_t attr = {
 435                                 NULL,
 436                                 obj->parent ? obj->parent->type : 0,
 437                                 obj->parent ? obj->parent->_name : NULL,
 438                                 obj->_name,
 439                                 ATTR(obj)->value,
 440                                 obj->last_update,
 441                                 obj->interval,
 442                                 (const char * const *)obj->backends,
 443                                 obj->backends_num,
 444                         };
 445                         if (obj->parent && (obj->parent->type != SDB_HOST)
 446                                         && obj->parent->parent)
 447                                 attr.hostname = obj->parent->parent->_name;
 448                         return w->store_attribute(&attr, wd);
 449                 }
 450         }
 451
 452         return -1;
 453 } /* sdb_store_emit */
 454
 455 int
 456 sdb_store_emit_full(sdb_store_obj_t *obj, sdb_store_matcher_t *filter,
 457                 sdb_store_writer_t *w, sdb_object_t *wd)
 458 {
 459         sdb_avltree_t *trees[] = { NULL, NULL, NULL };
 460         size_t i;
 461
 462         if (sdb_store_emit(obj, w, wd))
 463                 return -1;
 464
 465         if (obj->type == SDB_HOST) {
 466                 trees[0] = HOST(obj)->attributes;
 467                 trees[1] = HOST(obj)->metrics;
 468                 trees[2] = HOST(obj)->services;
 469         }
 470         else if (obj->type == SDB_SERVICE)
 471                 trees[0] = SVC(obj)->attributes;
 472         else if (obj->type == SDB_METRIC)
 473                 trees[0] = METRIC(obj)->attributes;
 474         else if (obj->type == SDB_ATTRIBUTE)
 475                 return 0;
 476         else
 477                 return -1;
 478
 479         for (i = 0; i < SDB_STATIC_ARRAY_LEN(trees); ++i) {
 480                 sdb_avltree_iter_t *iter;
 481
 482                 if (! trees[i])
 483                         continue;
 484
 485                 iter = sdb_avltree_get_iter(trees[i]);
 486                 while (sdb_avltree_iter_has_next(iter)) {
 487                         sdb_store_obj_t *child;
 488                         child = STORE_OBJ(sdb_avltree_iter_get_next(iter));
 489
 490                         if (filter && (! sdb_store_matcher_matches(filter, child, NULL)))
 491                                 continue;
 492
 493                         if (sdb_store_emit_full(child, filter, w, wd)) {
 494                                 sdb_avltree_iter_destroy(iter);
 495                                 return -1;
 496                         }
 497                 }
 498                 sdb_avltree_iter_destroy(iter);
 499         }
 500         return 0;
 501 } /* sdb_store_emit_full */
 502
 503 int
 504 sdb_store_json_finish(sdb_store_json_formatter_t *f)
 505 {
 506         if (! f)
 507                 return -1;
 508
 509         if (! f->context[0]) {
 510                 /* no content */
 511                 if (f->flags & SDB_WANT_ARRAY)
 512                         sdb_strbuf_append(f->buf, "[]");
 513                 return 0;
 514         }
 515
 516         while (f->current > 0) {
 517                 sdb_strbuf_append(f->buf, "}]");
 518                 --f->current;
 519         }
 520         sdb_strbuf_append(f->buf, "}");
 521
 522         if (f->flags & SDB_WANT_ARRAY)
 523                 sdb_strbuf_append(f->buf, "]");
 524         return 0;
 525 } /* sdb_store_json_finish */
 526
 527 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 528