src/core/store_json.c

   1 /*
   2  * SysDB - src/core/store_json.c
   3  * Copyright (C) 2013-2014 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_strbuf_t *buf;
  52
  53         /* The context describes the state of the formatter through
  54          * the path pointing to the current object */
  55         int context[8];
  56         size_t current;
  57
  58         /* The current host context when processing non-host objects */
  59         sdb_store_obj_t *current_host;
  60
  61         int type;
  62         int flags;
  63 };
  64
  65 /*
  66  * private helper functions
  67  */
  68
  69 static void
  70 escape_string(const char *src, char *dest)
  71 {
  72         size_t i = 1;
  73         dest[0] = '"';
  74         for ( ; *src; ++src) {
  75                 char c = *src;
  76                 if ((c == '"') || (c == '\\') || iscntrl((int)c)) {
  77                         dest[i] = '\\';
  78                         ++i;
  79                 }
  80                 switch (c) {
  81                         case '\a': dest[i] = 'a'; break;
  82                         case '\b': dest[i] = 'b'; break;
  83                         case '\t': dest[i] = 't'; break;
  84                         case '\n': dest[i] = 'n'; break;
  85                         case '\v': dest[i] = 'v'; break;
  86                         case '\f': dest[i] = 'f'; break;
  87                         case '\r': dest[i] = 'r'; break;
  88                         default: dest[i] = c; break;
  89                 }
  90                 ++i;
  91         }
  92         dest[i] = '"';
  93         dest[i + 1] = '\0';
  94 } /* escape_string */
  95
  96 static int
  97 json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
  98 {
  99         char time_str[64];
 100         char interval_str[64];
 101         char name[2 * strlen(SDB_OBJ(obj)->name) + 3];
 102         size_t i;
 103
 104         assert(f && obj);
 105
 106         if ((f->type != SDB_HOST) && (f->type == obj->type)) {
 107                 /* create the host for the current entry first */
 108                 assert(obj->parent && (obj->parent->type == SDB_HOST));
 109                 if (f->current_host != obj->parent) {
 110                         json_emit(f, obj->parent);
 111                         sdb_strbuf_append(f->buf, ", \"%ss\": [",
 112                                         SDB_STORE_TYPE_TO_NAME(obj->type));
 113                         f->current_host = obj->parent;
 114                 }
 115         }
 116
 117         escape_string(SDB_OBJ(obj)->name, name);
 118         sdb_strbuf_append(f->buf, "{\"name\": %s, ", name);
 119         if (obj->type == SDB_ATTRIBUTE) {
 120                 char tmp[sdb_data_strlen(&ATTR(obj)->value) + 1];
 121                 char val[2 * sizeof(tmp) + 3];
 122                 if (sdb_data_format(&ATTR(obj)->value, tmp, sizeof(tmp),
 123                                         SDB_DOUBLE_QUOTED) < 0)
 124                         snprintf(tmp, sizeof(tmp), "<error>");
 125
 126                 if (tmp[0] == '"') {
 127                         /* a string; escape_string handles quoting */
 128                         tmp[strlen(tmp) - 1] = '\0';
 129                         escape_string(tmp + 1, val);
 130                         sdb_strbuf_append(f->buf, "\"value\": %s, ", val);
 131                 }
 132                 else
 133                         sdb_strbuf_append(f->buf, "\"value\": %s, ", tmp);
 134         }
 135         else if (obj->type == SDB_METRIC) {
 136                 if (METRIC(obj)->store.type != NULL)
 137                         sdb_strbuf_append(f->buf, "\"timeseries\": true, ");
 138                 else
 139                         sdb_strbuf_append(f->buf, "\"timeseries\": false, ");
 140         }
 141
 142         /* TODO: make time and interval formats configurable */
 143         if (! sdb_strftime(time_str, sizeof(time_str),
 144                                 "%F %T %z", obj->last_update))
 145                 snprintf(time_str, sizeof(time_str), "<error>");
 146         time_str[sizeof(time_str) - 1] = '\0';
 147
 148         if (! sdb_strfinterval(interval_str, sizeof(interval_str),
 149                                 obj->interval))
 150                 snprintf(interval_str, sizeof(interval_str), "<error>");
 151         interval_str[sizeof(interval_str) - 1] = '\0';
 152
 153         sdb_strbuf_append(f->buf, "\"last_update\": \"%s\", "
 154                         "\"update_interval\": \"%s\", \"backends\": [",
 155                         time_str, interval_str);
 156
 157         for (i = 0; i < obj->backends_num; ++i) {
 158                 sdb_strbuf_append(f->buf, "\"%s\"", obj->backends[i]);
 159                 if (i < obj->backends_num - 1)
 160                         sdb_strbuf_append(f->buf, ",");
 161         }
 162         sdb_strbuf_append(f->buf, "]");
 163         return 0;
 164 } /* json_emit */
 165
 166 /*
 167  * public API
 168  */
 169
 170 sdb_store_json_formatter_t *
 171 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags)
 172 {
 173         sdb_store_json_formatter_t *f;
 174
 175         if (! buf)
 176                 return NULL;
 177
 178         if ((type != SDB_HOST) && (type != SDB_SERVICE) && (type != SDB_METRIC))
 179                 return NULL;
 180
 181         f = calloc(1, sizeof(*f));
 182         if (! f)
 183                 return NULL;
 184
 185         f->buf = buf;
 186         f->context[0] = 0;
 187         f->current = 0;
 188
 189         f->current_host = NULL;
 190
 191         f->type = type;
 192         f->flags = flags;
 193         return f;
 194 } /* sdb_store_json_formatter */
 195
 196 int
 197 sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
 198 {
 199         if ((! f) || (! obj))
 200                 return -1;
 201
 202         if ((f->type != SDB_HOST) && (obj->type == SDB_HOST)) {
 203                 sdb_log(SDB_LOG_ERR, "store: Unexpected object of type host "
 204                                 "during %s JSON serialization",
 205                                 SDB_STORE_TYPE_TO_NAME(f->type));
 206                 return -1;
 207         }
 208
 209         /* first top-level object */
 210         if (! f->context[0]) {
 211                 if (obj->type != f->type) {
 212                         sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
 213                                         "as the first element during %s JSON serialization",
 214                                         SDB_STORE_TYPE_TO_NAME(obj->type),
 215                                         SDB_STORE_TYPE_TO_NAME(f->type));
 216                         return -1;
 217                 }
 218                 if (f->flags & SDB_WANT_ARRAY)
 219                         sdb_strbuf_append(f->buf, "[");
 220                 assert(f->current == 0);
 221                 f->context[0] = obj->type;
 222                 return json_emit(f, obj);
 223         }
 224
 225         if ((f->current >= 1) && (obj->type != SDB_ATTRIBUTE)) {
 226                 /* new entry of a previous type or a new type on the same level;
 227                  * rewind to the right state */
 228                 while (f->current > 0) {
 229                         if (f->context[f->current] == obj->type)
 230                                 break;
 231                         sdb_strbuf_append(f->buf, "}]");
 232                         --f->current;
 233                 }
 234         }
 235         if ((obj->type == f->type) && (f->type != SDB_HOST))
 236                 if (obj->parent != f->current_host)
 237                         sdb_strbuf_append(f->buf, "}]");
 238
 239         if (obj->type == f->context[f->current]) {
 240                 /* new entry of the same type */
 241                 sdb_strbuf_append(f->buf, "},");
 242         }
 243         else if ((f->context[f->current] == SDB_HOST)
 244                         || (obj->type == SDB_ATTRIBUTE)) {
 245                 assert(obj->type != SDB_HOST);
 246                 /* all object types may be children of a host;
 247                  * attributes may be children of any type */
 248                 sdb_strbuf_append(f->buf, ", \"%ss\": [",
 249                                 SDB_STORE_TYPE_TO_NAME(obj->type));
 250                 ++f->current;
 251         }
 252         else {
 253                 sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
 254                                 "on level %zu during JSON serialization",
 255                                 SDB_STORE_TYPE_TO_NAME(obj->type), f->current);
 256                 return -1;
 257         }
 258
 259         json_emit(f, obj);
 260         assert(f->current < SDB_STATIC_ARRAY_LEN(f->context));
 261         f->context[f->current] = obj->type;
 262         return 0;
 263 } /* sdb_store_json_emit */
 264
 265 int
 266 sdb_store_json_emit_full(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj,
 267                 sdb_store_matcher_t *filter)
 268 {
 269         sdb_avltree_t *trees[] = { NULL, NULL, NULL };
 270         size_t i;
 271
 272         if (sdb_store_json_emit(f, obj))
 273                 return -1;
 274
 275         if (obj->type == SDB_HOST) {
 276                 trees[0] = HOST(obj)->attributes;
 277                 trees[1] = HOST(obj)->metrics;
 278                 trees[2] = HOST(obj)->services;
 279         }
 280         else if (obj->type == SDB_SERVICE)
 281                 trees[0] = SVC(obj)->attributes;
 282         else if (obj->type == SDB_METRIC)
 283                 trees[0] = METRIC(obj)->attributes;
 284         else if (obj->type == SDB_ATTRIBUTE)
 285                 return 0;
 286         else
 287                 return -1;
 288
 289         for (i = 0; i < SDB_STATIC_ARRAY_LEN(trees); ++i) {
 290                 sdb_avltree_iter_t *iter;
 291
 292                 if (! trees[i])
 293                         continue;
 294
 295                 iter = sdb_avltree_get_iter(trees[i]);
 296                 while (sdb_avltree_iter_has_next(iter)) {
 297                         sdb_store_obj_t *child;
 298                         child = STORE_OBJ(sdb_avltree_iter_get_next(iter));
 299
 300                         if (filter && (! sdb_store_matcher_matches(filter, child, NULL)))
 301                                 continue;
 302
 303                         if (sdb_store_json_emit_full(f, child, filter)) {
 304                                 sdb_avltree_iter_destroy(iter);
 305                                 return -1;
 306                         }
 307                 }
 308                 sdb_avltree_iter_destroy(iter);
 309         }
 310         return 0;
 311 } /* sdb_store_json_emit_full */
 312
 313 int
 314 sdb_store_json_finish(sdb_store_json_formatter_t *f)
 315 {
 316         if (! f)
 317                 return -1;
 318
 319         if (! f->context[0]) {
 320                 /* no content */
 321                 if (f->flags & SDB_WANT_ARRAY)
 322                         sdb_strbuf_append(f->buf, "[]");
 323                 return 0;
 324         }
 325
 326         while (f->current > 0) {
 327                 sdb_strbuf_append(f->buf, "}]");
 328                 --f->current;
 329         }
 330         if (f->context[0] != SDB_HOST) {
 331                 assert(f->type != SDB_HOST);
 332                 sdb_strbuf_append(f->buf, "}]}");
 333         }
 334         else
 335                 sdb_strbuf_append(f->buf, "}");
 336
 337         if (f->flags & SDB_WANT_ARRAY)
 338                 sdb_strbuf_append(f->buf, "]");
 339         return 0;
 340 } /* sdb_store_json_finish */
 341
 342 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 343