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_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         /* The current host context when processing non-host objects */
  62         sdb_store_obj_t *current_host;
  63
  64         int type;
  65         int flags;
  66 };
  67 #define F(obj) ((sdb_store_json_formatter_t *)(obj))
  68
  69 static int
  70 formatter_init(sdb_object_t *obj, va_list ap)
  71 {
  72         sdb_store_json_formatter_t *f = F(obj);
  73
  74         f->buf = va_arg(ap, sdb_strbuf_t *);
  75         if (! f->buf)
  76                 return -1;
  77
  78         f->type = va_arg(ap, int);
  79         if ((f->type != SDB_HOST) && (f->type != SDB_SERVICE) && (f->type != SDB_METRIC))
  80                 return -1;
  81
  82         f->flags = va_arg(ap, int);
  83
  84         f->context[0] = 0;
  85         f->current = 0;
  86
  87         f->current_host = NULL;
  88         return 0;
  89 } /* formatter_init */
  90
  91 static sdb_type_t formatter_type = {
  92         /* size = */ sizeof(sdb_store_json_formatter_t),
  93         /* init = */ formatter_init,
  94         /* destroy = */ NULL,
  95 };
  96
  97 /*
  98  * private helper functions
  99  */
 100
 101 static void
 102 escape_string(const char *src, char *dest)
 103 {
 104         size_t i = 1;
 105         dest[0] = '"';
 106         for ( ; *src; ++src) {
 107                 char c = *src;
 108                 if ((c == '"') || (c == '\\') || iscntrl((int)c)) {
 109                         dest[i] = '\\';
 110                         ++i;
 111                 }
 112                 switch (c) {
 113                         case '\a': dest[i] = 'a'; break;
 114                         case '\b': dest[i] = 'b'; break;
 115                         case '\t': dest[i] = 't'; break;
 116                         case '\n': dest[i] = 'n'; break;
 117                         case '\v': dest[i] = 'v'; break;
 118                         case '\f': dest[i] = 'f'; break;
 119                         case '\r': dest[i] = 'r'; break;
 120                         default: dest[i] = c; break;
 121                 }
 122                 ++i;
 123         }
 124         dest[i] = '"';
 125         dest[i + 1] = '\0';
 126 } /* escape_string */
 127
 128 static int
 129 json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
 130 {
 131         char time_str[64];
 132         char interval_str[64];
 133         char name[2 * strlen(SDB_OBJ(obj)->name) + 3];
 134         size_t i;
 135
 136         assert(f && obj);
 137
 138         if ((f->type != SDB_HOST) && (f->type == obj->type)) {
 139                 /* create the host for the current entry first */
 140                 assert(obj->parent && (obj->parent->type == SDB_HOST));
 141                 if (f->current_host != obj->parent) {
 142                         json_emit(f, obj->parent);
 143                         sdb_strbuf_append(f->buf, ", \"%ss\": [",
 144                                         SDB_STORE_TYPE_TO_NAME(obj->type));
 145                         f->current_host = obj->parent;
 146                 }
 147         }
 148
 149         escape_string(SDB_OBJ(obj)->name, name);
 150         sdb_strbuf_append(f->buf, "{\"name\": %s, ", name);
 151         if (obj->type == SDB_ATTRIBUTE) {
 152                 char tmp[sdb_data_strlen(&ATTR(obj)->value) + 1];
 153                 char val[2 * sizeof(tmp) + 3];
 154                 if (! sdb_data_format(&ATTR(obj)->value, tmp, sizeof(tmp),
 155                                         SDB_DOUBLE_QUOTED))
 156                         snprintf(tmp, sizeof(tmp), "<error>");
 157
 158                 if (tmp[0] == '"') {
 159                         /* a string; escape_string handles quoting */
 160                         tmp[strlen(tmp) - 1] = '\0';
 161                         escape_string(tmp + 1, val);
 162                         sdb_strbuf_append(f->buf, "\"value\": %s, ", val);
 163                 }
 164                 else
 165                         sdb_strbuf_append(f->buf, "\"value\": %s, ", tmp);
 166         }
 167         else if (obj->type == SDB_METRIC) {
 168                 if (METRIC(obj)->store.type != NULL)
 169                         sdb_strbuf_append(f->buf, "\"timeseries\": true, ");
 170                 else
 171                         sdb_strbuf_append(f->buf, "\"timeseries\": false, ");
 172         }
 173
 174         /* TODO: make time and interval formats configurable */
 175         if (! sdb_strftime(time_str, sizeof(time_str), obj->last_update))
 176                 snprintf(time_str, sizeof(time_str), "<error>");
 177         time_str[sizeof(time_str) - 1] = '\0';
 178
 179         if (! sdb_strfinterval(interval_str, sizeof(interval_str),
 180                                 obj->interval))
 181                 snprintf(interval_str, sizeof(interval_str), "<error>");
 182         interval_str[sizeof(interval_str) - 1] = '\0';
 183
 184         sdb_strbuf_append(f->buf, "\"last_update\": \"%s\", "
 185                         "\"update_interval\": \"%s\", \"backends\": [",
 186                         time_str, interval_str);
 187
 188         for (i = 0; i < obj->backends_num; ++i) {
 189                 sdb_strbuf_append(f->buf, "\"%s\"", obj->backends[i]);
 190                 if (i < obj->backends_num - 1)
 191                         sdb_strbuf_append(f->buf, ",");
 192         }
 193         sdb_strbuf_append(f->buf, "]");
 194         return 0;
 195 } /* json_emit */
 196
 197 /*
 198  * public API
 199  */
 200
 201 sdb_store_json_formatter_t *
 202 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags)
 203 {
 204         return F(sdb_object_create("json-formatter", formatter_type,
 205                                 buf, type, flags));
 206 } /* sdb_store_json_formatter */
 207
 208 int
 209 sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
 210 {
 211         if ((! f) || (! obj))
 212                 return -1;
 213
 214         if ((f->type != SDB_HOST) && (obj->type == SDB_HOST)) {
 215                 sdb_log(SDB_LOG_ERR, "store: Unexpected object of type host "
 216                                 "during %s JSON serialization",
 217                                 SDB_STORE_TYPE_TO_NAME(f->type));
 218                 return -1;
 219         }
 220
 221         /* first top-level object */
 222         if (! f->context[0]) {
 223                 if (obj->type != f->type) {
 224                         sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
 225                                         "as the first element during %s JSON serialization",
 226                                         SDB_STORE_TYPE_TO_NAME(obj->type),
 227                                         SDB_STORE_TYPE_TO_NAME(f->type));
 228                         return -1;
 229                 }
 230                 if (f->flags & SDB_WANT_ARRAY)
 231                         sdb_strbuf_append(f->buf, "[");
 232                 assert(f->current == 0);
 233                 f->context[0] = obj->type;
 234                 return json_emit(f, obj);
 235         }
 236
 237         if ((f->current >= 1) && (obj->type != SDB_ATTRIBUTE)) {
 238                 /* new entry of a previous type or a new type on the same level;
 239                  * rewind to the right state */
 240                 while (f->current > 0) {
 241                         if (f->context[f->current] == obj->type)
 242                                 break;
 243                         sdb_strbuf_append(f->buf, "}]");
 244                         --f->current;
 245                 }
 246         }
 247         if ((obj->type == f->type) && (f->type != SDB_HOST))
 248                 if (obj->parent != f->current_host)
 249                         sdb_strbuf_append(f->buf, "}]");
 250
 251         if (obj->type == f->context[f->current]) {
 252                 /* new entry of the same type */
 253                 sdb_strbuf_append(f->buf, "},");
 254         }
 255         else if ((f->context[f->current] == SDB_HOST)
 256                         || (obj->type == SDB_ATTRIBUTE)) {
 257                 assert(obj->type != SDB_HOST);
 258                 /* all object types may be children of a host;
 259                  * attributes may be children of any type */
 260                 sdb_strbuf_append(f->buf, ", \"%ss\": [",
 261                                 SDB_STORE_TYPE_TO_NAME(obj->type));
 262                 ++f->current;
 263         }
 264         else {
 265                 sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
 266                                 "on level %zu during JSON serialization",
 267                                 SDB_STORE_TYPE_TO_NAME(obj->type), f->current);
 268                 return -1;
 269         }
 270
 271         json_emit(f, obj);
 272         assert(f->current < SDB_STATIC_ARRAY_LEN(f->context));
 273         f->context[f->current] = obj->type;
 274         return 0;
 275 } /* sdb_store_json_emit */
 276
 277 int
 278 sdb_store_json_emit_full(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj,
 279                 sdb_store_matcher_t *filter)
 280 {
 281         sdb_avltree_t *trees[] = { NULL, NULL, NULL };
 282         size_t i;
 283
 284         if (sdb_store_json_emit(f, obj))
 285                 return -1;
 286
 287         if (obj->type == SDB_HOST) {
 288                 trees[0] = HOST(obj)->attributes;
 289                 trees[1] = HOST(obj)->metrics;
 290                 trees[2] = HOST(obj)->services;
 291         }
 292         else if (obj->type == SDB_SERVICE)
 293                 trees[0] = SVC(obj)->attributes;
 294         else if (obj->type == SDB_METRIC)
 295                 trees[0] = METRIC(obj)->attributes;
 296         else if (obj->type == SDB_ATTRIBUTE)
 297                 return 0;
 298         else
 299                 return -1;
 300
 301         for (i = 0; i < SDB_STATIC_ARRAY_LEN(trees); ++i) {
 302                 sdb_avltree_iter_t *iter;
 303
 304                 if (! trees[i])
 305                         continue;
 306
 307                 iter = sdb_avltree_get_iter(trees[i]);
 308                 while (sdb_avltree_iter_has_next(iter)) {
 309                         sdb_store_obj_t *child;
 310                         child = STORE_OBJ(sdb_avltree_iter_get_next(iter));
 311
 312                         if (filter && (! sdb_store_matcher_matches(filter, child, NULL)))
 313                                 continue;
 314
 315                         if (sdb_store_json_emit_full(f, child, filter)) {
 316                                 sdb_avltree_iter_destroy(iter);
 317                                 return -1;
 318                         }
 319                 }
 320                 sdb_avltree_iter_destroy(iter);
 321         }
 322         return 0;
 323 } /* sdb_store_json_emit_full */
 324
 325 int
 326 sdb_store_json_finish(sdb_store_json_formatter_t *f)
 327 {
 328         if (! f)
 329                 return -1;
 330
 331         if (! f->context[0]) {
 332                 /* no content */
 333                 if (f->flags & SDB_WANT_ARRAY)
 334                         sdb_strbuf_append(f->buf, "[]");
 335                 return 0;
 336         }
 337
 338         while (f->current > 0) {
 339                 sdb_strbuf_append(f->buf, "}]");
 340                 --f->current;
 341         }
 342         if (f->context[0] != SDB_HOST) {
 343                 assert(f->type != SDB_HOST);
 344                 sdb_strbuf_append(f->buf, "}]}");
 345         }
 346         else
 347                 sdb_strbuf_append(f->buf, "}");
 348
 349         if (f->flags & SDB_WANT_ARRAY)
 350                 sdb_strbuf_append(f->buf, "]");
 351         return 0;
 352 } /* sdb_store_json_finish */
 353
 354 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 355