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