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 static int
 124 json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
 125 {
 126         char time_str[64];
 127         char interval_str[64];
 128         char name[2 * strlen(SDB_OBJ(obj)->name) + 3];
 129         size_t i;
 130
 131         assert(f && obj);
 132
 133         escape_string(SDB_OBJ(obj)->name, name);
 134         sdb_strbuf_append(f->buf, "{\"name\": %s, ", name);
 135         if (obj->type == SDB_ATTRIBUTE) {
 136                 char tmp[sdb_data_strlen(&ATTR(obj)->value) + 1];
 137                 char val[2 * sizeof(tmp) + 3];
 138                 if (! sdb_data_format(&ATTR(obj)->value, tmp, sizeof(tmp),
 139                                         SDB_DOUBLE_QUOTED))
 140                         snprintf(tmp, sizeof(tmp), "<error>");
 141
 142                 if (tmp[0] == '"') {
 143                         /* a string; escape_string handles quoting */
 144                         tmp[strlen(tmp) - 1] = '\0';
 145                         escape_string(tmp + 1, val);
 146                         sdb_strbuf_append(f->buf, "\"value\": %s, ", val);
 147                 }
 148                 else
 149                         sdb_strbuf_append(f->buf, "\"value\": %s, ", tmp);
 150         }
 151         else if (obj->type == SDB_METRIC) {
 152                 if (METRIC(obj)->store.type != NULL)
 153                         sdb_strbuf_append(f->buf, "\"timeseries\": true, ");
 154                 else
 155                         sdb_strbuf_append(f->buf, "\"timeseries\": false, ");
 156         }
 157
 158         /* TODO: make time and interval formats configurable */
 159         if (! sdb_strftime(time_str, sizeof(time_str), obj->last_update))
 160                 snprintf(time_str, sizeof(time_str), "<error>");
 161         time_str[sizeof(time_str) - 1] = '\0';
 162
 163         if (! sdb_strfinterval(interval_str, sizeof(interval_str),
 164                                 obj->interval))
 165                 snprintf(interval_str, sizeof(interval_str), "<error>");
 166         interval_str[sizeof(interval_str) - 1] = '\0';
 167
 168         sdb_strbuf_append(f->buf, "\"last_update\": \"%s\", "
 169                         "\"update_interval\": \"%s\", \"backends\": [",
 170                         time_str, interval_str);
 171
 172         for (i = 0; i < obj->backends_num; ++i) {
 173                 sdb_strbuf_append(f->buf, "\"%s\"", obj->backends[i]);
 174                 if (i < obj->backends_num - 1)
 175                         sdb_strbuf_append(f->buf, ",");
 176         }
 177         sdb_strbuf_append(f->buf, "]");
 178         return 0;
 179 } /* json_emit */
 180
 181 /*
 182  * public API
 183  */
 184
 185 sdb_store_json_formatter_t *
 186 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags)
 187 {
 188         return F(sdb_object_create("json-formatter", formatter_type,
 189                                 buf, type, flags));
 190 } /* sdb_store_json_formatter */
 191
 192 int
 193 sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
 194 {
 195         if ((! f) || (! obj))
 196                 return -1;
 197
 198         /* first top-level object */
 199         if (! f->context[0]) {
 200                 if ((obj->type != f->type) && (obj->type != SDB_HOST)) {
 201                         sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
 202                                         "as the first element during %s JSON serialization",
 203                                         SDB_STORE_TYPE_TO_NAME(obj->type),
 204                                         SDB_STORE_TYPE_TO_NAME(f->type));
 205                         return -1;
 206                 }
 207                 if (f->flags & SDB_WANT_ARRAY)
 208                         sdb_strbuf_append(f->buf, "[");
 209                 assert(f->current == 0);
 210         }
 211         else {
 212                 if ((f->current >= 1) && (obj->type != SDB_ATTRIBUTE)) {
 213                         /* new entry of a previous type or a new type on the same level;
 214                          * rewind to the right state */
 215                         while (f->current > 0) {
 216                                 if (f->context[f->current] == obj->type)
 217                                         break;
 218                                 sdb_strbuf_append(f->buf, "}]");
 219                                 --f->current;
 220                         }
 221                 }
 222
 223                 if (obj->type == f->context[f->current]) {
 224                         /* new entry of the same type */
 225                         sdb_strbuf_append(f->buf, "},");
 226                 }
 227                 else if ((f->context[f->current] == SDB_HOST)
 228                                 || (obj->type == SDB_ATTRIBUTE)) {
 229                         assert(obj->type != SDB_HOST);
 230                         /* all object types may be children of a host;
 231                          * attributes may be children of any type */
 232                         sdb_strbuf_append(f->buf, ", \"%ss\": [",
 233                                         SDB_STORE_TYPE_TO_NAME(obj->type));
 234                         ++f->current;
 235                 }
 236                 else {
 237                         sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
 238                                         "on level %zu during JSON serialization",
 239                                         SDB_STORE_TYPE_TO_NAME(obj->type), f->current);
 240                         return -1;
 241                 }
 242         }
 243
 244         json_emit(f, obj);
 245         assert(f->current < SDB_STATIC_ARRAY_LEN(f->context));
 246         f->context[f->current] = obj->type;
 247         return 0;
 248 } /* sdb_store_json_emit */
 249
 250 int
 251 sdb_store_json_emit_full(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj,
 252                 sdb_store_matcher_t *filter)
 253 {
 254         sdb_avltree_t *trees[] = { NULL, NULL, NULL };
 255         size_t i;
 256
 257         if (sdb_store_json_emit(f, obj))
 258                 return -1;
 259
 260         if (obj->type == SDB_HOST) {
 261                 trees[0] = HOST(obj)->attributes;
 262                 trees[1] = HOST(obj)->metrics;
 263                 trees[2] = HOST(obj)->services;
 264         }
 265         else if (obj->type == SDB_SERVICE)
 266                 trees[0] = SVC(obj)->attributes;
 267         else if (obj->type == SDB_METRIC)
 268                 trees[0] = METRIC(obj)->attributes;
 269         else if (obj->type == SDB_ATTRIBUTE)
 270                 return 0;
 271         else
 272                 return -1;
 273
 274         for (i = 0; i < SDB_STATIC_ARRAY_LEN(trees); ++i) {
 275                 sdb_avltree_iter_t *iter;
 276
 277                 if (! trees[i])
 278                         continue;
 279
 280                 iter = sdb_avltree_get_iter(trees[i]);
 281                 while (sdb_avltree_iter_has_next(iter)) {
 282                         sdb_store_obj_t *child;
 283                         child = STORE_OBJ(sdb_avltree_iter_get_next(iter));
 284
 285                         if (filter && (! sdb_store_matcher_matches(filter, child, NULL)))
 286                                 continue;
 287
 288                         if (sdb_store_json_emit_full(f, child, filter)) {
 289                                 sdb_avltree_iter_destroy(iter);
 290                                 return -1;
 291                         }
 292                 }
 293                 sdb_avltree_iter_destroy(iter);
 294         }
 295         return 0;
 296 } /* sdb_store_json_emit_full */
 297
 298 int
 299 sdb_store_json_finish(sdb_store_json_formatter_t *f)
 300 {
 301         if (! f)
 302                 return -1;
 303
 304         if (! f->context[0]) {
 305                 /* no content */
 306                 if (f->flags & SDB_WANT_ARRAY)
 307                         sdb_strbuf_append(f->buf, "[]");
 308                 return 0;
 309         }
 310
 311         while (f->current > 0) {
 312                 sdb_strbuf_append(f->buf, "}]");
 313                 --f->current;
 314         }
 315         sdb_strbuf_append(f->buf, "}");
 316
 317         if (f->flags & SDB_WANT_ARRAY)
 318                 sdb_strbuf_append(f->buf, "]");
 319         return 0;
 320 } /* sdb_store_json_finish */
 321
 322 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 323