![[tokkee]](http://tokkee.org/images/avatar.png){kind=avatar}
diff --git a/src/core/store_json.c b/src/core/store_json.c
--- /dev/null
+++ b/src/core/store_json.c
@@ -0,0 +1,241 @@
+/*
+ * SysDB - src/core/store_json.c
+ * Copyright (C) 2013-2014 Sebastian 'tokkee' Harl <sh@tokkee.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This module implements JSON support.
+ */
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include "sysdb.h"
+#include "core/store-private.h"
+#include "utils/error.h"
+
+#include <assert.h>
+
+#include <stdlib.h>
+
+/*
+ * private data types
+ */
+
+struct sdb_store_json_formatter {
+ sdb_strbuf_t *buf;
+
+ /* The context describes the state of the formatter through
+ * the path pointing to the current object */
+ int context[8];
+ size_t current;
+};
+
+/*
+ * private helper functions
+ */
+
+static int
+json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
+{
+ char time_str[64];
+ char interval_str[64];
+ size_t i;
+
+ assert(f && obj);
+
+ sdb_strbuf_append(f->buf, "{\"name\": \"%s\", ", SDB_OBJ(obj)->name);
+ if (obj->type == SDB_ATTRIBUTE) {
+ char tmp[sdb_data_strlen(&ATTR(obj)->value) + 1];
+ if (sdb_data_format(&ATTR(obj)->value, tmp, sizeof(tmp),
+ SDB_DOUBLE_QUOTED) < 0)
+ snprintf(tmp, sizeof(tmp), "<error>");
+ sdb_strbuf_append(f->buf, "\"value\": %s, ", tmp);
+ }
+
+ /* TODO: make time and interval formats configurable */
+ if (! sdb_strftime(time_str, sizeof(time_str),
+ "%F %T %z", obj->last_update))
+ snprintf(time_str, sizeof(time_str), "<error>");
+ time_str[sizeof(time_str) - 1] = '\0';
+
+ if (! sdb_strfinterval(interval_str, sizeof(interval_str),
+ obj->interval))
+ snprintf(interval_str, sizeof(interval_str), "<error>");
+ interval_str[sizeof(interval_str) - 1] = '\0';
+
+ sdb_strbuf_append(f->buf, "\"last_update\": \"%s\", "
+ "\"update_interval\": \"%s\", \"backends\": [",
+ time_str, interval_str);
+
+ for (i = 0; i < obj->backends_num; ++i) {
+ sdb_strbuf_append(f->buf, "\"%s\"", obj->backends[i]);
+ if (i < obj->backends_num - 1)
+ sdb_strbuf_append(f->buf, ",");
+ }
+ sdb_strbuf_append(f->buf, "]");
+ return 0;
+} /* json_emit */
+
+/*
+ * public API
+ */
+
+sdb_store_json_formatter_t *
+sdb_store_json_formatter(sdb_strbuf_t *buf)
+{
+ sdb_store_json_formatter_t *f;
+
+ if (! buf)
+ return NULL;
+
+ f = calloc(1, sizeof(*f));
+ if (! f)
+ return NULL;
+
+ f->buf = buf;
+ f->context[0] = 0;
+ f->current = 0;
+ return f;
+} /* sdb_store_json_formatter */
+
+int
+sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
+{
+ if ((! f) || (! obj))
+ return -1;
+
+ /* first host */
+ if (! f->context[0]) {
+ assert(f->current == 0);
+ f->context[0] = SDB_HOST;
+ return json_emit(f, obj);
+ }
+
+ if (obj->type == f->context[f->current]) {
+ /* new entry of the same type */
+ sdb_strbuf_append(f->buf, "},");
+ }
+ else if ((f->context[f->current] == SDB_HOST)
+ || (obj->type == SDB_ATTRIBUTE)) {
+ assert(obj->type != SDB_HOST);
+ /* all object types may be children of a host;
+ * attributes may be children of any type */
+ sdb_strbuf_append(f->buf, ", \"%ss\": [",
+ SDB_STORE_TYPE_TO_NAME(obj->type));
+ ++f->current;
+ }
+ else if (f->current >= 1) {
+ /* new entry of a previous type or a new type on the same level
+ * -> rewind to the right state and then handle the new object */
+ assert(obj->type != SDB_ATTRIBUTE);
+ while (f->current > 0) {
+ if (f->context[f->current] == obj->type)
+ break;
+ assert(f->context[f->current] != SDB_HOST);
+ sdb_strbuf_append(f->buf, "}]");
+ --f->current;
+ }
+ return sdb_store_json_emit(f, obj);
+ }
+ else {
+ sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
+ "on level %zu during JSON serialization",
+ SDB_STORE_TYPE_TO_NAME(obj->type), f->current);
+ return -1;
+ }
+
+ json_emit(f, obj);
+ assert(f->current < SDB_STATIC_ARRAY_LEN(f->context));
+ f->context[f->current] = obj->type;
+ return 0;
+} /* sdb_store_json_emit */
+
+int
+sdb_store_json_emit_full(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj,
+ sdb_store_matcher_t *filter)
+{
+ sdb_avltree_t *trees[] = { NULL, NULL, NULL };
+ size_t i;
+
+ if (sdb_store_json_emit(f, obj))
+ return -1;
+
+ if (obj->type == SDB_HOST) {
+ trees[0] = HOST(obj)->attributes;
+ trees[1] = HOST(obj)->metrics;
+ trees[2] = HOST(obj)->services;
+ }
+ else if (obj->type == SDB_SERVICE)
+ trees[0] = SVC(obj)->attributes;
+ else if (obj->type == SDB_METRIC)
+ trees[0] = METRIC(obj)->attributes;
+ else if (obj->type == SDB_ATTRIBUTE)
+ return 0;
+ else
+ return -1;
+
+ for (i = 0; i < SDB_STATIC_ARRAY_LEN(trees); ++i) {
+ sdb_avltree_iter_t *iter;
+
+ if (! trees[i])
+ continue;
+
+ iter = sdb_avltree_get_iter(trees[i]);
+ while (sdb_avltree_iter_has_next(iter)) {
+ sdb_store_obj_t *child;
+ child = STORE_OBJ(sdb_avltree_iter_get_next(iter));
+
+ if (filter && (! sdb_store_matcher_matches(filter, child, NULL)))
+ continue;
+
+ if (sdb_store_json_emit_full(f, child, filter)) {
+ sdb_avltree_iter_destroy(iter);
+ return -1;
+ }
+ }
+ sdb_avltree_iter_destroy(iter);
+ }
+ return 0;
+} /* sdb_store_json_emit_full */
+
+int
+sdb_store_json_finish(sdb_store_json_formatter_t *f)
+{
+ if (! f)
+ return -1;
+
+ while (f->current > 0) {
+ sdb_strbuf_append(f->buf, "}]");
+ --f->current;
+ }
+ if (f->context[0])
+ sdb_strbuf_append(f->buf, "}");
+ return 0;
+} /* sdb_store_json_finish */
+
+/* vim: set tw=78 sw=4 ts=4 noexpandtab : */
+