Code

store: Added support for storing metric objects.
[sysdb.git] / src / core / store.c
index 587c527a5185699efe18d104d65f499c12801145..44e696cccf6549ec49707022d30c58a4f387da64 100644 (file)
@@ -1,6 +1,6 @@
 /*
  * SysDB - src/core/store.c
- * Copyright (C) 2012 Sebastian 'tokkee' Harl <sh@tokkee.org>
+ * Copyright (C) 2012-2013 Sebastian 'tokkee' Harl <sh@tokkee.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#if HAVE_CONFIG_H
+#      include "config.h"
+#endif /* HAVE_CONFIG_H */
+
 #include "sysdb.h"
-#include "core/store.h"
-#include "core/error.h"
+#include "core/store-private.h"
 #include "core/plugin.h"
-#include "utils/llist.h"
+#include "utils/avltree.h"
+#include "utils/error.h"
 
 #include <assert.h>
 
  * private variables
  */
 
-static sdb_llist_t *obj_list = NULL;
-static pthread_rwlock_t obj_lock = PTHREAD_RWLOCK_INITIALIZER;
+static sdb_avltree_t *hosts = NULL;
+static pthread_rwlock_t host_lock = PTHREAD_RWLOCK_INITIALIZER;
 
 /*
  * private types
  */
 
-static sdb_type_t sdb_store_obj_type;
+static sdb_type_t sdb_host_type;
+static sdb_type_t sdb_service_type;
+static sdb_type_t sdb_metric_type;
 static sdb_type_t sdb_attribute_type;
 
-struct store_obj;
-typedef struct store_obj store_obj_t;
-
-struct store_obj {
-       sdb_object_t super;
-       sdb_time_t last_update;
-       store_obj_t *parent;
-};
-#define STORE_OBJ(obj) ((store_obj_t *)(obj))
-#define STORE_CONST_OBJ(obj) ((const store_obj_t *)(obj))
-
-typedef struct {
-       store_obj_t super;
-
-       char *value;
-} sdb_attribute_t;
-#define SDB_ATTR(obj) ((sdb_attribute_t *)(obj))
-#define SDB_CONST_ATTR(obj) ((const sdb_attribute_t *)(obj))
-
-typedef struct {
-       store_obj_t super;
-
-       int type;
-       sdb_llist_t *children;
-
-       sdb_llist_t *attributes;
-} sdb_store_obj_t;
-#define SDB_STORE_OBJ(obj) ((sdb_store_obj_t *)(obj))
-#define SDB_CONST_STORE_OBJ(obj) ((const sdb_store_obj_t *)(obj))
-
-enum {
-       SDB_HOST = 1,
-       SDB_SERVICE,
-       SDB_ATTRIBUTE,
-};
-#define TYPE_TO_NAME(t) \
-       (((t) == SDB_HOST) ? "host" \
-               : ((t) == SDB_SERVICE) ? "service" \
-               : ((t) == SDB_ATTRIBUTE) ? "attribute" : "unknown")
-
-/* shortcuts for accessing the sdb_store_obj_t attributes
- * of inheriting objects */
-#define _last_update super.last_update
-
 static int
 store_obj_init(sdb_object_t *obj, va_list ap)
 {
-       store_obj_t *sobj = STORE_OBJ(obj);
-       sobj->last_update = va_arg(ap, sdb_time_t);
+       sdb_store_obj_t *sobj = STORE_OBJ(obj);
 
+       sobj->type = va_arg(ap, int);
+
+       sobj->last_update = va_arg(ap, sdb_time_t);
+       sobj->interval = 0;
+       sobj->backends = NULL;
+       sobj->backends_num = 0;
        sobj->parent = NULL;
        return 0;
 } /* store_obj_init */
@@ -112,64 +79,132 @@ store_obj_init(sdb_object_t *obj, va_list ap)
 static void
 store_obj_destroy(sdb_object_t *obj)
 {
-       const store_obj_t *sobj = STORE_OBJ(obj);
+       sdb_store_obj_t *sobj = STORE_OBJ(obj);
+       size_t i;
+
+       for (i = 0; i < sobj->backends_num; ++i)
+               free(sobj->backends[i]);
+       free(sobj->backends);
+       sobj->backends = NULL;
+       sobj->backends_num = 0;
 
        if (sobj->parent)
                sdb_object_deref(SDB_OBJ(sobj->parent));
 } /* store_obj_destroy */
 
 static int
-sdb_store_obj_init(sdb_object_t *obj, va_list ap)
+sdb_host_init(sdb_object_t *obj, va_list ap)
 {
-       sdb_store_obj_t *sobj = SDB_STORE_OBJ(obj);
+       sdb_host_t *sobj = HOST(obj);
        int ret;
 
+       /* this will consume the first argument (type) of ap */
        ret = store_obj_init(obj, ap);
        if (ret)
                return ret;
 
-       sobj->type = va_arg(ap, int);
-
-       sobj->children = sdb_llist_create();
-       if (! sobj->children)
+       sobj->services = sdb_avltree_create();
+       if (! sobj->services)
+               return -1;
+       sobj->metrics = sdb_avltree_create();
+       if (! sobj->metrics)
                return -1;
-       sobj->attributes = sdb_llist_create();
+       sobj->attributes = sdb_avltree_create();
+       if (! sobj->attributes)
+               return -1;
+       return 0;
+} /* sdb_host_init */
+
+static void
+sdb_host_destroy(sdb_object_t *obj)
+{
+       sdb_host_t *sobj = HOST(obj);
+       assert(obj);
+
+       store_obj_destroy(obj);
+
+       if (sobj->services)
+               sdb_avltree_destroy(sobj->services);
+       if (sobj->metrics)
+               sdb_avltree_destroy(sobj->metrics);
+       if (sobj->attributes)
+               sdb_avltree_destroy(sobj->attributes);
+} /* sdb_host_destroy */
+
+static int
+sdb_service_init(sdb_object_t *obj, va_list ap)
+{
+       sdb_service_t *sobj = SVC(obj);
+       int ret;
+
+       /* this will consume the first argument (type) of ap */
+       ret = store_obj_init(obj, ap);
+       if (ret)
+               return ret;
+
+       sobj->attributes = sdb_avltree_create();
        if (! sobj->attributes)
                return -1;
        return 0;
-} /* sdb_store_obj_init */
+} /* sdb_service_init */
 
 static void
-sdb_store_obj_destroy(sdb_object_t *obj)
+sdb_service_destroy(sdb_object_t *obj)
+{
+       sdb_service_t *sobj = SVC(obj);
+       assert(obj);
+
+       store_obj_destroy(obj);
+
+       if (sobj->attributes)
+               sdb_avltree_destroy(sobj->attributes);
+} /* sdb_service_destroy */
+
+static int
+sdb_metric_init(sdb_object_t *obj, va_list ap)
 {
-       sdb_store_obj_t *sobj = SDB_STORE_OBJ(obj);
+       sdb_metric_t *sobj = METRIC(obj);
+       int ret;
+
+       /* this will consume the first argument (type) of ap */
+       ret = store_obj_init(obj, ap);
+       if (ret)
+               return ret;
 
+       sobj->attributes = sdb_avltree_create();
+       if (! sobj->attributes)
+               return -1;
+       return 0;
+} /* sdb_metric_init */
+
+static void
+sdb_metric_destroy(sdb_object_t *obj)
+{
+       sdb_metric_t *sobj = METRIC(obj);
        assert(obj);
 
        store_obj_destroy(obj);
 
-       if (sobj->children)
-               sdb_llist_destroy(sobj->children);
        if (sobj->attributes)
-               sdb_llist_destroy(sobj->attributes);
-} /* sdb_store_obj_destroy */
+               sdb_avltree_destroy(sobj->attributes);
+} /* sdb_metric_destroy */
 
 static int
 sdb_attr_init(sdb_object_t *obj, va_list ap)
 {
-       const char *value;
+       const sdb_data_t *value;
        int ret;
 
+       /* this will consume the first two arguments
+        * (type and last_update) of ap */
        ret = store_obj_init(obj, ap);
        if (ret)
                return ret;
-       value = va_arg(ap, const char *);
+       value = va_arg(ap, const sdb_data_t *);
 
-       if (value) {
-               SDB_ATTR(obj)->value = strdup(value);
-               if (! SDB_ATTR(obj)->value)
+       if (value)
+               if (sdb_data_copy(&ATTR(obj)->value, value))
                        return -1;
-       }
        return 0;
 } /* sdb_attr_init */
 
@@ -179,21 +214,29 @@ sdb_attr_destroy(sdb_object_t *obj)
        assert(obj);
 
        store_obj_destroy(obj);
-
-       if (SDB_ATTR(obj)->value)
-               free(SDB_ATTR(obj)->value);
+       sdb_data_free_datum(&ATTR(obj)->value);
 } /* sdb_attr_destroy */
 
-static sdb_type_t sdb_store_obj_type = {
-       sizeof(sdb_store_obj_t),
+static sdb_type_t sdb_host_type = {
+       sizeof(sdb_host_t),
+       sdb_host_init,
+       sdb_host_destroy
+};
 
-       sdb_store_obj_init,
-       sdb_store_obj_destroy
+static sdb_type_t sdb_service_type = {
+       sizeof(sdb_service_t),
+       sdb_service_init,
+       sdb_service_destroy
+};
+
+static sdb_type_t sdb_metric_type = {
+       sizeof(sdb_metric_t),
+       sdb_metric_init,
+       sdb_metric_destroy
 };
 
 static sdb_type_t sdb_attribute_type = {
        sizeof(sdb_attribute_t),
-
        sdb_attr_init,
        sdb_attr_destroy
 };
@@ -202,228 +245,373 @@ static sdb_type_t sdb_attribute_type = {
  * private helper functions
  */
 
-static sdb_store_obj_t *
-sdb_store_lookup_in_list(sdb_llist_t *l, int type, const char *name)
+static sdb_host_t *
+lookup_host(const char *name)
 {
-       sdb_llist_iter_t *iter;
+       return HOST(sdb_avltree_lookup(hosts, name));
+} /* lookup_host */
 
-       if (! l)
-               return NULL;
+static int
+record_backend(sdb_store_obj_t *obj)
+{
+       const sdb_plugin_info_t *info;
+       char **tmp;
+       size_t i;
 
-       iter = sdb_llist_get_iter(l);
-       if (! iter)
-               return NULL;
+       info = sdb_plugin_current();
+       if (! info)
+               return 0;
 
-       while (sdb_llist_iter_has_next(iter)) {
-               sdb_store_obj_t *sobj = SDB_STORE_OBJ(sdb_llist_iter_get_next(iter));
-               assert(sobj);
+       for (i = 0; i < obj->backends_num; ++i)
+               if (!strcasecmp(obj->backends[i], info->plugin_name))
+                       return 0;
 
-               if ((sobj->type == type)
-                               && (! strcasecmp(SDB_OBJ(sobj)->name, name))) {
-                       sdb_llist_iter_destroy(iter);
-                       return sobj;
-               }
+       tmp = realloc(obj->backends,
+                       (obj->backends_num + 1) * sizeof(*obj->backends));
+       if (! tmp)
+               return -1;
 
-               sobj = sdb_store_lookup_in_list(sobj->children, type, name);
-               if (sobj) {
-                       sdb_llist_iter_destroy(iter);
-                       return sobj;
-               }
-       }
-       sdb_llist_iter_destroy(iter);
-       return NULL;
-} /* sdb_store_lookup_in_list */
+       obj->backends = tmp;
+       obj->backends[obj->backends_num] = strdup(info->plugin_name);
+       if (! obj->backends[obj->backends_num])
+               return -1;
 
-static sdb_store_obj_t *
-sdb_store_lookup(int type, const char *name)
-{
-       return sdb_store_lookup_in_list(obj_list, type, name);
-} /* sdb_store_lookup */
+       ++obj->backends_num;
+       return 0;
+} /* record_backend */
 
-/* The obj_lock has to be acquired before calling this function. */
 static int
-store_obj(int parent_type, const char *parent_name,
-               int type, const char *name, sdb_time_t last_update,
-               store_obj_t **updated_obj)
+store_obj(sdb_avltree_t *parent_tree, int type, const char *name,
+               sdb_time_t last_update, sdb_store_obj_t **updated_obj)
 {
-       char *parent_cname = NULL, *cname = NULL;
-
-       sdb_llist_t *parent_list;
-       store_obj_t *old;
+       sdb_store_obj_t *old, *new;
        int status = 0;
 
+       assert(parent_tree);
+
        if (last_update <= 0)
                last_update = sdb_gettime();
 
-       assert((parent_type == 0)
-                       || (parent_type == SDB_HOST)
-                       || (parent_type == SDB_SERVICE));
-       assert((type == 0)
-                       || (type == SDB_HOST)
-                       || (type == SDB_SERVICE)
-                       || (type == SDB_ATTRIBUTE));
-
-       if (parent_type == SDB_HOST) {
-               parent_cname = sdb_plugin_cname(strdup(parent_name));
-               if (! parent_cname) {
-                       sdb_log(SDB_LOG_ERR, "store: strdup failed");
-                       return -1;
-               }
-               parent_name = parent_cname;
-       }
-       if (type == SDB_HOST) {
-               cname = sdb_plugin_cname(strdup(name));
-               if (! cname) {
-                       sdb_log(SDB_LOG_ERR, "store: strdup failed");
-                       return -1;
-               }
-               name = cname;
-       }
-
-       if (! obj_list) {
-               if (! (obj_list = sdb_llist_create())) {
-                       free(parent_cname);
-                       free(cname);
-                       return -1;
-               }
-       }
-       parent_list = obj_list;
-
-       if (parent_type && parent_name) {
-               sdb_store_obj_t *parent;
-
-               parent = sdb_store_lookup(parent_type, parent_name);
-               if (! parent) {
-                       sdb_log(SDB_LOG_ERR, "store: Failed to store %s '%s' - "
-                                       "parent %s '%s' not found", TYPE_TO_NAME(type), name,
-                                       TYPE_TO_NAME(parent_type), parent_name);
-                       free(parent_cname);
-                       free(cname);
-                       return -1;
-               }
-
-               if (type == SDB_ATTRIBUTE)
-                       parent_list = parent->attributes;
-               else
-                       parent_list = parent->children;
-       }
-
-       /* TODO: only look into direct children? */
-       if (type == SDB_HOST)
-               /* make sure that each host is unique */
-               old = STORE_OBJ(sdb_store_lookup_in_list(obj_list, type, name));
-       else if (type == SDB_ATTRIBUTE)
-               old = STORE_OBJ(sdb_llist_search_by_name(parent_list, name));
-       else
-               old = STORE_OBJ(sdb_store_lookup_in_list(parent_list, type, name));
-
+       old = STORE_OBJ(sdb_avltree_lookup(parent_tree, name));
        if (old) {
                if (old->last_update > last_update) {
                        sdb_log(SDB_LOG_DEBUG, "store: Cannot update %s '%s' - "
-                                       "value too old (%"PRIscTIME" < %"PRIscTIME")",
-                                       TYPE_TO_NAME(type), name, last_update, old->last_update);
+                                       "value too old (%"PRIsdbTIME" < %"PRIsdbTIME")",
+                                       SDB_STORE_TYPE_TO_NAME(type), name,
+                                       last_update, old->last_update);
                        /* don't report an error; the object may be updated by multiple
                         * backends */
                        status = 1;
                }
+               else if (old->last_update == last_update) {
+                       /* don't report an error and also don't even log this to avoid
+                        * excessive noise on high sampling frequencies */
+                       status = 1;
+               }
                else {
+                       sdb_time_t interval = last_update - old->last_update;
                        old->last_update = last_update;
+                       if (interval) {
+                               if (old->interval)
+                                       old->interval = (sdb_time_t)((0.9 * (double)old->interval)
+                                                       + (0.1 * (double)interval));
+                               else
+                                       old->interval = interval;
+                       }
                }
 
-               if (updated_obj)
-                       *updated_obj = old;
+               new = old;
+               sdb_object_deref(SDB_OBJ(old));
        }
        else {
-               store_obj_t *new;
-
-               if (type == SDB_ATTRIBUTE)
+               if (type == SDB_ATTRIBUTE) {
                        /* the value will be updated by the caller */
                        new = STORE_OBJ(sdb_object_create(name, sdb_attribute_type,
-                                               last_update, NULL));
-               else
-                       new = STORE_OBJ(sdb_object_create(name, sdb_store_obj_type,
-                                               last_update, type));
+                                               type, last_update, NULL));
+               }
+               else {
+                       sdb_type_t t;
+                       t = type == SDB_HOST
+                               ? sdb_host_type
+                               : type == SDB_SERVICE
+                                       ? sdb_service_type
+                                       : sdb_metric_type;
+                       new = STORE_OBJ(sdb_object_create(name, t, type, last_update));
+               }
+
+               if (new) {
+                       status = sdb_avltree_insert(parent_tree, SDB_OBJ(new));
 
-               if (! new) {
+                       /* pass control to the tree or destroy in case of an error */
+                       sdb_object_deref(SDB_OBJ(new));
+               }
+               else {
                        char errbuf[1024];
                        sdb_log(SDB_LOG_ERR, "store: Failed to create %s '%s': %s",
-                                       TYPE_TO_NAME(type), name,
+                                       SDB_STORE_TYPE_TO_NAME(type), name,
                                        sdb_strerror(errno, errbuf, sizeof(errbuf)));
-                       free(parent_cname);
-                       free(cname);
-                       return -1;
+                       status = -1;
                }
+       }
+
+       if (status < 0)
+               return status;
+       assert(new);
+
+       if (updated_obj)
+               *updated_obj = new;
+
+       if (record_backend(new))
+               return -1;
+       return status;
+} /* store_obj */
 
-               /* TODO: insert type-aware; the current version works as long as we
-                * don't support to store hierarchical data */
-               status = sdb_llist_insert_sorted(parent_list, SDB_OBJ(new),
-                               sdb_object_cmp_by_name);
+static int
+store_attr(sdb_avltree_t *attributes, const char *key, const sdb_data_t *value,
+               sdb_time_t last_update)
+{
+       sdb_store_obj_t *attr = NULL;
+       int status;
+
+       status = store_obj(attributes, SDB_ATTRIBUTE, key, last_update, &attr);
+       if (status)
+               return status;
 
-               /* pass control to the list or destroy in case of an error */
-               sdb_object_deref(SDB_OBJ(new));
+       /* don't update unchanged values */
+       if (! sdb_data_cmp(&ATTR(attr)->value, value))
+               return status;
 
-               if (updated_obj)
-                       *updated_obj = new;
+       assert(attr);
+       if (sdb_data_copy(&ATTR(attr)->value, value))
+               return -1;
+       return status;
+} /* store_attr */
+
+/* The host_lock has to be acquired before calling this function. */
+static sdb_avltree_t *
+get_host_children(const char *hostname, int type)
+{
+       char *cname = NULL;
+       sdb_host_t *host;
+
+       assert(hostname);
+       assert((type == SDB_SERVICE) || (type == SDB_METRIC)
+                       || (type == SDB_ATTRIBUTE));
+
+       if (! hosts)
+               return NULL;
+
+       cname = sdb_plugin_cname(strdup(hostname));
+       if (! cname) {
+               sdb_log(SDB_LOG_ERR, "store: strdup failed");
+               return NULL;
        }
-       free(parent_cname);
+
+       host = lookup_host(cname);
        free(cname);
-       return status;
-} /* sdb_store_obj */
+       if (! host)
+               return NULL;
+
+       sdb_object_deref(SDB_OBJ(host));
+       if (type == SDB_ATTRIBUTE)
+               return host->attributes;
+       else if (type == SDB_METRIC)
+               return host->metrics;
+       else
+               return host->services;
+} /* get_host_children */
+
+/*
+ * store_common_tojson serializes common object attributes to JSON.
+ *
+ * The function never returns an error. Rather, an error message will be part
+ * of the serialized data.
+ */
+static void
+store_common_tojson(sdb_store_obj_t *obj, sdb_strbuf_t *buf)
+{
+       char time_str[64];
+       char interval_str[64];
+       size_t i;
+
+       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(buf, "\"last_update\": \"%s\", "
+                       "\"update_interval\": \"%s\", \"backends\": [",
+                       time_str, interval_str);
+
+       for (i = 0; i < obj->backends_num; ++i) {
+               sdb_strbuf_append(buf, "\"%s\"", obj->backends[i]);
+               if (i < obj->backends_num - 1)
+                       sdb_strbuf_append(buf, ",");
+       }
+       sdb_strbuf_append(buf, "]");
+} /* store_common_tojson */
+
+/*
+ * store_obj_tojson serializes attribute / metric / service objects to JSON.
+ *
+ * The function never returns an error. Rather, an error message will be part
+ * of the serialized data.
+ */
+static void
+store_obj_tojson(sdb_avltree_t *tree, int type, sdb_strbuf_t *buf,
+               sdb_store_matcher_t *filter, int flags)
+{
+       sdb_avltree_iter_t *iter;
+
+       assert((type == SDB_ATTRIBUTE)
+                       || (type == SDB_METRIC)
+                       || (type == SDB_SERVICE));
+
+       sdb_strbuf_append(buf, "[");
+       iter = sdb_avltree_get_iter(tree);
+       if (! iter) {
+               char errbuf[1024];
+               sdb_log(SDB_LOG_ERR, "store: Failed to retrieve %ss: %s\n",
+                               SDB_STORE_TYPE_TO_NAME(type),
+                               sdb_strerror(errno, errbuf, sizeof(errbuf)));
+               sdb_strbuf_append(buf, "{\"error\": \"failed to retrieve %ss: %s\"}",
+                               SDB_STORE_TYPE_TO_NAME(type), errbuf);
+       }
+
+       /* has_next returns false if the iterator is NULL */
+       while (sdb_avltree_iter_has_next(iter)) {
+               sdb_store_obj_t *sobj = STORE_OBJ(sdb_avltree_iter_get_next(iter));
+               assert(sobj);
+               assert(sobj->type == type);
+
+               if (filter && (! sdb_store_matcher_matches(filter, sobj, NULL)))
+                       continue;
+
+               sdb_strbuf_append(buf, "{\"name\": \"%s\", ", SDB_OBJ(sobj)->name);
+               if (sobj->type == SDB_ATTRIBUTE) {
+                       char tmp[sdb_data_strlen(&ATTR(sobj)->value) + 1];
+                       sdb_data_format(&ATTR(sobj)->value, tmp, sizeof(tmp),
+                                       SDB_DOUBLE_QUOTED);
+                       sdb_strbuf_append(buf, "\"value\": %s, ", tmp);
+               }
+               store_common_tojson(sobj, buf);
+
+               if ((sobj->type == SDB_SERVICE)
+                               && (! (flags & SDB_SKIP_ATTRIBUTES))) {
+                       sdb_strbuf_append(buf, ", \"attributes\": ");
+                       store_obj_tojson(SVC(sobj)->attributes, SDB_ATTRIBUTE,
+                                       buf, filter, flags);
+               }
+               else if ((sobj->type == SDB_METRIC)
+                               && (! (flags & SDB_SKIP_ATTRIBUTES))) {
+                       sdb_strbuf_append(buf, ", \"attributes\": ");
+                       store_obj_tojson(METRIC(sobj)->attributes, SDB_ATTRIBUTE,
+                                       buf, filter, flags);
+               }
+               sdb_strbuf_append(buf, "}");
+
+               if (sdb_avltree_iter_has_next(iter))
+                       sdb_strbuf_append(buf, ",");
+       }
+
+       sdb_avltree_iter_destroy(iter);
+       sdb_strbuf_append(buf, "]");
+} /* store_obj_tojson */
 
 /*
  * public API
  */
 
+void
+sdb_store_clear(void)
+{
+       sdb_avltree_destroy(hosts);
+       hosts = NULL;
+} /* sdb_store_clear */
+
 int
 sdb_store_host(const char *name, sdb_time_t last_update)
 {
-       int status;
+       char *cname = NULL;
+       int status = 0;
 
        if (! name)
                return -1;
 
-       pthread_rwlock_wrlock(&obj_lock);
-       status = store_obj(/* parent = */ 0, NULL,
-                       /* stored object = */ SDB_HOST, name, last_update,
-                       /* updated_obj = */ NULL);
-       pthread_rwlock_unlock(&obj_lock);
+       cname = sdb_plugin_cname(strdup(name));
+       if (! cname) {
+               sdb_log(SDB_LOG_ERR, "store: strdup failed");
+               return -1;
+       }
+
+       pthread_rwlock_wrlock(&host_lock);
+       if (! hosts)
+               if (! (hosts = sdb_avltree_create()))
+                       status = -1;
+
+       if (! status)
+               status = store_obj(hosts, SDB_HOST, cname, last_update, NULL);
+       pthread_rwlock_unlock(&host_lock);
+
+       free(cname);
        return status;
 } /* sdb_store_host */
 
 _Bool
 sdb_store_has_host(const char *name)
 {
-       sdb_store_obj_t *host;
+       sdb_host_t *host;
 
        if (! name)
                return NULL;
 
-       host = sdb_store_lookup(SDB_HOST, name);
+       host = lookup_host(name);
        return host != NULL;
 } /* sdb_store_has_host */
 
+sdb_store_obj_t *
+sdb_store_get_host(const char *name)
+{
+       sdb_host_t *host;
+
+       if (! name)
+               return NULL;
+
+       host = lookup_host(name);
+       if (! host)
+               return NULL;
+
+       return STORE_OBJ(host);
+} /* sdb_store_get_host */
+
 int
-sdb_store_attribute(const char *hostname, const char *key, const char *value,
+sdb_store_attribute(const char *hostname,
+               const char *key, const sdb_data_t *value,
                sdb_time_t last_update)
 {
-       int status;
-
-       store_obj_t *updated_attr = NULL;
+       sdb_avltree_t *attrs;
+       int status = 0;
 
        if ((! hostname) || (! key))
                return -1;
 
-       pthread_rwlock_wrlock(&obj_lock);
-       status = store_obj(/* parent = */ SDB_HOST, hostname,
-                       /* stored object = */ SDB_ATTRIBUTE, key, last_update,
-                       &updated_attr);
-
-       SDB_ATTR(updated_attr)->value = strdup(value);
-       if (! SDB_ATTR(updated_attr)->value) {
-               sdb_object_deref(SDB_OBJ(updated_attr));
+       pthread_rwlock_wrlock(&host_lock);
+       attrs = get_host_children(hostname, SDB_ATTRIBUTE);
+       if (! attrs) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to store attribute '%s' - "
+                               "host '%s' not found", key, hostname);
                status = -1;
        }
-       pthread_rwlock_unlock(&obj_lock);
+
+       if (! status)
+               status = store_attr(attrs, key, value, last_update);
+
+       pthread_rwlock_unlock(&host_lock);
        return status;
 } /* sdb_store_attribute */
 
@@ -431,117 +619,257 @@ int
 sdb_store_service(const char *hostname, const char *name,
                sdb_time_t last_update)
 {
-       int status;
+       sdb_avltree_t *services;
+
+       int status = 0;
 
        if ((! hostname) || (! name))
                return -1;
 
-       pthread_rwlock_wrlock(&obj_lock);
-       status = store_obj(/* parent = */ SDB_HOST, hostname,
-                       /* stored object = */ SDB_SERVICE, name, last_update,
-                       /* updated obj = */ NULL);
-       pthread_rwlock_unlock(&obj_lock);
+       pthread_rwlock_wrlock(&host_lock);
+       services = get_host_children(hostname, SDB_SERVICE);
+       if (! services) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to store service '%s' - "
+                               "host '%s' not found", name, hostname);
+               status = -1;
+       }
+
+       if (! status)
+               status = store_obj(services, SDB_SERVICE, name, last_update, NULL);
+       pthread_rwlock_unlock(&host_lock);
        return status;
 } /* sdb_store_service */
 
-/* TODO: actually support hierarchical data */
 int
-sdb_store_tojson(sdb_strbuf_t *buf)
+sdb_store_service_attr(const char *hostname, const char *service,
+               const char *key, const sdb_data_t *value, sdb_time_t last_update)
 {
-       sdb_llist_iter_t *host_iter;
+       sdb_avltree_t *services;
+       sdb_service_t *svc;
+       int status = 0;
 
-       if (! buf)
+       if ((! hostname) || (! service) || (! key))
                return -1;
 
-       pthread_rwlock_rdlock(&obj_lock);
+       pthread_rwlock_wrlock(&host_lock);
+       services = get_host_children(hostname, SDB_SERVICE);
+       if (! services) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to store attribute '%s' "
+                               "for service '%s' - host '%ss' not found",
+                               key, service, hostname);
+               pthread_rwlock_unlock(&host_lock);
+               return -1;
+       }
 
-       host_iter = sdb_llist_get_iter(obj_list);
-       if (! host_iter) {
-               pthread_rwlock_unlock(&obj_lock);
+       svc = SVC(sdb_avltree_lookup(services, service));
+       if (! svc) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to store attribute '%s' - "
+                               "service '%s/%s' not found", key, hostname, service);
+               status = -1;
+       }
+
+       if (! status)
+               status = store_attr(svc->attributes, key, value, last_update);
+
+       sdb_object_deref(SDB_OBJ(svc));
+       pthread_rwlock_unlock(&host_lock);
+       return status;
+} /* sdb_store_service_attr */
+
+int
+sdb_store_metric(const char *hostname, const char *name,
+               sdb_time_t last_update)
+{
+       sdb_avltree_t *metrics;
+
+       int status = 0;
+
+       if ((! hostname) || (! name))
                return -1;
+
+       pthread_rwlock_wrlock(&host_lock);
+       metrics = get_host_children(hostname, SDB_METRIC);
+       if (! metrics) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to store metric '%s' - "
+                               "host '%s' not found", name, hostname);
+               status = -1;
        }
 
-       sdb_strbuf_append(buf, "{\"hosts\":[");
+       if (! status)
+               status = store_obj(metrics, SDB_METRIC, name, last_update, NULL);
+       pthread_rwlock_unlock(&host_lock);
+       return status;
+} /* sdb_store_metric */
 
-       while (sdb_llist_iter_has_next(host_iter)) {
-               sdb_store_obj_t *host = SDB_STORE_OBJ(sdb_llist_iter_get_next(host_iter));
-               sdb_llist_iter_t *svc_iter;
-               sdb_llist_iter_t *attr_iter;
+int
+sdb_store_metric_attr(const char *hostname, const char *metric,
+               const char *key, const sdb_data_t *value, sdb_time_t last_update)
+{
+       sdb_avltree_t *metrics;
+       sdb_metric_t *m;
+       int status = 0;
 
-               char time_str[64];
+       if ((! hostname) || (! metric) || (! key))
+               return -1;
 
-               assert(host);
+       pthread_rwlock_wrlock(&host_lock);
+       metrics = get_host_children(hostname, SDB_METRIC);
+       if (! metrics) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to store attribute '%s' "
+                               "for metric '%s' - host '%ss' not found",
+                               key, metric, hostname);
+               pthread_rwlock_unlock(&host_lock);
+               return -1;
+       }
 
-               if (! sdb_strftime(time_str, sizeof(time_str),
-                                       "%F %T %z", host->_last_update))
-                       snprintf(time_str, sizeof(time_str), "<error>");
-               time_str[sizeof(time_str) - 1] = '\0';
+       m = METRIC(sdb_avltree_lookup(metrics, metric));
+       if (! m) {
+               sdb_log(SDB_LOG_ERR, "store: Failed to store attribute '%s' - "
+                               "metric '%s/%s' not found", key, hostname, metric);
+               status = -1;
+       }
 
-               sdb_strbuf_append(buf, "{\"name\": \"%s\", "
-                               "\"last_update\": \"%s\", "
-                               "\"attributes\": [",
-                               SDB_OBJ(host)->name, time_str);
+       if (! status)
+               status = store_attr(m->attributes, key, value, last_update);
 
-               attr_iter = sdb_llist_get_iter(host->attributes);
-               if (! attr_iter) {
-                       char errbuf[1024];
-                       sdb_log(SDB_LOG_ERR, "store: Failed to retrieve attributes: %s\n",
-                                       sdb_strerror(errno, errbuf, sizeof(errbuf)));
-                       sdb_strbuf_append(buf, "{\"error\": \"failed to retrieve "
-                                       "attributes: %s\"}", errbuf);
-               }
+       sdb_object_deref(SDB_OBJ(m));
+       pthread_rwlock_unlock(&host_lock);
+       return status;
+} /* sdb_store_metric_attr */
 
-               /* has_next returns false if the iterator is NULL */
-               while (sdb_llist_iter_has_next(attr_iter)) {
-                       sdb_attribute_t *attr = SDB_ATTR(sdb_llist_iter_get_next(attr_iter));
-                       assert(attr);
+int
+sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res)
+{
+       if ((! obj) || (! res))
+               return -1;
 
-                       if (! sdb_strftime(time_str, sizeof(time_str),
-                                               "%F %T %z", attr->_last_update))
-                               snprintf(time_str, sizeof(time_str), "<error>");
-                       time_str[sizeof(time_str) - 1] = '\0';
+       switch (field) {
+               case SDB_FIELD_LAST_UPDATE:
+                       res->type = SDB_TYPE_DATETIME;
+                       res->data.datetime = obj->last_update;
+                       break;
+               case SDB_FIELD_AGE:
+                       res->type = SDB_TYPE_DATETIME;
+                       res->data.datetime = sdb_gettime() - obj->last_update;
+                       break;
+               case SDB_FIELD_INTERVAL:
+                       res->type = SDB_TYPE_DATETIME;
+                       res->data.datetime = obj->interval;
+                       break;
+               case SDB_FIELD_BACKEND:
+                       /* TODO: add support for storing array values in a data object
+                        * for now, fall thru to the error case */
+               default:
+                       return -1;
+       }
+       return 0;
+} /* sdb_store_get_field */
 
-                       sdb_strbuf_append(buf, "{\"name\": \"%s\", "
-                                       "\"value\": \"%s\", \"last_update\": \"%s\"},",
-                                       SDB_OBJ(attr)->name, attr->value, time_str);
-               }
+int
+sdb_store_host_tojson(sdb_store_obj_t *h, sdb_strbuf_t *buf,
+               sdb_store_matcher_t *filter, int flags)
+{
+       sdb_host_t *host = HOST(h);
 
-               sdb_llist_iter_destroy(attr_iter);
-               sdb_strbuf_append(buf, "], \"services\": [");
+       if ((! h) || (h->type != SDB_HOST) || (! buf))
+               return -1;
 
-               svc_iter = sdb_llist_get_iter(host->children);
-               if (! svc_iter) {
-                       char errbuf[1024];
-                       sdb_log(SDB_LOG_ERR, "store: Failed to retrieve services: %s\n",
-                                       sdb_strerror(errno, errbuf, sizeof(errbuf)));
-                       sdb_strbuf_append(buf, "{\"error\": \"failed to retrieve "
-                                       "services: %s\"}", errbuf);
-               }
+       sdb_strbuf_append(buf, "{\"name\": \"%s\", ", SDB_OBJ(host)->name);
+       store_common_tojson(h, buf);
 
-               while (sdb_llist_iter_has_next(svc_iter)) {
-                       sdb_store_obj_t *svc = SDB_STORE_OBJ(sdb_llist_iter_get_next(svc_iter));
-                       assert(svc);
+       if (! (flags & SDB_SKIP_ATTRIBUTES)) {
+               sdb_strbuf_append(buf, ", \"attributes\": ");
+               store_obj_tojson(host->attributes, SDB_ATTRIBUTE, buf, filter, flags);
+       }
 
-                       if (! sdb_strftime(time_str, sizeof(time_str),
-                                               "%F %T %z", svc->_last_update))
-                               snprintf(time_str, sizeof(time_str), "<error>");
-                       time_str[sizeof(time_str) - 1] = '\0';
+       if (! (flags & SDB_SKIP_METRICS)) {
+               sdb_strbuf_append(buf, ", \"metrics\": ");
+               store_obj_tojson(host->metrics, SDB_METRIC, buf, filter, flags);
+       }
 
-                       sdb_strbuf_append(buf, "{\"name\": \"%s\", "
-                                       "\"last_update\": \"%s\"},",
-                                       SDB_OBJ(svc)->name, time_str);
-               }
+       if (! (flags & SDB_SKIP_SERVICES)) {
+               sdb_strbuf_append(buf, ", \"services\": ");
+               store_obj_tojson(host->services, SDB_SERVICE, buf, filter, flags);
+       }
+
+       sdb_strbuf_append(buf, "}");
+       return 0;
+} /* sdb_store_host_tojson */
 
-               sdb_llist_iter_destroy(svc_iter);
-               sdb_strbuf_append(buf, "]}");
+int
+sdb_store_tojson(sdb_strbuf_t *buf, sdb_store_matcher_t *filter, int flags)
+{
+       sdb_avltree_iter_t *host_iter;
+       size_t len;
+
+       if (! buf)
+               return -1;
+
+       pthread_rwlock_rdlock(&host_lock);
+
+       host_iter = sdb_avltree_get_iter(hosts);
+       if (! host_iter) {
+               pthread_rwlock_unlock(&host_lock);
+               return -1;
+       }
+
+       sdb_strbuf_append(buf, "{\"hosts\":[");
+
+       len = sdb_strbuf_len(buf);
+       while (sdb_avltree_iter_has_next(host_iter)) {
+               sdb_store_obj_t *host;
+
+               host = STORE_OBJ(sdb_avltree_iter_get_next(host_iter));
+               assert(host);
+
+               if (filter && (! sdb_store_matcher_matches(filter, host, NULL)))
+                       continue;
+
+               if (sdb_strbuf_len(buf) > len)
+                       sdb_strbuf_append(buf, ",");
+               len = sdb_strbuf_len(buf);
+
+               if (sdb_store_host_tojson(host, buf, filter, flags))
+                       return -1;
        }
 
        sdb_strbuf_append(buf, "]}");
 
-       sdb_llist_iter_destroy(host_iter);
-       pthread_rwlock_unlock(&obj_lock);
+       sdb_avltree_iter_destroy(host_iter);
+       pthread_rwlock_unlock(&host_lock);
        return 0;
 } /* sdb_store_tojson */
 
+/* TODO: actually support hierarchical data */
+int
+sdb_store_iterate(sdb_store_iter_cb cb, void *user_data)
+{
+       sdb_avltree_iter_t *host_iter;
+       int status = 0;
+
+       pthread_rwlock_rdlock(&host_lock);
+
+       host_iter = sdb_avltree_get_iter(hosts);
+       if (! host_iter)
+               status = -1;
+
+       /* has_next returns false if the iterator is NULL */
+       while (sdb_avltree_iter_has_next(host_iter)) {
+               sdb_store_obj_t *host;
+
+               host = STORE_OBJ(sdb_avltree_iter_get_next(host_iter));
+               assert(host);
+
+               if (cb(host, user_data)) {
+                       status = -1;
+                       break;
+               }
+       }
+
+       sdb_avltree_iter_destroy(host_iter);
+       pthread_rwlock_unlock(&host_lock);
+       return status;
+} /* sdb_store_iterate */
+
 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */