Code

store_json: Base the memstore emitter on the store-writer API.
[sysdb.git] / src / core / store_json.c
index a772dc39c8f67549c8205a0f63527672b6edf473..a069d8543872ea79e20edd8f31c0355f372488dd 100644 (file)
@@ -1,6 +1,6 @@
 /*
  * SysDB - src/core/store_json.c
- * Copyright (C) 2013-2014 Sebastian 'tokkee' Harl <sh@tokkee.org>
+ * Copyright (C) 2013-2015 Sebastian 'tokkee' Harl <sh@tokkee.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -48,6 +48,9 @@
  */
 
 struct sdb_store_json_formatter {
+       sdb_object_t super;
+
+       /* The string buffer to write to */
        sdb_strbuf_t *buf;
 
        /* The context describes the state of the formatter through
@@ -55,12 +58,58 @@ struct sdb_store_json_formatter {
        int context[8];
        size_t current;
 
-       /* The current host context when processing non-host objects */
-       sdb_store_obj_t *current_host;
-
        int type;
        int flags;
 };
+#define F(obj) ((sdb_store_json_formatter_t *)(obj))
+
+static int
+formatter_init(sdb_object_t *obj, va_list ap)
+{
+       sdb_store_json_formatter_t *f = F(obj);
+
+       f->buf = va_arg(ap, sdb_strbuf_t *);
+       if (! f->buf)
+               return -1;
+
+       f->type = va_arg(ap, int);
+       if ((f->type != SDB_HOST) && (f->type != SDB_SERVICE) && (f->type != SDB_METRIC))
+               return -1;
+
+       f->flags = va_arg(ap, int);
+
+       f->context[0] = 0;
+       f->current = 0;
+       return 0;
+} /* formatter_init */
+
+static sdb_type_t formatter_type = {
+       /* size = */ sizeof(sdb_store_json_formatter_t),
+       /* init = */ formatter_init,
+       /* destroy = */ NULL,
+};
+
+/* A generic representation of a stored object. */
+typedef struct {
+       /* identifier */
+       int type;
+       const char *name;
+
+       /* attribute value (optional) */
+       sdb_data_t *value;
+
+       /* metric's timeseries (optional)
+        * -1: unset
+        *  0: false
+        *  1: true */
+       int timeseries;
+
+       /* generic meta-data */
+       sdb_time_t last_update;
+       sdb_time_t interval;
+       size_t backends_num;
+       const char * const *backends;
+} obj_t;
 
 /*
  * private helper functions
@@ -93,33 +142,82 @@ escape_string(const char *src, char *dest)
        dest[i + 1] = '\0';
 } /* escape_string */
 
+/* handle_new_object takes care of all maintenance logic related to adding a
+ * new object. That is, it manages context information and emit the prefix and
+ * suffix of an object. */
 static int
-json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
+handle_new_object(sdb_store_json_formatter_t *f, int type)
+{
+       /* first top-level object */
+       if (! f->context[0]) {
+               if ((type != f->type) && (type != SDB_HOST)) {
+                       sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
+                                       "as the first element during %s JSON serialization",
+                                       SDB_STORE_TYPE_TO_NAME(type),
+                                       SDB_STORE_TYPE_TO_NAME(f->type));
+                       return -1;
+               }
+               if (f->flags & SDB_WANT_ARRAY)
+                       sdb_strbuf_append(f->buf, "[");
+               assert(f->current == 0);
+               f->context[f->current] = type;
+               return 0;
+       }
+
+       if ((f->context[f->current] != SDB_HOST)
+                       && (type != SDB_ATTRIBUTE)) {
+               /* new entry of the same type or a parent object;
+                * rewind to the right state */
+               while ((f->current > 0)
+                               && (f->context[f->current] != type)) {
+                       sdb_strbuf_append(f->buf, "}]");
+                       --f->current;
+               }
+       }
+
+       if (type == f->context[f->current]) {
+               /* new entry of the same type */
+               sdb_strbuf_append(f->buf, "},");
+       }
+       else if ((f->context[f->current] == SDB_HOST)
+                       || (type == SDB_ATTRIBUTE)) {
+               assert(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(type));
+               ++f->current;
+       }
+       else {
+               sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
+                               "on level %zu during JSON serialization",
+                               SDB_STORE_TYPE_TO_NAME(type), f->current);
+               return -1;
+       }
+
+       assert(f->current < SDB_STATIC_ARRAY_LEN(f->context));
+       f->context[f->current] = type;
+       return 0;
+} /* handle_new_object */
+
+static int
+json_emit(sdb_store_json_formatter_t *f, obj_t *obj)
 {
        char time_str[64];
        char interval_str[64];
-       char name[2 * strlen(SDB_OBJ(obj)->name) + 3];
+       char name[2 * strlen(obj->name) + 3];
        size_t i;
 
        assert(f && obj);
 
-       if ((f->type != SDB_HOST) && (f->type == obj->type)) {
-               /* create the host for the current entry first */
-               assert(obj->parent && (obj->parent->type == SDB_HOST));
-               if (f->current_host != obj->parent) {
-                       json_emit(f, obj->parent);
-                       sdb_strbuf_append(f->buf, ", \"%ss\": [",
-                                       SDB_STORE_TYPE_TO_NAME(obj->type));
-                       f->current_host = obj->parent;
-               }
-       }
+       handle_new_object(f, obj->type);
 
-       escape_string(SDB_OBJ(obj)->name, name);
+       escape_string(obj->name, name);
        sdb_strbuf_append(f->buf, "{\"name\": %s, ", name);
-       if (obj->type == SDB_ATTRIBUTE) {
-               char tmp[sdb_data_strlen(&ATTR(obj)->value) + 1];
+       if ((obj->type == SDB_ATTRIBUTE) && (obj->value)) {
+               char tmp[sdb_data_strlen(obj->value) + 1];
                char val[2 * sizeof(tmp) + 3];
-               if (! sdb_data_format(&ATTR(obj)->value, tmp, sizeof(tmp),
+               if (! sdb_data_format(obj->value, tmp, sizeof(tmp),
                                        SDB_DOUBLE_QUOTED))
                        snprintf(tmp, sizeof(tmp), "<error>");
 
@@ -132,16 +230,15 @@ json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
                else
                        sdb_strbuf_append(f->buf, "\"value\": %s, ", tmp);
        }
-       else if (obj->type == SDB_METRIC) {
-               if (METRIC(obj)->store.type != NULL)
+       else if ((obj->type == SDB_METRIC) && (obj->timeseries >= 0)) {
+               if (obj->timeseries)
                        sdb_strbuf_append(f->buf, "\"timeseries\": true, ");
                else
                        sdb_strbuf_append(f->buf, "\"timeseries\": false, ");
        }
 
        /* TODO: make time and interval formats configurable */
-       if (! sdb_strftime(time_str, sizeof(time_str),
-                               "%F %T %z", obj->last_update))
+       if (! sdb_strftime(time_str, sizeof(time_str), obj->last_update))
                snprintf(time_str, sizeof(time_str), "<error>");
        time_str[sizeof(time_str) - 1] = '\0';
 
@@ -163,34 +260,123 @@ json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
        return 0;
 } /* json_emit */
 
-/*
- * public API
- */
+static int
+emit_host(sdb_store_host_t *host, sdb_object_t *user_data)
+{
+       sdb_store_json_formatter_t *f = F(user_data);
 
-sdb_store_json_formatter_t *
-sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags)
+       if ((! host) || (! user_data))
+               return -1;
+
+       {
+               obj_t o = {
+                       SDB_HOST,
+                       host->name,
+
+                       /* value */ NULL,
+                       /* timeseries */ -1,
+
+                       host->last_update,
+                       host->interval,
+                       host->backends_num,
+                       (const char * const *)host->backends,
+               };
+
+               return json_emit(f, &o);
+       }
+} /* emit_host */
+
+static int
+emit_service(sdb_store_service_t *service, sdb_object_t *user_data)
 {
-       sdb_store_json_formatter_t *f;
+       sdb_store_json_formatter_t *f = F(user_data);
 
-       if (! buf)
-               return NULL;
+       if ((! service) || (! user_data))
+               return -1;
 
-       if ((type != SDB_HOST) && (type != SDB_SERVICE) && (type != SDB_METRIC))
-               return NULL;
+       {
+               obj_t o = {
+                       SDB_SERVICE,
+                       service->name,
 
-       f = calloc(1, sizeof(*f));
-       if (! f)
-               return NULL;
+                       /* value */ NULL,
+                       /* timeseries */ -1,
 
-       f->buf = buf;
-       f->context[0] = 0;
-       f->current = 0;
+                       service->last_update,
+                       service->interval,
+                       service->backends_num,
+                       (const char * const *)service->backends,
+               };
+
+               return json_emit(f, &o);
+       }
+} /* emit_service */
+
+static int
+emit_metric(sdb_store_metric_t *metric, sdb_object_t *user_data)
+{
+       sdb_store_json_formatter_t *f = F(user_data);
+
+       if ((! metric) || (! user_data))
+               return -1;
+
+       {
+               obj_t o = {
+                       SDB_METRIC,
+                       metric->name,
+
+                       /* value */ NULL,
+                       /* timeseries */ metric->store.type != NULL,
+
+                       metric->last_update,
+                       metric->interval,
+                       metric->backends_num,
+                       (const char * const *)metric->backends,
+               };
+
+               return json_emit(f, &o);
+       }
+} /* emit_metric */
+
+static int
+emit_attribute(sdb_store_attribute_t *attr, sdb_object_t *user_data)
+{
+       sdb_store_json_formatter_t *f = F(user_data);
+
+       if ((! attr) || (! user_data))
+               return -1;
+
+       {
+               obj_t o = {
+                       SDB_ATTRIBUTE,
+                       attr->key,
 
-       f->current_host = NULL;
+                       /* value */ &attr->value,
+                       /* timeseries */ -1,
 
-       f->type = type;
-       f->flags = flags;
-       return f;
+                       attr->last_update,
+                       attr->interval,
+                       attr->backends_num,
+                       (const char * const *)attr->backends,
+               };
+
+               return json_emit(f, &o);
+       }
+} /* emit_attribute */
+
+/*
+ * public API
+ */
+
+sdb_store_writer_t sdb_store_json_writer = {
+       emit_host, emit_service, emit_metric, emit_attribute,
+};
+
+sdb_store_json_formatter_t *
+sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags)
+{
+       return F(sdb_object_create("json-formatter", formatter_type,
+                               buf, type, flags));
 } /* sdb_store_json_formatter */
 
 int
@@ -199,67 +385,67 @@ sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
        if ((! f) || (! obj))
                return -1;
 
-       if ((f->type != SDB_HOST) && (obj->type == SDB_HOST)) {
-               sdb_log(SDB_LOG_ERR, "store: Unexpected object of type host "
-                               "during %s JSON serialization",
-                               SDB_STORE_TYPE_TO_NAME(f->type));
-               return -1;
-       }
-
-       /* first top-level object */
-       if (! f->context[0]) {
-               if (obj->type != f->type) {
-                       sdb_log(SDB_LOG_ERR, "store: Unexpected object of type %s "
-                                       "as the first element during %s JSON serialization",
-                                       SDB_STORE_TYPE_TO_NAME(obj->type),
-                                       SDB_STORE_TYPE_TO_NAME(f->type));
-                       return -1;
+       switch (obj->type) {
+       case SDB_HOST:
+               {
+                       sdb_store_host_t host = {
+                               obj->_name,
+                               obj->last_update,
+                               obj->interval,
+                               (const char * const *)obj->backends,
+                               obj->backends_num,
+                       };
+                       return sdb_store_json_writer.store_host(&host, SDB_OBJ(f));
                }
-               if (f->flags & SDB_WANT_ARRAY)
-                       sdb_strbuf_append(f->buf, "[");
-               assert(f->current == 0);
-               f->context[0] = obj->type;
-               return json_emit(f, obj);
-       }
-
-       if ((f->current >= 1) && (obj->type != SDB_ATTRIBUTE)) {
-               /* new entry of a previous type or a new type on the same level;
-                * rewind to the right state */
-               while (f->current > 0) {
-                       if (f->context[f->current] == obj->type)
-                               break;
-                       sdb_strbuf_append(f->buf, "}]");
-                       --f->current;
+       case SDB_SERVICE:
+               {
+                       sdb_store_service_t service = {
+                               obj->parent ? obj->parent->_name : NULL,
+                               obj->_name,
+                               obj->last_update,
+                               obj->interval,
+                               (const char * const *)obj->backends,
+                               obj->backends_num,
+                       };
+                       return sdb_store_json_writer.store_service(&service, SDB_OBJ(f));
+               }
+       case SDB_METRIC:
+               {
+                       sdb_store_metric_t metric = {
+                               obj->parent ? obj->parent->_name : NULL,
+                               obj->_name,
+                               {
+                                       METRIC(obj)->store.type,
+                                       METRIC(obj)->store.id,
+                               },
+                               obj->last_update,
+                               obj->interval,
+                               (const char * const *)obj->backends,
+                               obj->backends_num,
+                       };
+                       return sdb_store_json_writer.store_metric(&metric, SDB_OBJ(f));
+               }
+       case SDB_ATTRIBUTE:
+               {
+                       sdb_store_attribute_t attr = {
+                               NULL,
+                               obj->parent ? obj->parent->type : 0,
+                               obj->parent ? obj->parent->_name : NULL,
+                               obj->_name,
+                               ATTR(obj)->value,
+                               obj->last_update,
+                               obj->interval,
+                               (const char * const *)obj->backends,
+                               obj->backends_num,
+                       };
+                       if (obj->parent && (obj->parent->type != SDB_HOST)
+                                       && obj->parent->parent)
+                               attr.hostname = obj->parent->parent->_name;
+                       return sdb_store_json_writer.store_attribute(&attr, SDB_OBJ(f));
                }
-       }
-       if ((obj->type == f->type) && (f->type != SDB_HOST))
-               if (obj->parent != f->current_host)
-                       sdb_strbuf_append(f->buf, "}]");
-
-       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 {
-               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;
+       return -1;
 } /* sdb_store_json_emit */
 
 int
@@ -327,12 +513,7 @@ sdb_store_json_finish(sdb_store_json_formatter_t *f)
                sdb_strbuf_append(f->buf, "}]");
                --f->current;
        }
-       if (f->context[0] != SDB_HOST) {
-               assert(f->type != SDB_HOST);
-               sdb_strbuf_append(f->buf, "}]}");
-       }
-       else
-               sdb_strbuf_append(f->buf, "}");
+       sdb_strbuf_append(f->buf, "}");
 
        if (f->flags & SDB_WANT_ARRAY)
                sdb_strbuf_append(f->buf, "]");