Code

Build a more generic/powerful query API which writes to a store-writer.
authorSebastian Harl <sh@tokkee.org>
Tue, 6 Oct 2015 19:47:34 +0000 (21:47 +0200)
committerSebastian Harl <sh@tokkee.org>
Tue, 6 Oct 2015 19:47:34 +0000 (21:47 +0200)
Instead of letting the query implementation write JSON directly, let them emit
objects to a store-writer. This allows for more powerful and centralized
post-processing of the data and avoids code-duplication by moving all logic of
how to write out the data to the core. Also, this had a couple of nice side
effects and allowed for further simplication:

 - The TIMESERIES command is now handled by the front-end (based on a FETCH of
   the respective metric data); query plugin no longer have to implement this.

 - All protocol specific information is now handled by the frontend; query
   plugins no longer have to handle this (response-type).

 - Further separation of the memory-store and generic store code.

src/core/plugin.c
src/core/store.c
src/core/store_exec.c
src/frontend/query.c
src/include/core/plugin.h
src/include/core/store.h

index 8977699..3611be4 100644 (file)
@@ -1437,7 +1437,8 @@ sdb_plugin_fetch_timeseries(const char *type, const char *id,
 } /* sdb_plugin_fetch_timeseries */
 
 int
-sdb_plugin_query(sdb_ast_node_t *ast, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf)
+sdb_plugin_query(sdb_ast_node_t *ast,
+               sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf)
 {
        size_t n = sdb_llist_len(reader_list);
        reader_t *reader;
@@ -1449,8 +1450,7 @@ sdb_plugin_query(sdb_ast_node_t *ast, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf)
 
        if ((ast->type != SDB_AST_TYPE_FETCH)
                        && (ast->type != SDB_AST_TYPE_LIST)
-                       && (ast->type != SDB_AST_TYPE_LOOKUP)
-                       && (ast->type != SDB_AST_TYPE_TIMESERIES)) {
+                       && (ast->type != SDB_AST_TYPE_LOOKUP)) {
                sdb_log(SDB_LOG_ERR, "core: Cannot execute query of type %s",
                                SDB_AST_TYPE_TO_STRING(ast));
                sdb_strbuf_sprintf(errbuf, "Cannot execute query of type %s",
@@ -1472,7 +1472,8 @@ sdb_plugin_query(sdb_ast_node_t *ast, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf)
 
        q = reader->impl.prepare_query(ast, errbuf, reader->r_user_data);
        if (q)
-               status = reader->impl.execute_query(q, buf, errbuf, reader->r_user_data);
+               status = reader->impl.execute_query(q, w, SDB_OBJ(wd),
+                               errbuf, reader->r_user_data);
        else
                status = -1;
 
index dfa6ac9..fa72955 100644 (file)
@@ -689,11 +689,11 @@ prepare_query(sdb_ast_node_t *ast,
 
 static int
 execute_query(sdb_object_t *q,
-               sdb_strbuf_t *buf, sdb_strbuf_t *errbuf,
+               sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf,
                sdb_object_t *user_data)
 {
        return sdb_store_query_execute(SDB_STORE(user_data),
-                       QUERY(q), buf, errbuf);
+                       QUERY(q), w, wd, errbuf);
 } /* execute_query */
 
 sdb_store_reader_t sdb_store_reader = {
@@ -903,75 +903,6 @@ sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
        return 0;
 } /* sdb_store_get_attr */
 
-/* TODO: sdb_store_fetch_timeseries should move into the plugin module */
-
-int
-sdb_store_fetch_timeseries(sdb_store_t *store,
-               const char *hostname, const char *metric,
-               sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf)
-{
-       sdb_avltree_t *metrics;
-       host_t *host;
-       sdb_metric_t *m;
-
-       sdb_timeseries_t *ts;
-
-       int status = 0;
-
-       if ((! store) || (! hostname) || (! metric) || (! opts) || (! buf))
-               return -1;
-
-       pthread_rwlock_rdlock(&store->host_lock);
-       host = HOST(sdb_avltree_lookup(store->hosts, hostname));
-       metrics = get_host_children(host, SDB_METRIC);
-       sdb_object_deref(SDB_OBJ(host));
-       if (! metrics) {
-               sdb_log(SDB_LOG_ERR, "store: Failed to fetch time-series '%s/%s' "
-                               "- host '%s' not found", hostname, metric, hostname);
-               pthread_rwlock_unlock(&store->host_lock);
-               return -1;
-       }
-
-       m = METRIC(sdb_avltree_lookup(metrics, metric));
-       if (! m) {
-               sdb_log(SDB_LOG_ERR, "store: Failed to fetch time-series '%s/%s' "
-                               "- metric '%s' not found", hostname, metric, metric);
-               pthread_rwlock_unlock(&store->host_lock);
-               return -1;
-       }
-
-       if ((! m->store.type) || (! m->store.id)) {
-               sdb_log(SDB_LOG_ERR, "store: Failed to fetch time-series '%s/%s' "
-                               "- no data-store configured for the stored metric",
-                               hostname, metric);
-               sdb_object_deref(SDB_OBJ(m));
-               pthread_rwlock_unlock(&store->host_lock);
-               return -1;
-       }
-
-       {
-               char type[strlen(m->store.type) + 1];
-               char id[strlen(m->store.id) + 1];
-
-               strncpy(type, m->store.type, sizeof(type));
-               strncpy(id, m->store.id, sizeof(id));
-               pthread_rwlock_unlock(&store->host_lock);
-
-               ts = sdb_plugin_fetch_timeseries(type, id, opts);
-               if (! ts) {
-                       sdb_log(SDB_LOG_ERR, "store: Failed to fetch time-series '%s/%s' "
-                                       "- %s fetcher callback returned no data for '%s'",
-                                       hostname, metric, type, id);
-                       status = -1;
-               }
-       }
-
-       sdb_timeseries_tojson(ts, buf);
-       sdb_object_deref(SDB_OBJ(m));
-       sdb_timeseries_destroy(ts);
-       return status;
-} /* sdb_store_fetch_timeseries */
-
 int
 sdb_store_scan(sdb_store_t *store, int type,
                sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
index 6cf3a82..d4e3088 100644 (file)
@@ -84,16 +84,14 @@ lookup_tojson(sdb_store_obj_t *obj, sdb_store_matcher_t *filter,
  */
 
 static int
-exec_fetch(sdb_store_t *store, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf,
+exec_fetch(sdb_store_t *store,
+               sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf,
                int type, const char *hostname, const char *name,
                sdb_store_matcher_t *filter)
 {
-       uint32_t res_type = htonl(SDB_CONNECTION_FETCH);
-
        sdb_store_obj_t *host;
        sdb_store_obj_t *obj;
 
-       sdb_store_json_formatter_t *f;
        int status = 0;
 
        if ((! name) || ((type == SDB_HOST) && hostname)
@@ -135,137 +133,64 @@ exec_fetch(sdb_store_t *store, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf,
        }
        host = NULL;
 
-       f = sdb_store_json_formatter(buf, type, /* flags = */ 0);
-       if (! f) {
-               char err[1024];
-               sdb_log(SDB_LOG_ERR, "frontend: Failed to create "
-                               "JSON formatter to handle FETCH command: %s",
-                               sdb_strerror(errno, err, sizeof(err)));
-
-               sdb_strbuf_sprintf(errbuf, "Out of memory");
-               sdb_object_deref(SDB_OBJ(obj));
-               return -1;
-       }
-
-       sdb_strbuf_memcpy(buf, &res_type, sizeof(uint32_t));
        if (type != SDB_HOST)
-               status = sdb_store_emit(obj->parent,
-                               &sdb_store_json_writer, SDB_OBJ(f));
-       if (status || sdb_store_emit_full(obj, filter,
-                               &sdb_store_json_writer, SDB_OBJ(f))) {
+               status = sdb_store_emit(obj->parent, w, wd);
+       if (status || sdb_store_emit_full(obj, filter, w, wd)) {
                sdb_log(SDB_LOG_ERR, "frontend: Failed to serialize "
                                "%s %s.%s to JSON", SDB_STORE_TYPE_TO_NAME(type),
                                hostname, name);
                sdb_strbuf_sprintf(errbuf, "Out of memory");
-               sdb_object_deref(SDB_OBJ(f));
                sdb_object_deref(SDB_OBJ(obj));
                return -1;
        }
 
        sdb_object_deref(SDB_OBJ(obj));
-       sdb_store_json_finish(f);
-       sdb_object_deref(SDB_OBJ(f));
-
        return SDB_CONNECTION_DATA;
 } /* exec_fetch */
 
 static int
-exec_list(sdb_store_t *store, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf,
+exec_list(sdb_store_t *store,
+               sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf,
                int type, sdb_store_matcher_t *filter)
 {
-       uint32_t res_type = htonl(SDB_CONNECTION_LIST);
-       iter_t iter = { NULL, &sdb_store_json_writer, NULL };
-       sdb_store_json_formatter_t *f;
+       iter_t iter = { NULL, w, wd };
 
-       f = sdb_store_json_formatter(buf, type, SDB_WANT_ARRAY);
-       if (! f) {
-               char err[1024];
-               sdb_log(SDB_LOG_ERR, "frontend: Failed to create "
-                               "JSON formatter to handle LIST command: %s",
-                               sdb_strerror(errno, err, sizeof(err)));
-
-               sdb_strbuf_sprintf(errbuf, "Out of memory");
-               return -1;
-       }
-
-       iter.wd = SDB_OBJ(f);
-       sdb_strbuf_memcpy(buf, &res_type, sizeof(uint32_t));
        if (sdb_store_scan(store, type, /* m = */ NULL, filter, list_tojson, &iter)) {
                sdb_log(SDB_LOG_ERR, "frontend: Failed to serialize "
                                "store to JSON");
                sdb_strbuf_sprintf(errbuf, "Out of memory");
-               sdb_object_deref(SDB_OBJ(f));
                return -1;
        }
 
-       sdb_store_json_finish(f);
-       sdb_object_deref(SDB_OBJ(f));
-
        return SDB_CONNECTION_DATA;
 } /* exec_list */
 
 static int
-exec_lookup(sdb_store_t *store, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf,
+exec_lookup(sdb_store_t *store,
+               sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf,
                int type, sdb_store_matcher_t *m, sdb_store_matcher_t *filter)
 {
-       uint32_t res_type = htonl(SDB_CONNECTION_LOOKUP);
-       iter_t iter = { NULL, &sdb_store_json_writer, NULL };
-       sdb_store_json_formatter_t *f;
-
-       f = sdb_store_json_formatter(buf, type, SDB_WANT_ARRAY);
-       if (! f) {
-               char err[1024];
-               sdb_log(SDB_LOG_ERR, "frontend: Failed to create "
-                               "JSON formatter to handle LOOKUP command: %s",
-                               sdb_strerror(errno, err, sizeof(err)));
+       iter_t iter = { NULL, w, wd };
 
-               sdb_strbuf_sprintf(errbuf, "Out of memory");
-               return -1;
-       }
-
-       iter.wd = SDB_OBJ(f);
-       sdb_strbuf_memcpy(buf, &res_type, sizeof(uint32_t));
        if (sdb_store_scan(store, type, m, filter, lookup_tojson, &iter)) {
                sdb_log(SDB_LOG_ERR, "frontend: Failed to lookup %ss",
                                SDB_STORE_TYPE_TO_NAME(type));
                sdb_strbuf_sprintf(errbuf, "Failed to lookup %ss",
                                SDB_STORE_TYPE_TO_NAME(type));
-               sdb_object_deref(SDB_OBJ(f));
                return -1;
        }
 
-       sdb_store_json_finish(f);
-       sdb_object_deref(SDB_OBJ(f));
-
        return SDB_CONNECTION_DATA;
 } /* exec_lookup */
 
-static int
-exec_timeseries(sdb_store_t *store, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf,
-               const char *hostname, const char *metric,
-               sdb_timeseries_opts_t *opts)
-{
-       uint32_t res_type = htonl(SDB_CONNECTION_TIMESERIES);
-
-       sdb_strbuf_memcpy(buf, &res_type, sizeof(uint32_t));
-       if (sdb_store_fetch_timeseries(store, hostname, metric, opts, buf)) {
-               sdb_log(SDB_LOG_ERR, "frontend: Failed to fetch time-series");
-               sdb_strbuf_sprintf(errbuf, "Failed to fetch time-series");
-               return -1;
-       }
-
-       return SDB_CONNECTION_DATA;
-} /* exec_timeseries */
-
 /*
  * public API
  */
 
 int
 sdb_store_query_execute(sdb_store_t *store, sdb_store_query_t *q,
-               sdb_strbuf_t *buf, sdb_strbuf_t *errbuf)
+               sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf)
 {
-       sdb_timeseries_opts_t ts_opts;
        sdb_ast_node_t *ast;
 
        if (! q)
@@ -278,25 +203,18 @@ sdb_store_query_execute(sdb_store_t *store, sdb_store_query_t *q,
        ast = q->ast;
        switch (ast->type) {
        case SDB_AST_TYPE_FETCH:
-               return exec_fetch(store, buf, errbuf, SDB_AST_FETCH(ast)->obj_type,
+               return exec_fetch(store, w, wd, errbuf, SDB_AST_FETCH(ast)->obj_type,
                                SDB_AST_FETCH(ast)->hostname, SDB_AST_FETCH(ast)->name,
                                q->filter);
 
        case SDB_AST_TYPE_LIST:
-               return exec_list(store, buf, errbuf, SDB_AST_LIST(ast)->obj_type,
+               return exec_list(store, w, wd, errbuf, SDB_AST_LIST(ast)->obj_type,
                                q->filter);
 
        case SDB_AST_TYPE_LOOKUP:
-               return exec_lookup(store, buf, errbuf, SDB_AST_LOOKUP(ast)->obj_type,
+               return exec_lookup(store, w, wd, errbuf, SDB_AST_LOOKUP(ast)->obj_type,
                                q->matcher, q->filter);
 
-       case SDB_AST_TYPE_TIMESERIES:
-               ts_opts.start = SDB_AST_TIMESERIES(ast)->start;
-               ts_opts.end = SDB_AST_TIMESERIES(ast)->end;
-               return exec_timeseries(store, buf, errbuf,
-                               SDB_AST_TIMESERIES(ast)->hostname,
-                               SDB_AST_TIMESERIES(ast)->metric, &ts_opts);
-
        default:
                sdb_log(SDB_LOG_ERR, "store: Invalid query of type %s",
                                SDB_AST_TYPE_TO_STRING(ast));
index 56cd4ec..9a157fb 100644 (file)
 #include <ctype.h>
 #include <string.h>
 
+/*
+ * metric fetcher:
+ * Implements the callbacks necessary to read a metric object.
+ * TODO: FETCH should allow to ignore child elements (attributes); then, we'd
+ * only need store_host/store_metric.
+ */
+
+typedef struct {
+       char *type;
+       char *id;
+} metric_store_t;
+
+static int
+metric_fetcher_host(sdb_store_host_t __attribute__((unused)) *host,
+               sdb_object_t __attribute__((unused)) *user_data)
+{
+       return 0;
+} /* metric_fetcher_host */
+
+static int
+metric_fetcher_metric(sdb_store_metric_t *metric, sdb_object_t *user_data)
+{
+       metric_store_t *st = SDB_OBJ_WRAPPER(user_data)->data;
+
+       if ((! metric->store.type) || (! metric->store.id))
+               return 0;
+
+       st->type = strdup(metric->store.type);
+       st->id = strdup(metric->store.id);
+       if ((! st->type) || (! st->id))
+               return -1;
+       return 0;
+} /* metric_fetcher_metric */
+
+static int
+metric_fetcher_attr(sdb_store_attribute_t __attribute__((unused)) *attr,
+               sdb_object_t __attribute__((unused)) *user_data)
+{
+       return 0;
+} /* metric_fetcher_attr */
+
+static sdb_store_writer_t metric_fetcher = {
+       metric_fetcher_host, NULL, metric_fetcher_metric, metric_fetcher_attr,
+};
+
 /*
  * private helper functions
  */
@@ -59,6 +104,45 @@ sstrlen(const char *s)
        return s ? strlen(s) : 0;
 } /* sstrlen */
 
+static int
+exec_query(sdb_ast_node_t *ast, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf)
+{
+       sdb_store_json_formatter_t *f;
+       int type = 0, flags = 0;
+       uint32_t res_type = 0;
+       int status;
+
+       switch (ast->type) {
+       case SDB_AST_TYPE_FETCH:
+               type = SDB_AST_FETCH(ast)->obj_type;
+               res_type = htonl(SDB_CONNECTION_FETCH);
+               break;
+       case SDB_AST_TYPE_LIST:
+               type = SDB_AST_LIST(ast)->obj_type;
+               flags = SDB_WANT_ARRAY;
+               res_type = htonl(SDB_CONNECTION_LIST);
+               break;
+       case SDB_AST_TYPE_LOOKUP:
+               type = SDB_AST_LOOKUP(ast)->obj_type;
+               flags = SDB_WANT_ARRAY;
+               res_type = htonl(SDB_CONNECTION_LOOKUP);
+               break;
+       default:
+               sdb_strbuf_sprintf(errbuf, "invalid command %s (%#x)",
+                               SDB_AST_TYPE_TO_STRING(ast), ast->type);
+               return -1;
+       }
+
+       f = sdb_store_json_formatter(buf, type, flags);
+       sdb_strbuf_memcpy(buf, &res_type, sizeof(res_type));
+       status = sdb_plugin_query(ast, &sdb_store_json_writer, SDB_OBJ(f), errbuf);
+       if (status < 0)
+               sdb_strbuf_clear(buf);
+       sdb_store_json_finish(f);
+       sdb_object_deref(SDB_OBJ(f));
+       return status;
+} /* exec_query */
+
 static int
 exec_store(sdb_ast_store_t *st, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf)
 {
@@ -145,7 +229,58 @@ exec_store(sdb_ast_store_t *st, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf)
 } /* exec_store */
 
 static int
-exec_query(sdb_conn_t *conn, sdb_ast_node_t *ast)
+exec_timeseries(sdb_ast_timeseries_t *ts, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf)
+{
+       metric_store_t st = { NULL, NULL };
+       sdb_object_wrapper_t obj = SDB_OBJECT_WRAPPER_STATIC(&st);
+       sdb_ast_fetch_t fetch = SDB_AST_FETCH_INIT;
+       sdb_timeseries_opts_t opts = { 0, 0 };
+       sdb_timeseries_t *series = NULL;
+       int status;
+
+       if ((! ts) || (! ts->hostname) || (! ts->metric))
+               return -1;
+
+       fetch.obj_type = SDB_METRIC;
+       fetch.hostname = strdup(ts->hostname);
+       fetch.name = strdup(ts->metric);
+       opts.start = ts->start;
+       opts.end = ts->end;
+
+       status = sdb_plugin_query(SDB_AST_NODE(&fetch),
+                       &metric_fetcher, SDB_OBJ(&obj), errbuf);
+       if ((status < 0) || (! st.type) || (! st.id)) {
+               sdb_log(SDB_LOG_ERR, "frontend: Failed to fetch time-series '%s/%s' "
+                               "- no data-store configured for the stored metric",
+                               ts->hostname, ts->metric);
+               status = -1;
+       }
+       if (status >= 0) {
+               series = sdb_plugin_fetch_timeseries(st.type, st.id, &opts);
+               if (! series) {
+                       sdb_log(SDB_LOG_ERR, "frontend: Failed to fetch time-series '%s/%s' "
+                                       "- %s fetcher callback returned no data for '%s'",
+                                       ts->hostname, ts->metric, st.type, st.id);
+                       status = -1;
+               }
+       }
+
+       if (status >= 0) {
+               sdb_timeseries_tojson(series, buf);
+               sdb_timeseries_destroy(series);
+       }
+
+       free(fetch.hostname);
+       free(fetch.name);
+       if (st.type)
+               free(st.type);
+       if (st.id)
+               free(st.id);
+       return status;
+} /* exec_timeseries */
+
+static int
+exec_cmd(sdb_conn_t *conn, sdb_ast_node_t *ast)
 {
        sdb_strbuf_t *buf;
        int status;
@@ -160,10 +295,14 @@ exec_query(sdb_conn_t *conn, sdb_ast_node_t *ast)
                sdb_strbuf_sprintf(conn->errbuf, "Out of memory");
                return -1;
        }
+
        if (ast->type == SDB_AST_TYPE_STORE)
                status = exec_store(SDB_AST_STORE(ast), buf, conn->errbuf);
+       else if (ast->type == SDB_AST_TYPE_TIMESERIES)
+               status = exec_timeseries(SDB_AST_TIMESERIES(ast), buf, conn->errbuf);
        else
-               status = sdb_plugin_query(ast, buf, conn->errbuf);
+               status = exec_query(ast, buf, conn->errbuf);
+
        if (status < 0) {
                char query[conn->cmd_len + 1];
                strncpy(query, sdb_strbuf_string(conn->buf), conn->cmd_len);
@@ -176,7 +315,7 @@ exec_query(sdb_conn_t *conn, sdb_ast_node_t *ast)
 
        sdb_strbuf_destroy(buf);
        return status < 0 ? status : 0;
-} /* exec_query */
+} /* exec_cmd */
 
 /*
  * public API
@@ -227,7 +366,7 @@ sdb_conn_query(sdb_conn_t *conn)
        }
 
        if (ast) {
-               status = exec_query(conn, ast);
+               status = exec_cmd(conn, ast);
                sdb_object_deref(SDB_OBJ(ast));
        }
        sdb_llist_destroy(parsetree);
@@ -266,7 +405,7 @@ sdb_conn_fetch(sdb_conn_t *conn)
                        hostname[0] ? strdup(hostname) : NULL,
                        name[0] ? strdup(name) : NULL,
                        /* filter = */ NULL);
-       status = exec_query(conn, ast);
+       status = exec_cmd(conn, ast);
        sdb_object_deref(SDB_OBJ(ast));
        return status;
 } /* sdb_conn_fetch */
@@ -292,7 +431,7 @@ sdb_conn_list(sdb_conn_t *conn)
        }
 
        ast = sdb_ast_list_create((int)type, /* filter = */ NULL);
-       status = exec_query(conn, ast);
+       status = exec_cmd(conn, ast);
        sdb_object_deref(SDB_OBJ(ast));
        return status;
 } /* sdb_conn_list */
@@ -336,7 +475,7 @@ sdb_conn_lookup(sdb_conn_t *conn)
        }
 
        ast = sdb_ast_lookup_create((int)type, m, /* filter = */ NULL);
-       status = exec_query(conn, ast);
+       status = exec_cmd(conn, ast);
        if (! ast)
                sdb_object_deref(SDB_OBJ(m));
        sdb_object_deref(SDB_OBJ(ast));
@@ -443,7 +582,7 @@ sdb_conn_store(sdb_conn_t *conn)
 
        status = sdb_parser_analyze(ast, conn->errbuf);
        if (! status)
-               status = exec_query(conn, ast);
+               status = exec_cmd(conn, ast);
        sdb_object_deref(SDB_OBJ(ast));
        return status;
 } /* sdb_conn_store */
index 6b5a9f4..6c4a2e1 100644 (file)
@@ -446,7 +446,8 @@ sdb_plugin_fetch_timeseries(const char *type, const char *id,
  *  - a negative value else
  */
 int
-sdb_plugin_query(sdb_ast_node_t *ast, sdb_strbuf_t *buf, sdb_strbuf_t *errbuf);
+sdb_plugin_query(sdb_ast_node_t *ast,
+               sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf);
 
 /*
  * sdb_plugin_store_host, sdb_plugin_store_service, sdb_plugin_store_metric,
index f42d217..0cee913 100644 (file)
@@ -288,15 +288,12 @@ typedef struct {
         * execute_query:
         * Execute a previously prepared query. The callback may expect that only
         * queries prepared by its respective prepare callback will be passed to
-        * this function.
-        *
-        * TODO: Instead of letting the executor write directly to a string buffer
-        *       (which cannot easily be merged with other results), let it hand
-        *       all objects to a store-writer.
+        * this function. The query result will be passed back via the specified
+        * store writer.
         */
        int (*execute_query)(sdb_object_t *q,
-                       sdb_strbuf_t *buf, sdb_strbuf_t *errbuf,
-                       sdb_object_t *user_data);
+                       sdb_store_writer_t *w, sdb_object_t *wd,
+                       sdb_strbuf_t *errbuf, sdb_object_t *user_data);
 } sdb_store_reader_t;
 
 /*
@@ -462,7 +459,7 @@ sdb_store_query_prepare_matcher(sdb_ast_node_t *ast);
  */
 int
 sdb_store_query_execute(sdb_store_t *store, sdb_store_query_t *m,
-               sdb_strbuf_t *buf, sdb_strbuf_t *errbuf);
+               sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf);
 
 /*
  * sdb_store_expr_create: