timeseries: Add support for fetching specific data-sources.

[sysdb.git] / src / include / core / timeseries.h

diff --git a/src/include/core/timeseries.h b/src/include/core/timeseries.h
index 3a4029d8be4b2d46e8365d3904e9fcbfe1706a9f..ab74a11b35863c6cf75025ccfa6cca47312f1f81 100644 (file)
--- a/src/include/core/timeseries.h
+++ b/src/include/core/timeseries.h
@@ -29,12 +29,41 @@
 #define SDB_CORE_TIMESERIES_H 1
 
 #include "sysdb.h"
+#include "core/object.h"
 #include "core/time.h"
+#include "utils/strbuf.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+/*
+ * sdb_timeseries_info_t:
+ * Information about a timeseries.
+ */
+typedef struct {
+       char **data_names;
+       size_t data_names_len;
+} sdb_timeseries_info_t;
+
+/*
+ * sdb_timeseries_info_create:
+ * Allocate a timeseries information object.
+ *
+ * Returns:
+ *  - a newly allocated timeseries info object on success
+ *  - NULL else
+ */
+sdb_timeseries_info_t *
+sdb_timeseries_info_create(size_t data_names_len, const char * const *data_names);
+
+/*
+ * sdb_timeseries_info_destroy:
+ * Destroy a timeseries info object, freeing all of its memory.
+ */
+void
+sdb_timeseries_info_destroy(sdb_timeseries_info_t *ts_info);
+
 /*
  * A data-point describes a datum at a certain point of time.
  */
@@ -56,8 +85,9 @@ typedef struct {
        sdb_time_t end;
 
        sdb_data_point_t **data;
-       char **data_names;
        size_t data_len;
+       char **data_names;
+       size_t data_names_len;
 } sdb_timeseries_t;
 
 /*
@@ -67,8 +97,64 @@ typedef struct {
 typedef struct {
        sdb_time_t start;
        sdb_time_t end;
+
+       /* If specified, only fetch time-series with these names. */
+       const char * const *data_names;
+       size_t data_names_len;
 } sdb_timeseries_opts_t;
 
+/*
+ * sdb_timeseries_create:
+ * Allocate a time-series object, pre-populating the data_names information
+ * and allocating the data field.
+ *
+ * Returns:
+ *  - a newly allocated time-series object on success
+ *  - NULL else
+ */
+sdb_timeseries_t *
+sdb_timeseries_create(size_t data_names_len, const char * const *data_names,
+               size_t data_len);
+
+/*
+ * sdb_timeseries_destroy:
+ * Destroy a time-series object, freeing all of its memory.
+ */
+void
+sdb_timeseries_destroy(sdb_timeseries_t *ts);
+
+/*
+ * A timeseries fetcher fetches data from a timeseries data-store.
+ */
+typedef struct {
+       /*
+        * describe:
+        * Retrieve information about the timeseries from the data-store. The
+        * returned timeseries info object must be freeable using
+        * sdb_timeseries_info_destroy.
+        */
+       sdb_timeseries_info_t *(*describe)(const char *id, sdb_object_t *user_data);
+
+       /*
+        * fetch:
+        * Read timeseries data from the data-store. The returned timeseries
+        * object must be freeable using sdb_timeseries_destroy.
+        */
+       sdb_timeseries_t *(*fetch)(const char *id,
+                       sdb_timeseries_opts_t *opts, sdb_object_t *user_data);
+} sdb_timeseries_fetcher_t;
+
+/*
+ * sdb_timeseries_tojson:
+ * Serialize a time-series to JSON written to the specified string buffer.
+ *
+ * Returns:
+ *  - 0 on success
+ *  - a negative value else
+ */
+int
+sdb_timeseries_tojson(sdb_timeseries_t *ts, sdb_strbuf_t *buf);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif