1 /*
2 * SysDB - src/include/core/timeseries.h
3 * Copyright (C) 2014 Sebastian 'tokkee' Harl <sh@tokkee.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
28 #ifndef SDB_CORE_TIMESERIES_H
29 #define SDB_CORE_TIMESERIES_H 1
31 #include "sysdb.h"
32 #include "core/object.h"
33 #include "core/time.h"
34 #include "utils/strbuf.h"
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
40 /*
41 * sdb_timeseries_info_t:
42 * Information about a timeseries.
43 */
44 typedef struct {
45 char **data_names;
46 size_t data_names_len;
47 } sdb_timeseries_info_t;
49 /*
50 * sdb_timeseries_info_create:
51 * Allocate a timeseries information object.
52 *
53 * Returns:
54 * - a newly allocated timeseries info object on success
55 * - NULL else
56 */
57 sdb_timeseries_info_t *
58 sdb_timeseries_info_create(size_t data_names_len, const char * const *data_names);
60 /*
61 * sdb_timeseries_info_destroy:
62 * Destroy a timeseries info object, freeing all of its memory.
63 */
64 void
65 sdb_timeseries_info_destroy(sdb_timeseries_info_t *ts_info);
67 /*
68 * A data-point describes a datum at a certain point of time.
69 */
70 typedef struct {
71 sdb_time_t timestamp;
72 double value;
73 } sdb_data_point_t;
75 /*
76 * A timeseries describes one or more sequences of data-points. Multiple
77 * sequences will have a name each and share the same start and end times and
78 * number of data points.
79 *
80 * Start and end times may diverge slightly from the requested start and end
81 * times depending on the resolution available in the backend data-store.
82 */
83 typedef struct {
84 sdb_time_t start;
85 sdb_time_t end;
87 sdb_data_point_t **data;
88 size_t data_len;
89 char **data_names;
90 size_t data_names_len;
91 } sdb_timeseries_t;
93 /*
94 * Time-series options specify generic parameters to be used when fetching
95 * time-series data from a data-store.
96 */
97 typedef struct {
98 sdb_time_t start;
99 sdb_time_t end;
101 /* If specified, only fetch time-series with these names. */
102 const char * const *data_names;
103 size_t data_names_len;
104 } sdb_timeseries_opts_t;
106 /*
107 * sdb_timeseries_create:
108 * Allocate a time-series object, pre-populating the data_names information
109 * and allocating the data field.
110 *
111 * Returns:
112 * - a newly allocated time-series object on success
113 * - NULL else
114 */
115 sdb_timeseries_t *
116 sdb_timeseries_create(size_t data_names_len, const char * const *data_names,
117 size_t data_len);
119 /*
120 * sdb_timeseries_destroy:
121 * Destroy a time-series object, freeing all of its memory.
122 */
123 void
124 sdb_timeseries_destroy(sdb_timeseries_t *ts);
126 /*
127 * A timeseries fetcher fetches data from a timeseries data-store.
128 */
129 typedef struct {
130 /*
131 * describe:
132 * Retrieve information about the timeseries from the data-store. The
133 * returned timeseries info object must be freeable using
134 * sdb_timeseries_info_destroy.
135 */
136 sdb_timeseries_info_t *(*describe)(const char *id, sdb_object_t *user_data);
138 /*
139 * fetch:
140 * Read timeseries data from the data-store. The returned timeseries
141 * object must be freeable using sdb_timeseries_destroy.
142 */
143 sdb_timeseries_t *(*fetch)(const char *id,
144 sdb_timeseries_opts_t *opts, sdb_object_t *user_data);
145 } sdb_timeseries_fetcher_t;
147 /*
148 * sdb_timeseries_tojson:
149 * Serialize a time-series to JSON written to the specified string buffer.
150 *
151 * Returns:
152 * - 0 on success
153 * - a negative value else
154 */
155 int
156 sdb_timeseries_tojson(sdb_timeseries_t *ts, sdb_strbuf_t *buf);
158 #ifdef __cplusplus
159 } /* extern "C" */
160 #endif
162 #endif /* ! SDB_CORE_TIMESERIES_H */
164 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */