4a0960c1cbe0055f77c1c1c6d64a9f32aa566b82
1 /*
2 * SysDB - src/include/core/store.h
3 * Copyright (C) 2012 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_STORE_H
29 #define SDB_CORE_STORE_H 1
31 #include "sysdb.h"
32 #include "core/object.h"
33 #include "core/data.h"
34 #include "core/time.h"
35 #include "core/timeseries.h"
36 #include "parser/ast.h"
37 #include "utils/strbuf.h"
39 #include <stdbool.h>
40 #include <stdio.h>
42 #ifdef __cplusplus
43 extern "C" {
44 #endif
46 /*
47 * Store object types.
48 */
49 enum {
50 SDB_HOST = 1,
51 SDB_SERVICE,
52 SDB_METRIC,
54 SDB_ATTRIBUTE = 1 << 4,
56 /*
57 * Queryable fields of a stored object.
58 */
59 SDB_FIELD_NAME = 1 << 8, /* type: string */
60 SDB_FIELD_LAST_UPDATE, /* type: datetime */
61 SDB_FIELD_AGE, /* type: datetime */
62 SDB_FIELD_INTERVAL, /* type: datetime */
63 SDB_FIELD_BACKEND, /* type: array of strings */
64 SDB_FIELD_VALUE, /* attributes only; type: type of the value */
65 SDB_FIELD_TIMESERIES, /* metrics only; type: boolean */
66 };
67 #define SDB_STORE_TYPE_TO_NAME(t) \
68 (((t) == SDB_HOST) ? "host" \
69 : ((t) == SDB_SERVICE) ? "service" \
70 : ((t) == SDB_METRIC) ? "metric" \
71 : ((t) == SDB_ATTRIBUTE) ? "attribute" \
72 : ((t) == (SDB_ATTRIBUTE | SDB_HOST)) ? "host attribute" \
73 : ((t) == (SDB_ATTRIBUTE | SDB_SERVICE)) ? "service attribute" \
74 : ((t) == (SDB_ATTRIBUTE | SDB_METRIC)) ? "metric attribute" \
75 : "unknown")
77 #define SDB_FIELD_TO_NAME(f) \
78 (((f) == SDB_FIELD_NAME) ? "name" \
79 : ((f) == SDB_FIELD_LAST_UPDATE) ? "last-update" \
80 : ((f) == SDB_FIELD_AGE) ? "age" \
81 : ((f) == SDB_FIELD_INTERVAL) ? "interval" \
82 : ((f) == SDB_FIELD_BACKEND) ? "backend" \
83 : ((f) == SDB_FIELD_VALUE) ? "value" \
84 : ((f) == SDB_FIELD_TIMESERIES) ? "timeseries" \
85 : "unknown")
87 #define SDB_FIELD_TYPE(f) \
88 (((f) == SDB_FIELD_NAME) ? SDB_TYPE_STRING \
89 : ((f) == SDB_FIELD_LAST_UPDATE) ? SDB_TYPE_DATETIME \
90 : ((f) == SDB_FIELD_AGE) ? SDB_TYPE_DATETIME \
91 : ((f) == SDB_FIELD_INTERVAL) ? SDB_TYPE_DATETIME \
92 : ((f) == SDB_FIELD_BACKEND) ? (SDB_TYPE_ARRAY | SDB_TYPE_STRING) \
93 : ((f) == SDB_FIELD_VALUE) ? -1 /* unknown */ \
94 : ((f) == SDB_FIELD_TIMESERIES) ? SDB_TYPE_BOOLEAN \
95 : -1)
97 /*
98 * sdb_store_obj_t represents the super-class of any object stored in the
99 * database. It inherits from sdb_object_t and may safely be cast to a generic
100 * object to access its name.
101 */
102 struct sdb_store_obj;
103 typedef struct sdb_store_obj sdb_store_obj_t;
105 /*
106 * A metric store describes how to access a metric's data.
107 */
108 typedef struct {
109 const char *type;
110 const char *id;
111 } sdb_metric_store_t;
113 /*
114 * Expressions represent arithmetic expressions based on stored objects and
115 * their various attributes.
116 *
117 * An expression object inherits from sdb_object_t and, thus, may safely be
118 * cast to a generic object.
119 */
120 struct sdb_store_expr;
121 typedef struct sdb_store_expr sdb_store_expr_t;
122 #define SDB_STORE_EXPR(obj) ((sdb_store_expr_t *)(obj))
124 /*
125 * An expression iterator iterates over the values of an iterable expression
126 * (see sdb_store_expr_iterable).
127 */
128 struct sdb_store_expr_iter;
129 typedef struct sdb_store_expr_iter sdb_store_expr_iter_t;
131 /*
132 * Store matchers may be used to lookup hosts from the store based on their
133 * various attributes. Service and attribute matchers are applied to a host's
134 * services and attributes and evaluate to true if *any* service or attribute
135 * matches.
136 *
137 * A store matcher object inherits from sdb_object_t and, thus, may safely be
138 * cast to a generic object.
139 */
140 struct sdb_store_matcher;
141 typedef struct sdb_store_matcher sdb_store_matcher_t;
142 #define SDB_STORE_MATCHER(obj) ((sdb_store_matcher_t *)(obj))
144 /*
145 * A JSON formatter converts stored objects into the JSON format.
146 * See http://www.ietf.org/rfc/rfc4627.txt
147 */
148 struct sdb_store_json_formatter;
149 typedef struct sdb_store_json_formatter sdb_store_json_formatter_t;
151 /*
152 * A store writer describes the interface for plugins implementing a store.
153 */
154 typedef struct {
155 int (*store_host)(const char *name, sdb_time_t last_update,
156 sdb_object_t *user_data);
157 int (*store_service)(const char *hostname, const char *name,
158 sdb_time_t last_update, sdb_object_t *user_data);
159 int (*store_metric)(const char *hostname, const char *name,
160 sdb_metric_store_t *store, sdb_time_t last_update,
161 sdb_object_t *user_data);
162 int (*store_attribute)(const char *hostname,
163 const char *key, const sdb_data_t *value, sdb_time_t last_update,
164 sdb_object_t *user_data);
165 int (*store_service_attr)(const char *hostname, const char *service,
166 const char *key, const sdb_data_t *value, sdb_time_t last_update,
167 sdb_object_t *user_data);
168 int (*store_metric_attr)(const char *hostname, const char *metric,
169 const char *key, const sdb_data_t *value, sdb_time_t last_update,
170 sdb_object_t *user_data);
171 } sdb_store_writer_t;
173 /*
174 * sdb_store_init:
175 * Initialize the store sub-system. This function has to be called before
176 * doing any other store operations.
177 *
178 * Returns:
179 * - 0 on success
180 * - a negative value else
181 */
182 int
183 sdb_store_init(void);
185 /*
186 * sdb_store_clear:
187 * Clear the entire store and remove all stored objects.
188 */
189 void
190 sdb_store_clear(void);
192 /*
193 * sdb_store_host:
194 * Add/update a host in the store. If the host, identified by its
195 * canonicalized name, already exists, it will be updated according to the
196 * specified name and timestamp. Else, a new entry will be created in the
197 * store. Any memory required for storing the entry will be allocated an
198 * managed by the store itself.
199 *
200 * Returns:
201 * - 0 on success
202 * - a positive value if the new entry is older than the currently stored
203 * entry (in this case, no update will happen)
204 * - a negative value on error
205 */
206 int
207 sdb_store_host(const char *name, sdb_time_t last_update);
209 /*
210 * sdb_store_has_host:
211 * sdb_store_get_host:
212 * Query the store for a host by its (canonicalized) name.
213 *
214 * sdb_store_get_host increments the ref count of the host object. The caller
215 * needs to deref it when no longer using it.
216 */
217 bool
218 sdb_store_has_host(const char *name);
220 sdb_store_obj_t *
221 sdb_store_get_host(const char *name);
223 /*
224 * sdb_store_attribute:
225 * Add/update a host's attribute in the store. If the attribute, identified by
226 * its key, already exists for the specified host, it will be updated to the
227 * specified values. If the referenced host does not exist, an error will be
228 * reported. Else, a new entry will be created in the store. Any memory
229 * required for storing the entry will be allocated and managed by the store
230 * itself.
231 *
232 * Returns:
233 * - 0 on success
234 * - a positive value if the new entry is older than the currently stored
235 * entry (in this case, no update will happen)
236 * - a negative value on error
237 */
238 int
239 sdb_store_attribute(const char *hostname,
240 const char *key, const sdb_data_t *value,
241 sdb_time_t last_update);
243 /*
244 * sdb_store_service:
245 * Add/update a service in the store. If the service, identified by its name,
246 * already exists for the specified host, it will be updated according to the
247 * specified 'service' object. If the referenced host does not exist, an error
248 * will be reported. Else, a new entry will be created in the store. Any
249 * memory required for storing the entry will be allocated an managed by the
250 * store itself.
251 *
252 * Returns:
253 * - 0 on success
254 * - a positive value if the new entry is older than the currently stored
255 * entry (in this case, no update will happen)
256 * - a negative value on error
257 */
258 int
259 sdb_store_service(const char *hostname, const char *name,
260 sdb_time_t last_update);
262 /*
263 * sdb_store_service_attr:
264 * Add/update a service's attribute in the store. If the attribute, identified
265 * by its key, already exists for the specified service, it will be updated to
266 * the specified value. If the references service (for the specified host)
267 * does not exist, an error will be reported. Any memory required for storing
268 * the entry will be allocated and managed by the store itself.
269 *
270 * Returns:
271 * - 0 on success
272 * - a positive value if the new entry is older than the currently stored
273 * entry (in this case, no update will happen)
274 * - a negative value on error
275 */
276 int
277 sdb_store_service_attr(const char *hostname, const char *service,
278 const char *key, const sdb_data_t *value, sdb_time_t last_update);
280 /*
281 * sdb_store_metric:
282 * Add/update a metric in the store. If the metric, identified by its name,
283 * already exists for the specified host, it will be updated according to the
284 * specified 'metric' object. If the referenced host does not exist, an error
285 * will be reported. Else, a new entry will be created in the store. Any
286 * memory required for storing the entry will be allocated an managed by the
287 * store itself.
288 *
289 * If specified, the metric store describes where to access the metric's data.
290 *
291 * Returns:
292 * - 0 on success
293 * - a positive value if the new entry is older than the currently stored
294 * entry (in this case, no update will happen)
295 * - a negative value on error
296 */
297 int
298 sdb_store_metric(const char *hostname, const char *name,
299 sdb_metric_store_t *store, sdb_time_t last_update);
301 /*
302 * sdb_store_metric_attr:
303 * Add/update a metric's attribute in the store. If the attribute, identified
304 * by its key, already exists for the specified metric, it will be updated to
305 * the specified value. If the references metric (for the specified host)
306 * does not exist, an error will be reported. Any memory required for storing
307 * the entry will be allocated and managed by the store itself.
308 *
309 * Returns:
310 * - 0 on success
311 * - a positive value if the new entry is older than the currently stored
312 * entry (in this case, no update will happen)
313 * - a negative value on error
314 */
315 int
316 sdb_store_metric_attr(const char *hostname, const char *metric,
317 const char *key, const sdb_data_t *value, sdb_time_t last_update);
319 /*
320 * sdb_store_fetch_timeseries:
321 * Fetch the time-series described by the specified host's metric and
322 * serialize it as JSON into the provided string buffer.
323 *
324 * Returns:
325 * - 0 on success
326 * - a negative value else
327 */
328 int
329 sdb_store_fetch_timeseries(const char *hostname, const char *metric,
330 sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf);
332 /*
333 * sdb_store_get_child:
334 * Retrieve a host's child object of the specified type and name. The
335 * reference count of the child object will be incremented before returning
336 * it. The caller is responsible for releasing the object once it's no longer
337 * used.
338 *
339 * Returns:
340 * - the child object on success
341 * - NULL else
342 */
343 sdb_store_obj_t *
344 sdb_store_get_child(sdb_store_obj_t *host, int type, const char *name);
346 /*
347 * sdb_store_get_field:
348 * Get the value of a stored object's queryable field. The caller is
349 * responsible for freeing any dynamically allocated memory possibly stored in
350 * the returned value. If 'res' is NULL, the function will return whether the
351 * field exists.
352 *
353 * Returns:
354 * - 0 on success
355 * - a negative value else
356 */
357 int
358 sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res);
360 /*
361 * sdb_store_get_attr:
362 * Get the value of a stored object's attribute. The caller is responsible for
363 * freeing any dynamically allocated memory possibly stored in the returned
364 * value. If 'res' is NULL, the function will return whether the attribute
365 * exists. If specified, only attributes matching the filter will be
366 * considered.
367 *
368 * Returns:
369 * - 0 if the attribute exists
370 * - a negative value else
371 */
372 int
373 sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
374 sdb_store_matcher_t *filter);
376 /*
377 * Querying a store:
378 *
379 * - Query interface: A query is a formal description of an interaction with
380 * the store. It can be used, both, for read and write access. The query is
381 * described by its abstract syntax tree (AST). The parser package provides
382 * means to parse a string (SysQL) representation of the query into an AST.
383 *
384 * - Matcher / expression interface: This low-level interface provides direct
385 * control over how to access the store. It is used by the query
386 * implementation internally and can only be used for read access.
387 */
389 /*
390 * sdb_store_query_t:
391 * A parsed query readily prepared for execution.
392 */
393 struct sdb_store_query;
394 typedef struct sdb_store_query sdb_store_query_t;
396 /*
397 * sdb_store_query_prepare:
398 * Prepare the query described by 'ast' for execution in a store.
399 *
400 * Returns:
401 * - a store query on success
402 * - NULL else
403 */
404 sdb_store_query_t *
405 sdb_store_query_prepare(sdb_ast_node_t *ast);
407 /*
408 * sdb_store_query_prepare_matcher:
409 * Prepare the logical expression described by 'ast' for execution as a store
410 * matcher.
411 *
412 * Returns:
413 * - a matcher on success
414 * - NULL else
415 */
416 sdb_store_matcher_t *
417 sdb_store_query_prepare_matcher(sdb_ast_node_t *ast);
419 /*
420 * sdb_store_query_execute:
421 * Execute a previously prepared query. The query result will be written to
422 * 'buf' and any errors to 'errbuf'.
423 *
424 * Returns:
425 * - the result type (to be used by the server reply)
426 * - a negative value on error
427 */
428 int
429 sdb_store_query_execute(sdb_store_query_t *m,
430 sdb_strbuf_t *buf, sdb_strbuf_t *errbuf);
432 /*
433 * sdb_store_expr_create:
434 * Creates an arithmetic expression implementing the specified operator on the
435 * specified left and right operand.
436 *
437 * Returns:
438 * - an expression object on success
439 * - NULL else
440 */
441 sdb_store_expr_t *
442 sdb_store_expr_create(int op, sdb_store_expr_t *left, sdb_store_expr_t *right);
444 /*
445 * sdb_store_expr_typed:
446 * Creates an expression which evaluates in the context of an object's sibling
447 * as specified by the given type.
448 *
449 * Returns:
450 * - an expression object on success
451 * - NULL else
452 */
453 sdb_store_expr_t *
454 sdb_store_expr_typed(int typ, sdb_store_expr_t *expr);
456 /*
457 * sdb_store_expr_fieldvalue:
458 * Creates an expression which evaluates to the value of the specified
459 * queryable field of a stored object.
460 *
461 * Returns:
462 * - an expression object on success
463 * - NULL else
464 */
465 sdb_store_expr_t *
466 sdb_store_expr_fieldvalue(int field);
468 /*
469 * sdb_store_expr_attrvalue:
470 * Creates an expression which evaluates to the value of the specified
471 * attribute of a stored object. Evaluates to a NULL value if the attribute
472 * does not exist.
473 *
474 * Returns:
475 * - an expression object on success
476 * - NULL else
477 */
478 sdb_store_expr_t *
479 sdb_store_expr_attrvalue(const char *name);
481 /*
482 * sdb_store_expr_constvalue:
483 * Creates an expression which evaluates to the specified constant value.
484 *
485 * Returns:
486 * - an expression object on success
487 * - NULL else
488 */
489 sdb_store_expr_t *
490 sdb_store_expr_constvalue(const sdb_data_t *value);
492 /*
493 * sdb_store_expr_eval:
494 * Evaluate an expression for the specified stored object and stores the
495 * result in 'res'. The result's value will be allocated dynamically if
496 * necessary and, thus, should be free'd by the caller (e.g. using
497 * sdb_data_free_datum). The object may be NULL, in which case the expression
498 * needs to evaluate to a constant value. If specified, only objects matching
499 * the filter will be used during the evaluation.
500 *
501 * Returns:
502 * - 0 on success
503 * - a negative value else
504 */
505 int
506 sdb_store_expr_eval(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
507 sdb_data_t *res, sdb_store_matcher_t *filter);
509 /*
510 * sdb_store_expr_iterable:
511 * Check whether an expression, evaluated in the specified context (HOST,
512 * SERVICE, METRIC) is iterable, that is, if it may evaluate to multiple
513 * values.
514 */
515 bool
516 sdb_store_expr_iterable(sdb_store_expr_t *expr, int context);
518 /*
519 * sdb_store_expr_iter:
520 * Iterate over the elements of an iterable expression. sdb_store_expr_iter
521 * returns NULL if the expression is not iterable (for the specified object).
522 * See also sdb_store_expr_iterable.
523 *
524 * sdb_store_expr_iter_get_next returns NULL if there is no next element.
525 */
526 sdb_store_expr_iter_t *
527 sdb_store_expr_iter(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
528 sdb_store_matcher_t *filter);
529 void
530 sdb_store_expr_iter_destroy(sdb_store_expr_iter_t *iter);
532 bool
533 sdb_store_expr_iter_has_next(sdb_store_expr_iter_t *iter);
534 sdb_data_t
535 sdb_store_expr_iter_get_next(sdb_store_expr_iter_t *iter);
537 /*
538 * sdb_store_dis_matcher:
539 * Creates a matcher matching the disjunction (logical OR) of two matchers.
540 */
541 sdb_store_matcher_t *
542 sdb_store_dis_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
544 /*
545 * sdb_store_con_matcher:
546 * Creates a matcher matching the conjunction (logical AND) of two matchers.
547 */
548 sdb_store_matcher_t *
549 sdb_store_con_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
551 /*
552 * sdb_store_inv_matcher::
553 * Creates a matcher matching the inverse (logical NOT) of a matcher.
554 */
555 sdb_store_matcher_t *
556 sdb_store_inv_matcher(sdb_store_matcher_t *m);
558 /*
559 * sdb_store_any_matcher:
560 * Creates a matcher iterating over values of the first expression (which has
561 * to be iterable). It matches if *any* of those elements match 'm'. 'm' has
562 * to be an ary operation with the left operand unset.
563 */
564 sdb_store_matcher_t *
565 sdb_store_any_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
567 /*
568 * sdb_store_all_matcher:
569 * Creates a matcher iterating over values of the first expression (which has
570 * to be iterable). It matches if *all* of those elements match 'm'. 'm' has
571 * to be an ary operation with the left operand unset.
572 */
573 sdb_store_matcher_t *
574 sdb_store_all_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
576 /*
577 * sdb_store_in_matcher:
578 * Creates a matcher which matches if the right value evaluates to an array
579 * value and the left value is included in that array. See sdb_data_inarray
580 * for more details.
581 */
582 sdb_store_matcher_t *
583 sdb_store_in_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
585 /*
586 * sdb_store_lt_matcher, sdb_store_le_matcher, sdb_store_eq_matcher,
587 * sdb_store_ge_matcher, sdb_store_gt_matcher:
588 * Create conditional matchers comparing the values of two expressions. The
589 * matcher matches if the left expression compres less than, less or equal
590 * than, equal to, not equal to, greater or equal than, or greater than the
591 * right expression.
592 */
593 sdb_store_matcher_t *
594 sdb_store_lt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
595 sdb_store_matcher_t *
596 sdb_store_le_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
597 sdb_store_matcher_t *
598 sdb_store_eq_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
599 sdb_store_matcher_t *
600 sdb_store_ne_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
601 sdb_store_matcher_t *
602 sdb_store_ge_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
603 sdb_store_matcher_t *
604 sdb_store_gt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
606 /*
607 * sdb_store_regex_matcher:
608 * Creates a matcher which matches the string value the left expression
609 * evaluates to against the regular expression the right expression evaluates
610 * to. The right expression may either be a constant value regular expression
611 * or string or a dynamic value evaluating to a string. In the latter case,
612 * the string is compiled to a regex every time the matcher is executed.
613 */
614 sdb_store_matcher_t *
615 sdb_store_regex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
617 /*
618 * sdb_store_nregex_matcher:
619 * Creates a regex matcher just like sdb_store_regex_matcher except that it
620 * matches in case the regular expression does not match.
621 */
622 sdb_store_matcher_t *
623 sdb_store_nregex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
625 /*
626 * sdb_store_isnull_matcher:
627 * Creates a matcher matching NULL values.
628 */
629 sdb_store_matcher_t *
630 sdb_store_isnull_matcher(sdb_store_expr_t *expr);
632 /*
633 * sdb_store_istrue_matcher, sdb_store_isfalse_matcher:
634 * Creates a matcher matching boolean values.
635 */
636 sdb_store_matcher_t *
637 sdb_store_istrue_matcher(sdb_store_expr_t *expr);
638 sdb_store_matcher_t *
639 sdb_store_isfalse_matcher(sdb_store_expr_t *expr);
641 /*
642 * sdb_store_matcher_matches:
643 * Check whether the specified matcher matches the specified store object. If
644 * specified, the filter will be used to preselect objects for further
645 * evaluation. It is applied to any object that's used during the evaluation
646 * of the matcher. Only those objects matching the filter will be considered.
647 *
648 * Note that the filter is applied to all object types (hosts, service,
649 * metric, attribute). Thus, any object-specific matchers are mostly unsuited
650 * for this purpose and, if used, may result in unexpected behavior.
651 *
652 * Returns:
653 * - 1 if the object matches
654 * - 0 else
655 */
656 int
657 sdb_store_matcher_matches(sdb_store_matcher_t *m, sdb_store_obj_t *obj,
658 sdb_store_matcher_t *filter);
660 /*
661 * sdb_store_matcher_op_cb:
662 * Callback constructing a matcher operator.
663 */
664 typedef sdb_store_matcher_t *(*sdb_store_matcher_op_cb)
665 (sdb_store_expr_t *, sdb_store_expr_t *);
667 /*
668 * sdb_store_lookup_cb:
669 * Lookup callback. It is called for each matching object when looking up data
670 * in the store passing on the lookup filter and the specified user-data. The
671 * lookup aborts early if the callback returns non-zero.
672 */
673 typedef int (*sdb_store_lookup_cb)(sdb_store_obj_t *obj,
674 sdb_store_matcher_t *filter, void *user_data);
676 /*
677 * sdb_store_scan:
678 * Look up objects of the specified type in the store. The specified callback
679 * function is called for each object in the store matching 'm'. The function
680 * performs a full scan of all objects stored in the database. If specified,
681 * the filter will be used to preselect objects for further evaluation. See
682 * the description of 'sdb_store_matcher_matches' for details.
683 *
684 * Returns:
685 * - 0 on success
686 * - a negative value else
687 */
688 int
689 sdb_store_scan(int type, sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
690 sdb_store_lookup_cb cb, void *user_data);
692 /*
693 * Flags for JSON formatting.
694 */
695 enum {
696 SDB_WANT_ARRAY = 1 << 0,
697 };
699 /*
700 * sdb_store_json_formatter:
701 * Create a JSON formatter for the specified object types writing to the
702 * specified buffer.
703 */
704 sdb_store_json_formatter_t *
705 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags);
707 /*
708 * sdb_store_json_emit:
709 * Serialize a single object to JSON adding it to the string buffer associated
710 * with the formatter object. The serialized object will not include
711 * attributes or any child objects. Instead, call the function again for each
712 * of those objects. All attributes have to be emitted before any other
713 * children types. Use sdb_store_json_emit_full() to emit a full (filtered)
714 * object.
715 *
716 * Note that the output might not be valid JSON before calling
717 * sdb_store_json_finish().
718 *
719 * Returns:
720 * - 0 on success
721 * - a negative value else
722 */
723 int
724 sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj);
726 /*
727 * sdb_store_json_emit_full:
728 * Serialize a single object including it's attributes and all children to
729 * JSON, adding it to the string buffer associated with the formatter object.
730 * The filter, if specified, is applied to each attribute and child object.
731 * Only matching objects will be included in the output.
732 *
733 * Note that the output might not be valid JSON before calling
734 * sdb_store_json_finish().
735 *
736 * Returns:
737 * - 0 on success
738 * - a negative value else
739 */
740 int
741 sdb_store_json_emit_full(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj,
742 sdb_store_matcher_t *filter);
744 /*
745 * sdb_store_json_finish:
746 * Finish the JSON output. This function has to be called once after emiting
747 * all objects.
748 */
749 int
750 sdb_store_json_finish(sdb_store_json_formatter_t *f);
752 #ifdef __cplusplus
753 } /* extern "C" */
754 #endif
756 #endif /* ! SDB_CORE_STORE_H */
758 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */