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_t represents an in-memory store. It inherits from sdb_object_t
99 * and may safely be case to a generic object.
100 */
101 struct sdb_store;
102 typedef struct sdb_store sdb_store_t;
103 #define SDB_STORE(obj) ((sdb_store_t *)(obj))
105 /*
106 * sdb_store_obj_t represents the super-class of any stored object. It
107 * inherits from sdb_object_t and may safely be cast to a generic object to
108 * access its name.
109 */
110 struct sdb_store_obj;
111 typedef struct sdb_store_obj sdb_store_obj_t;
113 /*
114 * sdb_store_host_t represents the meta-data of a stored host object.
115 */
116 typedef struct {
117 const char *name;
119 sdb_time_t last_update;
120 sdb_time_t interval;
121 const char * const *backends;
122 size_t backends_num;
123 } sdb_store_host_t;
124 #define SDB_STORE_HOST_INIT { NULL, 0, 0, NULL, 0 }
126 /*
127 * sdb_store_service_t represents the meta-data of a stored service object.
128 */
129 typedef struct {
130 const char *hostname;
131 const char *name;
133 sdb_time_t last_update;
134 sdb_time_t interval;
135 const char * const *backends;
136 size_t backends_num;
137 } sdb_store_service_t;
138 #define SDB_STORE_SERVICE_INIT { NULL, NULL, 0, 0, NULL, 0 }
140 /*
141 * sdb_metric_store_t specifies how to access a metric's data.
142 */
143 typedef struct {
144 const char *type;
145 const char *id;
146 } sdb_metric_store_t;
148 /*
149 * sdb_store_metric_t represents the meta-data of a stored metric object.
150 */
151 typedef struct {
152 const char *hostname;
153 const char *name;
154 struct {
155 const char *type;
156 const char *id;
157 } store;
159 sdb_time_t last_update;
160 sdb_time_t interval;
161 const char * const *backends;
162 size_t backends_num;
163 } sdb_store_metric_t;
164 #define SDB_STORE_METRIC_INIT { NULL, NULL, { NULL, NULL }, 0, 0, NULL, 0 }
166 /*
167 * sdb_store_attribute_t represents a stored attribute.
168 */
169 typedef struct {
170 const char *hostname; /* optional */
171 int parent_type;
172 const char *parent;
173 const char *key;
174 sdb_data_t value;
176 sdb_time_t last_update;
177 sdb_time_t interval;
178 const char * const *backends;
179 size_t backends_num;
180 } sdb_store_attribute_t;
181 #define SDB_STORE_ATTRIBUTE_INIT { NULL, 0, NULL, NULL, SDB_DATA_INIT, 0, 0, NULL, 0 }
183 /*
184 * Expressions represent arithmetic expressions based on stored objects and
185 * their various attributes.
186 *
187 * An expression object inherits from sdb_object_t and, thus, may safely be
188 * cast to a generic object.
189 */
190 struct sdb_store_expr;
191 typedef struct sdb_store_expr sdb_store_expr_t;
192 #define SDB_STORE_EXPR(obj) ((sdb_store_expr_t *)(obj))
194 /*
195 * An expression iterator iterates over the values of an iterable expression.
196 */
197 struct sdb_store_expr_iter;
198 typedef struct sdb_store_expr_iter sdb_store_expr_iter_t;
200 /*
201 * Store matchers may be used to lookup hosts from the store based on their
202 * various attributes. Service and attribute matchers are applied to a host's
203 * services and attributes and evaluate to true if *any* service or attribute
204 * matches.
205 *
206 * A store matcher object inherits from sdb_object_t and, thus, may safely be
207 * cast to a generic object.
208 */
209 struct sdb_store_matcher;
210 typedef struct sdb_store_matcher sdb_store_matcher_t;
211 #define SDB_STORE_MATCHER(obj) ((sdb_store_matcher_t *)(obj))
213 /*
214 * A JSON formatter converts stored objects into the JSON format.
215 * See http://www.ietf.org/rfc/rfc4627.txt
216 *
217 * A JSON formatter object inherits from sdb_object_t and, thus, may safely be
218 * cast to a generic object.
219 */
220 struct sdb_store_json_formatter;
221 typedef struct sdb_store_json_formatter sdb_store_json_formatter_t;
223 /*
224 * A store writer describes the interface for plugins implementing a store.
225 *
226 * Any of the call-back functions shall return:
227 * - 0 on success
228 * - a positive value if the new entry is older than the currently stored
229 * entry (in this case, no update will happen)
230 * - a negative value on error
231 */
232 typedef struct {
233 /*
234 * store_host:
235 * Add/update a host in the store. If the host, identified by its
236 * canonicalized name, already exists, it will be updated according to the
237 * specified name and timestamp. Else, a new entry will be created in the
238 * store.
239 */
240 int (*store_host)(sdb_store_host_t *host, sdb_object_t *user_data);
242 /*
243 * store_service:
244 * Add/update a service in the store. If the service, identified by its
245 * name, already exists for the specified host, it will be updated
246 * according to the specified name and timestamp. If the referenced host
247 * does not exist, an error will be reported. Else, a new entry will be
248 * created in the store.
249 */
250 int (*store_service)(sdb_store_service_t *service, sdb_object_t *user_data);
252 /*
253 * store_metric:
254 * Add/update a metric in the store. If the metric, identified by its
255 * name, already exists for the specified host, it will be updated
256 * according to the specified attributes. If the referenced host does not
257 * exist, an error will be reported. Else, a new entry will be created in
258 * the store.
259 */
260 int (*store_metric)(sdb_store_metric_t *metric, sdb_object_t *user_data);
262 /*
263 * store_attribute:
264 * Add/update a host's attribute in the store. If the attribute,
265 * identified by its key, already exists for the specified host, it will
266 * be updated to the specified values. If the referenced host does not
267 * exist, an error will be reported. Else, a new entry will be created in
268 * the store.
269 */
270 int (*store_attribute)(sdb_store_attribute_t *attr, sdb_object_t *user_data);
271 } sdb_store_writer_t;
273 /*
274 * sdb_store_writer:
275 * A store writer implementation that provides an in-memory object store. It
276 * expects a store object as its user-data argument.
277 */
278 extern sdb_store_writer_t sdb_store_writer;
280 /*
281 * A store reader describes the interface to query a store implementation.
282 */
283 typedef struct {
284 /*
285 * prepare_query:
286 * Prepare the query described by 'ast' for execution.
287 */
288 sdb_object_t *(*prepare_query)(sdb_ast_node_t *ast,
289 sdb_strbuf_t *errbuf, sdb_object_t *user_data);
291 /*
292 * execute_query:
293 * Execute a previously prepared query. The callback may expect that only
294 * queries prepared by its respective prepare callback will be passed to
295 * this function. The query result will be passed back via the specified
296 * store writer.
297 */
298 int (*execute_query)(sdb_object_t *q,
299 sdb_store_writer_t *w, sdb_object_t *wd,
300 sdb_strbuf_t *errbuf, sdb_object_t *user_data);
301 } sdb_store_reader_t;
303 /*
304 * sdb_store_reader:
305 * A store reader implementation that uses an in-memory object store. It
306 * expects a store object as its user-data argument.
307 */
308 extern sdb_store_reader_t sdb_store_reader;
310 /*
311 * sdb_store_create:
312 * Allocate a new in-memory store.
313 */
314 sdb_store_t *
315 sdb_store_create(void);
317 /*
318 * sdb_store_host, sdb_store_service, sdb_store_metric, sdb_store_attribute,
319 * sdb_store_metric_attr:
320 * Store an object in the specified store. The hostname is expected to be
321 * canonical.
322 */
323 int
324 sdb_store_host(sdb_store_t *store, const char *name, sdb_time_t last_update);
325 int
326 sdb_store_service(sdb_store_t *store, const char *hostname, const char *name,
327 sdb_time_t last_update);
328 int
329 sdb_store_metric(sdb_store_t *store, const char *hostname, const char *name,
330 sdb_metric_store_t *metric_store, sdb_time_t last_update);
331 int
332 sdb_store_attribute(sdb_store_t *store, const char *hostname,
333 const char *key, const sdb_data_t *value, sdb_time_t last_update);
334 int
335 sdb_store_service_attr(sdb_store_t *store, const char *hostname,
336 const char *service, const char *key, const sdb_data_t *value,
337 sdb_time_t last_update);
338 int
339 sdb_store_metric_attr(sdb_store_t *store, const char *hostname,
340 const char *metric, const char *key, const sdb_data_t *value,
341 sdb_time_t last_update);
343 /*
344 * sdb_store_get_host:
345 * Query the specified store for a host by its (canonicalized) name.
346 *
347 * The function increments the ref count of the host object. The caller needs
348 * to deref it when no longer using it.
349 */
350 sdb_store_obj_t *
351 sdb_store_get_host(sdb_store_t *store, const char *name);
353 /*
354 * sdb_store_get_child:
355 * Retrieve a host's child object of the specified type and name. The
356 * reference count of the child object will be incremented before returning
357 * it. The caller is responsible for releasing the object once it's no longer
358 * used.
359 *
360 * Returns:
361 * - the child object on success
362 * - NULL else
363 */
364 sdb_store_obj_t *
365 sdb_store_get_child(sdb_store_obj_t *host, int type, const char *name);
367 /*
368 * sdb_store_get_field:
369 * Get the value of a stored object's queryable field. The caller is
370 * responsible for freeing any dynamically allocated memory possibly stored in
371 * the returned value. If 'res' is NULL, the function will return whether the
372 * field exists.
373 *
374 * Returns:
375 * - 0 on success
376 * - a negative value else
377 */
378 int
379 sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res);
381 /*
382 * sdb_store_get_attr:
383 * Get the value of a stored object's attribute. The caller is responsible for
384 * freeing any dynamically allocated memory possibly stored in the returned
385 * value. If 'res' is NULL, the function will return whether the attribute
386 * exists. If specified, only attributes matching the filter will be
387 * considered.
388 *
389 * Returns:
390 * - 0 if the attribute exists
391 * - a negative value else
392 */
393 int
394 sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
395 sdb_store_matcher_t *filter);
397 /*
398 * Querying a store:
399 *
400 * - Query interface: A query is a formal description of an interaction with
401 * the store. It can be used, both, for read and write access. The query is
402 * described by its abstract syntax tree (AST). The parser package provides
403 * means to parse a string (SysQL) representation of the query into an AST.
404 *
405 * - Matcher / expression interface: This low-level interface provides direct
406 * control over how to access the store. It is used by the query
407 * implementation internally and can only be used for read access.
408 */
410 /*
411 * sdb_store_query_t:
412 * A parsed query readily prepared for execution.
413 */
414 struct sdb_store_query;
415 typedef struct sdb_store_query sdb_store_query_t;
417 /*
418 * sdb_store_query_prepare:
419 * Prepare the query described by 'ast' for execution in a store.
420 *
421 * Returns:
422 * - a store query on success
423 * - NULL else
424 */
425 sdb_store_query_t *
426 sdb_store_query_prepare(sdb_ast_node_t *ast);
428 /*
429 * sdb_store_query_prepare_matcher:
430 * Prepare the logical expression described by 'ast' for execution as a store
431 * matcher.
432 *
433 * Returns:
434 * - a matcher on success
435 * - NULL else
436 */
437 sdb_store_matcher_t *
438 sdb_store_query_prepare_matcher(sdb_ast_node_t *ast);
440 /*
441 * sdb_store_query_execute:
442 * Execute a previously prepared query in the specified store. The query
443 * result will be written to 'buf' and any errors to 'errbuf'.
444 *
445 * Returns:
446 * - the result type (to be used by the server reply)
447 * - a negative value on error
448 */
449 int
450 sdb_store_query_execute(sdb_store_t *store, sdb_store_query_t *m,
451 sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf);
453 /*
454 * sdb_store_expr_create:
455 * Creates an arithmetic expression implementing the specified operator on the
456 * specified left and right operand.
457 *
458 * Returns:
459 * - an expression object on success
460 * - NULL else
461 */
462 sdb_store_expr_t *
463 sdb_store_expr_create(int op, sdb_store_expr_t *left, sdb_store_expr_t *right);
465 /*
466 * sdb_store_expr_typed:
467 * Creates an expression which evaluates in the context of an object's sibling
468 * as specified by the given type.
469 *
470 * Returns:
471 * - an expression object on success
472 * - NULL else
473 */
474 sdb_store_expr_t *
475 sdb_store_expr_typed(int typ, sdb_store_expr_t *expr);
477 /*
478 * sdb_store_expr_fieldvalue:
479 * Creates an expression which evaluates to the value of the specified
480 * queryable field of a stored object.
481 *
482 * Returns:
483 * - an expression object on success
484 * - NULL else
485 */
486 sdb_store_expr_t *
487 sdb_store_expr_fieldvalue(int field);
489 /*
490 * sdb_store_expr_attrvalue:
491 * Creates an expression which evaluates to the value of the specified
492 * attribute of a stored object. Evaluates to a NULL value if the attribute
493 * does not exist.
494 *
495 * Returns:
496 * - an expression object on success
497 * - NULL else
498 */
499 sdb_store_expr_t *
500 sdb_store_expr_attrvalue(const char *name);
502 /*
503 * sdb_store_expr_constvalue:
504 * Creates an expression which evaluates to the specified constant value.
505 *
506 * Returns:
507 * - an expression object on success
508 * - NULL else
509 */
510 sdb_store_expr_t *
511 sdb_store_expr_constvalue(const sdb_data_t *value);
513 /*
514 * sdb_store_expr_eval:
515 * Evaluate an expression for the specified stored object and stores the
516 * result in 'res'. The result's value will be allocated dynamically if
517 * necessary and, thus, should be free'd by the caller (e.g. using
518 * sdb_data_free_datum). The object may be NULL, in which case the expression
519 * needs to evaluate to a constant value. If specified, only objects matching
520 * the filter will be used during the evaluation.
521 *
522 * Returns:
523 * - 0 on success
524 * - a negative value else
525 */
526 int
527 sdb_store_expr_eval(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
528 sdb_data_t *res, sdb_store_matcher_t *filter);
530 /*
531 * sdb_store_expr_iter:
532 * Iterate over the elements of an iterable expression. sdb_store_expr_iter
533 * returns NULL if the expression is not iterable (for the specified object).
534 *
535 * sdb_store_expr_iter_get_next returns NULL if there is no next element.
536 */
537 sdb_store_expr_iter_t *
538 sdb_store_expr_iter(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
539 sdb_store_matcher_t *filter);
540 void
541 sdb_store_expr_iter_destroy(sdb_store_expr_iter_t *iter);
543 bool
544 sdb_store_expr_iter_has_next(sdb_store_expr_iter_t *iter);
545 sdb_data_t
546 sdb_store_expr_iter_get_next(sdb_store_expr_iter_t *iter);
548 /*
549 * sdb_store_dis_matcher:
550 * Creates a matcher matching the disjunction (logical OR) of two matchers.
551 */
552 sdb_store_matcher_t *
553 sdb_store_dis_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
555 /*
556 * sdb_store_con_matcher:
557 * Creates a matcher matching the conjunction (logical AND) of two matchers.
558 */
559 sdb_store_matcher_t *
560 sdb_store_con_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
562 /*
563 * sdb_store_inv_matcher::
564 * Creates a matcher matching the inverse (logical NOT) of a matcher.
565 */
566 sdb_store_matcher_t *
567 sdb_store_inv_matcher(sdb_store_matcher_t *m);
569 /*
570 * sdb_store_any_matcher:
571 * Creates a matcher iterating over values of the first expression (which has
572 * to be iterable). It matches if *any* of those elements match 'm'. 'm' has
573 * to be an ary operation with the left operand unset.
574 */
575 sdb_store_matcher_t *
576 sdb_store_any_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
578 /*
579 * sdb_store_all_matcher:
580 * Creates a matcher iterating over values of the first expression (which has
581 * to be iterable). It matches if *all* of those elements match 'm'. 'm' has
582 * to be an ary operation with the left operand unset.
583 */
584 sdb_store_matcher_t *
585 sdb_store_all_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
587 /*
588 * sdb_store_in_matcher:
589 * Creates a matcher which matches if the right value evaluates to an array
590 * value and the left value is included in that array. See sdb_data_inarray
591 * for more details.
592 */
593 sdb_store_matcher_t *
594 sdb_store_in_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
596 /*
597 * sdb_store_lt_matcher, sdb_store_le_matcher, sdb_store_eq_matcher,
598 * sdb_store_ge_matcher, sdb_store_gt_matcher:
599 * Create conditional matchers comparing the values of two expressions. The
600 * matcher matches if the left expression compres less than, less or equal
601 * than, equal to, not equal to, greater or equal than, or greater than the
602 * right expression.
603 */
604 sdb_store_matcher_t *
605 sdb_store_lt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
606 sdb_store_matcher_t *
607 sdb_store_le_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
608 sdb_store_matcher_t *
609 sdb_store_eq_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
610 sdb_store_matcher_t *
611 sdb_store_ne_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
612 sdb_store_matcher_t *
613 sdb_store_ge_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
614 sdb_store_matcher_t *
615 sdb_store_gt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
617 /*
618 * sdb_store_regex_matcher:
619 * Creates a matcher which matches the string value the left expression
620 * evaluates to against the regular expression the right expression evaluates
621 * to. The right expression may either be a constant value regular expression
622 * or string or a dynamic value evaluating to a string. In the latter case,
623 * the string is compiled to a regex every time the matcher is executed.
624 */
625 sdb_store_matcher_t *
626 sdb_store_regex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
628 /*
629 * sdb_store_nregex_matcher:
630 * Creates a regex matcher just like sdb_store_regex_matcher except that it
631 * matches in case the regular expression does not match.
632 */
633 sdb_store_matcher_t *
634 sdb_store_nregex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
636 /*
637 * sdb_store_isnull_matcher:
638 * Creates a matcher matching NULL values.
639 */
640 sdb_store_matcher_t *
641 sdb_store_isnull_matcher(sdb_store_expr_t *expr);
643 /*
644 * sdb_store_istrue_matcher, sdb_store_isfalse_matcher:
645 * Creates a matcher matching boolean values.
646 */
647 sdb_store_matcher_t *
648 sdb_store_istrue_matcher(sdb_store_expr_t *expr);
649 sdb_store_matcher_t *
650 sdb_store_isfalse_matcher(sdb_store_expr_t *expr);
652 /*
653 * sdb_store_matcher_matches:
654 * Check whether the specified matcher matches the specified store object. If
655 * specified, the filter will be used to preselect objects for further
656 * evaluation. It is applied to any object that's used during the evaluation
657 * of the matcher. Only those objects matching the filter will be considered.
658 *
659 * Note that the filter is applied to all object types (hosts, service,
660 * metric, attribute). Thus, any object-specific matchers are mostly unsuited
661 * for this purpose and, if used, may result in unexpected behavior.
662 *
663 * Returns:
664 * - 1 if the object matches
665 * - 0 else
666 */
667 int
668 sdb_store_matcher_matches(sdb_store_matcher_t *m, sdb_store_obj_t *obj,
669 sdb_store_matcher_t *filter);
671 /*
672 * sdb_store_matcher_op_cb:
673 * Callback constructing a matcher operator.
674 */
675 typedef sdb_store_matcher_t *(*sdb_store_matcher_op_cb)
676 (sdb_store_expr_t *, sdb_store_expr_t *);
678 /*
679 * sdb_store_lookup_cb:
680 * Lookup callback. It is called for each matching object when looking up data
681 * in the store passing on the lookup filter and the specified user-data. The
682 * lookup aborts early if the callback returns non-zero.
683 */
684 typedef int (*sdb_store_lookup_cb)(sdb_store_obj_t *obj,
685 sdb_store_matcher_t *filter, void *user_data);
687 /*
688 * sdb_store_scan:
689 * Look up objects of the specified type in the specified store. The specified
690 * callback function is called for each object in the store matching 'm'. The
691 * function performs a full scan of all stored objects. If specified, the
692 * filter will be used to preselect objects for further evaluation. See the
693 * description of 'sdb_store_matcher_matches' for details.
694 *
695 * Returns:
696 * - 0 on success
697 * - a negative value else
698 */
699 int
700 sdb_store_scan(sdb_store_t *store, int type,
701 sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
702 sdb_store_lookup_cb cb, void *user_data);
704 /*
705 * Flags for JSON formatting.
706 */
707 enum {
708 SDB_WANT_ARRAY = 1 << 0,
709 };
711 /*
712 * sdb_store_json_formatter:
713 * Create a JSON formatter for the specified object types writing to the
714 * specified buffer.
715 */
716 sdb_store_json_formatter_t *
717 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags);
719 /*
720 * sdb_store_emit:
721 * Serialize a single object to JSON adding it to the string buffer associated
722 * with the formatter object. The serialized object will not include
723 * attributes or any child objects. Instead, call the function again for each
724 * of those objects. All attributes have to be emitted before any other
725 * children types. Use sdb_store_emit_full() to emit a full (filtered) object.
726 *
727 * Note that the output might not be valid JSON before calling
728 * sdb_store_json_finish().
729 *
730 * Returns:
731 * - 0 on success
732 * - a negative value else
733 */
734 int
735 sdb_store_emit(sdb_store_obj_t *obj, sdb_store_writer_t *w, sdb_object_t *wd);
737 /*
738 * sdb_store_emit_full:
739 * Serialize a single object including it's attributes and all children to
740 * JSON, adding it to the string buffer associated with the formatter object.
741 * The filter, if specified, is applied to each attribute and child object.
742 * Only matching objects will be included in the output.
743 *
744 * Note that the output might not be valid JSON before calling
745 * sdb_store_json_finish().
746 *
747 * Returns:
748 * - 0 on success
749 * - a negative value else
750 */
751 int
752 sdb_store_emit_full(sdb_store_obj_t *obj, sdb_store_matcher_t *filter,
753 sdb_store_writer_t *w, sdb_object_t *wd);
755 /*
756 * sdb_store_json_finish:
757 * Finish the JSON output. This function has to be called once after emiting
758 * all objects.
759 */
760 int
761 sdb_store_json_finish(sdb_store_json_formatter_t *f);
763 /*
764 * sdb_store_json_writer:
765 * A store writer implementation that generates JSON output. It expects a
766 * store JSON formatter as its user-data argument.
767 */
768 extern sdb_store_writer_t sdb_store_json_writer;
770 #ifdef __cplusplus
771 } /* extern "C" */
772 #endif
774 #endif /* ! SDB_CORE_STORE_H */
776 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */