4038fe4da91c0fc0c70a68b4ba833e3cba67da5c
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_fetch_timeseries:
355 * Fetch the time-series described by the specified host's metric and
356 * serialize it as JSON into the provided string buffer. The host data is
357 * retrieved from the specified store.
358 *
359 * Returns:
360 * - 0 on success
361 * - a negative value else
362 */
363 int
364 sdb_store_fetch_timeseries(sdb_store_t *store,
365 const char *hostname, const char *metric,
366 sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf);
368 /*
369 * sdb_store_get_child:
370 * Retrieve a host's child object of the specified type and name. The
371 * reference count of the child object will be incremented before returning
372 * it. The caller is responsible for releasing the object once it's no longer
373 * used.
374 *
375 * Returns:
376 * - the child object on success
377 * - NULL else
378 */
379 sdb_store_obj_t *
380 sdb_store_get_child(sdb_store_obj_t *host, int type, const char *name);
382 /*
383 * sdb_store_get_field:
384 * Get the value of a stored object's queryable field. The caller is
385 * responsible for freeing any dynamically allocated memory possibly stored in
386 * the returned value. If 'res' is NULL, the function will return whether the
387 * field exists.
388 *
389 * Returns:
390 * - 0 on success
391 * - a negative value else
392 */
393 int
394 sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res);
396 /*
397 * sdb_store_get_attr:
398 * Get the value of a stored object's attribute. The caller is responsible for
399 * freeing any dynamically allocated memory possibly stored in the returned
400 * value. If 'res' is NULL, the function will return whether the attribute
401 * exists. If specified, only attributes matching the filter will be
402 * considered.
403 *
404 * Returns:
405 * - 0 if the attribute exists
406 * - a negative value else
407 */
408 int
409 sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
410 sdb_store_matcher_t *filter);
412 /*
413 * Querying a store:
414 *
415 * - Query interface: A query is a formal description of an interaction with
416 * the store. It can be used, both, for read and write access. The query is
417 * described by its abstract syntax tree (AST). The parser package provides
418 * means to parse a string (SysQL) representation of the query into an AST.
419 *
420 * - Matcher / expression interface: This low-level interface provides direct
421 * control over how to access the store. It is used by the query
422 * implementation internally and can only be used for read access.
423 */
425 /*
426 * sdb_store_query_t:
427 * A parsed query readily prepared for execution.
428 */
429 struct sdb_store_query;
430 typedef struct sdb_store_query sdb_store_query_t;
432 /*
433 * sdb_store_query_prepare:
434 * Prepare the query described by 'ast' for execution in a store.
435 *
436 * Returns:
437 * - a store query on success
438 * - NULL else
439 */
440 sdb_store_query_t *
441 sdb_store_query_prepare(sdb_ast_node_t *ast);
443 /*
444 * sdb_store_query_prepare_matcher:
445 * Prepare the logical expression described by 'ast' for execution as a store
446 * matcher.
447 *
448 * Returns:
449 * - a matcher on success
450 * - NULL else
451 */
452 sdb_store_matcher_t *
453 sdb_store_query_prepare_matcher(sdb_ast_node_t *ast);
455 /*
456 * sdb_store_query_execute:
457 * Execute a previously prepared query in the specified store. The query
458 * result will be written to 'buf' and any errors to 'errbuf'.
459 *
460 * Returns:
461 * - the result type (to be used by the server reply)
462 * - a negative value on error
463 */
464 int
465 sdb_store_query_execute(sdb_store_t *store, sdb_store_query_t *m,
466 sdb_store_writer_t *w, sdb_object_t *wd, sdb_strbuf_t *errbuf);
468 /*
469 * sdb_store_expr_create:
470 * Creates an arithmetic expression implementing the specified operator on the
471 * specified left and right operand.
472 *
473 * Returns:
474 * - an expression object on success
475 * - NULL else
476 */
477 sdb_store_expr_t *
478 sdb_store_expr_create(int op, sdb_store_expr_t *left, sdb_store_expr_t *right);
480 /*
481 * sdb_store_expr_typed:
482 * Creates an expression which evaluates in the context of an object's sibling
483 * as specified by the given type.
484 *
485 * Returns:
486 * - an expression object on success
487 * - NULL else
488 */
489 sdb_store_expr_t *
490 sdb_store_expr_typed(int typ, sdb_store_expr_t *expr);
492 /*
493 * sdb_store_expr_fieldvalue:
494 * Creates an expression which evaluates to the value of the specified
495 * queryable field of a stored object.
496 *
497 * Returns:
498 * - an expression object on success
499 * - NULL else
500 */
501 sdb_store_expr_t *
502 sdb_store_expr_fieldvalue(int field);
504 /*
505 * sdb_store_expr_attrvalue:
506 * Creates an expression which evaluates to the value of the specified
507 * attribute of a stored object. Evaluates to a NULL value if the attribute
508 * does not exist.
509 *
510 * Returns:
511 * - an expression object on success
512 * - NULL else
513 */
514 sdb_store_expr_t *
515 sdb_store_expr_attrvalue(const char *name);
517 /*
518 * sdb_store_expr_constvalue:
519 * Creates an expression which evaluates to the specified constant value.
520 *
521 * Returns:
522 * - an expression object on success
523 * - NULL else
524 */
525 sdb_store_expr_t *
526 sdb_store_expr_constvalue(const sdb_data_t *value);
528 /*
529 * sdb_store_expr_eval:
530 * Evaluate an expression for the specified stored object and stores the
531 * result in 'res'. The result's value will be allocated dynamically if
532 * necessary and, thus, should be free'd by the caller (e.g. using
533 * sdb_data_free_datum). The object may be NULL, in which case the expression
534 * needs to evaluate to a constant value. If specified, only objects matching
535 * the filter will be used during the evaluation.
536 *
537 * Returns:
538 * - 0 on success
539 * - a negative value else
540 */
541 int
542 sdb_store_expr_eval(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
543 sdb_data_t *res, sdb_store_matcher_t *filter);
545 /*
546 * sdb_store_expr_iter:
547 * Iterate over the elements of an iterable expression. sdb_store_expr_iter
548 * returns NULL if the expression is not iterable (for the specified object).
549 *
550 * sdb_store_expr_iter_get_next returns NULL if there is no next element.
551 */
552 sdb_store_expr_iter_t *
553 sdb_store_expr_iter(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
554 sdb_store_matcher_t *filter);
555 void
556 sdb_store_expr_iter_destroy(sdb_store_expr_iter_t *iter);
558 bool
559 sdb_store_expr_iter_has_next(sdb_store_expr_iter_t *iter);
560 sdb_data_t
561 sdb_store_expr_iter_get_next(sdb_store_expr_iter_t *iter);
563 /*
564 * sdb_store_dis_matcher:
565 * Creates a matcher matching the disjunction (logical OR) of two matchers.
566 */
567 sdb_store_matcher_t *
568 sdb_store_dis_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
570 /*
571 * sdb_store_con_matcher:
572 * Creates a matcher matching the conjunction (logical AND) of two matchers.
573 */
574 sdb_store_matcher_t *
575 sdb_store_con_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
577 /*
578 * sdb_store_inv_matcher::
579 * Creates a matcher matching the inverse (logical NOT) of a matcher.
580 */
581 sdb_store_matcher_t *
582 sdb_store_inv_matcher(sdb_store_matcher_t *m);
584 /*
585 * sdb_store_any_matcher:
586 * Creates a matcher iterating over values of the first expression (which has
587 * to be iterable). It matches if *any* of those elements match 'm'. 'm' has
588 * to be an ary operation with the left operand unset.
589 */
590 sdb_store_matcher_t *
591 sdb_store_any_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
593 /*
594 * sdb_store_all_matcher:
595 * Creates a matcher iterating over values of the first expression (which has
596 * to be iterable). It matches if *all* of those elements match 'm'. 'm' has
597 * to be an ary operation with the left operand unset.
598 */
599 sdb_store_matcher_t *
600 sdb_store_all_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
602 /*
603 * sdb_store_in_matcher:
604 * Creates a matcher which matches if the right value evaluates to an array
605 * value and the left value is included in that array. See sdb_data_inarray
606 * for more details.
607 */
608 sdb_store_matcher_t *
609 sdb_store_in_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
611 /*
612 * sdb_store_lt_matcher, sdb_store_le_matcher, sdb_store_eq_matcher,
613 * sdb_store_ge_matcher, sdb_store_gt_matcher:
614 * Create conditional matchers comparing the values of two expressions. The
615 * matcher matches if the left expression compres less than, less or equal
616 * than, equal to, not equal to, greater or equal than, or greater than the
617 * right expression.
618 */
619 sdb_store_matcher_t *
620 sdb_store_lt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
621 sdb_store_matcher_t *
622 sdb_store_le_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
623 sdb_store_matcher_t *
624 sdb_store_eq_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
625 sdb_store_matcher_t *
626 sdb_store_ne_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
627 sdb_store_matcher_t *
628 sdb_store_ge_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
629 sdb_store_matcher_t *
630 sdb_store_gt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
632 /*
633 * sdb_store_regex_matcher:
634 * Creates a matcher which matches the string value the left expression
635 * evaluates to against the regular expression the right expression evaluates
636 * to. The right expression may either be a constant value regular expression
637 * or string or a dynamic value evaluating to a string. In the latter case,
638 * the string is compiled to a regex every time the matcher is executed.
639 */
640 sdb_store_matcher_t *
641 sdb_store_regex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
643 /*
644 * sdb_store_nregex_matcher:
645 * Creates a regex matcher just like sdb_store_regex_matcher except that it
646 * matches in case the regular expression does not match.
647 */
648 sdb_store_matcher_t *
649 sdb_store_nregex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
651 /*
652 * sdb_store_isnull_matcher:
653 * Creates a matcher matching NULL values.
654 */
655 sdb_store_matcher_t *
656 sdb_store_isnull_matcher(sdb_store_expr_t *expr);
658 /*
659 * sdb_store_istrue_matcher, sdb_store_isfalse_matcher:
660 * Creates a matcher matching boolean values.
661 */
662 sdb_store_matcher_t *
663 sdb_store_istrue_matcher(sdb_store_expr_t *expr);
664 sdb_store_matcher_t *
665 sdb_store_isfalse_matcher(sdb_store_expr_t *expr);
667 /*
668 * sdb_store_matcher_matches:
669 * Check whether the specified matcher matches the specified store object. If
670 * specified, the filter will be used to preselect objects for further
671 * evaluation. It is applied to any object that's used during the evaluation
672 * of the matcher. Only those objects matching the filter will be considered.
673 *
674 * Note that the filter is applied to all object types (hosts, service,
675 * metric, attribute). Thus, any object-specific matchers are mostly unsuited
676 * for this purpose and, if used, may result in unexpected behavior.
677 *
678 * Returns:
679 * - 1 if the object matches
680 * - 0 else
681 */
682 int
683 sdb_store_matcher_matches(sdb_store_matcher_t *m, sdb_store_obj_t *obj,
684 sdb_store_matcher_t *filter);
686 /*
687 * sdb_store_matcher_op_cb:
688 * Callback constructing a matcher operator.
689 */
690 typedef sdb_store_matcher_t *(*sdb_store_matcher_op_cb)
691 (sdb_store_expr_t *, sdb_store_expr_t *);
693 /*
694 * sdb_store_lookup_cb:
695 * Lookup callback. It is called for each matching object when looking up data
696 * in the store passing on the lookup filter and the specified user-data. The
697 * lookup aborts early if the callback returns non-zero.
698 */
699 typedef int (*sdb_store_lookup_cb)(sdb_store_obj_t *obj,
700 sdb_store_matcher_t *filter, void *user_data);
702 /*
703 * sdb_store_scan:
704 * Look up objects of the specified type in the specified store. The specified
705 * callback function is called for each object in the store matching 'm'. The
706 * function performs a full scan of all stored objects. If specified, the
707 * filter will be used to preselect objects for further evaluation. See the
708 * description of 'sdb_store_matcher_matches' for details.
709 *
710 * Returns:
711 * - 0 on success
712 * - a negative value else
713 */
714 int
715 sdb_store_scan(sdb_store_t *store, int type,
716 sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
717 sdb_store_lookup_cb cb, void *user_data);
719 /*
720 * Flags for JSON formatting.
721 */
722 enum {
723 SDB_WANT_ARRAY = 1 << 0,
724 };
726 /*
727 * sdb_store_json_formatter:
728 * Create a JSON formatter for the specified object types writing to the
729 * specified buffer.
730 */
731 sdb_store_json_formatter_t *
732 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags);
734 /*
735 * sdb_store_emit:
736 * Serialize a single object to JSON adding it to the string buffer associated
737 * with the formatter object. The serialized object will not include
738 * attributes or any child objects. Instead, call the function again for each
739 * of those objects. All attributes have to be emitted before any other
740 * children types. Use sdb_store_emit_full() to emit a full (filtered) object.
741 *
742 * Note that the output might not be valid JSON before calling
743 * sdb_store_json_finish().
744 *
745 * Returns:
746 * - 0 on success
747 * - a negative value else
748 */
749 int
750 sdb_store_emit(sdb_store_obj_t *obj, sdb_store_writer_t *w, sdb_object_t *wd);
752 /*
753 * sdb_store_emit_full:
754 * Serialize a single object including it's attributes and all children to
755 * JSON, adding it to the string buffer associated with the formatter object.
756 * The filter, if specified, is applied to each attribute and child object.
757 * Only matching objects will be included in the output.
758 *
759 * Note that the output might not be valid JSON before calling
760 * sdb_store_json_finish().
761 *
762 * Returns:
763 * - 0 on success
764 * - a negative value else
765 */
766 int
767 sdb_store_emit_full(sdb_store_obj_t *obj, sdb_store_matcher_t *filter,
768 sdb_store_writer_t *w, sdb_object_t *wd);
770 /*
771 * sdb_store_json_finish:
772 * Finish the JSON output. This function has to be called once after emiting
773 * all objects.
774 */
775 int
776 sdb_store_json_finish(sdb_store_json_formatter_t *f);
778 /*
779 * sdb_store_json_writer:
780 * A store writer implementation that generates JSON output. It expects a
781 * store JSON formatter as its user-data argument.
782 */
783 extern sdb_store_writer_t sdb_store_json_writer;
785 #ifdef __cplusplus
786 } /* extern "C" */
787 #endif
789 #endif /* ! SDB_CORE_STORE_H */
791 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */