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index a8208bf7d9a0a849e16c6316616af092e4b1e9b5..678af6ff9e706f85a33080ac5a377142e17b0e23 100644 (file)
--- a/src/include/core/store.h
+++ b/src/include/core/store.h
#include "core/data.h"
#include "core/time.h"
#include "core/timeseries.h"
+#include "parser/ast.h"
#include "utils/strbuf.h"
#include <stdbool.h>
SDB_FIELD_AGE, /* type: datetime */
SDB_FIELD_INTERVAL, /* type: datetime */
SDB_FIELD_BACKEND, /* type: array of strings */
+ SDB_FIELD_VALUE, /* attributes only; type: type of the value */
+ SDB_FIELD_TIMESERIES, /* metrics only; type: boolean */
};
#define SDB_STORE_TYPE_TO_NAME(t) \
(((t) == SDB_HOST) ? "host" \
: ((f) == SDB_FIELD_LAST_UPDATE) ? "last-update" \
: ((f) == SDB_FIELD_AGE) ? "age" \
: ((f) == SDB_FIELD_INTERVAL) ? "interval" \
- : ((f) == SDB_FIELD_BACKEND) ? "backend" : "unknown")
+ : ((f) == SDB_FIELD_BACKEND) ? "backend" \
+ : ((f) == SDB_FIELD_VALUE) ? "value" \
+ : ((f) == SDB_FIELD_TIMESERIES) ? "timeseries" \
+ : "unknown")
#define SDB_FIELD_TYPE(f) \
(((f) == SDB_FIELD_NAME) ? SDB_TYPE_STRING \
: ((f) == SDB_FIELD_AGE) ? SDB_TYPE_DATETIME \
: ((f) == SDB_FIELD_INTERVAL) ? SDB_TYPE_DATETIME \
: ((f) == SDB_FIELD_BACKEND) ? (SDB_TYPE_ARRAY | SDB_TYPE_STRING) \
+ : ((f) == SDB_FIELD_VALUE) ? -1 /* unknown */ \
+ : ((f) == SDB_FIELD_TIMESERIES) ? SDB_TYPE_BOOLEAN \
: -1)
/*
- * sdb_store_obj_t represents the super-class of any object stored in the
- * database. It inherits from sdb_object_t and may safely be cast to a generic
- * object to access its name.
+ * sdb_store_t represents an in-memory store. It inherits from sdb_object_t
+ * and may safely be case to a generic object.
+ */
+struct sdb_store;
+typedef struct sdb_store sdb_store_t;
+#define SDB_STORE(obj) ((sdb_store_t *)(obj))
+
+/*
+ * sdb_store_obj_t represents the super-class of any stored object. It
+ * inherits from sdb_object_t and may safely be cast to a generic object to
+ * access its name.
*/
struct sdb_store_obj;
typedef struct sdb_store_obj sdb_store_obj_t;
+/*
+ * A metric store describes how to access a metric's data.
+ */
+typedef struct {
+ const char *type;
+ const char *id;
+} sdb_metric_store_t;
+
/*
* Expressions represent arithmetic expressions based on stored objects and
* their various attributes.
typedef struct sdb_store_expr sdb_store_expr_t;
#define SDB_STORE_EXPR(obj) ((sdb_store_expr_t *)(obj))
+/*
+ * An expression iterator iterates over the values of an iterable expression.
+ */
+struct sdb_store_expr_iter;
+typedef struct sdb_store_expr_iter sdb_store_expr_iter_t;
+
/*
* Store matchers may be used to lookup hosts from the store based on their
* various attributes. Service and attribute matchers are applied to a host's
/*
* A JSON formatter converts stored objects into the JSON format.
* See http://www.ietf.org/rfc/rfc4627.txt
+ *
+ * A JSON formatter object inherits from sdb_object_t and, thus, may safely be
+ * cast to a generic object.
*/
struct sdb_store_json_formatter;
typedef struct sdb_store_json_formatter sdb_store_json_formatter_t;
/*
- * sdb_store_clear:
- * Clear the entire store and remove all stored objects.
- */
-void
-sdb_store_clear(void);
-
-/*
- * sdb_store_host:
- * Add/update a host in the store. If the host, identified by its
- * canonicalized name, already exists, it will be updated according to the
- * specified name and timestamp. Else, a new entry will be created in the
- * store. Any memory required for storing the entry will be allocated an
- * managed by the store itself.
+ * A store writer describes the interface for plugins implementing a store.
*
- * Returns:
+ * Any of the call-back functions shall return:
* - 0 on success
* - a positive value if the new entry is older than the currently stored
* entry (in this case, no update will happen)
* - a negative value on error
*/
-int
-sdb_store_host(const char *name, sdb_time_t last_update);
+typedef struct {
+ /*
+ * store_host:
+ * Add/update a host in the store. If the host, identified by its
+ * canonicalized name, already exists, it will be updated according to the
+ * specified name and timestamp. Else, a new entry will be created in the
+ * store.
+ */
+ int (*store_host)(const char *name, sdb_time_t last_update,
+ sdb_object_t *user_data);
-/*
- * sdb_store_has_host:
- * sdb_store_get_host:
- * Query the store for a host by its (canonicalized) name.
- *
- * sdb_store_get_host increments the ref count of the host object. The caller
- * needs to deref it when no longer using it.
- */
-bool
-sdb_store_has_host(const char *name);
+ /*
+ * store_service:
+ * Add/update a service in the store. If the service, identified by its
+ * name, already exists for the specified host, it will be updated
+ * according to the specified name and timestamp. If the referenced host
+ * does not exist, an error will be reported. Else, a new entry will be
+ * created in the store.
+ */
+ int (*store_service)(const char *hostname, const char *name,
+ sdb_time_t last_update, sdb_object_t *user_data);
-sdb_store_obj_t *
-sdb_store_get_host(const char *name);
+ /*
+ * store_metric:
+ * Add/update a metric in the store. If the metric, identified by its
+ * name, already exists for the specified host, it will be updated
+ * according to the specified attributes. If the referenced host does not
+ * exist, an error will be reported. Else, a new entry will be created in
+ * the store.
+ */
+ int (*store_metric)(const char *hostname, const char *name,
+ sdb_metric_store_t *store, sdb_time_t last_update,
+ sdb_object_t *user_data);
+
+ /*
+ * store_attribute:
+ * Add/update a host's attribute in the store. If the attribute,
+ * identified by its key, already exists for the specified host, it will
+ * be updated to the specified values. If the referenced host does not
+ * exist, an error will be reported. Else, a new entry will be created in
+ * the store.
+ */
+ int (*store_attribute)(const char *hostname,
+ const char *key, const sdb_data_t *value, sdb_time_t last_update,
+ sdb_object_t *user_data);
+
+ /*
+ * store_service_attr:
+ * Add/update a service's attribute in the store. If the attribute,
+ * identified by its key, already exists for the specified service, it
+ * will be updated to the specified value. If the references service (for
+ * the specified host) does not exist, an error will be reported.
+ */
+ int (*store_service_attr)(const char *hostname, const char *service,
+ const char *key, const sdb_data_t *value, sdb_time_t last_update,
+ sdb_object_t *user_data);
+
+ /*
+ * store_metric_attr:
+ * Add/update a metric's attribute in the store. If the attribute,
+ * identified by its key, already exists for the specified metric, it will
+ * be updated to the specified value. If the references metric (for the
+ * specified host) does not exist, an error will be reported.
+ */
+ int (*store_metric_attr)(const char *hostname, const char *metric,
+ const char *key, const sdb_data_t *value, sdb_time_t last_update,
+ sdb_object_t *user_data);
+} sdb_store_writer_t;
/*
- * sdb_store_attribute:
- * Add/update a host's attribute in the store. If the attribute, identified by
- * its key, already exists for the specified host, it will be updated to the
- * specified values. If the referenced host does not exist, an error will be
- * reported. Else, a new entry will be created in the store. Any memory
- * required for storing the entry will be allocated and managed by the store
- * itself.
- *
- * Returns:
- * - 0 on success
- * - a positive value if the new entry is older than the currently stored
- * entry (in this case, no update will happen)
- * - a negative value on error
+ * sdb_store_writer:
+ * A store writer implementation that provides an in-memory object store. It
+ * expects a store object as its user-data argument.
*/
-int
-sdb_store_attribute(const char *hostname,
- const char *key, const sdb_data_t *value,
- sdb_time_t last_update);
+extern sdb_store_writer_t sdb_store_writer;
/*
- * sdb_store_service:
- * Add/update a service in the store. If the service, identified by its name,
- * already exists for the specified host, it will be updated according to the
- * specified 'service' object. If the referenced host does not exist, an error
- * will be reported. Else, a new entry will be created in the store. Any
- * memory required for storing the entry will be allocated an managed by the
- * store itself.
- *
- * Returns:
- * - 0 on success
- * - a positive value if the new entry is older than the currently stored
- * entry (in this case, no update will happen)
- * - a negative value on error
+ * A store reader describes the interface to query a store implementation.
*/
-int
-sdb_store_service(const char *hostname, const char *name,
- sdb_time_t last_update);
+typedef struct {
+ /*
+ * prepare_query:
+ * Prepare the query described by 'ast' for execution.
+ */
+ sdb_object_t *(*prepare_query)(sdb_ast_node_t *ast,
+ sdb_strbuf_t *errbuf, sdb_object_t *user_data);
+
+ /*
+ * execute_query:
+ * Execute a previously prepared query. The callback may expect that only
+ * queries prepared by its respective prepare callback will be passed to
+ * this function.
+ *
+ * TODO: Instead of letting the executor write directly to a string buffer
+ * (which cannot easily be merged with other results), let it hand
+ * all objects to a store-writer.
+ */
+ int (*execute_query)(sdb_object_t *q,
+ sdb_strbuf_t *buf, sdb_strbuf_t *errbuf,
+ sdb_object_t *user_data);
+} sdb_store_reader_t;
/*
- * sdb_store_service_attr:
- * Add/update a service's attribute in the store. If the attribute, identified
- * by its key, already exists for the specified service, it will be updated to
- * the specified value. If the references service (for the specified host)
- * does not exist, an error will be reported. Any memory required for storing
- * the entry will be allocated and managed by the store itself.
- *
- * Returns:
- * - 0 on success
- * - a positive value if the new entry is older than the currently stored
- * entry (in this case, no update will happen)
- * - a negative value on error
+ * sdb_store_reader:
+ * A store reader implementation that uses an in-memory object store. It
+ * expects a store object as its user-data argument.
*/
-int
-sdb_store_service_attr(const char *hostname, const char *service,
- const char *key, const sdb_data_t *value, sdb_time_t last_update);
+extern sdb_store_reader_t sdb_store_reader;
/*
- * A metric store describes how to access a metric's data.
+ * sdb_store_create:
+ * Allocate a new in-memory store.
*/
-typedef struct {
- const char *type;
- const char *id;
-} sdb_metric_store_t;
+sdb_store_t *
+sdb_store_create(void);
/*
- * sdb_store_metric:
- * Add/update a metric in the store. If the metric, identified by its name,
- * already exists for the specified host, it will be updated according to the
- * specified 'metric' object. If the referenced host does not exist, an error
- * will be reported. Else, a new entry will be created in the store. Any
- * memory required for storing the entry will be allocated an managed by the
- * store itself.
- *
- * If specified, the metric store describes where to access the metric's data.
- *
- * Returns:
- * - 0 on success
- * - a positive value if the new entry is older than the currently stored
- * entry (in this case, no update will happen)
- * - a negative value on error
+ * sdb_store_host, sdb_store_service, sdb_store_metric, sdb_store_attribute,
+ * sdb_store_metric_attr:
+ * Store an object in the specified store. The hostname is expected to be
+ * canonical.
*/
int
-sdb_store_metric(const char *hostname, const char *name,
- sdb_metric_store_t *store, sdb_time_t last_update);
+sdb_store_host(sdb_store_t *store, const char *name, sdb_time_t last_update);
+int
+sdb_store_service(sdb_store_t *store, const char *hostname, const char *name,
+ sdb_time_t last_update);
+int
+sdb_store_metric(sdb_store_t *store, const char *hostname, const char *name,
+ sdb_metric_store_t *metric_store, sdb_time_t last_update);
+int
+sdb_store_attribute(sdb_store_t *store, const char *hostname,
+ const char *key, const sdb_data_t *value, sdb_time_t last_update);
+int
+sdb_store_service_attr(sdb_store_t *store, const char *hostname,
+ const char *service, const char *key, const sdb_data_t *value,
+ sdb_time_t last_update);
+int
+sdb_store_metric_attr(sdb_store_t *store, const char *hostname,
+ const char *metric, const char *key, const sdb_data_t *value,
+ sdb_time_t last_update);
/*
- * sdb_store_metric_attr:
- * Add/update a metric's attribute in the store. If the attribute, identified
- * by its key, already exists for the specified metric, it will be updated to
- * the specified value. If the references metric (for the specified host)
- * does not exist, an error will be reported. Any memory required for storing
- * the entry will be allocated and managed by the store itself.
+ * sdb_store_get_host:
+ * Query the specified store for a host by its (canonicalized) name.
*
- * Returns:
- * - 0 on success
- * - a positive value if the new entry is older than the currently stored
- * entry (in this case, no update will happen)
- * - a negative value on error
+ * The function increments the ref count of the host object. The caller needs
+ * to deref it when no longer using it.
*/
-int
-sdb_store_metric_attr(const char *hostname, const char *metric,
- const char *key, const sdb_data_t *value, sdb_time_t last_update);
+sdb_store_obj_t *
+sdb_store_get_host(sdb_store_t *store, const char *name);
/*
* sdb_store_fetch_timeseries:
* Fetch the time-series described by the specified host's metric and
- * serialize it as JSON into the provided string buffer.
+ * serialize it as JSON into the provided string buffer. The host data is
+ * retrieved from the specified store.
*
* Returns:
* - 0 on success
* - a negative value else
*/
int
-sdb_store_fetch_timeseries(const char *hostname, const char *metric,
+sdb_store_fetch_timeseries(sdb_store_t *store,
+ const char *hostname, const char *metric,
sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf);
/*
* the returned value. If 'res' is NULL, the function will return whether the
* field exists.
*
- * Note: Retrieving the backend this way is not currently supported.
- *
* Returns:
* - 0 on success
* - a negative value else
sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
sdb_store_matcher_t *filter);
+/*
+ * Querying a store:
+ *
+ * - Query interface: A query is a formal description of an interaction with
+ * the store. It can be used, both, for read and write access. The query is
+ * described by its abstract syntax tree (AST). The parser package provides
+ * means to parse a string (SysQL) representation of the query into an AST.
+ *
+ * - Matcher / expression interface: This low-level interface provides direct
+ * control over how to access the store. It is used by the query
+ * implementation internally and can only be used for read access.
+ */
+
+/*
+ * sdb_store_query_t:
+ * A parsed query readily prepared for execution.
+ */
+struct sdb_store_query;
+typedef struct sdb_store_query sdb_store_query_t;
+
+/*
+ * sdb_store_query_prepare:
+ * Prepare the query described by 'ast' for execution in a store.
+ *
+ * Returns:
+ * - a store query on success
+ * - NULL else
+ */
+sdb_store_query_t *
+sdb_store_query_prepare(sdb_ast_node_t *ast);
+
+/*
+ * sdb_store_query_prepare_matcher:
+ * Prepare the logical expression described by 'ast' for execution as a store
+ * matcher.
+ *
+ * Returns:
+ * - a matcher on success
+ * - NULL else
+ */
+sdb_store_matcher_t *
+sdb_store_query_prepare_matcher(sdb_ast_node_t *ast);
+
+/*
+ * sdb_store_query_execute:
+ * Execute a previously prepared query in the specified store. The query
+ * result will be written to 'buf' and any errors to 'errbuf'.
+ *
+ * Returns:
+ * - the result type (to be used by the server reply)
+ * - a negative value on error
+ */
+int
+sdb_store_query_execute(sdb_store_t *store, sdb_store_query_t *m,
+ sdb_strbuf_t *buf, sdb_strbuf_t *errbuf);
+
/*
* sdb_store_expr_create:
* Creates an arithmetic expression implementing the specified operator on the
sdb_store_expr_eval(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
sdb_data_t *res, sdb_store_matcher_t *filter);
+/*
+ * sdb_store_expr_iter:
+ * Iterate over the elements of an iterable expression. sdb_store_expr_iter
+ * returns NULL if the expression is not iterable (for the specified object).
+ *
+ * sdb_store_expr_iter_get_next returns NULL if there is no next element.
+ */
+sdb_store_expr_iter_t *
+sdb_store_expr_iter(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
+ sdb_store_matcher_t *filter);
+void
+sdb_store_expr_iter_destroy(sdb_store_expr_iter_t *iter);
+
+bool
+sdb_store_expr_iter_has_next(sdb_store_expr_iter_t *iter);
+sdb_data_t
+sdb_store_expr_iter_get_next(sdb_store_expr_iter_t *iter);
+
/*
* sdb_store_dis_matcher:
* Creates a matcher matching the disjunction (logical OR) of two matchers.
/*
* sdb_store_any_matcher:
- * Creates a matcher iterating over objects of the specified type. It matches
- * if *any* of those objects match 'm'.
+ * Creates a matcher iterating over values of the first expression (which has
+ * to be iterable). It matches if *any* of those elements match 'm'. 'm' has
+ * to be an ary operation with the left operand unset.
*/
sdb_store_matcher_t *
-sdb_store_any_matcher(int type, sdb_store_matcher_t *m);
+sdb_store_any_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
/*
* sdb_store_all_matcher:
- * Creates a matcher iterating over objects of the specified type. It matches
- * if *all* of those objects match 'm'.
+ * Creates a matcher iterating over values of the first expression (which has
+ * to be iterable). It matches if *all* of those elements match 'm'. 'm' has
+ * to be an ary operation with the left operand unset.
*/
sdb_store_matcher_t *
-sdb_store_all_matcher(int type, sdb_store_matcher_t *m);
+sdb_store_all_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
/*
* sdb_store_in_matcher:
sdb_store_isnull_matcher(sdb_store_expr_t *expr);
/*
- * sdb_store_isnnull_matcher:
- * Creates a matcher matching non-NULL values.
+ * sdb_store_istrue_matcher, sdb_store_isfalse_matcher:
+ * Creates a matcher matching boolean values.
*/
sdb_store_matcher_t *
-sdb_store_isnnull_matcher(sdb_store_expr_t *expr);
+sdb_store_istrue_matcher(sdb_store_expr_t *expr);
+sdb_store_matcher_t *
+sdb_store_isfalse_matcher(sdb_store_expr_t *expr);
/*
* sdb_store_matcher_matches:
typedef sdb_store_matcher_t *(*sdb_store_matcher_op_cb)
(sdb_store_expr_t *, sdb_store_expr_t *);
-/*
- * sdb_store_parse_matcher_op:
- * Parse a matcher operator and return a constructor for the respective
- * matcher.
- *
- * Returns:
- * - matcher operator constructor on success
- * - NULL else
- */
-sdb_store_matcher_op_cb
-sdb_store_parse_matcher_op(const char *op);
-
-/*
- * sdb_store_parse_object_type:
- * Parse the type name of a stored object.
- *
- * Returns:
- * - the object type on success
- * - a negative value else
- */
-int
-sdb_store_parse_object_type(const char *name);
-
-/*
- * sdb_store_parse_object_type_plural:
- * Parse the type name (plural) of a stored object.
- *
- * Returns:
- * - the object type on success
- * - a negative value else
- */
-int
-sdb_store_parse_object_type_plural(const char *name);
-
-/*
- * sdb_store_parse_field_name:
- * Parse the name of a stored object's queryable field.
- *
- * Returns:
- * - the field id on success
- * - a negative value else
- */
-int
-sdb_store_parse_field_name(const char *name);
-
/*
* sdb_store_lookup_cb:
* Lookup callback. It is called for each matching object when looking up data
/*
* sdb_store_scan:
- * Look up objects of the specified type in the store. The specified callback
- * function is called for each object in the store matching 'm'. The function
- * performs a full scan of all objects stored in the database. If specified,
- * the filter will be used to preselect objects for further evaluation. See
- * the description of 'sdb_store_matcher_matches' for details.
+ * Look up objects of the specified type in the specified store. The specified
+ * callback function is called for each object in the store matching 'm'. The
+ * function performs a full scan of all stored objects. If specified, the
+ * filter will be used to preselect objects for further evaluation. See the
+ * description of 'sdb_store_matcher_matches' for details.
*
* Returns:
* - 0 on success
* - a negative value else
*/
int
-sdb_store_scan(int type, sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
+sdb_store_scan(sdb_store_t *store, int type,
+ sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
sdb_store_lookup_cb cb, void *user_data);
/*