| Overview |  |
Behaviours: ra_machine.
Khepri private low-level API.
This module exposes the private "low-level" API to the Khepri database and
state machine. Main functions correspond to Ra commands implemented by the
state machine. All functions in khepri are built on top of this
module.
keep_while_conds_map() = #{khepri_path:native_path() => khepri_condition:native_keep_while()}
Per-node keep_while conditions.
keep_while_conds_revidx() = #{khepri_path:native_path() => #{khepri_path:native_path() => ok}}
Internal reverse index of the keep_while conditions. If node A depends on a condition on node B, then this reverse index will have a "node B => node A" entry.
machine_config() = #config{store_id = khepri:store_id(), member = ra:server_id(), snapshot_interval = non_neg_integer()}
Configuration record, holding read-only or rarely changing fields.
stat() = #{payload_version := khepri:payload_version(), child_list_version := khepri:child_list_version()}
Stats attached to each node in the tree structure.
state() = #khepri_machine{config = khepri_machine:machine_config(), root = khepri_machine:tree_node(), keep_while_conds = khepri_machine:keep_while_conds_map(), keep_while_conds_revidx = khepri_machine:keep_while_conds_revidx(), triggers = #{khepri:trigger_id() => #{sproc := khepri_path:native_path(), event_filter := khepri_evf:event_filter()}}, emitted_triggers = [khepri_machine:triggered()], metrics = #{applied_command_count => non_neg_integer()}}
State of this Ra state machine.
tree_node() = #node{stat = khepri_machine:stat(), payload = khepri_payload:payload(), child_nodes = #{khepri_path:component() := #node{stat = khepri_machine:stat(), payload = khepri_payload:payload(), child_nodes = #{khepri_path:component() := #node{}}}}}
A node in the tree structure.
triggered() = #triggered{id = khepri:trigger_id(), event_filter = khepri_evf:event_filter(), sproc = khepri_fun:standalone_fun(), props = map()}
| get/3 | Returns all tree nodes matching the path pattern. |
| count/3 | Counts all tree nodes matching the path pattern. |
| delete/3 | Deletes all tree nodes matching the path pattern. |
| transaction/4 | Runs a transaction and returns the result. |
| run_sproc/4 | Executes a stored procedure. |
| register_trigger/5 | Registers a trigger. |
get(StoreId, PathPattern, Options) -> Result
StoreId = khepri:store_id()PathPattern = khepri_path:pattern()Options = khepri:query_options()Result = khepri:result()StoreId: the name of the Ra cluster.
PathPattern: the path (or path pattern) to the nodes to get.
Options: query options such as favor.
returns: an {ok, Result} tuple with a map with zero, one or more entries,
or an {error, Reason} tuple.
Returns all tree nodes matching the path pattern.
count(StoreId, PathPattern, Options) -> Result
StoreId = khepri:store_id()PathPattern = khepri_path:pattern()Options = khepri:query_options()Result = khepri:ok(integer()) | khepri:error()StoreId: the name of the Ra cluster.
PathPattern: the path (or path pattern) to the nodes to count.
Options: query options such as favor.
returns: an {ok, Count} tuple with the number of matching tree nodes, or
an {error, Reason} tuple.
Counts all tree nodes matching the path pattern.
delete(StoreId, PathPattern, Options) -> Result
StoreId = khepri:store_id()PathPattern = khepri_path:pattern()Options = khepri:command_options()Result = khepri:result() | NoRetIfAsyncNoRetIfAsync = okStoreId: the name of the Ra cluster.
PathPattern: the path (or path pattern) to the nodes to delete.
Options: command options such as the command type.
returns: in the case of a synchronous delete, an {ok, Result} tuple with
a map with zero, one or more entries, or an {error, Reason} tuple; in the
case of an asynchronous put, always ok (the actual return value may be
sent by a message if a correlation ID was specified).
Deletes all tree nodes matching the path pattern.
transaction(StoreId, Fun, ReadWrite, Options) -> Ret
StoreId = khepri:store_id()Fun = khepri_tx:tx_fun()ReadWrite = ro | rw | autoOptions = khepri:command_options() | khepri:query_options()Ret = Atomic | Aborted | NoRetIfAsyncAtomic = {atomic, khepri_tx:tx_fun_result()}Aborted = khepri_tx:tx_abort()NoRetIfAsync = okStoreId: the name of the Ra cluster.
Fun: an arbitrary anonymous function.
ReadWrite: the read/write or read-only nature of the transaction.
Options: command options such as the command type.
returns: in the case of a synchronous transaction, {atomic, Result} where
Result is the return value of Fun, or {aborted, Reason} if the
anonymous function was aborted; in the case of an asynchronous transaction,
always ok (the actual return value may be sent by a message if a
correlation ID was specified).
Runs a transaction and returns the result.
run_sproc(StoreId, PathPattern, Args, Options) -> Ret
StoreId = khepri:store_id()PathPattern = khepri_path:pattern()Args = [any()]Options = khepri:query_options()Ret = any()StoreId: the name of the Ra cluster.
PathPattern: the path to the stored procedure.
Args: the list of args to pass to the stored procedure; its length
must be equal to the stored procedure arity.
Options: options to tune the tree traversal or the returned structure
content.
returns: the result of the stored procedure execution, or throws an exception if the node does not exist, does not hold a stored procedure or if there was an error.
Executes a stored procedure.
The stored procedure is executed in the context of the caller ofrun_sproc/3.
register_trigger(StoreId, TriggerId, EventFilter, StoredProcPath, Options) -> Ret
StoreId = khepri:store_id()TriggerId = khepri:trigger_id()EventFilter = khepri_evf:event_filter() | khepri_path:pattern()StoredProcPath = khepri_path:path()Options = khepri:command_options()Ret = ok | khepri:error()StoreId: the name of the Ra cluster.
TriggerId: the name of the trigger.
EventFilter: the event filter used to associate an event with a
stored procedure.
StoredProcPath: the path to the stored procedure to execute when the
corresponding event occurs.
returns: ok if the trigger was registered, an {error, Reason} tuple
otherwise.
Registers a trigger.
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