postgresql/src/include/backup/basebackup_target.h

67 lines
2.8 KiB
C

/*-------------------------------------------------------------------------
*
* basebackup_target.h
* Extensibility framework for adding base backup targets.
*
* Portions Copyright (c) 2010-2024, PostgreSQL Global Development Group
*
* src/include/backup/basebackup_target.h
*
*-------------------------------------------------------------------------
*/
#ifndef BASEBACKUP_TARGET_H
#define BASEBACKUP_TARGET_H
#include "backup/basebackup_sink.h"
struct BaseBackupTargetHandle;
typedef struct BaseBackupTargetHandle BaseBackupTargetHandle;
/*
* Extensions can call this function to create new backup targets.
*
* 'name' is the name of the new target.
*
* 'check_detail' is a function that accepts a target name and target detail
* and either throws an error (if the target detail is not valid or some other
* problem, such as a permissions issue, is detected) or returns a pointer to
* the data that will be needed to create a bbsink implementing that target.
* The second argument will be NULL if the TARGET_DETAIL option to the
* BASE_BACKUP command was not specified.
*
* 'get_sink' is a function that creates the bbsink. The first argument
* is the successor sink; the sink created by this function should always
* forward to this sink. The second argument is the pointer returned by a
* previous call to the 'check_detail' function.
*
* In practice, a user will type something like "pg_basebackup --target foo:bar
* -Xfetch". That will cause the server to look for a backup target named
* "foo". If one is found, the check_detail callback will be invoked for the
* string "bar", and whatever that callback returns will be passed as the
* second argument to the get_sink callback.
*/
extern void BaseBackupAddTarget(char *name,
void *(*check_detail) (char *, char *),
bbsink *(*get_sink) (bbsink *, void *));
/*
* These functions are used by the core code to access base backup targets
* added via BaseBackupAddTarget(). The core code will pass the TARGET and
* TARGET_DETAIL strings obtained from the user to BaseBackupGetTargetHandle,
* which will either throw an error (if the TARGET is not recognized or the
* check_detail hook for that TARGET doesn't like the TARGET_DETAIL) or
* return a BaseBackupTargetHandle object that can later be passed to
* BaseBackupGetSink.
*
* BaseBackupGetSink constructs a bbsink implementing the desired target
* using the BaseBackupTargetHandle and the successor bbsink. It does this
* by arranging to call the get_sink() callback provided by the extension
* that implements the base backup target.
*/
extern BaseBackupTargetHandle *BaseBackupGetTargetHandle(char *target,
char *target_detail);
extern bbsink *BaseBackupGetSink(BaseBackupTargetHandle *handle,
bbsink *next_sink);
#endif