Log Message:
py-barman: updated to 2.4

Version 2.4:
-   Add standard and retry hook scripts for backup deletion (pre/post)
-   Add standard and retry hook scripts for recovery (pre/post)
-   Add standard and retry hook scripts for WAL deletion (pre/post)
-   Add --standby-mode option to barman recover to add standby_mode = on
    in pre-generated recovery.conf
-   Add --target-action option to barman recover, allowing users to add
    shutdown, pause or promote to the pre-generated recovery.conf file
-   Improve usability of point-in-time recovery with consistency checks
    (e.g. recovery time is after end time of backup)
-   Minor documentation improvements
-   Drop support for Python 3.3

Relevant bug fixes:
-   Fix remote get_file_content method, preventing
    incremental recovery from happening
-   Unicode issues with command
-   Add --wal-method=none when pg_basebackup >= 10

Minor bug fixes:
-   Stop process manager module from ovewriting lock files content
-   Relax the rules for rsync output parsing
-   Ignore vanished files in streaming directory
-   Case insensitive slot names
-   Make DataTransferFailure.from_command_error() more resilient
-   Rename command() to barman_command()
-   Initialise synchronous standby names list if not set
-   Correct placeholders ordering
-   Force datestyle to iso for replication connections
-   Returns error if delete command does not remove the backup
-   Fix exception when calling is_power_of_two(None)
-   Downgraded sync standby names messages to debug

Version 2.3:
-   Add support to PostgreSQL 10
-   Follow naming changes in PostgreSQL 10:
    -   The switch-xlog command has been renamed to switch-wal.
    -   In commands output, the xlog word has been changed to WAL and
        location has been changed to LSN when appropriate.
-   Add the --network-compression/--no-network-compression options to
    barman recover to enable or disable network compression at run-time
-   Add --target-immediate option to recover command, in order to exit
    recovery when a consistent state is reached (end of the backup,
    available from PostgreSQL 9.4)
-   Show cluster state (master or standby) with barman status command
-   Documentation improvements
-   Bug fixes:
    -   Fix high memory usage with parallel_jobs > 1
    -   Better handling of errors using parallel copy
    -   Make barman diagnose more robust with system exceptions
    -   Let archive-wal ignore files with .tmp extension

Version 2.2:
-   Implement parallel copy for backup/recovery through the
    parallel_jobs global/server option to be overridden by the --jobs or
    -j runtime option for the backup and recover command. Parallel
    backup is available only for the rsync copy method. By default, it
    is set to 1 (for behaviour compatibility with previous versions).
-   Support custom WAL size for PostgreSQL 8.4 and newer. At backup
    time, Barman retrieves from PostgreSQL wal_segment_size and
    wal_block_size values and computes the necessary calculations.
-   Improve check command to ensure that incoming directory is empty
    when archiver=off, and streaming directory is empty when
    streaming_archiver=off
-   Add external_configuration to backup_options so that users can
    instruct Barman to ignore backup of configuration files when they
    are not inside PGDATA (default for Debian/Ubuntu installations). In
    this case, Barman does not display a warning anymore.
-   Add --get-wal and --no-get-wal options to barman recover
-   Add max_incoming_wals_queue global/server option for the check
    command so that a non blocking error is returned in case incoming
    WAL directories for both archiver and the streaming_archiver contain
    more files than the specified value.
-   Documentation improvements
-   File format changes:
    -   The format of backup.info file has changed. For this reason a
        backup taken with Barman 2.2 cannot be read by a previous
        version of Barman. But, backups taken by previous versions can
        be read by Barman 2.2.
-   Minor bug fixes:
    -   Allow replication-status to work against a standby
    -   Close any PostgreSQL connection before starting pg_basebackup
    -   Safely handle paths containing special characters
    -   Archive .partial files after promotion of streaming source
    -   Recursively create directories during recovery
    -   Improve xlog.db locking
    -   Remove tablespace_map file during recover
    -   Reconnect to PostgreSQL if connection drops

Version 2.1:
-   Add --archive and --archive-timeout options to switch-xlog command
-   Preliminary support for PostgreSQL 10
-   Minor additions:
    -   Add last archived WAL info to diagnose output
    -   Add start time and execution time to the output of delete
        command
-   Minor bug fixes:
    -   Return failure for get-wal command on inactive server
    -   Make streaming_archiver_names and streaming_backup_name options
        global
    -   Fix rsync failures due to files truncated during transfer
    -   Correctly handle compressed history files
    -   Avoid de-referencing symlinks in pg_tblspc when preparing
        recovery
    -   Fix comparison of last archiving failure
    -   Avoid failing recovery if postgresql.conf is not writable
    -   Fix output of replication-status command
    -   Exclude files from backups like pg_basebackup
    -   Exclude directories from other Postgres versions while copying
        tablespaces
    -   Make retry hook script options global

Version 2.0 - 27 Sep 2016

-   Support for pg_basebackup and base backups over the PostgreSQL
    streaming replication protocol with backup_method=postgres
    (PostgreSQL 9.1 or higher required)

-   Support for physical replication slots through the slot_name
    configuration option as well as the --create-slot and --drop-slot
    options for the receive-wal command (PostgreSQL 9.4 or higher
    required). When slot_name is specified and streaming_archiver is
    enabled, receive-wal transparently integrates with pg_receivexlog,
    and check makes sure that slots exist and are actively used

-   Support for the new backup API introduced in PostgreSQL 9.6, which
    transparently enables concurrent backups and backups from standby
    servers using the standard rsync method of backup. Concurrent backup
    was only possible for PostgreSQL 9.2 to 9.5 versions through the
    pgespresso extension. The new backup API will make pgespresso
    redundant in the future

-   If properly configured, Barman can function as a synchronous standby
    in terms of WAL streaming. By properly setting the
    streaming_archiver_name in the synchronous_standby_names priority
    list on the master, and enabling replication slot support, the
    receive-wal command can now be part of a PostgreSQL synchronous
    replication cluster, bringing RPO=0 (PostgreSQL 9.5.5 or
    higher required)

-   Introduce barman-wal-restore, a standard and robust script written
    in Python that can be used as restore_command in recovery.conf files
    of any standby server of a cluster. It supports remote parallel
    fetching of WAL files by efficiently invoking get-wal through SSH.
    Currently available as a separate project called barman-cli. The
    barman-cli package is required for remote recovery when get-wal is
    listed in recovery_options

-   Control the maximum execution time of the check command through the
    check_timeout global/server configuration option (30 seconds
    by default)

-   Limit the number of WAL segments that are processed by an
    archive-wal run, through the archiver_batch_size and
    streaming_archiver_batch_size global/server options which control
    archiving of WAL segments coming from, respectively, the standard
    archiver and receive-wal

-   Removed locking of the XLOG database during check operations

-   The show-backup command is now aware of timelines and properly
    displays which timelines can be used as recovery targets for a given
    base backup. Internally, Barman is now capable of parsing .history
    files

-   Improved the logic behind the retry mechanism when copy operations
    experience problems. This involves backup (rsync and postgres) as
    well as remote recovery (rsync)

-   Code refactoring involving remote command and physical copy
    interfaces

-   Bug fixes:
    -   Correctly handle .history files from streaming
    -   Fix replication-status on PostgreSQL 9.1
    -   Fix replication-status when sent and write locations are not
        available
    -   Fix misleading message on pg_receivexlog termination