Add autobackup functionality to CLI

Adds autobackup (integrated, managed VM backups with automatic remote
filesystem mounting, included backup expiry/removal and automatic
full/incremental selection, independent from the manual "pvc vm backup"
commands) to the CLI client.

This is a bit of a large command to handle only inside the CLI client,
but this was chosen as it's the only real place for it aside from an
external script.

There are several major restrictions on this command, mainly that it
must be run from the primary coordinator using the "local" connection,
and that it must be run as "root".

The command is designed to run in a cron/systemd timer installed by
pvc-ansible when the appropriate group_vars are enabled, and otherwise
not touched.

client-cli/pvc/cli/cli.py

@@ -51,7 +51,9 @@ import click
 ###############################################################################
 
 
-CONTEXT_SETTINGS = dict(help_option_names=["-h", "--help"], max_content_width=120)
+CONTEXT_SETTINGS = dict(
+    help_option_names=["-h", "--help"], max_content_width=MAX_CONTENT_WIDTH
+)
 IS_COMPLETION = True if environ.get("_PVC_COMPLETE", "") == "complete" else False
 
 CLI_CONFIG = dict()
@@ -1734,6 +1736,64 @@ def cli_vm_backup_remove(domain, backup_datestring, backup_path):
     finish(retcode, retmsg)
 
 
+###############################################################################
+# > pvc vm autobackup
+###############################################################################
+@click.command(
+    name="autobackup", short_help="Perform automatic virtual machine backups."
+)
+@connection_req
+@click.option(
+    "-f",
+    "--configuration",
+    "autobackup_cfgfile",
+    envvar="PVC_AUTOBACKUP_CFGFILE",
+    default=DEFAULT_AUTOBACKUP_FILENAME,
+    show_default=True,
+    help="Override default config file location.",
+)
+@click.option(
+    "--force-full",
+    "force_full_flag",
+    default=False,
+    is_flag=True,
+    help="Force all backups to be full backups this run.",
+)
+def cli_vm_autobackup(autobackup_cfgfile, force_full_flag):
+    """
+    Perform automated backups of VMs, with integrated cleanup and full/incremental scheduling.
+
+    This command enables automatic backup of PVC VMs at the block level, leveraging the various "pvc vm backup"
+    functions with an internal rentention and cleanup system as well as determination of full vs. incremental
+    backups at different intervals. VMs are selected based on configured VM tags. The destination storage
+    may either be local, or provided by a remote filesystem which is automatically mounted and unmounted during
+    the backup run.
+
+    NOTE: This command performs its tasks in a local context. It MUST be run from the cluster's active primary
+    coordinator using the "local" connection only; if either is not correct, the command will error.
+
+    NOTE: This command should be run as the same user as the API daemon, usually "root" with "sudo -E" or in
+    a cronjob as "root", to ensure permissions are correct on the backup files. Failure to do so will still take
+    the backup, but the state update write will likely fail and the backup will become untracked. The command
+    will prompt for confirmation if it is found not to be running as "root" and this cannot be bypassed.
+
+    This command should be run from cron or a timer at a regular interval (e.g. daily, hourly, etc.) which defines
+    how often backups are taken. Backup format (full/incremental) and retention is based only on the number of
+    recorded backups, not on the time interval between them. Backups taken manually outside of the "autobackup"
+    command are not counted towards the format or retention of autobackups.
+
+    The PVC_AUTOBACKUP_CFGFILE envvar or "-f"/"--configuration" option can be used to override the default
+    configuration file path if required by a particular run. For full details of the possible options, please
+    see the example configuration file at "/usr/share/pvc/autobackup.sample.yaml".
+
+    The "--force-full" option can be used to force all configured VMs to perform a "full" level backup this run,
+    which can help synchronize the backups of existing VMs with new ones.
+    """
+
+    # All work here is done in the helper function for portability; we don't even use "finish"
+    vm_autobackup(CLI_CONFIG, autobackup_cfgfile, force_full_flag)
+
+
 ###############################################################################
 # > pvc vm tag
 ###############################################################################
@@ -5807,6 +5867,7 @@ cli_vm_backup.add_command(cli_vm_backup_create)
 cli_vm_backup.add_command(cli_vm_backup_restore)
 cli_vm_backup.add_command(cli_vm_backup_remove)
 cli_vm.add_command(cli_vm_backup)
+cli_vm.add_command(cli_vm_autobackup)
 cli_vm_tag.add_command(cli_vm_tag_get)
 cli_vm_tag.add_command(cli_vm_tag_add)
 cli_vm_tag.add_command(cli_vm_tag_remove)