upgrade.py 文件源码

def check_for_upgrade() -> Result:
    """
    If the config has changed this will initiated a rolling upgrade

    :return:
    """
    config = hookenv.config()
    if not config.changed("source"):
        # No upgrade requested
        log("No upgrade requested")
        return Ok(())

    log("Getting current_version")
    current_version = get_glusterfs_version()

    log("Adding new source line")
    source = config["source"]
    if not source:
        # No upgrade requested
        log("Source not set.  Cannot continue with upgrade")
        return Ok(())
    add_source(source)
    log("Calling apt update")
    apt_update()

    log("Getting proposed_version")
    apt_pkg.init_system()
    proposed_version = get_candidate_package_version("glusterfs-server")
    if proposed_version.is_err():
        return Err(proposed_version.value)
    version_compare = apt_pkg.version_compare(a=proposed_version.value,
                                              b=current_version)

    # Using semantic versioning if the new version is greater
    # than we allow the upgrade
    if version_compare > 0:
        log("current_version: {}".format(current_version))
        log("new_version: {}".format(proposed_version.value))
        log("{} to {} is a valid upgrade path.  Proceeding.".format(
            current_version, proposed_version.value))
        return roll_cluster(proposed_version.value)
    else:
        # Log a helpful error message
        log("Invalid upgrade path from {} to {}. The new version needs to be \
                            greater than the old version".format(
            current_version, proposed_version.value), ERROR)
        return Ok(())