Struct ManifestContext 

pub(crate) struct ManifestContext {
    pub(crate) manifest_manager: RwLock<RegionManifestManager>,
    state: AtomicCell<RegionRoleState>,
    staging_partition_info: Mutex<Option<StagingPartitionInfo>>,
}

Context to update the region manifest.

Fields

manifest_manager: RwLock<RegionManifestManager>

Manager to maintain manifest for this region.

state: AtomicCell<RegionRoleState>

The state of the region. The region checks the state before updating manifest.

staging_partition_info: Mutex<Option<StagingPartitionInfo>>

Partition info of the region in staging mode.

During the staging mode, the region metadata in VersionControlRef is not updated, so we need to store the partition info separately.

Implementations

impl ManifestContext

pub(crate) fn new( manager: RegionManifestManager, state: RegionRoleState, ) -> Self

pub(crate) fn staging_partition_info(&self) -> Option<StagingPartitionInfo>

pub(crate) fn set_staging_partition_info( &self, staging_partition_info: StagingPartitionInfo, )

fn clear_staging_partition_info(&self)

pub(crate) fn exit_staging( &self, region_id: RegionId, next_state: RegionRoleState, ) -> Result<()>

pub(crate) async fn manifest_version(&self) -> ManifestVersion

pub(crate) async fn has_update(&self) -> Result<bool>

pub(crate) fn current_state(&self) -> RegionRoleState

Returns the current region role state.

pub(crate) async fn install_manifest_to( &self, version: ManifestVersion, ) -> Result<Arc<RegionManifest>>

Installs the manifest changes from the current version to the target version (inclusive).

Returns installed RegionManifest. Note: This function is not guaranteed to install the target version strictly. The installed version may be greater than the target version.

pub(crate) async fn update_manifest( &self, expect_state: RegionLeaderState, action_list: RegionMetaActionList, is_staging: bool, ) -> Result<ManifestVersion>

Updates the manifest if current state is expect_state.

pub(crate) fn set_role(&self, next_role: RegionRole, region_id: RegionId)

Sets the [RegionRole].

                 +---------------------+
                 |   Staging Leader    |
                 +----------+----------+
                            |
                            v
    +----------+     +------+-------+     +-------------+
    | Follower | <-> |    Leader    | <-> | Downgrading |
    +-----+----+     +------+-------+     +------+------+
          ^                 ^                    |
          +-----------------+--------------------+

State Transitions

From Follower:

• Follower -> Leader

From Leader:

• Leader -> Follower
• Leader -> Downgrading Leader

From Staging Leader:

• Staging Leader -> Leader
• Staging Leader -> Follower
• Staging Leader -> Downgrading Leader

From Downgrading Leader:

• Downgrading Leader -> Leader
• Downgrading Leader -> Follower

pub(crate) async fn manifest(&self) -> Arc<RegionManifest>

Returns the normal manifest of the region.

pub(crate) async fn staging_manifest(&self) -> Option<Arc<RegionManifest>>

Returns the staging manifest of the region.

Trait Implementations

impl Debug for ManifestContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.