Struct ReadStateService

pub struct ReadStateService {
    network: Network,
    non_finalized_state_receiver: WatchReceiver<NonFinalizedState>,
    db: ZebraDb,
    block_write_task: Option<Arc<JoinHandle<()>>>,
}

A read-only service for accessing Zebra’s cached blockchain state.

This service provides read-only access to:

• the non-finalized state: the ~100 most recent blocks.
• the finalized state: older blocks that have many confirmations.

Requests to this service are processed in parallel, ignoring any blocks queued by the read-write StateService.

This quick response behavior is better for most state users. It allows other async tasks to make progress while concurrently reading data from disk.

Fields

network: Network

The configured Zcash network.

non_finalized_state_receiver: WatchReceiver<NonFinalizedState>

A watch channel with a cached copy of the NonFinalizedState.

This state is only updated between requests, so it might include some block data that is also on disk.

db: ZebraDb

The shared inner on-disk database for the finalized state.

RocksDB allows reads and writes via a shared reference, but ZebraDb doesn’t expose any write methods or types.

This chain is updated concurrently with requests, so it might include some block data that is also in best_mem.

block_write_task: Option<Arc<JoinHandle<()>>>

A shared handle to a task that writes blocks to the NonFinalizedState or FinalizedState, once the queues have received all their parent blocks.

Used to check for panics when writing blocks.

Implementations

impl ReadStateService

pub(crate) fn new( finalized_state: &FinalizedState, block_write_task: Option<Arc<JoinHandle<()>>>, non_finalized_state_receiver: Receiver<NonFinalizedState>, ) -> Self

Creates a new read-only state service, using the provided finalized state and block write task handle.

Returns the newly created service, and a watch channel for updating the shared recent non-finalized chain.

fn latest_non_finalized_state(&self) -> NonFinalizedState

Gets a clone of the latest non-finalized state from the non_finalized_state_receiver

fn latest_best_chain(&self) -> Option<Arc<Chain>>

Gets a clone of the latest, best non-finalized chain from the non_finalized_state_receiver

pub fn db(&self) -> &ZebraDb

Test-only access to the inner database. Can be used to modify the database without doing any consensus checks.

pub fn log_db_metrics(&self)

Logs rocksdb metrics using the read only state service.

Trait Implementations

impl Clone for ReadStateService

fn clone(&self) -> ReadStateService

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ReadStateService

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

Formats the value using the given formatter.

impl Drop for ReadStateService

fn drop(&mut self)

Executes the destructor for this type.

impl Service<ReadRequest> for ReadStateService

type Response = ReadResponse

Responses given by the service.

type Error = Box<dyn Error + Sync + Send>

Errors produced by the service.

type Future = Pin<Box<dyn Future<Output = Result<<ReadStateService as Service<ReadRequest>>::Response, <ReadStateService as Service<ReadRequest>>::Error>> + Send>>

The future response value.

fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>>

Returns Poll::Ready(Ok(())) when the service is able to process requests.

fn call(&mut self, req: ReadRequest) -> Self::Future

Process the request and return the response asynchronously.