Transaction Stream Step

The TransactionStreamStep is a foundational component in the transaction processing pipeline. It establishes a gRPC connection with the TransactionStream service, fetches transactions in batches, and outputs them for further processing. This step also manages connection retries and reconnections in case of transient failures. Typically, this is the initial step in a processor, responsible for streaming transactions for downstream steps.

1. Fetch Transactions: Retrieves transaction batches from a gRPC service.
2. Manage Connections: Handles gRPC reconnections to ensure a resilient stream.
3. Provide Metadata: Attaches contextual information like versions and timestamps to the transactions.

The TransactionStreamStep struct is defined as follows:

pub struct TransactionStreamStep
where
    Self: Sized + Send + 'static,
{
    transaction_stream_config: TransactionStreamConfig,
    pub transaction_stream: Mutex<TransactionStreamInternal>,
}

• The TransactionStreamStep connects to the gRPC TransactionStream service.
• It continuously polls for new transactions using the poll method.
• Each batch is wrapped in a TransactionContext, which includes metadata such as:
  • Start and end versions.
  • Timestamps of transactions.
  • Batch size in bytes.
• If the connection is interrupted, it attempts to reconnect seamlessly.