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Ledger Backends

A ledger backend is a source of Stellar network ledger data. The ingest SDK supports two primary ledger backends, both implementing the ledgerbackend interface. This interface always returns ledger data as LedgerCloseMeta, which is XDR-encoded ledger metadata object.

  1. Captive Core – Invokes the stellar-core binary as a subprocess which connects to the live Stellar network and fetches network data (i.e., ledgers).
  2. BufferedStorageBackend – Retrieves ledger metadata from cloud storage.
  3. RPCLedgerBackend – Retrieves ledger metadata from an RPC server.

Each backend has its own setup and configuration requirements, which are covered in the following sections.

LedgerCloseMeta Structure​

xdr.LedgerCloseMeta captures a detailed record of all state changes during the closing of a Stellar ledger. It includes:

  • LedgerHeader – Metadata about the ledger, including:

    • Ledger sequence number
    • Previous ledger hash
    • Close time
    • Bucketlist hash

  • TxSet – The set of transactions included in the ledger.

  • TxProcessing – Execution results of each transaction, including:

    • Success or failure of operations within transactions
    • OperationMeta, which tracks LedgerEntryChanges caused by transactions

  • UpgradesProcessing – Any protocol upgrades applied in this ledger.

  • ScpInfo – Details of the consensus process that finalized this ledger.

  • EvictedLedgerKeys – Keys of ledger entries removed due to expiration.