Module sync

The syncer downloads and verifies large numbers of blocks from peers to Zebra.

It is used when Zebra is a long way behind the current chain tip.

Modules

• downloads 🔒
  A download stream for Zebra’s block syncer.
• end_of_support
  End of support checking task.
• gossip 🔒
  A task that gossips newly verified block::Hashes to peers.
• progress 🔒
  Progress tracking for blockchain syncing.
• recent_sync_lengths 🔒
  A channel which holds a list of recent syncer response lengths.
• status 🔒
  Syncer chain tip status, based on recent block locator responses from peers.

Structs

• ChainSync
• CheckedTip 🔒
  Helps work around defects in the bitcoin protocol by checking whether the returned hashes actually extend a chain tip.
• Config
  Sync configuration section.
• RecentSyncLengths
  A helper type which holds a list of recent syncer response lengths. These sync lengths can be used to work out if Zebra has reached the end of the chain.
• SyncStatus
  A helper type to determine if the synchronizer has likely reached the chain tip.

Enums

• BlockGossipError
  Errors that can occur when gossiping committed blocks

Constants

• BLOCK_DOWNLOAD_RETRY_LIMIT 🔒
  Controls how many times we will retry each block download.
• BLOCK_DOWNLOAD_TIMEOUT 🔒
  Controls how long we wait for a block download request to complete.
• BLOCK_VERIFY_TIMEOUT 🔒
  Controls how long we wait for a block verify request to complete.
• DEFAULT_CHECKPOINT_CONCURRENCY_LIMIT
  The default for the user-specified lookahead limit.
• FANOUT 🔒
  Controls the number of peers used for each ObtainTips and ExtendTips request.
• FINAL_CHECKPOINT_BLOCK_VERIFY_TIMEOUT 🔒
  A shorter timeout used for the first few blocks after the final checkpoint.
• FINAL_CHECKPOINT_BLOCK_VERIFY_TIMEOUT_LIMIT 🔒
  The number of blocks after the final checkpoint that get the shorter timeout.
• GENESIS_TIMEOUT_RETRY 🔒
  Controls how long we wait to retry a failed attempt to download and verify the genesis block.
• MAX_TIPS_RESPONSE_HASH_COUNT
  The expected maximum number of hashes in an ObtainTips or ExtendTips response.
• MIN_CHECKPOINT_CONCURRENCY_LIMIT
  A lower bound on the user-specified checkpoint verification concurrency limit.
• MIN_CONCURRENCY_LIMIT
  A lower bound on the user-specified concurrency limit.
• PEER_GOSSIP_DELAY
  Controls how long we wait between gossiping successive blocks or transactions.
• SYNC_RESTART_DELAY 🔒
  Controls how long we wait to restart syncing after finishing a sync run.
• TIPS_RESPONSE_TIMEOUT
  Controls how long we wait for a tips response to return.
• VERIFICATION_PIPELINE_SCALING_MULTIPLIER
  A multiplier used to calculate the extra number of blocks we allow in the verifier, state, and block commit pipelines, on top of the lookahead limit.

Functions

• gossip_best_tip_block_hashes
  Run continuously, gossiping newly verified block::Hashes to peers.
• show_block_chain_progress
  Logs Zebra’s estimated progress towards the chain tip every minute or so, and updates a terminal progress bar every few seconds.