Config: confused by skip_block_download_wait

[jotapea]

Hello, newbie user here.

After some time researching, I don't know if I am missing some step using the skip_block_download_wait = true configuration. If not, and is just not possible to use electrs during initial block download, then I'll be curious about the main use cases for such configuration.

Edit: Maybe is for the non-initial block downloads? Also found out that the "proxy" calls, like blockchain.transaction.get, do work.

---

Have you read the documentation?
Yes.

How did you configure electrs?

Running it with docker compose for local tests:

config.toml

daemon_rpc_addr = "bitcoind:8332"
daemon_p2p_addr = "bitcoind:8333"
auth = "rpc:rpc"
db_dir = "/data"
electrum_rpc_addr = "0.0.0.0:50001"
skip_block_download_wait = true

Environment variables: ENV RUST_BACKTRACE=1, ENV RUST_LOG=info
Arguments: target/release/electrs --conf config.toml

Debug output of configuration

Starting electrs 0.10.5 on x86_64 linux with Config { network: Bitcoin, db_path: "/data/bitcoin", db_log_dir: None, daemon_dir: "/root/.bitcoin", daemon_auth: UserPass("rpc", ""), daemon_rpc_addr: 172.21.0.3:8332, daemon_p2p_addr: 172.21.0.3:8333, electrum_rpc_addr: 0.0.0.0:50001, monitoring_addr: 127.0.0.1:4224, wait_duration: 10s, jsonrpc_timeout: 15s, index_batch_size: 10, index_lookup_limit: None, reindex_last_blocks: 0, auto_reindex: true, ignore_mempool: false, sync_once: false, skip_block_download_wait: true, disable_electrum_rpc: false, server_banner: "Welcome to electrs 0.10.5 (Electrum Rust Server)!", signet_magic: f9beb4d9, args: [] }

Expected behavior
I expected calls like blockchain.headers.subscribe and blockchain.block.header to return results for blocks that have already been synced by bitcoind.

Actual behavior
blockchain.headers.subscribe returns height 0 and blockchain.block.header with height 2 returns error 'no header at 2'.

---

The same setup without the skip_block_download_wait = true worked, electrs synced after bitcoin and I was able to make successful calls. So, I am now focused on learning about this specific configuration.

Tried to find an answer in this repo, the docs and searching the web. Finally tried reading the code, but I can't figure it out with my limited rust knowledge.

Thank you for your work and time.

[Kixunil]

I don't know what's wrong but FYI it got added in #410 and it supposedly worked at the time.

[jotapea]

Thank you @Kixunil. Maybe I'll try to run that older version, or just continue learning Rust and get into the code.