README
¶
Sync benchmark: feeder-sim
Captures feeder gateway (FGW) responses for a block range, then serves them from memory behind a simulated chain tip. Removes FGW latency, rate limits and chain activity from sync benchmarks.
Use
make feeder-sim # -> build/feeder-sim
build/feeder-sim --data ./data/mainnet --network mainnet --from 1500000 --to 1501000 --listen off # capture
build/feeder-sim --data ./data/mainnet --from 1500000 --to 1501000 # serve, 2s cadence
build/feeder-sim --data ./data/mainnet --from 1500000 --to 1501000 --speed 1 # serve, captured block times
build/feeder-sim --data ./data/mainnet --from 1500000 --to 1501000 --tip 1501000 # serve everything at once
Capture is resumable. A 400 from the FGW usually means --to is above the tip. One --data
directory per network, checked via get_contract_addresses. Without --network the sim is offline and fails on a missing file; with
--network it fills gaps before serving.
Flags
| Flag | Meaning | Default |
|---|---|---|
--data |
dataset directory (required) | |
--from, --to |
block range, inclusive (required) | |
--network |
capture source: mainnet, sepolia, sepolia-integration |
offline |
--listen |
host:port; :7070 binds all interfaces; off = capture only |
127.0.0.1:7070 |
--tip |
initial tip, in [from, to] |
from |
--interval |
advance the tip by one block every interval | 2s |
--speed |
replay captured block timestamps at this multiplier; excludes --interval |
unset |
--latency |
fixed delay added to every response, no jitter | 0 |
--api-key |
X-Throttling-Bypass header during capture |
|
--concurrency |
parallel capture requests | 8 |
--capture-timeout |
per-request timeout during capture | 30s |
--capture-retries |
retries per request during capture | 5 |
--log-level |
debug, info, warn, error |
info |
blockNumber=latest resolves to the tip. Blocks above the tip get 400 (debug log). Classes are not tip-gated.
Juno
juno --db-path <copy of a DB synced to from-1> \
--cn-name mainnet --cn-feeder-url http://127.0.0.1:7070/feeder_gateway/ \
--cn-gateway-url http://127.0.0.1:7070/gateway/ \
--cn-l2-chain-id SN_MAIN --cn-l1-chain-id 1 \
--cn-core-contract-address 0xc662c410c0ecf747543f5ba90660f6abebd9c8c4 \
--cn-unverifiable-range 0,0 --preconfirmed-poll-interval 0 --metrics
- Restore the DB copy before every run. To prepare a DB at
X-1, run against the sim with--tip X-1. - Keep the range at Starknet v0.13.2 or later; older blocks fail hash verification on custom networks.
- Juno retries a 400 ten times with backoff, so wall clock between blocks measures the retry
schedule. Measure
sync_step_durationinstead, or use--tip <to>for throughput.
Dataset layout
One gzipped file per FGW response:
<data>/
get_contract_addresses.json.gz
get_block/<N>.json.gz # headerOnly=true
get_state_update/<N>.json.gz # includeBlock=true&includeSignature=true
get_class_by_hash/<hash>.json.gz # blockNumber=latest
get_compiled_class_by_class_hash/<hash>.json.gz # blockNumber=latest
Timestamps, class lists and completeness are derived from the state updates at startup.
Directories
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