block_lag_exporter

Simple metrics exporter to export latest block lag for evm-based chains. It exports 2 metrics:

• head_lag_seconds - histogram with values from uptime
• head_lag_seconds_last - gauge with latest value of block lag

and 2 endpoints on http://0.0.0.0:${LISTENER_PORT}:

• /metrics - to scrape prometheus metrics
• /health - to check liveness

Default values are optimized to use it as a k8s geth/geth-like sidecar Use following environment variables to override defaults:

• LISTENER_PORT=8000 - port to listen
• WS_URL=ws://localhost:8545 - websocket URL to connect and subscribe to new blocks
• WS_READ_TIMEOUT=25 - websocket timeout to wait for new blocks data
• HIST_BUCKETS=0.05,0.08,0.1,0.15,0.2,0.3,0.4,0.6,0.8,1.0,1.2,1.6,2.0,2.5,3.0,4.0,8.0,+Inf - override prometheus histogram buckets for histogram metric
• MAX_BLOCK_LAG=60.0 - all data above this threshold will be logged, but not added to metrics. This exporter is intended to monitor
  the current block lag instead of initial sync-up/catch-up.