better logs and only allow being 1 block behind

src/block_watcher.rs

@@ -121,12 +121,10 @@ impl BlockWatcher {
 
             // TODO: include time since last update?
             info!(
-                "{:?} = {} Ts: {:?}, block number: {}, age: {}s {}",
+                "{:?} = {}, {}, {} sec, {}",
                 new_block.hash.unwrap(),
-                rpc,
-                // TODO: human readable time?
-                new_block.timestamp,
                 new_block.number.unwrap(),
+                rpc,
                 now - new_block.timestamp.as_u64() as i64,
                 label_slow_heads
             );

src/main.rs

@@ -345,10 +345,16 @@ async fn main() {
             vec![("ws://10.11.12.16:8545", 0), ("ws://10.11.12.16:8946", 0)],
             // paid nodes
             // TODO: add paid nodes (with rate limits)
-            // free nodes
-            // TODO: add rate limits
             vec![
-                ("https://main-rpc.linkpool.io", 0),
+                // chainstack.com archive
+                (
+                    "wss://ws-nd-373-761-850.p2pify.com/106d73af4cebc487df5ba92f1ad8dee7",
+                    0,
+                ),
+            ],
+            // free nodes
+            vec![
+                // ("https://main-rpc.linkpool.io", 0), // linkpool is slow
                 ("https://rpc.ankr.com/eth", 0),
             ],
         ],

src/provider.rs

@@ -1,6 +1,6 @@
 ///! Communicate with a web3 providers
 use derive_more::From;
-use ethers::prelude::Middleware;
+use ethers::prelude::{BlockNumber, Middleware};
 use futures::StreamExt;
 use std::time::Duration;
 use std::{cmp::Ordering, sync::Arc};
@@ -40,16 +40,21 @@ impl Web3Provider {
 
         // TODO: automatically reconnect
         match &self {
-            Web3Provider::Http(_provider) => {
+            Web3Provider::Http(provider) => {
                 // TODO: there is a "watch_blocks" function, but a lot of public nodes do not support the necessary rpc endpoints
                 // TODO: how often?
+                // TODO: maybe it would be better to have one interval for all of these, but this works for now
                 let mut interval = interval(Duration::from_secs(2));
 
                 loop {
                     // wait for 2 seconds
                     interval.tick().await;
 
-                    unimplemented!("todo: send block number")
+                    match provider.get_block(BlockNumber::Latest).await {
+                        Ok(Some(block)) => block_watcher_sender.send((url.clone(), block)).unwrap(),
+                        Ok(None) => warn!("no black at {}", url),
+                        Err(e) => warn!("getBlock at {} failed: {}", url, e),
+                    }
                 }
             }
             Web3Provider::Ws(provider) => {

src/provider_tiers.rs

@@ -155,7 +155,7 @@ impl Web3ProviderTier {
         for selected_rpc in self.rpcs.read().await.iter() {
             // check that the server is synced
             if !block_watcher
-                .is_synced(selected_rpc.clone(), 3)
+                .is_synced(selected_rpc.clone(), 1)
                 .await
                 .expect("checking is_synced failed")
             {