fix: log errors on block download failure; implement max retries (#503)

### Description

Before this PR, Chainhook would loop infinitely if there is a problem
downloading a BTC block, and it wouldn't log much information as to what
was causing the failure. This PR implements better logging, and breaks
out of the loop at 10 failed attempts.

components/chainhook-sdk/src/indexer/bitcoin/mod.rs

@@ -153,18 +153,21 @@ pub async fn download_and_parse_block_with_retry(
     ctx: &Context,
 ) -> Result<BitcoinBlockFullBreakdown, String> {
     let mut errors_count = 0;
+    let max_retries = 10;
     let block = loop {
         match download_and_parse_block(http_client, block_hash, bitcoin_config, ctx).await {
             Ok(result) => break result,
-            Err(_e) => {
+            Err(e) => {
                 errors_count += 1;
-                if errors_count > 3 {
+                if errors_count > 3 && errors_count < max_retries {
                     ctx.try_log(|logger| {
                         slog::warn!(
                             logger,
-                            "unable to fetch and parse block #{block_hash}: will retry in a few seconds (attempt #{errors_count}).",
+                            "unable to fetch and parse block #{block_hash}: will retry in a few seconds (attempt #{errors_count}). Error: {e}",
                         )
                     });
+                } else if errors_count == max_retries {
+                    return Err(format!("unable to fetch and parse block #{block_hash} after {errors_count} attempts. Error: {e}"));
                 }
                 std::thread::sleep(std::time::Duration::from_secs(1));
             }
@@ -180,18 +183,21 @@ pub async fn retrieve_block_hash_with_retry(
     ctx: &Context,
 ) -> Result<String, String> {
     let mut errors_count = 0;
+    let max_retries = 10;
     let block_hash = loop {
         match retrieve_block_hash(http_client, block_height, bitcoin_config, ctx).await {
             Ok(result) => break result,
-            Err(_e) => {
+            Err(e) => {
                 errors_count += 1;
-                if errors_count > 3 {
+                if errors_count > 3 && errors_count < max_retries {
                     ctx.try_log(|logger| {
                         slog::warn!(
                             logger,
-                            "unable to retrieve block hash #{block_height}: will retry in a few seconds (attempt #{errors_count}).",
+                            "unable to retrieve block hash #{block_height}: will retry in a few seconds (attempt #{errors_count}). Error: {e}",
                         )
                     });
+                } else if errors_count == max_retries {
+                    return Err(format!("unable to retrieve block hash #{block_height} after {errors_count} attempts. Error: {e}"));
                 }
                 std::thread::sleep(std::time::Duration::from_secs(2));
             }