Testnet stability (#451)

* Change reduced tree for adding weightless node

* Add more comments for reduced tree fork choice

* Small refactor on reduced tree for readability

* Move test_harness forking logic into itself

* Add new `AncestorIter` trait to store

* Add unfinished tests to fork choice

* Make `beacon_state.genesis_block_root` public

* Add failing lmd_ghost fork choice tests

* Extend fork_choice tests, create failing test

* Implement Debug for generic ReducedTree

* Add lazy_static to fork choice tests

* Add verify_integrity fn to reduced tree

* Fix bugs in reduced tree

* Ensure all reduced tree tests verify integrity

* Slightly alter reduce tree test params

* Add (failing) reduced tree test

* Fix bug in fork choice

Iter ancestors was not working well with skip slots

* Put maximum depth for common ancestor search

Ensures that we don't search back past the finalized root.

* Add basic finalization tests for reduced tree

* Change fork choice to use beacon_block_root

Previously it was using target_root, which was wrong

* Change reduced tree for adding weightless node

* Add more comments for reduced tree fork choice

* Small refactor on reduced tree for readability

* Move test_harness forking logic into itself

* Add new `AncestorIter` trait to store

* Add unfinished tests to fork choice

* Make `beacon_state.genesis_block_root` public

* Add failing lmd_ghost fork choice tests

* Extend fork_choice tests, create failing test

* Implement Debug for generic ReducedTree

* Add lazy_static to fork choice tests

* Add verify_integrity fn to reduced tree

* Fix bugs in reduced tree

* Ensure all reduced tree tests verify integrity

* Slightly alter reduce tree test params

* Add (failing) reduced tree test

* Fix bug in fork choice

Iter ancestors was not working well with skip slots

* Put maximum depth for common ancestor search

Ensures that we don't search back past the finalized root.

* Add basic finalization tests for reduced tree

* Add network dir CLI flag

* Simplify "NewSlot" log message

* Rename network-dir CLI flag

* Change fork choice to use beacon_block_root

Previously it was using target_root, which was wrong

* Update db dir size for metrics

* Change slog to use `FullFormat` logging

* Update some comments and log formatting

* Add prom gauge for best block root

* Only add known target blocks to fork choice

* Add finalized and justified root prom metrics

* Add CLI flag for setting log level

* Add logger to beacon chain

* Add debug-level CLI flag to validator

* Allow block processing if fork choice fails

* Create warn log when there's low libp2p peer count

* Minor change to logging

* Make ancestor iter return option

* Disable fork choice test when !debug_assertions

* Fix type, removed code fragment

* Tidy some borrow-checker evading

* Lower reduced tree random test iterations

beacon_node/client/src/lib.rs

@@ -190,29 +190,38 @@ impl<T: BeaconChainTypes> Drop for Client<T> {
 }
 
 fn do_state_catchup<T: BeaconChainTypes>(chain: &Arc<BeaconChain<T>>, log: &slog::Logger) {
-    if let Some(genesis_height) = chain.slots_since_genesis() {
-        let result = chain.catchup_state();
+    // Only attempt to `catchup_state` if we can read the slot clock.
+    if let Some(current_slot) = chain.read_slot_clock() {
+        let state_catchup_result = chain.catchup_state();
+
+        let best_slot = chain.head().beacon_block.slot;
+        let latest_block_root = chain.head().beacon_block_root;
 
         let common = o!(
-            "best_slot" => chain.head().beacon_block.slot,
-            "latest_block_root" => format!("{}", chain.head().beacon_block_root),
-            "wall_clock_slot" => chain.read_slot_clock().unwrap(),
-            "state_slot" => chain.head().beacon_state.slot,
-            "slots_since_genesis" => genesis_height,
+            "skip_slots" => current_slot.saturating_sub(best_slot),
+            "best_block_root" => format!("{}", latest_block_root),
+            "best_block_slot" => best_slot,
+            "slot" => current_slot,
         );
 
-        match result {
-            Ok(_) => info!(
+        if let Err(e) = state_catchup_result {
+            error!(
                 log,
-                "NewSlot";
-                common
-            ),
-            Err(e) => error!(
-                log,
-                "StateCatchupFailed";
+                "State catchup failed";
                 "error" => format!("{:?}", e),
                 common
-            ),
-        };
-    }
+            )
+        } else {
+            info!(
+                log,
+                "Slot start";
+                common
+            )
+        }
+    } else {
+        error!(
+            log,
+            "Beacon chain running whilst slot clock is unavailable."
+        );
+    };
 }