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/src/run.rs

@@ -15,6 +15,12 @@ use tokio::runtime::TaskExecutor;
 use tokio_timer::clock::Clock;
 use types::{MainnetEthSpec, MinimalEthSpec};
 
+/// Reads the configuration and initializes a `BeaconChain` with the required types and parameters.
+///
+/// Spawns an executor which performs syncing, networking, block production, etc.
+///
+/// Blocks the current thread, returning after the `BeaconChain` has exited or a `Ctrl+C`
+/// signal.
 pub fn run_beacon_node(
     client_config: ClientConfig,
     eth2_config: Eth2Config,
@@ -38,7 +44,7 @@ pub fn run_beacon_node(
 
     warn!(
         log,
-        "This software is EXPERIMENTAL and provides no guarantees or warranties."
+        "Ethereum 2.0 is pre-release. This software is experimental."
     );
 
     info!(
@@ -46,6 +52,7 @@ pub fn run_beacon_node(
         "Starting beacon node";
         "p2p_listen_address" => format!("{:?}", &other_client_config.network.listen_address),
         "data_dir" => format!("{:?}", other_client_config.data_dir()),
+        "network_dir" => format!("{:?}", other_client_config.network.network_dir),
         "spec_constants" => &spec_constants,
         "db_type" => &other_client_config.db_type,
     );
@@ -92,7 +99,8 @@ pub fn run_beacon_node(
     result
 }
 
-pub fn run<T>(
+/// Performs the type-generic parts of launching a `BeaconChain`.
+fn run<T>(
     db_path: &Path,
     client_config: ClientConfig,
     eth2_config: Eth2Config,