Add CLI flags

beacon_node/client/src/config.rs

@@ -75,6 +75,7 @@ pub struct Config {
     pub chain: beacon_chain::ChainConfig,
     pub eth1: eth1::Config,
     pub execution_endpoints: Option<Vec<SensitiveUrl>>,
+    pub total_terminal_difficulty_override: Option<u64>,
     pub http_api: http_api::Config,
     pub http_metrics: http_metrics::Config,
     pub monitoring_api: Option<monitoring_api::Config>,
@@ -96,6 +97,7 @@ impl Default for Config {
             sync_eth1_chain: false,
             eth1: <_>::default(),
             execution_endpoints: None,
+            total_terminal_difficulty_override: None,
             disabled_forks: Vec::new(),
             graffiti: Graffiti::default(),
             http_api: <_>::default(),

beacon_node/src/cli.rs

@@ -348,6 +348,38 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                 .help("Specifies how many blocks the database should cache in memory [default: 5]")
                 .takes_value(true)
         )
+        /*
+         * Execution Layer Integration
+         */
+        .arg(
+            Arg::with_name("merge")
+                .long("merge")
+                .help("Enable the features necessary to run merge testnets. This feature \
+                       is unstable and is for developers only.")
+                .takes_value(false),
+        )
+        .arg(
+            Arg::with_name("execution-endpoints")
+                .long("execution-endpoints")
+                .value_name("EXECUTION-ENDPOINTS")
+                .help("One or more comma-delimited server endpoints for HTTP JSON-RPC connection. \
+                       If multiple endpoints are given the endpoints are used as fallback in the \
+                       given order. Also enables the --merge flag. \
+                       If this flag is omitted and the --eth1-endpoints is supplied, those values \
+                       will be used. Defaults to http://127.0.0.1:8545.")
+                .takes_value(true)
+        )
+        .arg(
+            Arg::with_name("terminal-total-difficulty-override")
+                .long("terminal-total-difficulty-override")
+                .value_name("TERMINAL_TOTAL_DIFFICULTY")
+                .help("Used to coordinate manual overrides to the TERMINAL_TOTAL_DIFFICULTY parameter. \
+                       This flag should only be used if the user has a clear understanding that \
+                       the broad Ethereum community has elected to override the terminal difficulty. \
+                       Failure to do so will cause your node to experience a consensus failure. \
+                       Be extremely careful with the use of this flag.")
+                .takes_value(true)
+        )
 
         /*
          * Database purging and compaction.

beacon_node/src/config.rs

@@ -212,6 +212,31 @@ pub fn get_config<E: EthSpec>(
         client_config.eth1.purge_cache = true;
     }
 
+    if let Some(endpoints) = cli_args.value_of("execution-endpoints") {
+        client_config.sync_eth1_chain = true;
+        client_config.execution_endpoints = endpoints
+            .split(',')
+            .map(|s| SensitiveUrl::parse(s))
+            .collect::<Result<_, _>>()
+            .map(Some)
+            .map_err(|e| format!("execution-endpoints contains an invalid URL {:?}", e))?;
+    } else if cli_args.is_present("merge") {
+        client_config.execution_endpoints = Some(client_config.eth1.endpoints.clone());
+    }
+
+    if let Some(total_terminal_difficulty) =
+        clap_utils::parse_optional(cli_args, "total-terminal-difficulty-override")?
+    {
+        if client_config.execution_endpoints.is_none() {
+            return Err(
+                "The --merge flag must be provided when using --total-terminal-difficulty-override"
+                    .into(),
+            );
+        }
+
+        client_config.total_terminal_difficulty_override = Some(total_terminal_difficulty);
+    }
+
     if let Some(freezer_dir) = cli_args.value_of("freezer-dir") {
         client_config.freezer_db_path = Some(PathBuf::from(freezer_dir));
     }