Add a no-wait flag for voluntary exits (#2292)

## Issue Addressed

N/A

## Proposed Changes

Adds a `no-wait` flag to the validator exit command which exits right after publishing the voluntary exit to the beacon chain. It does not wait for confirmation that the exit has been included in the beacon chain. By default, the flag is false.

cc @stefa2k

account_manager/src/validator/exit.rs

@@ -19,6 +19,7 @@ pub const CMD: &str = "exit";
 pub const KEYSTORE_FLAG: &str = "keystore";
 pub const PASSWORD_FILE_FLAG: &str = "password-file";
 pub const BEACON_SERVER_FLAG: &str = "beacon-node";
+pub const NO_WAIT: &str = "no-wait";
 pub const PASSWORD_PROMPT: &str = "Enter the keystore password";
 
 pub const DEFAULT_BEACON_NODE: &str = "http://localhost:5052/";
@@ -52,6 +53,11 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                 .default_value(&DEFAULT_BEACON_NODE)
                 .takes_value(true),
         )
+        .arg(
+            Arg::with_name(NO_WAIT)
+                .long(NO_WAIT)
+                .help("Exits after publishing the voluntary exit without waiting for confirmation that the exit was included in the beacon chain")
+        )
         .arg(
             Arg::with_name(STDIN_INPUTS_FLAG)
                 .long(STDIN_INPUTS_FLAG)
@@ -64,6 +70,7 @@ pub fn cli_run<E: EthSpec>(matches: &ArgMatches, env: Environment<E>) -> Result<
     let password_file_path: Option<PathBuf> =
         clap_utils::parse_optional(matches, PASSWORD_FILE_FLAG)?;
     let stdin_inputs = matches.is_present(STDIN_INPUTS_FLAG);
+    let no_wait = matches.is_present(NO_WAIT);
 
     let spec = env.eth2_config().spec.clone();
     let server_url: String = clap_utils::parse_required(matches, BEACON_SERVER_FLAG)?;
@@ -84,6 +91,7 @@ pub fn cli_run<E: EthSpec>(matches: &ArgMatches, env: Environment<E>) -> Result<
         &spec,
         stdin_inputs,
         &testnet_config,
+        no_wait,
     ))?;
 
     Ok(())
@@ -97,6 +105,7 @@ async fn publish_voluntary_exit<E: EthSpec>(
     spec: &ChainSpec,
     stdin_inputs: bool,
     testnet_config: &Eth2NetworkConfig,
+    no_wait: bool,
 ) -> Result<(), String> {
     let genesis_data = get_geneisis_data(client).await?;
     let testnet_genesis_root = testnet_config
@@ -169,6 +178,10 @@ async fn publish_voluntary_exit<E: EthSpec>(
         return Ok(());
     }
 
+    if no_wait {
+        return Ok(());
+    }
+
     loop {
         // Sleep for a slot duration and then check if voluntary exit was processed
         // by checking the validator status.

book/src/voluntary-exit.md

@@ -64,5 +64,9 @@ Enter the exit phrase from the above URL to confirm the voluntary exit:
 Exit my validator
 
 Successfully published voluntary exit for validator 0xabcd
+Voluntary exit has been accepted into the beacon chain, but not yet finalized. Finalization may take several minutes or longer. Before finalization there is a low probability that the exit may be reverted.
+Current epoch: 29946, Exit epoch: 29951, Withdrawable epoch: 30207
+Please keep your validator running till exit epoch
+Exit epoch in approximately 1920 secs
 ```