feat: presign for validator account (#6747)

#6746


  Add a --presign flag to emit the json output to stdout instead of publishing the exit

Cargo.lock

@@ -30,6 +30,7 @@ dependencies = [
  "filesystem",
  "safe_arith",
  "sensitive_url",
+ "serde_json",
  "slashing_protection",
  "slot_clock",
  "tempfile",

account_manager/Cargo.toml

@@ -22,6 +22,7 @@ eth2_wallet_manager = { path = "../common/eth2_wallet_manager" }
 filesystem = { workspace = true }
 safe_arith = { workspace = true }
 sensitive_url = { workspace = true }
+serde_json = { workspace = true }
 slashing_protection = { workspace = true }
 slot_clock = { workspace = true }
 tokio = { workspace = true }

account_manager/src/validator/exit.rs

@@ -11,6 +11,7 @@ use eth2_keystore::Keystore;
 use eth2_network_config::Eth2NetworkConfig;
 use safe_arith::SafeArith;
 use sensitive_url::SensitiveUrl;
+use serde_json;
 use slot_clock::{SlotClock, SystemTimeSlotClock};
 use std::path::{Path, PathBuf};
 use std::time::Duration;
@@ -24,6 +25,7 @@ pub const BEACON_SERVER_FLAG: &str = "beacon-node";
 pub const NO_WAIT: &str = "no-wait";
 pub const NO_CONFIRMATION: &str = "no-confirmation";
 pub const PASSWORD_PROMPT: &str = "Enter the keystore password";
+pub const PRESIGN: &str = "presign";
 
 pub const DEFAULT_BEACON_NODE: &str = "http://localhost:5052/";
 pub const CONFIRMATION_PHRASE: &str = "Exit my validator";
@@ -74,6 +76,15 @@ pub fn cli_app() -> Command {
                 .action(ArgAction::SetTrue)
                 .help_heading(FLAG_HEADER)
         )
+        .arg(
+            Arg::new(PRESIGN)
+                .long(PRESIGN)
+                .help("Only presign the voluntary exit message without publishing it")
+                .default_value("false")
+                .action(ArgAction::SetTrue)
+                .help_heading(FLAG_HEADER)
+                .display_order(0)
+        )
 }
 
 pub fn cli_run<E: EthSpec>(matches: &ArgMatches, env: Environment<E>) -> Result<(), String> {
@@ -84,6 +95,7 @@ pub fn cli_run<E: EthSpec>(matches: &ArgMatches, env: Environment<E>) -> Result<
     let stdin_inputs = cfg!(windows) || matches.get_flag(STDIN_INPUTS_FLAG);
     let no_wait = matches.get_flag(NO_WAIT);
     let no_confirmation = matches.get_flag(NO_CONFIRMATION);
+    let presign = matches.get_flag(PRESIGN);
 
     let spec = env.eth2_config().spec.clone();
     let server_url: String = clap_utils::parse_required(matches, BEACON_SERVER_FLAG)?;
@@ -107,6 +119,7 @@ pub fn cli_run<E: EthSpec>(matches: &ArgMatches, env: Environment<E>) -> Result<
         &eth2_network_config,
         no_wait,
         no_confirmation,
+        presign,
     ))?;
 
     Ok(())
@@ -123,6 +136,7 @@ async fn publish_voluntary_exit<E: EthSpec>(
     eth2_network_config: &Eth2NetworkConfig,
     no_wait: bool,
     no_confirmation: bool,
+    presign: bool,
 ) -> Result<(), String> {
     let genesis_data = get_geneisis_data(client).await?;
     let testnet_genesis_root = eth2_network_config
@@ -154,6 +168,23 @@ async fn publish_voluntary_exit<E: EthSpec>(
         validator_index,
     };
 
+    // Sign the voluntary exit. We sign ahead of the prompt as that step is only important for the broadcast
+    let signed_voluntary_exit =
+        voluntary_exit.sign(&keypair.sk, genesis_data.genesis_validators_root, spec);
+    if presign {
+        eprintln!(
+            "Successfully pre-signed voluntary exit for validator {}. Not publishing.",
+            keypair.pk
+        );
+
+        // Convert to JSON and print
+        let string_output = serde_json::to_string_pretty(&signed_voluntary_exit)
+            .map_err(|e| format!("Unable to convert to JSON: {}", e))?;
+
+        println!("{}", string_output);
+        return Ok(());
+    }
+
     eprintln!(
         "Publishing a voluntary exit for validator: {} \n",
         keypair.pk
@@ -174,9 +205,7 @@ async fn publish_voluntary_exit<E: EthSpec>(
     };
 
     if confirmation == CONFIRMATION_PHRASE {
-        // Sign and publish the voluntary exit to network
-        let signed_voluntary_exit =
-            voluntary_exit.sign(&keypair.sk, genesis_data.genesis_validators_root, spec);
+        // Publish the voluntary exit to network
         client
             .post_beacon_pool_voluntary_exits(&signed_voluntary_exit)
             .await