Add graffiti cli flag to the validator client. (#1425)

## Issue Addressed

#1419

## Proposed Changes

Creates a `--graffiti` cli flag in the validator client. If the flag is set, it overrides graffiti in the beacon node. 

## Additional Info

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -1564,12 +1564,13 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         &self,
         randao_reveal: Signature,
         slot: Slot,
+        validator_graffiti: Option<Graffiti>,
     ) -> Result<BeaconBlockAndState<T::EthSpec>, BlockProductionError> {
         let state = self
             .state_at_slot(slot - 1, StateSkipConfig::WithStateRoots)
             .map_err(|_| BlockProductionError::UnableToProduceAtSlot(slot))?;
 
-        self.produce_block_on_state(state, slot, randao_reveal)
+        self.produce_block_on_state(state, slot, randao_reveal, validator_graffiti)
     }
 
     /// Produce a block for some `slot` upon the given `state`.
@@ -1585,6 +1586,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         mut state: BeaconState<T::EthSpec>,
         produce_at_slot: Slot,
         randao_reveal: Signature,
+        validator_graffiti: Option<Graffiti>,
     ) -> Result<BeaconBlockAndState<T::EthSpec>, BlockProductionError> {
         metrics::inc_counter(&metrics::BLOCK_PRODUCTION_REQUESTS);
         let timer = metrics::start_timer(&metrics::BLOCK_PRODUCTION_TIMES);
@@ -1652,6 +1654,12 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
             }
         }
 
+        // Override the beacon node's graffiti with graffiti from the validator, if present.
+        let graffiti = match validator_graffiti {
+            Some(graffiti) => graffiti,
+            None => self.graffiti,
+        };
+
         let mut block = SignedBeaconBlock {
             message: BeaconBlock {
                 slot: state.slot,
@@ -1661,7 +1669,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                 body: BeaconBlockBody {
                     randao_reveal,
                     eth1_data,
-                    graffiti: self.graffiti,
+                    graffiti,
                     proposer_slashings: proposer_slashings.into(),
                     attester_slashings: attester_slashings.into(),
                     attestations: self

beacon_node/beacon_chain/src/test_utils.rs

@@ -520,7 +520,7 @@ where
 
         let (block, state) = self
             .chain
-            .produce_block_on_state(state, slot, randao_reveal)
+            .produce_block_on_state(state, slot, randao_reveal, None)
             .expect("should produce block");
 
         let signed_block = block.sign(sk, &state.fork, state.genesis_validators_root, &self.spec);

beacon_node/rest_api/src/validator.rs

@@ -1,4 +1,6 @@
-use crate::helpers::{check_content_type_for_json, publish_beacon_block_to_network};
+use crate::helpers::{
+    check_content_type_for_json, parse_hex_ssz_bytes, publish_beacon_block_to_network,
+};
 use crate::response_builder::ResponseBuilder;
 use crate::{ApiError, ApiResult, NetworkChannel, UrlQuery};
 use beacon_chain::{
@@ -288,8 +290,14 @@ pub fn get_new_beacon_block<T: BeaconChainTypes>(
     let slot = query.slot()?;
     let randao_reveal = query.randao_reveal()?;
 
+    let validator_graffiti = if let Some((_key, value)) = query.first_of_opt(&["graffiti"]) {
+        Some(parse_hex_ssz_bytes(&value)?)
+    } else {
+        None
+    };
+
     let (new_block, _state) = beacon_chain
-        .produce_block(randao_reveal, slot)
+        .produce_block(randao_reveal, slot, validator_graffiti)
         .map_err(|e| {
             error!(
                 log,

beacon_node/rest_api/tests/test.rs

@@ -460,7 +460,7 @@ fn validator_block_post() {
             remote_node
                 .http
                 .validator()
-                .produce_block(slot, randao_reveal),
+                .produce_block(slot, randao_reveal, None),
         )
         .expect("should fetch block from http api");
 
@@ -547,7 +547,7 @@ fn validator_block_get() {
             remote_node
                 .http
                 .validator()
-                .produce_block(slot, randao_reveal.clone()),
+                .produce_block(slot, randao_reveal.clone(), None),
         )
         .expect("should fetch block from http api");
 
@@ -555,7 +555,50 @@ fn validator_block_get() {
         .client
         .beacon_chain()
         .expect("client should have beacon chain")
-        .produce_block(randao_reveal, slot)
+        .produce_block(randao_reveal, slot, None)
+        .expect("should produce block");
+
+    assert_eq!(
+        block, expected_block,
+        "the block returned from the API should be as expected"
+    );
+}
+
+#[test]
+fn validator_block_get_with_graffiti() {
+    let mut env = build_env();
+
+    let spec = &E::default_spec();
+
+    let node = build_node(&mut env, testing_client_config());
+    let remote_node = node.remote_node().expect("should produce remote node");
+
+    let beacon_chain = node
+        .client
+        .beacon_chain()
+        .expect("client should have beacon chain");
+
+    let slot = Slot::new(1);
+    let randao_reveal = get_randao_reveal(beacon_chain, slot, spec);
+
+    let block = env
+        .runtime()
+        .block_on(remote_node.http.validator().produce_block(
+            slot,
+            randao_reveal.clone(),
+            Some(*b"test-graffiti-test-graffiti-test"),
+        ))
+        .expect("should fetch block from http api");
+
+    let (expected_block, _state) = node
+        .client
+        .beacon_chain()
+        .expect("client should have beacon chain")
+        .produce_block(
+            randao_reveal,
+            slot,
+            Some(*b"test-graffiti-test-graffiti-test"),
+        )
         .expect("should produce block");
 
     assert_eq!(

common/remote_beacon_node/src/lib.rs

@@ -11,8 +11,8 @@ use std::marker::PhantomData;
 use std::time::Duration;
 use types::{
     Attestation, AttestationData, AttesterSlashing, BeaconBlock, BeaconState, CommitteeIndex,
-    Epoch, EthSpec, Fork, Hash256, ProposerSlashing, PublicKey, PublicKeyBytes, Signature,
-    SignedAggregateAndProof, SignedBeaconBlock, Slot, SubnetId,
+    Epoch, EthSpec, Fork, Graffiti, Hash256, ProposerSlashing, PublicKey, PublicKeyBytes,
+    Signature, SignedAggregateAndProof, SignedBeaconBlock, Slot, SubnetId,
 };
 use url::Url;
 
@@ -313,18 +313,21 @@ impl<E: EthSpec> Validator<E> {
         &self,
         slot: Slot,
         randao_reveal: Signature,
+        graffiti: Option<Graffiti>,
     ) -> Result<BeaconBlock<E>, Error> {
         let client = self.0.clone();
         let url = self.url("block")?;
-        client
-            .json_get::<BeaconBlock<E>>(
-                url,
-                vec![
+
+        let mut query_pairs = vec![
             ("slot".into(), format!("{}", slot.as_u64())),
             ("randao_reveal".into(), as_ssz_hex_string(&randao_reveal)),
-                ],
-            )
-            .await
+        ];
+
+        if let Some(graffiti_bytes) = graffiti {
+            query_pairs.push(("graffiti".into(), as_ssz_hex_string(&graffiti_bytes)));
+        }
+
+        client.json_get::<BeaconBlock<E>>(url, query_pairs).await
     }
 
     /// Subscribes a list of validators to particular slots for attestation production/publication.

validator_client/src/block_service.rs

@@ -7,7 +7,7 @@ use slog::{crit, debug, error, info, trace, warn};
 use slot_clock::SlotClock;
 use std::ops::Deref;
 use std::sync::Arc;
-use types::{EthSpec, PublicKey, Slot};
+use types::{EthSpec, Graffiti, PublicKey, Slot};
 
 /// Builds a `BlockService`.
 pub struct BlockServiceBuilder<T, E: EthSpec> {
@@ -15,6 +15,7 @@ pub struct BlockServiceBuilder<T, E: EthSpec> {
     slot_clock: Option<Arc<T>>,
     beacon_node: Option<RemoteBeaconNode<E>>,
     context: Option<RuntimeContext<E>>,
+    graffiti: Option<Graffiti>,
 }
 
 impl<T: SlotClock + 'static, E: EthSpec> BlockServiceBuilder<T, E> {
@@ -24,6 +25,7 @@ impl<T: SlotClock + 'static, E: EthSpec> BlockServiceBuilder<T, E> {
             slot_clock: None,
             beacon_node: None,
             context: None,
+            graffiti: None,
         }
     }
 
@@ -47,6 +49,11 @@ impl<T: SlotClock + 'static, E: EthSpec> BlockServiceBuilder<T, E> {
         self
     }
 
+    pub fn graffiti(mut self, graffiti: Option<Graffiti>) -> Self {
+        self.graffiti = graffiti;
+        self
+    }
+
     pub fn build(self) -> Result<BlockService<T, E>, String> {
         Ok(BlockService {
             inner: Arc::new(Inner {
@@ -62,6 +69,7 @@ impl<T: SlotClock + 'static, E: EthSpec> BlockServiceBuilder<T, E> {
                 context: self
                     .context
                     .ok_or_else(|| "Cannot build BlockService without runtime_context")?,
+                graffiti: self.graffiti,
             }),
         })
     }
@@ -73,6 +81,7 @@ pub struct Inner<T, E: EthSpec> {
     slot_clock: Arc<T>,
     beacon_node: RemoteBeaconNode<E>,
     context: RuntimeContext<E>,
+    graffiti: Option<Graffiti>,
 }
 
 /// Attempts to produce attestations for any block producer(s) at the start of the epoch.
@@ -214,7 +223,7 @@ impl<T: SlotClock + 'static, E: EthSpec> BlockService<T, E> {
             .beacon_node
             .http
             .validator()
-            .produce_block(slot, randao_reveal)
+            .produce_block(slot, randao_reveal, self.graffiti)
             .await
             .map_err(|e| format!("Error from beacon node when producing block: {:?}", e))?;
 

validator_client/src/cli.rs

@@ -60,4 +60,12 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                       node is not synced.",
                 ),
         )
+        // This overwrites the graffiti configured in the beacon node.
+        .arg(
+            Arg::with_name("graffiti")
+                .long("graffiti")
+                .help("Specify your custom graffiti to be included in blocks.")
+                .value_name("GRAFFITI")
+                .takes_value(true)
+        )
 }

validator_client/src/config.rs

@@ -2,6 +2,7 @@ use clap::ArgMatches;
 use clap_utils::{parse_optional, parse_path_with_default_in_home_dir};
 use serde_derive::{Deserialize, Serialize};
 use std::path::PathBuf;
+use types::{Graffiti, GRAFFITI_BYTES_LEN};
 
 pub const DEFAULT_HTTP_SERVER: &str = "http://localhost:5052/";
 pub const DEFAULT_DATA_DIR: &str = ".lighthouse/validators";
@@ -27,6 +28,8 @@ pub struct Config {
     pub strict_lockfiles: bool,
     /// If true, don't scan the validators dir for new keystores.
     pub disable_auto_discover: bool,
+    /// Graffiti to be inserted everytime we create a block.
+    pub graffiti: Option<Graffiti>,
 }
 
 impl Default for Config {
@@ -45,6 +48,7 @@ impl Default for Config {
             allow_unsynced_beacon_node: false,
             strict_lockfiles: false,
             disable_auto_discover: false,
+            graffiti: None,
         }
     }
 }
@@ -80,6 +84,26 @@ impl Config {
             config.secrets_dir = secrets_dir;
         }
 
+        if let Some(input_graffiti) = cli_args.value_of("graffiti") {
+            let graffiti_bytes = input_graffiti.as_bytes();
+            if graffiti_bytes.len() > GRAFFITI_BYTES_LEN {
+                return Err(format!(
+                    "Your graffiti is too long! {} bytes maximum!",
+                    GRAFFITI_BYTES_LEN
+                ));
+            } else {
+                // Default graffiti to all 0 bytes.
+                let mut graffiti = Graffiti::default();
+
+                // Copy the provided bytes over.
+                //
+                // Panic-free because `graffiti_bytes.len()` <= `GRAFFITI_BYTES_LEN`.
+                graffiti[..graffiti_bytes.len()].copy_from_slice(&graffiti_bytes);
+
+                config.graffiti = Some(graffiti);
+            }
+        }
+
         Ok(config)
     }
 }

validator_client/src/lib.rs

@@ -216,6 +216,7 @@ impl<T: EthSpec> ProductionValidatorClient<T> {
             .validator_store(validator_store.clone())
             .beacon_node(beacon_node.clone())
             .runtime_context(context.service_context("block".into()))
+            .graffiti(config.graffiti)
             .build()?;
 
         let attestation_service = AttestationServiceBuilder::new()