expose chain identifier in rpc (MystenLabs#12064)

## Description 

Sometimes it's easy to mistake two networks (testnet v.s. mainnet), this
adds a way to query the rpc to see which network the node is in. Also
add a CLI option.

## Test Plan 

tested locally.

---
If your changes are not user-facing and not a breaking change, you can
skip the following section. Otherwise, please indicate what changed, and
then add to the Release Notes section as highlighted during the release
process.

### Type of Change (Check all that apply)

- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes

crates/sui-core/src/authority.rs

@@ -65,6 +65,7 @@ use sui_types::crypto::{
     default_hash, AggregateAuthoritySignature, AuthorityKeyPair, AuthoritySignInfo, NetworkKeyPair,
     Signer,
 };
+use sui_types::digests::ChainIdentifier;
 use sui_types::digests::TransactionEventsDigest;
 use sui_types::dynamic_field::{DynamicFieldInfo, DynamicFieldName, DynamicFieldType, Field};
 use sui_types::effects::{
@@ -162,7 +163,7 @@ pub mod test_authority_builder;
 pub(crate) mod authority_notify_read;
 pub(crate) mod authority_store;
 
-static CHAIN_IDENTIFIER: OnceCell<CheckpointDigest> = OnceCell::new();
+static CHAIN_IDENTIFIER: OnceCell<ChainIdentifier> = OnceCell::new();
 
 pub type ReconfigConsensusMessage = (
     AuthorityKeyPair,
@@ -2297,7 +2298,7 @@ impl AuthorityState {
     }
 
     /// Chain Identifier is the digest of the genesis checkpoint.
-    pub fn get_chain_identifier(&self) -> Option<CheckpointDigest> {
+    pub fn get_chain_identifier(&self) -> Option<ChainIdentifier> {
         if let Some(digest) = CHAIN_IDENTIFIER.get() {
             return Some(*digest);
         }
@@ -2308,8 +2309,8 @@ impl AuthorityState {
             .ok()?
             .tap_none(|| error!("Genesis checkpoint is missing from DB"))?;
         // It's ok if the value is already set due to data races.
-        let _ = CHAIN_IDENTIFIER.set(*checkpoint.digest());
-        Some(*checkpoint.digest())
+        let _ = CHAIN_IDENTIFIER.set(ChainIdentifier::from(*checkpoint.digest()));
+        Some(ChainIdentifier::from(*checkpoint.digest()))
     }
 
     pub fn get_move_object<T>(&self, object_id: &ObjectID) -> SuiResult<T>

crates/sui-indexer/src/apis/read_api.rs

@@ -16,7 +16,7 @@ use sui_json_rpc_types::{
 };
 use sui_open_rpc::Module;
 use sui_types::base_types::{ObjectID, SequenceNumber};
-use sui_types::digests::TransactionDigest;
+use sui_types::digests::{ChainIdentifier, TransactionDigest};
 use sui_types::sui_serde::BigInt;
 
 use crate::errors::IndexerError;
@@ -367,6 +367,15 @@ where
         protocol_config_guard.stop_and_record();
         protocol_config_resp
     }
+
+    async fn get_chain_identifier(&self) -> RpcResult<String> {
+        let ci = self
+            .state
+            .get_checkpoint(CheckpointId::SequenceNumber(0))
+            .await?
+            .digest;
+        Ok(ChainIdentifier::from(ci).to_string())
+    }
 }
 
 impl<S> SuiRpcModule for ReadApi<S>

crates/sui-json-rpc/src/api/read.rs

@@ -148,4 +148,8 @@ pub trait ReadApi {
         /// An optional protocol version specifier. If omitted, the latest protocol config table for the node will be returned.
         version: Option<BigInt<u64>>,
     ) -> RpcResult<ProtocolConfigResponse>;
+
+    /// Return the chain's identifier
+    #[method(name = "getChainIdentifier")]
+    async fn get_chain_identifier(&self) -> RpcResult<String>;
 }

crates/sui-json-rpc/src/read_api.rs

@@ -935,6 +935,17 @@ impl ReadApiServer for ReadApi {
                 .map(ProtocolConfigResponse::from)?)
         })
     }
+
+    #[instrument(skip(self))]
+    async fn get_chain_identifier(&self) -> RpcResult<String> {
+        with_tracing!(async move {
+            let ci = self
+                .state
+                .get_chain_identifier()
+                .ok_or(anyhow!("Chain identifier not found"))?;
+            Ok(ci.to_string())
+        })
+    }
 }
 
 impl SuiRpcModule for ReadApi {

crates/sui-node/src/main.rs

@@ -2,7 +2,6 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use clap::Parser;
-use fastcrypto::encoding::{Encoding, Hex};
 use mysten_common::sync::async_once_cell::AsyncOnceCell;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -126,8 +125,7 @@ fn main() {
     runtimes.metrics.spawn(async move {
         let node = node_once_cell_clone.get().await;
         let chain_identifier = match node.state().get_chain_identifier() {
-            // Unwrap safe: Checkpoint Digest is 32 bytes long
-            Some(chain_identifier) => Hex::encode(chain_identifier.into_inner().get(0..4).unwrap()),
+            Some(chain_identifier) => chain_identifier.to_string(),
             None => "Unknown".to_string(),
         };
 

crates/sui-open-rpc/spec/openrpc.json

@@ -495,6 +495,23 @@
         }
       ]
     },
+    {
+      "name": "sui_getChainIdentifier",
+      "tags": [
+        {
+          "name": "Read API"
+        }
+      ],
+      "description": "Return the chain's identifier",
+      "params": [],
+      "result": {
+        "name": "String",
+        "required": true,
+        "schema": {
+          "type": "string"
+        }
+      }
+    },
     {
       "name": "sui_getCheckpoint",
       "tags": [

crates/sui-sdk/src/apis.rs

@@ -169,6 +169,10 @@ impl ReadApi {
             .await?)
     }
 
+    pub async fn get_chain_identifier(&self) -> SuiRpcResult<String> {
+        Ok(self.api.http.get_chain_identifier().await?)
+    }
+
     /// Return a checkpoint
     pub async fn get_checkpoint(&self, id: CheckpointId) -> SuiRpcResult<Checkpoint> {
         Ok(self.api.http.get_checkpoint(id).await?)

crates/sui-telemetry/src/lib.rs

@@ -8,9 +8,6 @@ use std::time::{SystemTime, UNIX_EPOCH};
 use sui_core::authority::AuthorityState;
 use tracing::trace;
 
-use fastcrypto::encoding::Encoding;
-use fastcrypto::encoding::Hex;
-
 pub(crate) const GA_API_SECRET: &str = "zeq-aYEzS0aGdRJ8kNZTEg";
 pub(crate) const GA_EVENT_NAME: &str = "node_telemetry_event";
 pub(crate) const GA_MEASUREMENT_ID: &str = "G-96DM59YK2F";
@@ -45,8 +42,7 @@ pub async fn send_telemetry_event(state: Arc<AuthorityState>, is_validator: bool
     let git_rev = env!("CARGO_PKG_VERSION").to_string();
     let ip_address = get_ip().await;
     let chain_identifier = match state.get_chain_identifier() {
-        // Unwrap safe: Checkpoint Digest is 32 bytes long
-        Some(chain_identifier) => Hex::encode(chain_identifier.into_inner().get(0..4).unwrap()),
+        Some(chain_identifier) => chain_identifier.to_string(),
         None => "Unknown".to_string(),
     };
     let since_the_epoch = SystemTime::now()

crates/sui-types/src/digests.rs

@@ -111,6 +111,28 @@ impl fmt::UpperHex for Digest {
     }
 }
 
+/// Representation of a network's identifier by the genesis checkpoint's digest
+#[derive(
+    Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize, JsonSchema,
+)]
+pub struct ChainIdentifier(CheckpointDigest);
+
+impl fmt::Display for ChainIdentifier {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for byte in self.0 .0 .0[0..4].iter() {
+            write!(f, "{:02x}", byte)?;
+        }
+
+        Ok(())
+    }
+}
+
+impl From<CheckpointDigest> for ChainIdentifier {
+    fn from(digest: CheckpointDigest) -> Self {
+        Self(digest)
+    }
+}
+
 /// Representation of a Checkpoint's digest
 #[derive(
     Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize, JsonSchema,

crates/sui/src/client_commands.rs

@@ -613,6 +613,10 @@ pub enum SuiClientCommands {
         #[clap(long)]
         signatures: Vec<String>,
     },
+
+    /// Query the chain identifier from the rpc endpoint.
+    #[clap(name = "chain-identifier")]
+    ChainIdentifier,
 }
 
 impl SuiClientCommands {
@@ -1069,6 +1073,15 @@ impl SuiClientCommands {
                     .collect();
                 SuiClientCommandResult::Gas(coins)
             }
+            SuiClientCommands::ChainIdentifier => {
+                let ci = context
+                    .get_client()
+                    .await?
+                    .read_api()
+                    .get_chain_identifier()
+                    .await?;
+                SuiClientCommandResult::ChainIdentifier(ci)
+            }
             SuiClientCommands::SplitCoin {
                 coin_id,
                 amounts,
@@ -1501,6 +1514,9 @@ impl Display for SuiClientCommandResult {
                     writeln!(writer, " {0: ^66} | {1: ^11}", gas.id(), gas.value())?;
                 }
             }
+            SuiClientCommandResult::ChainIdentifier(ci) => {
+                writeln!(writer, "{}", ci)?;
+            }
             SuiClientCommandResult::SplitCoin(response) => {
                 write!(writer, "{}", write_transaction_response(response)?)?;
             }
@@ -1746,6 +1762,7 @@ pub enum SuiClientCommandResult {
     SyncClientState,
     NewAddress((SuiAddress, String, SignatureScheme)),
     Gas(Vec<GasCoin>),
+    ChainIdentifier(String),
     SplitCoin(SuiTransactionBlockResponse),
     MergeCoin(SuiTransactionBlockResponse),
     Switch(SwitchResponse),