Implement the access to the shard_id (#4781)

## Motivation

For debugging purposes, it is useful to access the shard index of the
validators for a fixed chain.

## Proposal

The implementation is straightforward:
* Add it as an endpoint to the proxy.
* Add it as a feature to the "linera" client.


## Test Plan

No test has been added to the CI.
However, the function has been tested locally with the following steps.
A: Starting the validators
```bash
   ./target/debug/linera storage delete-all --storage service:tcp:localhost:1235:table_a
   rm -rf /tmp/WORK && mkdir -p /tmp/WORK
   export RUST_BACKTRACE=full
   ./target/debug/linera net up --policy-config testnet --storage service:tcp:localhost:1235:table_a --validators 4 --shards 4 --path /tmp/WORK
```

B: Running the faucet
```bash
   export LINERA_WALLET="/tmp/WORK/wallet_0.json"
   export LINERA_KEYSTORE="/tmp/WORK/keystore_0.json"
   export LINERA_STORAGE="rocksdb:/tmp/WORK/client_0.db"
   ./target/debug/linera faucet --amount 1000 --port 8079 --storage-path /tmp/WORK/faucet_storage.sqlite
```

C: Creating a chain, showing
```bash
   rm -rf /tmp/WORK_B && mkdir -p /tmp/WORK_B
   export LINERA_WALLET="/tmp/WORK_B/wallet_0.json"
   export LINERA_KEYSTORE="/tmp/WORK_B/keystore_0.json"
   export LINERA_STORAGE="rocksdb:/tmp/WORK_B/client_0.db"
   export FAUCET_URL=http://localhost:8079
   ./target/debug/linera wallet init --faucet $FAUCET_URL
   ./target/debug/linera wallet request-chain --faucet $FAUCET_URL
   ./target/debug/linera wallet show
```

D: Showing up the result from the obtained `ChainId`
```bash
   ./target/debug/linera query-shard-info 42a1c60a969b9c6ce893fd3746ec6084e0c336820f1336fa40e39e4aa5708c5b
Querying validators for shard information about chain 42a1c60a969b9c6ce893fd3746ec6084e0c336820f1336fa40e39e4aa5708c5b.

Chain ID: 42a1c60a969b9c6ce893fd3746ec6084e0c336820f1336fa40e39e4aa5708c5b
Validator Shard Information:

  Validator: 033f3e155e7c0c7fae94692df5501eeab55e98a8c086e568cb672d7a8270e7c08f
    Address: grpc:localhost:13004
    Total Shards: 4
    Shard ID for chain: 0

  Validator: 02b7742453a60ad3e2d615f59aa6b00d72d0b126ea9181264f3bd459eb1e42b557
    Address: grpc:localhost:13003
    Total Shards: 4
    Shard ID for chain: 3

  Validator: 03b99ffb3804db5fa05534a5eb0bc890add528acb66b39931bca878ee2b68f72a7
    Address: grpc:localhost:13001
    Total Shards: 4
    Shard ID for chain: 2

  Validator: 02e33d49cc2279adfdfea6cafa523d739f95969ebddd13a96720f0dffafb2dceb2
    Address: grpc:localhost:13002
    Total Shards: 4
    Shard ID for chain: 1
```




## Release Plan

If this is feasible, then we should backport it to the TestNet Conway
branch.

## Links

None.

Author: MathieuDutSik

CLI.md

@@ -21,6 +21,7 @@ This document contains the help content for the `linera` command-line program.
 * [`linera process-inbox`↴](#linera-process-inbox)
 * [`linera query-validator`↴](#linera-query-validator)
 * [`linera query-validators`↴](#linera-query-validators)
+* [`linera query-shard-info`↴](#linera-query-shard-info)
 * [`linera sync-validator`↴](#linera-sync-validator)
 * [`linera sync-all-validators`↴](#linera-sync-all-validators)
 * [`linera set-validator`↴](#linera-set-validator)
@@ -94,6 +95,7 @@ Client implementation and command-line tool for the Linera blockchain
 * `process-inbox` — Process all pending incoming messages from the inbox of the given chain by creating as many blocks as needed to execute all (non-failing) messages. Failing messages will be marked as rejected and may bounce to their sender depending on their configuration
 * `query-validator` — Show the version and genesis config hash of a new validator, and print a warning if it is incompatible. Also print some information about the given chain while we are at it
 * `query-validators` — Show the current set of validators for a chain. Also print some information about the given chain while we are at it
+* `query-shard-info` — Query validators for shard information about a specific chain
 * `sync-validator` — Synchronizes a validator with the local state of chains
 * `sync-all-validators` — Synchronizes all validators with the local state of chains
 * `set-validator` — Add or modify a validator (admin only)
@@ -494,6 +496,18 @@ Show the current set of validators for a chain. Also print some information abou
 
 
 
+## `linera query-shard-info`
+
+Query validators for shard information about a specific chain
+
+**Usage:** `linera query-shard-info <CHAIN_ID>`
+
+###### **Arguments:**
+
+* `<CHAIN_ID>` — The chain to query shard information for
+
+
+
 ## `linera sync-validator`
 
 Synchronizes a validator with the local state of chains

linera-core/src/data_types.rs

@@ -238,6 +238,16 @@ pub struct ChainInfoResponse {
     pub signature: Option<ValidatorSignature>,
 }
 
+/// Information about shard allocation for a chain.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+#[cfg_attr(with_testing, derive(Eq, PartialEq))]
+pub struct ShardInfo {
+    /// The shard ID that will process this chain.
+    pub shard_id: usize,
+    /// The total number of shards in the validator.
+    pub total_shards: usize,
+}
+
 /// An internal request between chains within a validator.
 #[derive(Clone, Debug, Serialize, Deserialize)]
 #[cfg_attr(with_testing, derive(Eq, PartialEq))]

linera-core/src/node.rs

@@ -163,6 +163,12 @@ pub trait ValidatorNode {
 
     /// Returns the missing `Blob`s by their IDs.
     async fn missing_blob_ids(&self, blob_ids: Vec<BlobId>) -> Result<Vec<BlobId>, NodeError>;
+
+    /// Gets shard information for a specific chain.
+    async fn get_shard_info(
+        &self,
+        chain_id: ChainId,
+    ) -> Result<crate::data_types::ShardInfo, NodeError>;
 }
 
 /// Turn an address into a validator node.

linera-core/src/unit_tests/test_utils.rs

@@ -272,6 +272,17 @@ where
         })
         .await
     }
+
+    async fn get_shard_info(
+        &self,
+        _chain_id: ChainId,
+    ) -> Result<crate::data_types::ShardInfo, NodeError> {
+        // For test purposes, return a dummy shard info
+        Ok(crate::data_types::ShardInfo {
+            shard_id: 0,
+            total_shards: 1,
+        })
+    }
 }
 
 impl<S> LocalValidatorClient<S>

linera-rpc/proto/rpc.proto

@@ -66,6 +66,9 @@ service ValidatorNode {
   // Request the network description seen by this node.
   rpc GetNetworkDescription(google.protobuf.Empty) returns (NetworkDescription);
 
+  // Request shard information for a specific chain.
+  rpc GetShardInfo(ChainId) returns (ShardInfo);
+
   // Download a blob.
   rpc DownloadBlob(BlobId) returns (BlobContent);
 
@@ -156,6 +159,12 @@ message NetworkDescription {
     CryptoHash genesis_committee_blob_hash = 5;
 }
 
+// Information about shard configuration for a specific chain.
+message ShardInfo {
+    uint64 shard_id = 1;
+    uint64 total_shards = 2;
+}
+
 // A request for client to subscribe to notifications for a given `ChainId`
 message SubscriptionRequest {
   repeated ChainId chain_ids = 1;

linera-rpc/src/client.rs

@@ -298,4 +298,16 @@ impl ValidatorNode for Client {
             Client::Simple(simple_client) => simple_client.missing_blob_ids(blob_ids).await?,
         })
     }
+
+    async fn get_shard_info(
+        &self,
+        chain_id: ChainId,
+    ) -> Result<linera_core::data_types::ShardInfo, NodeError> {
+        Ok(match self {
+            Client::Grpc(grpc_client) => grpc_client.get_shard_info(chain_id).await?,
+
+            #[cfg(with_simple_network)]
+            Client::Simple(simple_client) => simple_client.get_shard_info(chain_id).await?,
+        })
+    }
 }

linera-rpc/src/grpc/client.rs

@@ -497,4 +497,16 @@ impl ValidatorNode for GrpcClient {
     async fn missing_blob_ids(&self, blob_ids: Vec<BlobId>) -> Result<Vec<BlobId>, NodeError> {
         Ok(client_delegate!(self, missing_blob_ids, blob_ids)?.try_into()?)
     }
+
+    #[instrument(target = "grpc_client", skip(self), err(level = Level::WARN), fields(address = self.address))]
+    async fn get_shard_info(
+        &self,
+        chain_id: ChainId,
+    ) -> Result<linera_core::data_types::ShardInfo, NodeError> {
+        let response = client_delegate!(self, get_shard_info, chain_id)?;
+        Ok(linera_core::data_types::ShardInfo {
+            shard_id: response.shard_id as usize,
+            total_shards: response.total_shards as usize,
+        })
+    }
 }

linera-rpc/src/lib.rs

@@ -20,7 +20,7 @@ pub mod simple;
 pub mod grpc;
 
 pub use client::Client;
-pub use message::RpcMessage;
+pub use message::{RpcMessage, ShardInfo};
 pub use node_provider::{NodeOptions, NodeProvider};
 
 #[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]

linera-rpc/src/message.rs

@@ -19,10 +19,20 @@ use linera_version::VersionInfo;
 use serde::{Deserialize, Serialize};
 
 use crate::{
-    HandleConfirmedCertificateRequest, HandleLiteCertRequest, HandleTimeoutCertificateRequest,
-    HandleValidatedCertificateRequest,
+    config::ShardId, HandleConfirmedCertificateRequest, HandleLiteCertRequest,
+    HandleTimeoutCertificateRequest, HandleValidatedCertificateRequest,
 };
 
+/// Information about shard configuration for a specific chain.
+#[derive(Clone, Serialize, Deserialize, Debug)]
+#[cfg_attr(with_testing, derive(Eq, PartialEq))]
+pub struct ShardInfo {
+    /// The ID of the shard assigned to the chain.
+    pub shard_id: ShardId,
+    /// The total number of shards in the validator network.
+    pub total_shards: usize,
+}
+
 #[derive(Clone, Serialize, Deserialize, Debug)]
 #[cfg_attr(with_testing, derive(Eq, PartialEq))]
 pub enum RpcMessage {
@@ -65,6 +75,8 @@ pub enum RpcMessage {
 
     BlobLastUsedByCertificate(Box<BlobId>),
     BlobLastUsedByCertificateResponse(Box<ConfirmedBlockCertificate>),
+    ShardInfoQuery(ChainId),
+    ShardInfoResponse(ShardInfo),
 }
 
 impl RpcMessage {
@@ -85,6 +97,7 @@ impl RpcMessage {
             DownloadPendingBlob(request) => request.0,
             DownloadCertificatesByHeights(chain_id, _) => *chain_id,
             HandlePendingBlob(request) => request.0,
+            ShardInfoQuery(chain_id) => *chain_id,
             Vote(_)
             | Error(_)
             | ChainInfoResponse(_)
@@ -107,6 +120,7 @@ impl RpcMessage {
             | BlobLastUsedByCertificateResponse(_)
             | MissingBlobIds(_)
             | MissingBlobIdsResponse(_)
+            | ShardInfoResponse(_)
             | DownloadCertificatesResponse(_) => {
                 return None;
             }
@@ -123,6 +137,7 @@ impl RpcMessage {
         match self {
             VersionInfoQuery
             | NetworkDescriptionQuery
+            | ShardInfoQuery(_)
             | UploadBlob(_)
             | DownloadBlob(_)
             | DownloadConfirmedBlock(_)
@@ -143,6 +158,7 @@ impl RpcMessage {
             | ChainInfoResponse(_)
             | VersionInfoResponse(_)
             | NetworkDescriptionResponse(_)
+            | ShardInfoResponse(_)
             | UploadBlobResponse(_)
             | DownloadPendingBlob(_)
             | DownloadPendingBlobResponse(_)
@@ -269,6 +285,17 @@ impl TryFrom<RpcMessage> for BlobId {
     }
 }
 
+impl TryFrom<RpcMessage> for ShardInfo {
+    type Error = NodeError;
+    fn try_from(message: RpcMessage) -> Result<Self, Self::Error> {
+        match message {
+            RpcMessage::ShardInfoResponse(shard_info) => Ok(shard_info),
+            RpcMessage::Error(error) => Err(*error),
+            _ => Err(NodeError::UnexpectedMessage),
+        }
+    }
+}
+
 impl From<NodeError> for RpcMessage {
     fn from(error: NodeError) -> Self {
         RpcMessage::Error(Box::new(error))

linera-rpc/src/simple/client.rs

@@ -259,4 +259,16 @@ impl ValidatorNode for SimpleClient {
     async fn missing_blob_ids(&self, blob_ids: Vec<BlobId>) -> Result<Vec<BlobId>, NodeError> {
         self.query(RpcMessage::MissingBlobIds(blob_ids)).await
     }
+
+    async fn get_shard_info(
+        &self,
+        chain_id: ChainId,
+    ) -> Result<linera_core::data_types::ShardInfo, NodeError> {
+        let rpc_shard_info: crate::message::ShardInfo =
+            self.query(RpcMessage::ShardInfoQuery(chain_id)).await?;
+        Ok(linera_core::data_types::ShardInfo {
+            shard_id: rpc_shard_info.shard_id,
+            total_shards: rpc_shard_info.total_shards,
+        })
+    }
 }