dcache/src/network/raft_network_impl.rs

/*
 * mCaptcha - A proof of work based DoS protection system
 * Copyright © 2021 Aravinth Manivannan <realravinth@batsense.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
use async_trait::async_trait;
use openraft::error::InstallSnapshotError;
use openraft::error::NetworkError;
use openraft::error::RPCError;
use openraft::error::RaftError;
use openraft::error::RemoteError;
use openraft::raft::AppendEntriesRequest;
use openraft::raft::AppendEntriesResponse;
use openraft::raft::InstallSnapshotRequest;
use openraft::raft::InstallSnapshotResponse;
use openraft::raft::VoteRequest;
use openraft::raft::VoteResponse;
use openraft::BasicNode;
use openraft::RaftNetwork;
use openraft::RaftNetworkFactory;
use serde::de::DeserializeOwned;
use serde::Serialize;

use crate::ExampleNodeId;
use crate::ExampleTypeConfig;

pub struct ExampleNetwork {}

impl ExampleNetwork {
    pub async fn send_rpc<Req, Resp, Err>(
        &self,
        target: ExampleNodeId,
        target_node: &BasicNode,
        uri: &str,
        req: Req,
    ) -> Result<Resp, RPCError<ExampleNodeId, BasicNode, Err>>
    where
        Req: Serialize,
        Err: std::error::Error + DeserializeOwned,
        Resp: DeserializeOwned,
    {
        let addr = &target_node.addr;

        let url = format!("http://{}/{}", addr, uri);

        tracing::debug!("send_rpc to url: {}", url);

        let client = reqwest::Client::new();

        tracing::debug!("client is created for: {}", url);

        let resp = client
            .post(url)
            .json(&req)
            .send()
            .await
            .map_err(|e| RPCError::Network(NetworkError::new(&e)))?;

        tracing::debug!("client.post() is sent");

        let res: Result<Resp, Err> = resp
            .json()
            .await
            .map_err(|e| RPCError::Network(NetworkError::new(&e)))?;

        res.map_err(|e| RPCError::RemoteError(RemoteError::new(target, e)))
    }
}

// NOTE: This could be implemented also on `Arc<ExampleNetwork>`, but since it's empty, implemented
// directly.
#[async_trait]
impl RaftNetworkFactory<ExampleTypeConfig> for ExampleNetwork {
    type Network = ExampleNetworkConnection;

    async fn new_client(&mut self, target: ExampleNodeId, node: &BasicNode) -> Self::Network {
        ExampleNetworkConnection {
            owner: ExampleNetwork {},
            target,
            target_node: node.clone(),
        }
    }
}

pub struct ExampleNetworkConnection {
    owner: ExampleNetwork,
    target: ExampleNodeId,
    target_node: BasicNode,
}

#[async_trait]
impl RaftNetwork<ExampleTypeConfig> for ExampleNetworkConnection {
    async fn send_append_entries(
        &mut self,
        req: AppendEntriesRequest<ExampleTypeConfig>,
    ) -> Result<
        AppendEntriesResponse<ExampleNodeId>,
        RPCError<ExampleNodeId, BasicNode, RaftError<ExampleNodeId>>,
    > {
        self.owner
            .send_rpc(self.target, &self.target_node, "raft-append", req)
            .await
    }

    async fn send_install_snapshot(
        &mut self,
        req: InstallSnapshotRequest<ExampleTypeConfig>,
    ) -> Result<
        InstallSnapshotResponse<ExampleNodeId>,
        RPCError<ExampleNodeId, BasicNode, RaftError<ExampleNodeId, InstallSnapshotError>>,
    > {
        self.owner
            .send_rpc(self.target, &self.target_node, "raft-snapshot", req)
            .await
    }

    async fn send_vote(
        &mut self,
        req: VoteRequest<ExampleNodeId>,
    ) -> Result<
        VoteResponse<ExampleNodeId>,
        RPCError<ExampleNodeId, BasicNode, RaftError<ExampleNodeId>>,
    > {
        self.owner
            .send_rpc(self.target, &self.target_node, "raft-vote", req)
            .await
    }
}