tari_comms 6.2.0-pre.0

A peer-to-peer messaging system
Documentation 
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//  Copyright 2020, The Tari Project
//
//  Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
//  following conditions are met:
//
//  1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
//  disclaimer.
//
//  2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
//  following disclaimer in the documentation and/or other materials provided with the distribution.
//
//  3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
//  products derived from this software without specific prior written permission.
//
//  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
//  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
//  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
//  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
//  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
//  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
//  USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

//! # RPC protocol
//!
//! Provides a request/response protocol that supports streaming.
//! Available with the `rpc` crate feature.

#[cfg(test)]
mod test;

/// Maximum frame size of each RPC message. This is enforced in tokio's length delimited codec.
/// This can be thought of as the hard limit on message size.
///
/// This is the messaging protocol frame size (8 MiB) plus 1 KiB, so that the RPC frame is a strict superset of the
/// messaging frame: the RPC response payload is capped at this frame size minus the response header (see
/// `max_response_payload_size`), so anything that fits in a messaging frame (e.g. a propagated block) also fits in an
/// RPC response (e.g. when the same block is fetched during sync).
pub const RPC_MAX_FRAME_SIZE: usize = crate::protocol::messaging::MAX_FRAME_LENGTH + 1024; // 8 MiB + 1 KiB

/// The maximum size of an encoded RPC request. Only responses need the larger [RPC_MAX_FRAME_SIZE] (to carry anything
/// that fits in a messaging frame); requests keep the previous 6 MiB cap. The server rejects a larger request before
/// decoding it.
///
/// This byte cap does not bound decode memory on its own: prost allocates a full struct per embedded message, so a
/// small payload of empty elements can decode into many times its size. The bound on decode memory is the item budget
/// enforced by [crate::decode_budget] before every decode, together with the server's session limits.
pub const RPC_MAX_REQUEST_SIZE: usize = 6 * 1024 * 1024;
const _: () = assert!(RPC_MAX_REQUEST_SIZE <= RPC_MAX_FRAME_SIZE);

/// The maximum request payload size
const fn max_request_size() -> usize {
    RPC_MAX_REQUEST_SIZE
}

/// The maximum size for a single RPC response body excluding response header overhead
pub const fn max_response_payload_size() -> usize {
    // RpcResponse overhead is:
    // - 4 varint protobuf fields, each field ID is 1 byte
    // - 3 u32 fields, VarInt(u32::MAX) is 5 bytes
    // - 1 length varint for the payload, allow for 5 bytes to be safe (max_payload_size being technically too small is
    //   fine, being too large isn't)
    const MAX_HEADER_SIZE: usize = 4 + 4 * 5;
    RPC_MAX_FRAME_SIZE - MAX_HEADER_SIZE
}

mod body;
pub use body::{Body, ClientStreaming, IntoBody, Streaming};

pub use crate::decode_budget::{DEFAULT_MAX_DECODE_ITEMS, DecodeBudget};

mod context;

mod server;
pub use server::{NamedProtocolService, RpcServer, RpcServerBuilder, RpcServerError, RpcServerHandle, mock};

mod client;
pub use client::{
    RpcClient,
    RpcClientBuilder,
    RpcClientConfig,
    pool,
    pool::{RpcClientLease, RpcClientPool, RpcClientPoolError, RpcPoolClient},
};

mod either;

mod message;
pub use message::{Request, Response};

mod error;
pub use error::{HandshakeRejectReason, RpcError};

mod handshake;
pub use handshake::{Handshake, RpcHandshakeError};

mod status;
pub use status::{RpcStatus, RpcStatusCode, RpcStatusResultExt};

mod not_found;

// Re-exports used to keep things orderly in the #[tari_rpc] proc macro
pub mod __macro_reexports {
    pub use std::{
        boxed::Box,
        result::Result::{Err, Ok},
    };

    pub use futures::{future, future::BoxFuture};
    pub use tokio::io::{AsyncRead, AsyncWrite};
    pub use tower::Service;

    pub use crate::{
        Bytes,
        framing::CanonicalFraming,
        protocol::{
            ProtocolId,
            rpc::{
                Body,
                ClientStreaming,
                DEFAULT_MAX_DECODE_ITEMS,
                IntoBody,
                RpcClient,
                RpcClientBuilder,
                RpcError,
                RpcStatus,
                message::{Request, Response},
                pool::RpcPoolClient,
                server::{NamedProtocolService, RpcServerError},
            },
        },
        stream_id::StreamId,
    };
}