peasub 0.2.0

A metadata-private gossip protocol built on peashape, with constant-rate or Poisson-distributed cover traffic.
Documentation 
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//! Error types returned by the public API.

use thiserror::Error;

/// All errors that can be surfaced to the application through the
/// public `peasub` API.
#[derive(Debug, Error)]
#[non_exhaustive]
pub enum Error {
    /// The application payload is too large to fit in a single
    /// gossip frame. The maximum size is `message_size - ID_SIZE`
    /// bytes. Either shrink the payload or raise `message_size`.
    #[error("payload too large: {size} bytes, maximum is {max}")]
    PayloadTooLarge {
        /// The size of the offending payload, in bytes.
        size: usize,
        /// The maximum payload size accepted by this node, in
        /// bytes.
        max: usize,
    },

    /// The application outbox is full. This happens when `publish`
    /// is called faster than the cover rate for a sustained
    /// period, so the queue of pending application messages has
    /// reached `app_outbox_capacity`. The caller should either
    /// slow down, raise the cover rate, or raise
    /// `app_outbox_capacity`.
    #[error("application outbox is full; the cover rate is too low for the current publish rate")]
    AppOutboxFull,

    /// An I/O error from the underlying `pea2pea` transport, e.g.
    /// a failed `connect`, `bind`, or socket read.
    #[error("I/O error: {0}")]
    Io(#[from] std::io::Error),
}

impl From<peashape::Error> for Error {
    fn from(e: peashape::Error) -> Self {
        match e {
            peashape::Error::PayloadTooLarge { size, max } => Error::PayloadTooLarge { size, max },
            peashape::Error::LaneFull => Error::AppOutboxFull,
            peashape::Error::Io(io) => Error::Io(io),
            // The `peashape::Error` enum is `non_exhaustive`, so a
            // wildcard arm is required to future-proof the
            // conversion against variants added in newer
            // peashape versions.
            other => Error::Io(std::io::Error::other(other.to_string())),
        }
    }
}