Add unsafe attester crate

eth2/attester/src/traits.rs

@@ -0,0 +1,51 @@
+use types::{AttestationData, Signature};
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum BeaconNodeError {
+    RemoteFailure(String),
+    DecodeFailure,
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum PublishOutcome {
+    ValidAttestation,
+    InvalidAttestation(String),
+}
+
+/// Defines the methods required to produce and publish blocks on a Beacon Node.
+pub trait BeaconNode: Send + Sync {
+    fn produce_attestation_data(
+        &self,
+        slot: u64,
+        shard: u64,
+    ) -> Result<Option<AttestationData>, BeaconNodeError>;
+
+    fn publish_attestation_data(
+        &self,
+        attestation_data: AttestationData,
+        signature: Signature,
+        validator_index: u64,
+    ) -> Result<PublishOutcome, BeaconNodeError>;
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum DutiesReaderError {
+    UnknownValidator,
+    UnknownEpoch,
+    EpochLengthIsZero,
+    Poisoned,
+}
+
+/// Informs a validator of their duties (e.g., block production).
+pub trait DutiesReader: Send + Sync {
+    /// Returns `Some(shard)` if this slot is an attestation slot. Otherwise, returns `None.`
+    fn attestation_shard(&self, slot: u64) -> Result<Option<u64>, DutiesReaderError>;
+
+    /// Returns `Some(shard)` if this slot is an attestation slot. Otherwise, returns `None.`
+    fn validator_index(&self) -> Option<u64>;
+}
+
+/// Signs message using an internally-maintained private key.
+pub trait Signer {
+    fn bls_sign(&self, message: &[u8]) -> Option<Signature>;
+}