created attester_service and started to create an attester_thread in main of validator_client (lighthouse-255)

validator_client/src/attester_service/mod.rs

@@ -0,0 +1,51 @@
+use attester::{Attester, BeaconNode, DutiesReader, PollOutcome as AttesterPollOutcome, Signer};
+use slog::Logger;
+use slot_clock::SlotClock;
+use std::time::Duration;
+
+pub struct AttesterService<T: SlotClock, U: BeaconNode, V: DutiesReader, W: Signer> {
+    pub attester: Attester<T, U, V, W>,
+    pub poll_interval_millis: u64,
+    pub log: Logger,
+}
+
+impl<T: SlotClock, U: BeaconNode, V: DutiesReader, W: Signer> AttesterService<T, U, V, W> {
+    /// Run a loop which polls the Attester each `poll_interval_millis` millseconds.
+    ///
+    /// Logs the results of the polls.
+    pub fn run(&mut self) {
+        loop {
+            match self.attester.poll() {
+                Err(error) => {
+                    error!(self.log, "Attester poll error"; "error" => format!("{:?}", error))
+                }
+                Ok(AttesterPollOutcome::AttestationProduced(slot)) => {
+                    info!(self.log, "Produced Attestation"; "slot" => slot)
+                }
+                Ok(AttesterPollOutcome::SlashableAttestationNotProduced(slot)) => {
+                    warn!(self.log, "Slashable attestation was not produced"; "slot" => slot)
+                }
+                Ok(AttesterPollOutcome::AttestationNotRequired(slot)) => {
+                    info!(self.log, "Attestation not required"; "slot" => slot)
+                }
+                Ok(AttesterPollOutcome::ProducerDutiesUnknown(slot)) => {
+                    error!(self.log, "Attestation duties unknown"; "slot" => slot)
+                }
+                Ok(AttesterPollOutcome::SlotAlreadyProcessed(slot)) => {
+                    warn!(self.log, "Attempted to re-process slot"; "slot" => slot)
+                }
+                Ok(AttesterPollOutcome::BeaconNodeUnableToProduceAttestation(slot)) => {
+                    error!(self.log, "Beacon node unable to produce attestation"; "slot" => slot)
+                }
+                Ok(AttesterPollOutcome::SignerRejection(slot)) => {
+                    error!(self.log, "The cryptographic signer refused to sign the attestation"; "slot" => slot)
+                }
+                Ok(AttesterPollOutcome::ValidatorIsUnknown(slot)) => {
+                    error!(self.log, "The Beacon Node does not recognise the validator"; "slot" => slot)
+                }
+            };
+
+            std::thread::sleep(Duration::from_millis(self.poll_interval_millis));
+        }
+    }
+}