Added context to the sync committee duties error

CHANGELOG.md

@@ -10,5 +10,6 @@
 
 ### Additions and Improvements
 - Added `--p2p-static-peers-url` option to read static peers from a URL or file
+- Added node epoch and computed slot to the sync committee duties failure message for more context about the failure condition.
 
 ### Bug Fixes

beacon/validator/src/main/java/tech/pegasys/teku/validator/coordinator/ValidatorApiHandler.java

@@ -802,15 +802,17 @@ private SafeFuture<Optional<BeaconState>> getStateForCommitteeDuties(
                 return SafeFuture.completedFuture(Optional.of(bestState));
               }
 
-              final UInt64 lastQueryableEpoch =
+              final UInt64 maxQueryableEpoch =
                   syncCommitteeUtil.computeLastEpochOfNextSyncCommitteePeriod(
                       combinedChainDataClient.getCurrentEpoch());
-              if (lastQueryableEpoch.isLessThan(epoch)) {
+              if (maxQueryableEpoch.isLessThan(epoch)) {
+                final Optional<UInt64> networkCurrentSlot =
+                    chainDataProvider.getNetworkCurrentSlot();
                 return SafeFuture.failedFuture(
                     new IllegalArgumentException(
-                        "Cannot calculate sync committee duties for epoch "
-                            + epoch
-                            + " because it is not within the current or next sync committee periods"));
+                        String.format(
+                            "Cannot calculate sync committee duties for epoch %s because it is not within the current or next sync committee periods (node current epoch %s, computed current slot %s)",
+                            epoch, combinedChainDataClient.getCurrentEpoch(), networkCurrentSlot)));
               }
 
               final UInt64 requiredEpoch;

data/provider/src/main/java/tech/pegasys/teku/api/ChainDataProvider.java

@@ -148,6 +148,10 @@ public GenesisData getGenesisData() {
         spec.atEpoch(ZERO).getConfig().getGenesisForkVersion());
   }
 
+  public Optional<UInt64> getNetworkCurrentSlot() {
+    return recentChainData.getCurrentSlot();
+  }
+
   public tech.pegasys.teku.spec.datastructures.genesis.GenesisData getGenesisStateData() {
     if (!isStoreAvailable()) {
       throw new ChainDataUnavailableException();