utilize minContextSlot to ensure that results from the same slots will not be processed (#13)

Co-authored-by: solpkr <solpkr1@gmail.com>

src/scripts/crank.ts

@@ -172,6 +172,9 @@ async function run() {
     (market) => market['_decoded'].eventQueue,
   );
 
+  //pass a minimum Context Slot to GMA
+  let minContextSlot = 0;
+
   // noinspection InfiniteLoopJS
   while (true) {
     try {
@@ -181,8 +184,13 @@ async function run() {
       const eventQueueAccts = await getMultipleAccounts(
         connection,
         eventQueuePks,
+        'processed',
+        minContextSlot,
       );
 
+     //increase the minContextSlot to avoid processing the same slot twice
+     minContextSlot = eventQueueAccts[0].context.slot + 1;
+
       for (let i = 0; i < eventQueueAccts.length; i++) {
         const accountInfo = eventQueueAccts[i].accountInfo;
         const events = decodeEventQueue(accountInfo.data);
@@ -279,11 +287,23 @@ async function run() {
 
       }
 
-      await sleep(interval);
+
 
     } catch (e) {
-      log.error(e);
+      if (e instanceof Error) {
+
+        switch (e.message){
+          case 'Minimum context slot has not been reached':
+            //lightweight warning message for known "safe" errors
+            log.warn(e.message);
+            break;
+          default:
+            log.error(e);
+        }
+
+      }
     }
+    await sleep(interval);
   }
 }
 

src/utils/utils.ts

@@ -13,6 +13,7 @@ export async function getMultipleAccounts(
   connection: Connection,
   publicKeys: PublicKey[],
   commitment?: Commitment,
+  minContextSlot?: number,
 ): Promise<
   {
     publicKey: PublicKey;
@@ -32,10 +33,15 @@ export async function getMultipleAccounts(
     ]).then((a) => a[0].concat(a[1]));
   }
   const publicKeyStrs = publicKeys.map((pk) => pk.toBase58());
+
   // load connection commitment as a default
   commitment ||= connection.commitment;
 
-  const args = commitment ? [publicKeyStrs, { commitment }] : [publicKeyStrs];
+  // set no minimum context slot by default
+  minContextSlot ||= 0;
+
+  const args = commitment ? [publicKeyStrs, { commitment,minContextSlot }] : [publicKeyStrs, {minContextSlot}];
+
   // @ts-ignore
   const resp = await connection._rpcRequest('getMultipleAccounts', args);
   if (resp.error) {