Add intermittent gasPrice Buffer Logic (#690)

During long lived operations of the relay it's possible for the relay to observe a change int eh gasPrice calculation needed by submitted transactions.
As a result some checks are often 1 tiny bar off

- add logic to provide a buffer for gas price prechecks - default to 1 tinybar
- add tests
- updated helm chart with default value

Signed-off-by: Nana Essilfie-Conduah <[email protected]>

Author: Nana-EC

.env.example

@@ -19,4 +19,5 @@ RATE_LIMIT_DISABLED =
 ETH_GET_LOGS_BLOCK_RANGE_LIMIT =
 DEV_MODE =
 MIRROR_NODE_RETRIES =
-MIRROR_NODE_RETRY_DELAY =
+MIRROR_NODE_RETRY_DELAY =
+GAS_PRICE_TINY_BAR_BUFFER =

README.md

@@ -83,6 +83,7 @@ RATE_LIMIT_DISABLED = false
 DEV_MODE = false
 MIRROR_NODE_RETRIES = 3
 MIRROR_NODE_RETRY_DELAY = 500
+GAS_PRICE_TINY_BAR_BUFFER = 10000000000
 ```
 
 Note: Read more about `DEV_MODE` [here](docs/dev-mode.md)

helm-chart/templates/deployment.yaml

@@ -150,6 +150,12 @@ spec:
                 name: {{ include "json-rpc-relay.fullname" . }}
                 key: DEV_MODE
                 optional: true
+          - name: GAS_PRICE_TINY_BAR_BUFFER
+            valueFrom:
+              configMapKeyRef:
+                name: {{ include "json-rpc-relay.fullname" . }}
+                key: GAS_PRICE_TINY_BAR_BUFFER
+                optional: true
         ports:
           - containerPort: {{ .Values.ports.containerPort }}
             name: {{ .Values.ports.name  }}

helm-chart/values.yaml

@@ -112,6 +112,7 @@ config:
   ETH_GET_LOGS_BLOCK_RANGE_LIMIT: 1000
   RATE_LIMIT_DISABLED: false
   DEV_MODE: false
+  GAS_PRICE_TINY_BAR_BUFFER: 10000000000
 
 # Enable rolling_restarts if SDK calls fail this is usually due to stale connections that get cycled on restart
 rolling_restart:

packages/relay/src/lib/precheck.ts

@@ -18,13 +18,12 @@
  *
  */
 
-import * as ethers from 'ethers';
 import { predefined } from './errors/JsonRpcError';
 import { MirrorNodeClient, SDKClient } from './clients';
 import { EthImpl } from './eth';
 import { Logger } from 'pino';
 import constants from './constants';
-import { Transaction } from 'ethers';
+import { ethers, Transaction } from 'ethers';
 import { formatRequestIdMessage } from '../formatters';
 
 export class Precheck {
@@ -110,11 +109,20 @@ export class Precheck {
    */
   gasPrice(tx: Transaction, gasPrice: number, requestId?: string) {
     const requestIdPrefix = formatRequestIdMessage(requestId);
-    const minGasPrice = ethers.ethers.BigNumber.from(gasPrice);
+    const minGasPrice = ethers.BigNumber.from(gasPrice);
     const txGasPrice = tx.gasPrice || tx.maxFeePerGas!.add(tx.maxPriorityFeePerGas!);
     const passes = txGasPrice.gte(minGasPrice);
 
     if (!passes) {
+      if (process.env.GAS_PRICE_TINY_BAR_BUFFER) {
+        // Check if failure is within buffer range (Often it's by 1 tinybar) as network gasprice calculation can change slightly.
+        // e.g gasPrice=1450000000000, requiredGasPrice=1460000000000, in which case we should allow users to go through and let the network check
+        const txGasPriceWithBuffer = txGasPrice.add(ethers.BigNumber.from(process.env.GAS_PRICE_TINY_BAR_BUFFER));
+        if (txGasPriceWithBuffer.gte(minGasPrice)) {
+          return;
+        }
+      }
+
       this.logger.trace(`${requestIdPrefix} Failed gas price precheck for sendRawTransaction(transaction=%s, gasPrice=%s, requiredGasPrice=%s)`, JSON.stringify(tx), txGasPrice, minGasPrice);
       throw predefined.GAS_PRICE_TOO_LOW;
     }
@@ -142,10 +150,10 @@ export class Precheck {
 
     try {
       tinybars = await this.sdkClient.getAccountBalanceInTinyBar(accountResponse.account, callerName, requestId);
-      result.passes = ethers.ethers.BigNumber.from(tinybars.toString()).mul(constants.TINYBAR_TO_WEIBAR_COEF).gte(txTotalValue);
+      result.passes = ethers.BigNumber.from(tinybars.toString()).mul(constants.TINYBAR_TO_WEIBAR_COEF).gte(txTotalValue);
     } catch (error: any) {
       this.logger.trace(`${requestIdPrefix} Error on balance precheck for sendRawTransaction(transaction=%s, totalValue=%s, error=%s)`, JSON.stringify(tx), txTotalValue, error.message);
-      throw predefined.INTERNAL_ERROR();
+      throw predefined.INTERNAL_ERROR('balance precheck');
     }
 
     if (!result.passes) {

packages/relay/tests/lib/precheck.spec.ts

@@ -39,6 +39,7 @@ describe('Precheck', async function() {
 
     const txWithMatchingChainId = '0x02f87482012a0485a7a358200085a7a3582000832dc6c09400000000000000000000000000000000000003f78502540be40080c001a006f4cd8e6f84b76a05a5c1542a08682c928108ef7163d9c1bf1f3b636b1cd1fba032097cbf2dda17a2dcc40f62c97964d9d930cdce2e8a9df9a8ba023cda28e4ad';
     const parsedTxWithMatchingChainId = ethers.utils.parseTransaction(txWithMatchingChainId);
+    const parsedTxGasPrice = 1440000000000;
     const txWithNonMatchingChainId = '0xf86a0385a7a3582000832dc6c09400000000000000000000000000000000000003f78502540be400801ca06750e92db52fa708e27f94f27e0cfb7f5800f9b657180bb2e94c1520cfb1fb6da01bec6045068b6db38b55017bb8b50166699384bc1791fd8331febab0cf629a2a';
     const parsedTxWithNonMatchingChainId = ethers.utils.parseTransaction(txWithNonMatchingChainId);
     const txWithValueMoreThanOneTinyBar = '0xf8628080809449858d4445908c12fcf70251d3f4682e8c9c381085174876e800801ba015ec73d3e329c7f5c0228be39bf30758f974d69468847dd507082c89ec453fe2a04124cc1dd6ac07417e7cdbe04cb99d698bddc6ce4d04054dd8978dec3493f3d2';
@@ -135,42 +136,6 @@ describe('Precheck', async function() {
         });
     });
 
-    describe('gas price', async function() {
-        it('should return true for gas price gt to required gas price', async function() {
-            const result = precheck.gasPrice(parsedTxWithMatchingChainId, 10);
-            expect(result).to.not.exist;
-        });
-
-        it('should return true for gas price equal to required gas price', async function() {
-            const result = precheck.gasPrice(parsedTxWithMatchingChainId, defaultGasPrice);
-            expect(result).to.not.exist;
-        });
-
-        it('should not pass for non-matching chainId', async function() {
-            try {
-                precheck.chainId(parsedTxWithNonMatchingChainId);
-                expectedError();
-            }
-            catch(e: any) {
-                expect(e).to.exist;
-                expect(e.code).to.eq(-32000);
-                expect(e.message).to.eq('ChainId (0x0) not supported. The correct chainId is 0x12a');
-            }
-        });
-
-        it('should not pass for gas price not enough', async function() {
-            const minGasPrice = 1000 * constants.TINYBAR_TO_WEIBAR_COEF;
-            try {
-                precheck.gasPrice(parsedTxWithMatchingChainId, minGasPrice);
-                expectedError();
-            } catch(e: any) {
-                expect(e).to.exist;
-                expect(e.code).to.eq(-32009);
-                expect(e.message).to.eq('Gas price below configured minimum gas price');
-            }
-        });
-    });
-
     describe('gasLimit', async function() {
         const defaultTx = {
             value: oneTinyBar,
@@ -228,6 +193,16 @@ describe('Precheck', async function() {
     });
 
     describe('gas price', async function() {
+        let initialMinGasPriceBuffer;
+        before(async () =>{
+            initialMinGasPriceBuffer = process.env.GAS_PRICE_TINY_BAR_BUFFER;
+            process.env.GAS_PRICE_TINY_BAR_BUFFER = '10000000000'; // 1 tinybar
+        })
+
+        after(async () =>{
+            process.env.GAS_PRICE_TINY_BAR_BUFFER = initialMinGasPriceBuffer;
+        })
+
         it('should pass for gas price gt to required gas price', async function() {
             const result = precheck.gasPrice(parsedTxWithMatchingChainId, 10);
             expect(result).to.not.exist;
@@ -249,6 +224,11 @@ describe('Precheck', async function() {
                 expect(e.message).to.eq('Gas price below configured minimum gas price');
             }
         });
+
+        it('should pass for gas price not enough but within buffer', async function() {
+            const adjustedGasPrice = parsedTxGasPrice + Number(process.env.GAS_PRICE_TINY_BAR_BUFFER);
+            precheck.gasPrice(parsedTxWithMatchingChainId, adjustedGasPrice);
+        });
     });
 
     describe('balance', async function() {

packages/server/tests/localAcceptance.env

@@ -24,4 +24,5 @@ HBAR_RATE_LIMIT_DURATION = 80000
 RATE_LIMIT_DISABLED = false
 DEV_MODE = false
 MIRROR_NODE_RETRIES = 3
-MIRROR_NODE_RETRY_DELAY = 500
+MIRROR_NODE_RETRY_DELAY = 500
+GAS_PRICE_TINY_BAR_BUFFER = 10000000000