feat: add a tx gasPrice Buffer to reduce INSUFFICIENT_TX_FEE cases

charts/hedera-json-rpc-relay/value-test.yaml

@@ -135,6 +135,7 @@ config:
   DEBUG_API_ENABLED: false
   FILTER_API_ENABLED: true
   MULTI_SET: true
+  GAS_PRICE_PERCENTAGE_BUFFER: 0
 
 # Enable rolling_restarts if SDK calls fail this is usually due to stale connections that get cycled on restart
 rolling_restart:

charts/hedera-json-rpc-relay/values.yaml

@@ -53,6 +53,7 @@ config:
   DEBUG_API_ENABLED: false
   FILTER_API_ENABLED: true
   MULTI_SET: true
+  GAS_PRICE_PERCENTAGE_BUFFER: 0
 
 # -- Extra environment variables from existing secrets or configmaps
 extraEnvFrom: []

docs/configuration.md

@@ -67,6 +67,7 @@ Unless you need to set a non-default value, it is recommended to only populate o
 | `FEE_HISTORY_MAX_RESULTS`                   | "10"                     | The maximum number of results to returns as part of `eth_feeHistory`.                                                                                                                                                                                                                                  |
 | `ETH_FEE_HISTORY_FIXED`                     | "true"                   | Flag to set if eth_feeHistory should return a fixed fee for the set of results.                                                                                                                                                                                                                        |
 | `ETH_POPULATE_SYNTHETIC_CONTRACT_RESULTS`   | "true"                   | Flag to set if the relay should populate the contract results for synthetic contracts.                                                                                                                                                                                                                 |
+| `GAS_PRICE_PERCENTAGE_BUFFER`               | "0"                      | The additional buffer that adds a percentage on top of the calculated network gasPrice. This may be used by operators to reduce the chances of `INSUFFICIENT_TX_FEE` errors experienced by users caused by minor fluctuations in the exchange rate.                                                    |
 | `GAS_PRICE_TINY_BAR_BUFFER`                 | "10000000000"            | The additional buffer range to allow during a relay precheck of gas price. This supports slight fluctuations in network gasprice calculations.                                                                                                                                                         |
 | `HAPI_CLIENT_DURATION_RESET`                | "3600000"                | Time until client reinitialization. (ms)                                                                                                                                                                                                                                                               |
 | `HAPI_CLIENT_ERROR_RESET`                   | [21, 50]                 | Array of status codes, which when encountered will trigger a reinitialization. Status codes are availble [here](https://github.com/hashgraph/hedera-protobufs/blob/main/services/response_code.proto).                                                                                                 |

packages/relay/src/lib/eth.ts

@@ -26,6 +26,7 @@ import { IContractCallRequest, IContractCallResponse, MirrorNodeClient } from '.
 import { JsonRpcError, predefined } from './errors/JsonRpcError';
 import { SDKClientError } from './errors/SDKClientError';
 import { MirrorNodeClientError } from './errors/MirrorNodeClientError';
+import { Utils } from './../utils';
 import constants from './constants';
 import { Precheck } from './precheck';
 import {
@@ -729,7 +730,8 @@ export class EthImpl implements Eth {
       );
 
       if (!gasPrice) {
-        gasPrice = await this.getFeeWeibars(EthImpl.ethGasPrice, requestIdPrefix);
+        gasPrice = Utils.addPercentageBufferToGasPrice(await this.getFeeWeibars(EthImpl.ethGasPrice, requestIdPrefix));
+
         this.cacheService.set(
           constants.CACHE_KEY.GAS_PRICE,
           gasPrice,

packages/relay/src/utils.ts

@@ -0,0 +1,38 @@
+/*-
+ *
+ * Hedera JSON RPC Relay
+ *
+ * Copyright (C) 2024 Hedera Hashgraph, LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+import constants from './lib/constants';
+
+export class Utils {
+  public static readonly addPercentageBufferToGasPrice = (gasPrice: number): number => {
+    // converting to tinybar and afterward to weibar again is needed
+    // in order to handle the possibility of an invalid floating number being calculated as a gas price
+    // e.g.
+    //   current gas price = 126
+    //   buffer = 10%
+    //   buffered gas price = 126 + 12.6 = 138.6 <--- invalid tinybars
+    gasPrice +=
+      Math.round(
+        (gasPrice / constants.TINYBAR_TO_WEIBAR_COEF) * (Number(process.env.GAS_PRICE_PERCENTAGE_BUFFER || 0) / 100),
+      ) * constants.TINYBAR_TO_WEIBAR_COEF;
+
+    return gasPrice;
+  };
+}

packages/relay/tests/lib/eth/eth_gasPrice.spec.ts

@@ -30,6 +30,7 @@ import { DEFAULT_NETWORK_FEES, NOT_FOUND_RES } from './eth-config';
 import { predefined } from '../../../src/lib/errors/JsonRpcError';
 import RelayAssertions from '../../assertions';
 import { generateEthTestEnv } from './eth-helpers';
+import { toHex } from '../../helpers';
 
 dotenv.config({ path: path.resolve(__dirname, '../test.env') });
 use(chaiAsPromised);
@@ -90,6 +91,42 @@ describe('@ethGasPrice Gas Price spec', async function () {
       await RelayAssertions.assertRejection(predefined.COULD_NOT_ESTIMATE_GAS_PRICE, ethImpl.gasPrice, true, ethImpl);
     });
 
+    describe('@ethGasPrice different value for GAS_PRICE_PERCENTAGE_BUFFER env', async function () {
+      const GAS_PRICE_PERCENTAGE_BUFFER_TESTCASES = {
+        'eth_gasPrice with GAS_PRICE_PERCENTAGE_BUFFER set to 10%': '10',
+        'eth_gasPrice with GAS_PRICE_PERCENTAGE_BUFFER set to floating % that results in floating number for buffered gas price':
+          '10.25',
+      };
+
+      for (let testCaseName in GAS_PRICE_PERCENTAGE_BUFFER_TESTCASES) {
+        it(testCaseName, async function () {
+          const GAS_PRICE_PERCENTAGE_BUFFER = GAS_PRICE_PERCENTAGE_BUFFER_TESTCASES[testCaseName];
+          const initialGasPrice = await ethImpl.gasPrice();
+          process.env.GAS_PRICE_PERCENTAGE_BUFFER = GAS_PRICE_PERCENTAGE_BUFFER;
+
+          await cacheService.clear();
+
+          const gasPriceWithBuffer = await ethImpl.gasPrice();
+          process.env.GAS_PRICE_PERCENTAGE_BUFFER = '0';
+
+          const expectedInitialGasPrice = toHex(DEFAULT_NETWORK_FEES.fees[2].gas * constants.TINYBAR_TO_WEIBAR_COEF);
+          const expectedGasPriceWithBuffer = toHex(
+            Number(expectedInitialGasPrice) +
+              Math.round(
+                (Number(expectedInitialGasPrice) / constants.TINYBAR_TO_WEIBAR_COEF) *
+                  (Number(GAS_PRICE_PERCENTAGE_BUFFER || 0) / 100),
+              ) *
+                constants.TINYBAR_TO_WEIBAR_COEF,
+          );
+
+          expect(expectedInitialGasPrice).to.not.equal(expectedGasPriceWithBuffer);
+          expect(initialGasPrice).to.not.equal(gasPriceWithBuffer);
+          expect(initialGasPrice).to.equal(expectedInitialGasPrice);
+          expect(gasPriceWithBuffer).to.equal(expectedGasPriceWithBuffer);
+        });
+      }
+    });
+
     describe('eth_gasPrice not found', async function () {
       beforeEach(() => {
         restMock.onGet(`network/fees`).reply(404, NOT_FOUND_RES);

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

@@ -0,0 +1,48 @@
+/*-
+ *
+ * Hedera JSON RPC Relay
+ *
+ * Copyright (C) 2024 Hedera Hashgraph, LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+import { expect } from 'chai';
+import { Utils } from '../../src/utils';
+import constants from '../../src/lib/constants';
+
+describe('Utils', () => {
+  describe('addPercentageBufferToGasPrice', () => {
+    afterEach(() => {
+      process.env.GAS_PRICE_PERCENTAGE_BUFFER = '0';
+    });
+
+    const TW_COEF = constants.TINYBAR_TO_WEIBAR_COEF;
+    const TEST_CASES = [
+      { testName: 'zero input', buffer: '0', input: 0, output: 0 },
+      { testName: 'buffer 0%', buffer: '0', input: 10 * TW_COEF, output: 10 * TW_COEF },
+      { testName: 'buffer 7%', buffer: '7', input: 140 * TW_COEF, output: 150 * TW_COEF },
+      { testName: 'buffer 10%', buffer: '10', input: 126 * TW_COEF, output: 139 * TW_COEF },
+      { testName: 'buffer 12.25%', buffer: '12.25', input: 56 * TW_COEF, output: 63 * TW_COEF },
+      { testName: 'negative buffer -6%', buffer: '-6', input: 100 * TW_COEF, output: 94 * TW_COEF },
+      { testName: 'negative buffer -12.58%', buffer: '-12.58', input: 136 * TW_COEF, output: 119 * TW_COEF },
+    ];
+    for (let i in TEST_CASES) {
+      it(TEST_CASES[i].testName, () => {
+        process.env.GAS_PRICE_PERCENTAGE_BUFFER = TEST_CASES[i].buffer;
+        expect(Utils.addPercentageBufferToGasPrice(TEST_CASES[i].input)).to.equal(TEST_CASES[i].output);
+      });
+    }
+  });
+});