fix(epochs): move epoch to class that fetches epoch information from …

…contract

Since we are not computing epochs ourselves, we need to fetch the epoch information from the contract when we run a new report. This moves that logic to a class that fetches epoch information on every execution of running a report. It will cache the result until the epoch is over, based on network time rather than local system time.

package.json

@@ -9,7 +9,7 @@
     "url": "https://github.com/ar-io/ar-io-observer"
   },
   "dependencies": {
-    "@ar.io/sdk": "1.2.0-alpha.1",
+    "@ar.io/sdk": "1.2.0-alpha.2",
     "@ardrive/ardrive-promise-cache": "^1.1.4",
     "@ardrive/turbo-sdk": "^1.0.1",
     "ajv": "^8.12.0",

src/epochs/contract-epoch-source.ts

@@ -0,0 +1,80 @@
+/**
+ * AR.IO Observer
+ * Copyright (C) 2023 Permanent Data Solutions, Inc. All Rights Reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+import { AoIORead, IO } from '@ar.io/sdk';
+
+import * as config from '../config.js';
+import { BlockSource, EpochTimestampParams, HeightSource } from '../types.js';
+import { EpochTimestampSource as IEpochTimestampSource } from '../types.js';
+
+export class ContractEpochSource implements IEpochTimestampSource {
+  private contract: AoIORead;
+  private blockSource: BlockSource;
+  private heightSource: HeightSource;
+  private epochParams: EpochTimestampParams | undefined;
+
+  constructor({
+    contract = IO.init({ processId: config.IO_PROCESS_ID }),
+    blockSource,
+    heightSource,
+  }: {
+    contract?: AoIORead;
+    blockSource: BlockSource;
+    heightSource: HeightSource;
+  }) {
+    this.contract = contract;
+    this.blockSource = blockSource;
+    this.heightSource = heightSource;
+  }
+
+  async getEpochParams(): Promise<EpochTimestampParams> {
+    // cache the epoch params for the duration of the epoch to avoid unnecessary contract calls
+    const height = await this.heightSource.getHeight();
+    const block = await this.blockSource.getBlockByHeight(height);
+    const networkTimestamp = block.timestamp * 1000;
+    if (
+      this.epochParams !== undefined &&
+      this.epochParams.epochEndTimestamp > networkTimestamp
+    ) {
+      return this.epochParams;
+    }
+    const { startTimestamp, startHeight, endTimestamp, epochIndex } =
+      await this.contract.getCurrentEpoch();
+    return {
+      epochStartTimestamp: startTimestamp,
+      epochStartHeight: startHeight,
+      epochEndTimestamp: endTimestamp,
+      epochIndex,
+    };
+  }
+
+  async getEpochStartTimestamp(): Promise<number> {
+    return this.getEpochParams().then((params) => params.epochStartTimestamp);
+  }
+
+  async getEpochEndTimestamp(): Promise<number> {
+    return this.getEpochParams().then((params) => params.epochEndTimestamp);
+  }
+
+  async getEpochStartHeight(): Promise<number> {
+    return this.getEpochParams().then((params) => params.epochStartHeight);
+  }
+
+  async getEpochIndex(): Promise<number> {
+    return this.getEpochParams().then((params) => params.epochIndex);
+  }
+}

src/protocol.ts → src/epochs/static-epoch-source.ts

@@ -18,21 +18,10 @@
 import {
   HeightSource,
   EpochHeightSource as IEpochHeightSource,
-  EpochTimestampSource as IEpochTimestampSource,
-} from './types.js';
+} from '../types.js';
 
 export const START_HEIGHT = 0;
-export const START_TIMESTAMP = 0;
-export const EPOCH_BLOCK_LENGTH_MS = 60 * 1000 * 60 * 24; // 1 day
 export const EPOCH_BLOCK_LENGTH = 5000;
-export const TESTNET_CONTRACT_SETTINGS = {
-  minLockLength: 5,
-  maxLockLength: 720 * 365 * 3,
-  minNetworkJoinStakeAmount: 5_000,
-  minGatewayJoinLength: 2,
-  gatewayLeaveLength: 2,
-  operatorStakeWithdrawLength: 5,
-};
 
 export function getEpochEnd({
   startHeight,
@@ -72,13 +61,6 @@ interface EpochParams {
   epochBlockLength: number;
 }
 
-interface EpochTimestampParams {
-  epochStartTimestamp: number;
-  epochStartHeight: number;
-  epochEndTimestamp: number;
-  epochIndex: number;
-}
-
 export class EpochHeightSource implements IEpochHeightSource {
   private heightSource: HeightSource;
   private epochParams: EpochParams;
@@ -113,37 +95,3 @@ export class EpochHeightSource implements IEpochHeightSource {
     });
   }
 }
-
-export class EpochTimestampSource implements IEpochTimestampSource {
-  private epochParams: EpochTimestampParams;
-
-  constructor({
-    epochParams = {
-      epochStartTimestamp: 0,
-      epochEndTimestamp: 1000 * 60 * 60 * 24, // 1 day
-      epochStartHeight: 0,
-      epochIndex: 0,
-    },
-  }: {
-    epochParams?: EpochTimestampParams;
-    heightSource: HeightSource;
-  }) {
-    this.epochParams = epochParams;
-  }
-
-  async getEpochStartTimestamp(): Promise<number> {
-    return this.epochParams.epochStartTimestamp;
-  }
-
-  async getEpochEndTimestamp(): Promise<number> {
-    return this.epochParams.epochEndTimestamp;
-  }
-
-  async getEpochStartHeight(): Promise<number> {
-    return this.epochParams.epochStartHeight;
-  }
-
-  async getEpochIndex(): Promise<number> {
-    return this.epochParams.epochIndex;
-  }
-}

src/system.ts

@@ -36,18 +36,14 @@ import { CachedEntropySource } from './entropy/cached-entropy-source.js';
 import { ChainEntropySource } from './entropy/chain-entropy-source.js';
 import { CompositeEntropySource } from './entropy/composite-entropy-source.js';
 import { RandomEntropySource } from './entropy/random-entropy-source.js';
+import { ContractEpochSource } from './epochs/contract-epoch-source.js';
 import { ContractHostsSource } from './hosts/contract-hosts-source.js';
 import { StaticHostsSource } from './hosts/static-hosts-source.js';
 import log from './log.js';
 import { ContractNamesSource } from './names/contract-names-source.js';
 import { RandomArnsNamesSource } from './names/random-arns-names-source.js';
 import { StaticArnsNameList } from './names/static-arns-name-list.js';
 import { Observer } from './observer.js';
-import {
-  EPOCH_BLOCK_LENGTH_MS,
-  EpochTimestampSource,
-  START_TIMESTAMP,
-} from './protocol.js';
 import { ContractReportSink } from './store/contract-report-sink.js';
 import { FsReportStore } from './store/fs-report-store.js';
 import {
@@ -122,40 +118,10 @@ const observedGatewayHostList =
         contract: networkContract,
       });
 
-// Attempt to read the start height and epoch block length from the contract - default to constants if it fails
-const {
-  startTimestamp: epochStartTimestamp,
-  endTimestamp: epochEndTimestamp,
-  startHeight: epochStartHeight,
-  epochIndex,
-} = await networkContract.getCurrentEpoch().catch((error: any) => {
-  log.error(`Unable to get start height from contract - using default values`, {
-    message: error?.message,
-    stack: error?.stack,
-  });
-  return {
-    startTimestamp: START_TIMESTAMP,
-    endTimestamp: EPOCH_BLOCK_LENGTH_MS,
-    epochIndex: 0,
-    startHeight: 0,
-  };
-});
-
-log.info('Using epoch information for entropy and reports', {
-  epochStartTimestamp,
-  epochEndTimestamp,
-  epochIndex,
-  epochStartHeight,
-});
-
-export const epochSelector = new EpochTimestampSource({
+export const epochSource = new ContractEpochSource({
+  contract: networkContract,
+  blockSource: chainSource,
   heightSource: chainSource,
-  epochParams: {
-    epochStartTimestamp: epochStartTimestamp,
-    epochEndTimestamp: epochEndTimestamp,
-    epochIndex: epochIndex,
-    epochStartHeight: epochStartHeight,
-  },
 });
 
 const namesSource = new ContractNamesSource({
@@ -193,7 +159,7 @@ const chosenNamesSource = new RandomArnsNamesSource({
 export const observer = new Observer({
   observerAddress: config.OBSERVER_WALLET,
   referenceGatewayHost: config.REFERENCE_GATEWAY_HOST,
-  epochSource: epochSelector,
+  epochSource,
   observedGatewayHostList,
   prescribedNamesSource: namesSource,
   chosenNamesSource,
@@ -306,6 +272,7 @@ export async function updateAndSaveCurrentReport() {
     log.info('Report cached');
 
     log.info('Getting observers from contract state...');
+    const epochIndex = await epochSource.getEpochIndex();
     // Get selected observers for the current epoch from the contract
     const observers: string[] = await networkContract
       .getPrescribedObservers({ epochIndex })

src/types.ts

@@ -27,6 +27,18 @@ export interface HeightSource {
   getHeight(): Promise<number>;
 }
 
+//
+// Epochs
+//
+
+export interface EpochTimestampParams {
+  epochStartTimestamp: number;
+  epochStartHeight: number;
+  epochEndTimestamp: number;
+  epochIndex: number;
+}
+
+// deprecated
 export interface EpochHeightSource {
   getEpochStartHeight(): Promise<number>;
   getEpochEndHeight(): Promise<number>;

yarn.lock

@@ -32,10 +32,10 @@
     call-me-maybe "^1.0.1"
     js-yaml "^4.1.0"
 
-"@ar.io/sdk@1.2.0-alpha.1":
-  version "1.2.0-alpha.1"
-  resolved "https://registry.yarnpkg.com/@ar.io/sdk/-/sdk-1.2.0-alpha.1.tgz#16891e85feab3b4197191c4100272225bf866f34"
-  integrity sha512-4C4JBo6GuaqEm4FnRvJ6n9z4dYA2g++duDRiErsRnOeqmt0ZpuHA4p3vucMBT5d6Bp3nrgckPx+estxRGUqDzg==
+"@ar.io/sdk@1.2.0-alpha.2":
+  version "1.2.0-alpha.2"
+  resolved "https://registry.yarnpkg.com/@ar.io/sdk/-/sdk-1.2.0-alpha.2.tgz#5a9c94ee1574d7868dae008be218e492ec6d4dc2"
+  integrity sha512-9qyMXXFJAYZ8bVIQpH43aLVyXNwn47Qpk0roSPsJ6LBkjOuDZUeiEQoEnPkdhJZciWiKcvPJC9D3Zs0jExxn+g==
   dependencies:
     "@permaweb/aoconnect" "^0.0.55"
     arbundles "0.11.0"