feat: add parsing of health check event

infra/quicknode.tf

@@ -20,6 +20,18 @@ resource "quicknode_notification" "notification" {
   enabled         = true
 }
 
+# Creates a new QuickAlert event listener for `MedianUpdated` events on our SortedOracles contract,
+# which is used as a health check event to ensure quicknode alerts are firing.
+resource "quicknode_notification" "healthcheck" {
+  name    = "Healthcheck event"
+  network = "celo-mainnet"
+
+  # Decoded version: `tx_logs_address == '0xefb84935239dacdecf7c5ba76d8de40b077b7b33' && tx_logs_topic0 == '0xa9981ebfc3b766a742486e898f54959b050a66006dbce1a4155c1f84a08bcf41' && tx_logs_topic1 == '0x000000000000000000000000765de816845861e75a25fca122bb6898b8b1282a'`
+  expression      = "dHhfbG9nc19hZGRyZXNzID09ICcweGVmYjg0OTM1MjM5ZGFjZGVjZjdjNWJhNzZkOGRlNDBiMDc3YjdiMzMnICYmIHR4X2xvZ3NfdG9waWMwID09ICcweGE5OTgxZWJmYzNiNzY2YTc0MjQ4NmU4OThmNTQ5NTliMDUwYTY2MDA2ZGJjZTFhNDE1NWMxZjg0YTA4YmNmNDEnICYmIHR4X2xvZ3NfdG9waWMxID09ICcweDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDc2NWRlODE2ODQ1ODYxZTc1YTI1ZmNhMTIyYmI2ODk4YjhiMTI4MmEn"
+  destination_ids = [resource.quicknode_destination.destination.id]
+  enabled         = true
+}
+
 # Creates a new QuickAlert destination that forwards all received `ProposalCreated` transaction receipts to our Cloud Function
 resource "quicknode_destination" "destination" {
   name         = "Cloud Function"

package.json

@@ -17,7 +17,8 @@
     "prestart": "npm run build",
     "start": "NODE_ENV=development functions-framework --target=watchdogNotifier",
     "test": "curl -H \"Content-Type: application/json\" -d @src/proposal-created.fixture.json localhost:8080",
-    "test-in-prod": "./test-deployed-function.sh"
+    "test-in-prod": "./test-deployed-function.sh",
+    "test:healthcheck": "curl -H \"Content-Type: application/json\" -d @src/health-check.fixture.json localhost:8080"
   },
   "dependencies": {
     "@google-cloud/functions-framework": "^3.4.0",

src/health-check.fixture.json

@@ -0,0 +1,48 @@
+[
+  {
+    "blockHash": "0x3c3de1a0ae100d33d9a7863ddc59cdf6ec628c42bebf0854e18c462a7e2f6b90",
+    "blockNumber": "0x1990dc7",
+    "contractAddress": "",
+    "cumulativeGasUsed": "0x8e7542",
+    "effectiveGasPrice": "0x1bf08eb00",
+    "from": "0xfe9925e6ae9c4cd50ae471b90766aaef37ad307e",
+    "gasUsed": "0x4a836",
+    "logs": [
+      {
+        "address": "0xefb84935239dacdecf7c5ba76d8de40b077b7b33",
+        "blockHash": "0x3c3de1a0ae100d33d9a7863ddc59cdf6ec628c42bebf0854e18c462a7e2f6b90",
+        "blockNumber": "0x1990dc7",
+        "data": "0x00000000000000000000000000000000000000000000000000000000669f37b9000000000000000000000000000000000000000000007ae21ecba8aa70ef8750",
+        "logIndex": "0xc5",
+        "removed": false,
+        "topics": [
+          "0x7cebb17173a9ed273d2b7538f64395c0ebf352ff743f1cf8ce66b437a6144213",
+          "0x000000000000000000000000765de816845861e75a25fca122bb6898b8b1282a",
+          "0x000000000000000000000000fe9925e6ae9c4cd50ae471b90766aaef37ad307e"
+        ],
+        "transactionHash": "0x1091e1d6babb1711b30d6328f9d9755cc4e7d5004f9ef88c9526b1642f5f35e1",
+        "transactionIndex": "0x3"
+      },
+      {
+        "address": "0xefb84935239dacdecf7c5ba76d8de40b077b7b33",
+        "blockHash": "0x3c3de1a0ae100d33d9a7863ddc59cdf6ec628c42bebf0854e18c462a7e2f6b90",
+        "blockNumber": "0x1990dc7",
+        "data": "0x000000000000000000000000000000000000000000007aef59d1fabdfb4cfc30",
+        "logIndex": "0xc6",
+        "removed": false,
+        "topics": [
+          "0xa9981ebfc3b766a742486e898f54959b050a66006dbce1a4155c1f84a08bcf41",
+          "0x000000000000000000000000765de816845861e75a25fca122bb6898b8b1282a"
+        ],
+        "transactionHash": "0x1091e1d6babb1711b30d6328f9d9755cc4e7d5004f9ef88c9526b1642f5f35e1",
+        "transactionIndex": "0x3"
+      }
+    ],
+    "logsBloom": "0x00800000000000000000200000000000000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000000000000000004000000000000000020000000000000000000000000400000008400000000100000000000000000000000000000000000000000401000000000000800000000000000000000000000000000000000800000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000",
+    "status": "0x1",
+    "to": "0xefb84935239dacdecf7c5ba76d8de40b077b7b33",
+    "transactionHash": "0x1091e1d6babb1711b30d6328f9d9755cc4e7d5004f9ef88c9526b1642f5f35e1",
+    "transactionIndex": "0x3",
+    "type": "0x0"
+  }
+]

src/index.ts

@@ -16,8 +16,18 @@ export const watchdogNotifier: HttpFunction = async (
     const parsedEvents = parseTransactionReceipts(req.body);
 
     for (const parsedEvent of parsedEvents) {
-      await sendDiscordNotification(parsedEvent.event, parsedEvent.txHash);
-      await sendTelegramNotification(parsedEvent.event, parsedEvent.txHash);
+      switch (parsedEvent.event.eventName) {
+        case "ProposalCreated":
+          await sendDiscordNotification(parsedEvent.event, parsedEvent.txHash);
+          await sendTelegramNotification(parsedEvent.event, parsedEvent.txHash);
+          break;
+        case "MedianUpdated":
+          // Acts a health check/heartbeat for the service, as it's a frequently emitted event
+          console.info("[HealthCheck]: Block", parsedEvent.block);
+          break;
+        default:
+          throw new Error("Unknown event type", parsedEvent.event);
+      }
     }
 
     res.status(200).send("Event successfully processed");

src/parse-transaction-receipts.ts

@@ -3,31 +3,38 @@ import { decodeEventLog } from "viem";
 
 // Internal
 import GovernorABI from "./governor-abi.js";
-import { ProposalCreatedEvent } from "./types.js";
+import { HealthCheckEvent, ProposalCreatedEvent } from "./types.js";
 import hasLogs from "./utils/has-logs.js";
+import isHealthCheckEvent from "./utils/is-health-check-event.js";
 import isProposalCreatedEvent from "./utils/is-proposal-created-event.js";
 import isTransactionReceipt from "./utils/is-transaction-receipt.js";
-
-// For debugging with SortedOracles:
-// import SortedOraclesABI from "./sorted-oracles-abi.js";
+import SortedOraclesABI from "./sorted-oracles-abi.js";
 
 /**
  * Parse request body containing raw transaction receipts
  */
 export default function parseTransactionReceipts(
   matchedTransactionReceipts: unknown,
-): { event: ProposalCreatedEvent; txHash: string }[] {
+): {
+  block?: number;
+  event: ProposalCreatedEvent | HealthCheckEvent;
+  txHash: string;
+}[] {
   const result = [];
   if (!Array.isArray(matchedTransactionReceipts)) {
     throw new Error(
-      `Request body is not an array of transaction receipts but was: ${JSON.stringify(matchedTransactionReceipts)}`,
+      `Request body is not an array of transaction receipts but was: ${JSON.stringify(
+        matchedTransactionReceipts,
+      )}`,
     );
   }
 
   for (const receipt of matchedTransactionReceipts) {
     if (!isTransactionReceipt(receipt)) {
       throw new Error(
-        `'receipt' is not of type 'TransactionReceipt': ${JSON.stringify(receipt)}`,
+        `'receipt' is not of type 'TransactionReceipt': ${JSON.stringify(
+          receipt,
+        )}`,
       );
     }
 
@@ -42,24 +49,44 @@ export default function parseTransactionReceipts(
         throw new Error("No topics found in log");
       }
 
-      const event = decodeEventLog({
-        // For debugging with SortedOracles:
-        // abi: SortedOraclesABI,
-        abi: GovernorABI,
-        data: log.data as `0x${string}`,
-        topics: log.topics as [
-          signature: `0x${string}`,
-          ...args: `0x${string}`[],
-        ],
-      });
+      try {
+        const event = decodeEventLog({
+          abi: GovernorABI,
+          data: log.data as `0x${string}`,
+          topics: log.topics as [
+            signature: `0x${string}`,
+            ...args: `0x${string}`[],
+          ],
+        });
 
-      if (!isProposalCreatedEvent(event)) {
-        throw new Error(
-          `Event is not a ProposalCreatedEvent: ${JSON.stringify(event)}`,
-        );
-      }
+        if (isProposalCreatedEvent(event)) {
+          result.push({
+            event,
+            txHash: log.transactionHash,
+          });
+        }
+        // eslint-disable-next-line no-empty
+      } catch {}
+
+      try {
+        const event = decodeEventLog({
+          abi: SortedOraclesABI,
+          data: log.data as `0x${string}`,
+          topics: log.topics as [
+            signature: `0x${string}`,
+            ...args: `0x${string}`[],
+          ],
+        });
 
-      result.push({ event, txHash: log.transactionHash });
+        if (isHealthCheckEvent(event)) {
+          result.push({
+            block: Number(receipt.blockNumber),
+            event,
+            txHash: log.transactionHash,
+          });
+        }
+        // eslint-disable-next-line no-empty
+      } catch {}
     }
   }
 

src/types.ts

@@ -41,3 +41,12 @@ export interface ProposalCreatedEvent {
     version: number;
   };
 }
+
+export interface HealthCheckEvent {
+  eventName: "MedianUpdated";
+  block: number;
+  args: {
+    token: `0x${string}`;
+    value: bigint;
+  };
+}

src/utils/is-health-check-event.ts

@@ -0,0 +1,21 @@
+import type { DecodeEventLogReturnType } from "viem";
+import type SortedOraclesABI from "../sorted-oracles-abi.js";
+import type { HealthCheckEvent } from "../types.js";
+
+export default function isHealthCheckEvent(
+  event: DecodeEventLogReturnType<typeof SortedOraclesABI> | null | undefined,
+): event is HealthCheckEvent {
+  if (
+    event === null ||
+    event === undefined ||
+    typeof event !== "object" ||
+    !("args" in event)
+  ) {
+    return false;
+  }
+  return (
+    event.eventName === "MedianUpdated" &&
+    "token" in event.args &&
+    "value" in event.args
+  );
+}