refactor: metrics module (#140)

# Description

This refactors the metrics to make it more explicit when used within
consuming code.

# Changes

- [x] Metrics now scoped to a module

## How to test
1. Run in testing environment and observe metrics continue to work.

src/commands/run.ts

@@ -1,7 +1,6 @@
 import { RunOptions } from "../types";
-import { getLogger, DBService } from "../utils";
+import { getLogger, DBService, ApiService } from "../utils";
 import { ChainContext } from "../domain";
-import { ApiService } from "../utils/api";
 
 /**
  * Run the watch-tower 👀🐮

src/domain/addContract.ts

@@ -3,6 +3,7 @@ import {
   getLogger,
   handleExecutionError,
   isComposableCowCompatible,
+  metrics,
 } from "../utils";
 import { BytesLike, ethers } from "ethers";
 
@@ -20,17 +21,6 @@ import {
 
 import { ChainContext } from "./chainContext";
 import { ConditionalOrderParams } from "@cowprotocol/cow-sdk";
-import {
-  addContractRunsTotal,
-  addContractsErrorsTotal,
-  addContractsRunDurationSeconds,
-  measureTime,
-  merkleRootTotal,
-  ownersTotal,
-  singleOrdersTotal,
-  activeOrdersTotal,
-  activeOwnersTotal,
-} from "../utils/metrics";
 
 /**
  * Listens to these events on the `ComposableCoW` contract:
@@ -44,13 +34,13 @@ export async function addContract(
   event: ConditionalOrderCreatedEvent
 ) {
   const { chainId } = context;
-  await measureTime({
+  await metrics.measureTime({
     action: () => _addContract(context, event),
     labelValues: [chainId.toString()],
-    durationMetric: addContractsRunDurationSeconds,
-    totalRunsMetric: addContractRunsTotal,
+    durationMetric: metrics.addContractsRunDurationSeconds,
+    totalRunsMetric: metrics.addContractRunsTotal,
     errorHandler: handleExecutionError,
-    errorMetric: addContractsErrorsTotal,
+    errorMetric: metrics.addContractsErrorsTotal,
   });
 }
 
@@ -79,7 +69,7 @@ async function _addContract(
     registry
   );
   if (added) {
-    ownersTotal.labels(context.chainId.toString()).inc();
+    metrics.ownersTotal.labels(context.chainId.toString()).inc();
     numContractsAdded++;
   } else {
     log.error(
@@ -110,6 +100,7 @@ export async function _registerNewOrder(
 ): Promise<{ error: boolean; added: boolean }> {
   const log = getLogger("addContract:_registerNewOrder");
   const { transactionHash: tx } = event;
+  const { network } = registry;
   let added = false;
   try {
     // Check if the log is a ConditionalOrderCreated event
@@ -134,7 +125,7 @@ export async function _registerNewOrder(
         registry
       );
       added = true;
-      singleOrdersTotal.labels(registry.network).inc();
+      metrics.singleOrdersTotal.labels(network).inc();
     } else if (
       event.topics[0] == composableCow.getEventTopic("MerkleRootSet")
     ) {
@@ -175,7 +166,7 @@ export async function _registerNewOrder(
             registry
           );
           added = true;
-          merkleRootTotal.labels(registry.network).inc();
+          metrics.merkleRootTotal.labels(network).inc();
         }
       }
     }
@@ -209,8 +200,9 @@ export function add(
 ) {
   const log = getLogger("addContract:add");
   const { handler, salt, staticInput } = params;
-  if (registry.ownerOrders.has(owner)) {
-    const conditionalOrders = registry.ownerOrders.get(owner);
+  const { network, ownerOrders } = registry;
+  if (ownerOrders.has(owner)) {
+    const conditionalOrders = ownerOrders.get(owner);
     log.info(
       `Adding conditional order to already existing owner contract ${owner}`,
       { tx, handler, salt, staticInput }
@@ -234,7 +226,7 @@ export function add(
         orders: new Map(),
         composableCow,
       });
-      activeOrdersTotal.labels(registry.network).inc();
+      metrics.activeOrdersTotal.labels(network).inc();
     }
   } else {
     log.info(`Adding conditional order to new owner contract ${owner}:`, {
@@ -247,8 +239,8 @@ export function add(
       owner,
       new Set([{ tx, params, proof, orders: new Map(), composableCow }])
     );
-    activeOwnersTotal.labels(registry.network).inc();
-    activeOrdersTotal.labels(registry.network).inc();
+    metrics.activeOwnersTotal.labels(network).inc();
+    metrics.activeOrdersTotal.labels(network).inc();
   }
 }
 

src/domain/chainContext.ts

@@ -22,15 +22,8 @@ import {
   DBService,
   getLogger,
   isRunningInKubernetesPod,
+  metrics,
 } from "../utils";
-import {
-  blockHeight,
-  blockProducingRate,
-  eventsProcessedTotal,
-  processBlockDurationSeconds,
-  reorgDepth,
-  reorgsTotal,
-} from "../utils/metrics";
 import { hexZeroPad } from "ethers/lib/utils";
 import { FilterPolicy } from "../utils/filterPolicy";
 
@@ -183,7 +176,9 @@ export class ChainContext {
     const { pageSize } = this;
 
     // Set the block height metric
-    blockHeight.labels(chainId.toString()).set(lastProcessedBlock?.number ?? 0);
+    metrics.blockHeight
+      .labels(chainId.toString())
+      .set(lastProcessedBlock?.number ?? 0);
 
     // Start watching from (not including) the last processed block (if any)
     let fromBlock = lastProcessedBlock
@@ -269,7 +264,9 @@ export class ChainContext {
           await this.registry.write();
 
           // Set the block height metric
-          blockHeight.labels(chainId.toString()).set(Number(blockNumber));
+          metrics.blockHeight
+            .labels(chainId.toString())
+            .set(Number(blockNumber));
         } catch (err) {
           log.error(`Error processing block ${blockNumber}`, err);
         }
@@ -334,16 +331,16 @@ export class ChainContext {
 
         // Set the block time metric
         const _blockTime = block.timestamp - lastBlockReceived.timestamp;
-        blockProducingRate.labels(chainId.toString()).set(_blockTime);
+        metrics.blockProducingRate.labels(chainId.toString()).set(_blockTime);
 
         if (
           blockNumber <= lastBlockReceived.number &&
           block.hash !== lastBlockReceived.hash
         ) {
           // This is a re-org, so process the block again
-          reorgsTotal.labels(chainId.toString()).inc();
+          metrics.reorgsTotal.labels(chainId.toString()).inc();
           log.info(`Re-org detected, re-processing block ${blockNumber}`);
-          reorgDepth
+          metrics.reorgDepth
             .labels(chainId.toString())
             .set(lastBlockReceived.number - blockNumber + 1);
         }
@@ -361,7 +358,7 @@ export class ChainContext {
           // Block height metric
           this.registry.lastProcessedBlock = blockToRegistryBlock(block);
           this.registry.write();
-          blockHeight.labels(chainId.toString()).set(Number(blockNumber));
+          metrics.blockHeight.labels(chainId.toString()).set(blockNumber);
         } catch {
           log.error(`Error processing block ${blockNumber}`);
         }
@@ -457,7 +454,7 @@ async function processBlock(
   blockTimestampOverride?: number
 ) {
   const { provider, chainId } = context;
-  const timer = processBlockDurationSeconds
+  const timer = metrics.processBlockDurationSeconds
     .labels(context.chainId.toString())
     .startTimer();
   const log = getLogger(
@@ -481,7 +478,7 @@ async function processBlock(
           return false;
         });
       log.info(`Result of "addContract": ${_formatResult(result)}`);
-      eventsProcessedTotal.labels(chainId.toString()).inc();
+      metrics.eventsProcessedTotal.labels(chainId.toString()).inc();
     }
   }
 

src/domain/checkForAndPlaceOrder.ts

@@ -14,6 +14,7 @@ import {
   getLogger,
   pollConditionalOrder,
   handleOnChainCustomError,
+  metrics,
 } from "../utils";
 import {
   ConditionalOrder as ConditionalOrderSDK,
@@ -30,18 +31,6 @@ import {
   formatEpoch,
 } from "@cowprotocol/cow-sdk";
 import { ChainContext, SDK_BACKOFF_NUM_OF_ATTEMPTS } from "./chainContext";
-import {
-  pollingOnChainDurationSeconds,
-  activeOrdersTotal,
-  activeOwnersTotal,
-  orderBookDiscreteOrdersTotal,
-  orderBookErrorsTotal,
-  pollingOnChainChecksTotal,
-  pollingRunsTotal,
-  pollingUnexpectedErrorsTotal,
-  pollingOnChainEthersErrorsTotal,
-  measureTime,
-} from "../utils/metrics";
 import { FilterAction } from "../utils/filterPolicy";
 import { validateOrder } from "../utils/filterOrder";
 
@@ -230,7 +219,7 @@ export async function checkForAndPlaceOrder(
       const action = deleted ? "Stop Watching" : "Failed to stop watching";
 
       log.debug(`${action} conditional order from TX ${conditionalOrder.tx}`);
-      activeOrdersTotal.labels(chainId.toString()).dec();
+      metrics.activeOrdersTotal.labels(chainId.toString()).dec();
     }
   }
 
@@ -239,7 +228,7 @@ export async function checkForAndPlaceOrder(
   for (const [owner, conditionalOrders] of Array.from(ownerOrders.entries())) {
     if (conditionalOrders.size === 0) {
       ownerOrders.delete(owner);
-      activeOwnersTotal.labels(chainId.toString()).dec();
+      metrics.activeOwnersTotal.labels(chainId.toString()).dec();
     }
   }
 
@@ -274,7 +263,7 @@ async function _processConditionalOrder(
   const id = ConditionalOrderSDK.leafToId(conditionalOrder.params);
   const metricLabels = [chainId.toString(), handler, owner, id];
   try {
-    pollingRunsTotal.labels(...metricLabels).inc();
+    metrics.pollingRunsTotal.labels(...metricLabels).inc();
 
     const proof = conditionalOrder.proof
       ? conditionalOrder.proof.path.map((c) => c.toString())
@@ -310,7 +299,7 @@ async function _processConditionalOrder(
       // Unsupported Order Type (unknown handler)
       // For now, fallback to legacy behavior
       // TODO: Decide in the future what to do. Probably, move the error handling to the SDK and kill the poll Legacy
-      pollResult = await measureTime({
+      pollResult = await metrics.measureTime({
         action: () =>
           _pollLegacy(
             context,
@@ -321,8 +310,8 @@ async function _processConditionalOrder(
             orderRef
           ),
         labelValues: metricLabels,
-        durationMetric: pollingOnChainDurationSeconds,
-        totalRunsMetric: pollingOnChainChecksTotal,
+        durationMetric: metrics.pollingOnChainDurationSeconds,
+        totalRunsMetric: metrics.pollingOnChainChecksTotal,
       });
     }
 
@@ -389,7 +378,7 @@ async function _processConditionalOrder(
       signature,
     };
   } catch (e: any) {
-    pollingUnexpectedErrorsTotal.labels(...metricLabels).inc();
+    metrics.pollingUnexpectedErrorsTotal.labels(...metricLabels).inc();
     return {
       result: PollResultCode.UNEXPECTED_ERROR,
       error: e,
@@ -488,7 +477,7 @@ async function _placeOrder(params: {
     log.debug(`Post order details`, postOrder);
     if (!dryRun) {
       const orderUid = await orderBook.sendOrder(postOrder);
-      orderBookDiscreteOrdersTotal.labels(...metricLabels).inc();
+      metrics.orderBookDiscreteOrdersTotal.labels(...metricLabels).inc();
       log.info(`API response`, { orderUid });
     }
   } catch (error: any) {
@@ -544,7 +533,7 @@ function _handleOrderBookError(
   metricLabels: string[]
 ): Omit<PollResultSuccess, "order" | "signature"> | PollResultErrors {
   const apiError = body?.errorType as OrderPostError.errorType;
-  orderBookErrorsTotal
+  metrics.orderBookErrorsTotal
     .labels(...metricLabels, status.toString(), apiError)
     .inc();
   if (status === 400) {
@@ -649,7 +638,7 @@ async function _pollLegacy(
     // We can only get here from some provider / ethers failure. As the contract hasn't had it's say
     // we will defer to try again.
     log.error(`ethers/call Unexpected error`, error);
-    pollingOnChainEthersErrorsTotal.labels(...metricLabels).inc();
+    metrics.pollingOnChainEthersErrorsTotal.labels(...metricLabels).inc();
     return {
       result: PollResultCode.TRY_NEXT_BLOCK,
       reason:

src/types/model.ts

@@ -4,8 +4,7 @@ import { BytesLike, ethers } from "ethers";
 
 import type { ConditionalOrderCreatedEvent } from "./generated/ComposableCoW";
 import { ConditionalOrderParams, PollResult } from "@cowprotocol/cow-sdk";
-import { DBService } from "../utils";
-import { activeOrdersTotal, activeOwnersTotal } from "../utils/metrics";
+import { DBService, metrics } from "../utils";
 
 // Standardise the storage key
 const LAST_NOTIFIED_ERROR_STORAGE_KEY = "LAST_NOTIFIED_ERROR";
@@ -167,12 +166,12 @@ export class Registry {
       .catch(() => null);
 
     // Return registry (on its latest version)
-    activeOwnersTotal.labels(network).set(ownerOrders.size);
+    metrics.activeOwnersTotal.labels(network).set(ownerOrders.size);
     const numOrders = Array.from(ownerOrders.values()).reduce(
       (acc, o) => acc + o.size,
       0
     );
-    activeOrdersTotal.labels(network).set(numOrders);
+    metrics.activeOrdersTotal.labels(network).set(numOrders);
 
     return new Registry(
       ownerOrders,

src/utils/contracts.ts

@@ -8,7 +8,7 @@ import {
   SupportedChainId,
 } from "@cowprotocol/cow-sdk";
 import { getLogger } from "./logging";
-import { pollingOnChainInvalidInterfacesTotal } from "./metrics";
+import { metrics } from ".";
 
 // Selectors that are required to be part of the contract's bytecode in order to be considered compatible
 const REQUIRED_SELECTORS = [
@@ -293,7 +293,6 @@ export function handleOnChainCustomError(params: {
           `Order for safe ${owner} where the Safe has swap guard enabled. Deleting order...`
         );
         return dropOrder("The conditional order didn't pass the swap guard");
-      // TODO: Add metrics to track this
       case CustomErrorSelectors.ORDER_NOT_VALID:
         const reason = msgWithSelector(parsedCustomError.message);
         log.info(
@@ -333,7 +332,7 @@ export function handleOnChainCustomError(params: {
     log.debug(
       `Contract returned a non-compliant interface revert via getTradeableOrderWithSignature. Simulate: https://dashboard.tenderly.co/gp-v2/watch-tower-prod/simulator/new?network=${chainId}&contractAddress=${target}&rawFunctionInput=${callData}`
     );
-    pollingOnChainInvalidInterfacesTotal.labels(...metricLabels).inc();
+    metrics.pollingOnChainInvalidInterfacesTotal.labels(...metricLabels).inc();
     return {
       result: PollResultCode.DONT_TRY_AGAIN,
       reason: "Order returned a non-compliant (invalid/erroneous) revert hint",

src/utils/index.ts

@@ -4,3 +4,5 @@ export * from "./poll";
 export * from "./misc";
 export * from "./db";
 export * from "./logging";
+export * from "./api";
+export * as metrics from "./metrics";