chore: metrics todo and naming (#95)

# Description
This PR addresses issues around naming conventions for the prometheus
metrics. Best efforts have been followed to adhere to [best
practices](https://prometheus.io/docs/practices/naming/).

# Changes

- [x] Revised metric naming and labeling to be in accordance with best
practices.
- [x] Removed custom API prometheus metrics and replaced with
middleware.

## How to test

1. Run a sync from contract genesis.
2. Observe via `http://127.0.0.1:8080/metrics` there respective metrics
changing.

## Related Issues

Related #78, #70

package.json

@@ -21,6 +21,7 @@
     "@commitlint/config-conventional": "^17.6.7",
     "@typechain/ethers-v5": "^11.1.1",
     "@types/express": "^4.17.18",
+    "@types/express-prometheus-middleware": "^1.2.1",
     "@types/jest": "^29.5.3",
     "@types/node": "^18.16.3",
     "@types/node-slack": "^0.0.31",
@@ -45,6 +46,7 @@
     "chalk": "^4.1.2",
     "ethers": "^5.7.2",
     "express": "^4.18.2",
+    "express-prometheus-middleware": "^1.2.0",
     "graphql-request": "^6.1.0",
     "level": "^8.0.0",
     "level-ts": "^2.1.0",

src/domain/addContract.ts

@@ -1,5 +1,9 @@
-import { toConditionalOrderParams, getLogger } from "../utils";
-import { MetricsService } from "../utils/metrics";
+import {
+  toConditionalOrderParams,
+  getLogger,
+  handleExecutionError,
+  isComposableCowCompatible,
+} from "../utils";
 import { BytesLike, ethers } from "ethers";
 
 import {
@@ -14,17 +18,19 @@ import {
   Registry,
 } from "../types";
 
-import { isComposableCowCompatible, handleExecutionError } from "../utils";
 import { ChainContext } from "./chainContext";
 import { ConditionalOrderParams } from "@cowprotocol/cow-sdk";
-
-const {
-  newOwnerCount,
-  addNewOwnerErrorCount,
-  addContractSingleOrderCount,
-  addContractMerkleRootSetCount,
-  ownersPopulation,
-} = MetricsService;
+import {
+  addContractRunsTotal,
+  addContractsErrorsTotal,
+  addContractsRunDurationSeconds,
+  measureTime,
+  merkleRootTotal,
+  newContractsTotal,
+  singleOrdersTotal,
+  activeOrdersTotal,
+  activeOwnersTotal,
+} from "../utils/metrics";
 
 /**
  * Listens to these events on the `ComposableCoW` contract:
@@ -37,7 +43,15 @@ export async function addContract(
   context: ChainContext,
   event: ConditionalOrderCreatedEvent
 ) {
-  return _addContract(context, event).catch(handleExecutionError);
+  const { chainId } = context;
+  await measureTime({
+    action: () => _addContract(context, event),
+    labelValues: [chainId.toString()],
+    durationMetric: addContractsRunDurationSeconds,
+    totalRunsMetric: addContractRunsTotal,
+    errorHandler: handleExecutionError,
+    errorMetric: addContractsErrorsTotal,
+  });
 }
 
 async function _addContract(
@@ -65,15 +79,12 @@ async function _addContract(
     registry
   );
   if (added) {
-    newOwnerCount.labels(context.chainId.toString()).inc();
+    newContractsTotal.labels(context.chainId.toString()).inc();
     numContractsAdded++;
   } else {
     log.error(
       `Failed to register Smart Order from tx ${tx} on block ${blockNumber}. Error: ${error}`
     );
-    addNewOwnerErrorCount
-      .labels(context.chainId.toString(), "_addContract")
-      .inc();
   }
   hasErrors ||= error;
 
@@ -123,7 +134,7 @@ export async function _registerNewOrder(
         registry
       );
       added = true;
-      addContractSingleOrderCount.labels(registry.network).inc();
+      singleOrdersTotal.labels(registry.network).inc();
     } else if (
       event.topics[0] == composableCow.getEventTopic("MerkleRootSet")
     ) {
@@ -164,7 +175,7 @@ export async function _registerNewOrder(
             registry
           );
           added = true;
-          addContractMerkleRootSetCount.labels(registry.network).inc();
+          merkleRootTotal.labels(registry.network).inc();
         }
       }
     }
@@ -223,6 +234,7 @@ export function add(
         orders: new Map(),
         composableCow,
       });
+      activeOrdersTotal.labels(registry.network).inc();
     }
   } else {
     log.info(`Adding conditional order to new owner contract ${owner}:`, {
@@ -235,7 +247,8 @@ export function add(
       owner,
       new Set([{ tx, params, proof, orders: new Map(), composableCow }])
     );
-    ownersPopulation.labels(registry.network).inc();
+    activeOwnersTotal.labels(registry.network).inc();
+    activeOrdersTotal.labels(registry.network).inc();
   }
 }
 

src/domain/chainContext.ts

@@ -12,21 +12,19 @@ import { addContract } from "./addContract";
 import { checkForAndPlaceOrder } from "./checkForAndPlaceOrder";
 import { ethers } from "ethers";
 import { composableCowContract, DBService, getLogger } from "../utils";
-import { MetricsService } from "../utils/metrics";
+import {
+  blockHeight,
+  blockTime,
+  eventsProcessedTotal,
+  processBlockDurationSeconds,
+  reorgDepth,
+  reorgsTotal,
+} from "../utils/metrics";
 
 const WATCHDOG_FREQUENCY = 5 * 1000; // 5 seconds
 
 const MULTICALL3 = "0xcA11bde05977b3631167028862bE2a173976CA11";
 
-// Metrics
-const {
-  blockWatcherBlockHeight,
-  blockWatcherReorgCount,
-  blockWatcherBlockTime,
-  blockWatcherNumEventsProcessed,
-  processBlockDuration,
-} = MetricsService;
-
 /**
  * The chain context handles watching a single chain for new conditional orders
  * and executing them.
@@ -102,9 +100,7 @@ export class ChainContext {
     const { pageSize } = this;
 
     // Set the block height metric
-    blockWatcherBlockHeight
-      .labels(chainId.toString())
-      .set(lastProcessedBlock ?? 0);
+    blockHeight.labels(chainId.toString()).set(lastProcessedBlock ?? 0);
 
     // Start watching from (not including) the last processed block (if any)
     let fromBlock = lastProcessedBlock
@@ -181,9 +177,7 @@ export class ChainContext {
           await this.registry.write();
 
           // Set the block height metric
-          blockWatcherBlockHeight
-            .labels(chainId.toString())
-            .set(Number(blockNumber));
+          blockHeight.labels(chainId.toString()).set(Number(blockNumber));
         } catch (err) {
           log.error(`Error processing block ${blockNumber}`, err);
         }
@@ -246,16 +240,19 @@ export class ChainContext {
         log.debug(`New block ${blockNumber}`);
         // Set the block time metric
         const now = new Date().getTime();
-        const blockTime = now - timeLastBlockProcessed;
+        const _blockTime = (now - timeLastBlockProcessed) / 1000;
         timeLastBlockProcessed = now;
 
         // Set the block time metric
-        blockWatcherBlockTime.labels(chainId.toString()).set(blockTime);
+        blockTime.labels(chainId.toString()).set(_blockTime);
 
         if (blockNumber <= lastBlockReceived) {
           // This may be a re-org, so process the block again
-          blockWatcherReorgCount.labels(chainId.toString()).inc();
+          reorgsTotal.labels(chainId.toString()).inc();
           log.info(`Re-org detected, re-processing block ${blockNumber}`);
+          reorgDepth
+            .labels(chainId.toString())
+            .set(lastBlockReceived - blockNumber + 1);
         }
         lastBlockReceived = blockNumber;
 
@@ -269,9 +266,7 @@ export class ChainContext {
           await processBlock(this, Number(blockNumber), events);
 
           // Block height metric
-          blockWatcherBlockHeight
-            .labels(chainId.toString())
-            .set(Number(blockNumber));
+          blockHeight.labels(chainId.toString()).set(Number(blockNumber));
         } catch {
           log.error(`Error processing block ${blockNumber}`);
         }
@@ -322,7 +317,7 @@ async function processBlock(
   blockTimestampOverride?: number
 ) {
   const { provider, chainId } = context;
-  const timer = processBlockDuration
+  const timer = processBlockDurationSeconds
     .labels(context.chainId.toString())
     .startTimer();
   const log = getLogger(`chainContext:processBlock:${chainId}:${blockNumber}`);
@@ -343,7 +338,7 @@ async function processBlock(
           return false;
         });
       log.info(`Result of "addContract": ${_formatResult(result)}`);
-      blockWatcherNumEventsProcessed.labels(chainId.toString()).inc();
+      eventsProcessedTotal.labels(chainId.toString()).inc();
     }
   }