client: make prom client optional

packages/client/bin/cli.ts

@@ -42,7 +42,6 @@ import { loadKZG } from 'kzg-wasm'
 import { Level } from 'level'
 import { homedir } from 'os'
 import * as path from 'path'
-import * as promClient from 'prom-client'
 import * as readline from 'readline'
 import * as url from 'url'
 import * as yargs from 'yargs'
@@ -54,7 +53,7 @@ import { LevelDB } from '../src/execution/level.js'
 import { getLogger } from '../src/logging.js'
 import { Event } from '../src/types.js'
 import { parseMultiaddrs } from '../src/util/index.js'
-import { setupMetrics } from '../src/util/metrics.js'
+import { loadPromClient, setupMetrics } from '../src/util/metrics.js'
 
 import { helprpc, startRPCServers } from './startRpc.js'
 
@@ -1088,7 +1087,8 @@ async function run() {
   let metricsServer: http.Server | undefined
   if (args.prometheus === true) {
     // Create custom metrics
-    prometheusMetrics = setupMetrics()
+    const promClient = await loadPromClient()
+    prometheusMetrics = await setupMetrics()
 
     const register = new promClient.Registry()
     register.setDefaultLabels({

packages/client/package.json

@@ -87,7 +87,6 @@
     "level": "^8.0.0",
     "mcl-wasm": "^1.5.0",
     "memory-level": "^1.0.0",
-    "prom-client": "^15.1.0",
     "verkle-cryptography-wasm": "^0.4.5",
     "winston": "^3.3.3",
     "winston-daily-rotate-file": "^4.5.5",
@@ -108,6 +107,9 @@
     "testdouble-timers": "^0.1.1",
     "ws": "^8.14.2"
   },
+  "optionalDependencies": {
+    "prom-client": "^15.1.0"
+  },
   "engines": {
     "node": ">=18"
   }

packages/client/src/config.ts

@@ -9,7 +9,8 @@ import { Event, EventBus } from './types.js'
 import { isBrowser, short } from './util/index.js'
 
 import type { Logger } from './logging.js'
-import type { EventBusType, MultiaddrLike, PrometheusMetrics } from './types.js'
+import type { EventBusType, MultiaddrLike } from './types.js'
+import type { PrometheusMetrics } from './util/metrics.js'
 import type { BlockHeader } from '@ethereumjs/block'
 import type { VM, VMProfilerOpts } from '@ethereumjs/vm'
 import type { Multiaddr } from '@multiformats/multiaddr'

packages/client/src/types.ts

@@ -7,7 +7,6 @@ import type { Block, BlockHeader } from '@ethereumjs/block'
 import type { DefaultStateManager } from '@ethereumjs/statemanager'
 import type { Address } from '@ethereumjs/util'
 import type { Multiaddr } from '@multiformats/multiaddr'
-import type * as promClient from 'prom-client'
 
 /**
  * Types for the central event bus, emitted
@@ -176,10 +175,3 @@ export interface ClientOpts {
   ignoreStatelessInvalidExecs?: boolean
   useJsCrypto?: boolean
 }
-
-export type PrometheusMetrics = {
-  legacyTxGauge: promClient.Gauge<string>
-  accessListEIP2930TxGauge: promClient.Gauge<string>
-  feeMarketEIP1559TxGauge: promClient.Gauge<string>
-  blobEIP4844TxGauge: promClient.Gauge<string>
-}

packages/client/src/util/metrics.ts

@@ -1,6 +1,16 @@
-import * as promClient from 'prom-client'
+import type * as promClient from 'prom-client'
 
-export const setupMetrics = () => {
+export const loadPromClient = async () => {
+  try {
+    const promClient = await import('prom-client')
+    return promClient
+  } catch (error) {
+    throw new Error('Missing prom-client import')
+  }
+}
+
+export const setupMetrics = async () => {
+  const promClient = await loadPromClient()
   return {
     legacyTxGauge: new promClient.Gauge({
       name: 'legacy_transactions_in_transaction_pool',
@@ -20,3 +30,10 @@ export const setupMetrics = () => {
     }),
   }
 }
+
+export type PrometheusMetrics = {
+  legacyTxGauge: promClient.Gauge<string>
+  accessListEIP2930TxGauge: promClient.Gauge<string>
+  feeMarketEIP1559TxGauge: promClient.Gauge<string>
+  blobEIP4844TxGauge: promClient.Gauge<string>
+}