fix: cache dynamo clients to avoid too many open files error

packages/lambda/src/content-claims.js

@@ -2,12 +2,10 @@
 import * as Sentry from '@sentry/serverless'
 import { createServer, walkClaims } from '@web3-storage/content-claims/server'
 import * as CAR from '@ucanto/transport/car'
-import { DynamoDBClient } from '@aws-sdk/client-dynamodb'
-import { S3Client } from '@aws-sdk/client-s3'
 import { Config } from 'sst/node/config'
 import * as Link from 'multiformats/link'
 import { CARWriterStream } from 'carstream'
-import { getServiceSigner, notNully } from './lib/config.js'
+import { getDynamoClient, getS3Client, getServiceSigner, notNully } from './lib/config.js'
 import { DynamoTable } from './lib/store/dynamo-table.js'
 import { S3Bucket } from './lib/store/s3-bucket.js'
 import { ClaimStorage, TieredClaimFetcher, BlockIndexClaimFetcher } from './lib/store/index.js'
@@ -93,11 +91,11 @@ export const postUcanInvocation = async event => {
   }
 
   const dynamoRegion = notNully('CLAIM_TABLE_REGION', process.env)
-  const dynamoClient = new DynamoDBClient({ region: dynamoRegion })
+  const dynamoClient = getDynamoClient(dynamoRegion)
   const table = new DynamoTable(dynamoClient, notNully('CLAIM_TABLE', process.env))
 
   const bucketRegion = notNully('CLAIM_BUCKET_REGION', process.env)
-  const bucketClient = new S3Client({ region: bucketRegion })
+  const bucketClient = getS3Client(bucketRegion)
   const bucket = new S3Bucket(bucketClient, notNully('CLAIM_BUCKET', process.env))
 
   const claimStore = new ClaimStorage({ table, bucket })
@@ -131,11 +129,11 @@ export const postUcanInvocation = async event => {
  */
 export const getClaims = async event => {
   const dynamoRegion = notNully('CLAIM_TABLE_REGION', process.env)
-  const dynamoClient = new DynamoDBClient({ region: dynamoRegion })
+  const dynamoClient = getDynamoClient(dynamoRegion)
   const table = new DynamoTable(dynamoClient, notNully('CLAIM_TABLE', process.env))
 
   const bucketRegion = notNully('CLAIM_BUCKET_REGION', process.env)
-  const bucketClient = new S3Client({ region: bucketRegion })
+  const bucketClient = getS3Client(bucketRegion)
   const bucket = new S3Bucket(bucketClient, notNully('CLAIM_BUCKET', process.env))
 
   /** @type {import('@web3-storage/content-claims/server/api').ClaimFetcher} */
@@ -144,7 +142,7 @@ export const getClaims = async event => {
   if (process.env.BLOCK_INDEX_TABLE) {
     const blkIdxTable = process.env.BLOCK_INDEX_TABLE
     const blkIdxRegion = process.env.BLOCK_INDEX_REGION ?? dynamoRegion
-    const blkIdxDynamo = new DynamoDBClient({ region: blkIdxRegion })
+    const blkIdxDynamo = getDynamoClient(blkIdxRegion)
     const blkIdxClaimFetcher = new BlockIndexClaimFetcher(blkIdxDynamo, blkIdxTable, signer)
     claimFetcher = new TieredClaimFetcher([claimFetcher, blkIdxClaimFetcher])
   }

packages/lambda/src/lib/config.js

@@ -1,5 +1,7 @@
 import { DID } from '@ucanto/server'
 import * as ed25519 from '@ucanto/principal/ed25519'
+import { S3Client } from '@aws-sdk/client-s3'
+import { DynamoDBClient } from '@aws-sdk/client-dynamodb'
 
 /**
  * Given a config, return a ucanto Signer object representing the service
@@ -28,3 +30,25 @@ export function notNully (key, obj) {
   if (value == null) throw new Error(`unexpected null/undefined key in object: ${key}`)
   return value
 }
+
+/** @type {Record<string, import('@aws-sdk/client-dynamodb').DynamoDBClient>} */
+const dynamoClients = {}
+
+/** @param {string} region */
+export function getDynamoClient (region) {
+  if (!dynamoClients[region]) {
+    dynamoClients[region] = new DynamoDBClient({ region })
+  }
+  return dynamoClients[region]
+}
+
+/** @type {Record<string, import('@aws-sdk/client-s3').S3Client>} */
+const s3Clients = {}
+
+/** @param {string} region */
+export function getS3Client (region) {
+  if (!s3Clients[region]) {
+    s3Clients[region] = new S3Client({ region })
+  }
+  return s3Clients[region]
+}