DYNAMO_BATCH_WRITE_COMMAND_CONCURRENCY now can be set by env

README.md

@@ -50,6 +50,12 @@ AWS link: https://d1gwt3w78t4dm3.cloudfront.net
 
 Vercel link: https://open-next.vercel.app
 
+## Configuration
+
+### Environment variables
+
+- DYNAMO_BATCH_WRITE_COMMAND_CONCURRENCY: The number of concurrent batch write commands to DynamoDB. Defaults to 4 in an effort to leave plenty of DynamoDB write request capacity for the production load.
+
 ## Contribute
 
 To run `OpenNext` locally:

packages/open-next/src/adapters/constants.ts

@@ -1 +1,25 @@
 export const MAX_DYNAMO_BATCH_WRITE_ITEM_COUNT = 25;
+
+/**
+ * Sending to dynamo X commands at a time, using about X * 25 write units per batch to not overwhelm DDB
+ * and give production plenty of room to work with. With DDB Response times, you can expect about 10 batches per second.
+ */
+const DEFAULT_DYNAMO_BATCH_WRITE_COMMAND_CONCURRENCY = 4;
+
+export const getDynamoBatchWriteCommandConcurrency = (): number => {
+  const dynamoBatchWriteCommandConcurrencyFromEnv =
+    process.env.DYNAMO_BATCH_WRITE_COMMAND_CONCURRENCY;
+  const parsedDynamoBatchWriteCommandConcurrencyFromEnv =
+    dynamoBatchWriteCommandConcurrencyFromEnv
+      ? parseInt(dynamoBatchWriteCommandConcurrencyFromEnv)
+      : undefined;
+
+  if (
+    parsedDynamoBatchWriteCommandConcurrencyFromEnv &&
+    !isNaN(parsedDynamoBatchWriteCommandConcurrencyFromEnv)
+  ) {
+    return parsedDynamoBatchWriteCommandConcurrencyFromEnv;
+  }
+
+  return DEFAULT_DYNAMO_BATCH_WRITE_COMMAND_CONCURRENCY;
+};

packages/open-next/src/adapters/dynamo-provider.ts

@@ -5,7 +5,10 @@ import {
 import { CdkCustomResourceEvent, CdkCustomResourceResponse } from "aws-lambda";
 import { readFileSync } from "fs";
 
-import { MAX_DYNAMO_BATCH_WRITE_ITEM_COUNT } from "./constants.js";
+import {
+  getDynamoBatchWriteCommandConcurrency,
+  MAX_DYNAMO_BATCH_WRITE_ITEM_COUNT,
+} from "./constants.js";
 import { chunk } from "./util.js";
 
 const PHYSICAL_RESOURCE_ID = "dynamodb-cache";
@@ -36,12 +39,6 @@ export async function handler(
   }
 }
 
-/**
- * Sending to dynamo X commands at a time, using about X * 25 write units per batch to not overwhelm DDB
- * and give production plenty of room to work with. With DDB Response times, you can expect about 10 batches per second.
- */
-const DYNAMO_BATCH_WRITE_COMMAND_CONCURRENCY = 4;
-
 async function insert(): Promise<CdkCustomResourceResponse> {
   const tableName = process.env.CACHE_DYNAMO_TABLE!;
 
@@ -65,7 +62,7 @@ async function insert(): Promise<CdkCustomResourceResponse> {
 
   const paramsChunks = chunk(
     batchWriteParamsArray,
-    DYNAMO_BATCH_WRITE_COMMAND_CONCURRENCY,
+    getDynamoBatchWriteCommandConcurrency(),
   );
 
   for (const paramsChunk of paramsChunks) {