From 33eb2e5963b7e0edaa7fae1fde412222d6e5e364 Mon Sep 17 00:00:00 2001
From: Arda TANRIKULU <ardatanrikulu@gmail.com>
Date: Fri, 1 Nov 2024 14:40:22 +0300
Subject: [PATCH] enhance(gateway-cli): respect available memory while forking
 processes

---
 .changeset/serious-buses-learn.md         |  5 +++++
 packages/gateway/src/cli.ts               | 11 ++++++-----
 packages/gateway/src/getMaxConcurrency.ts | 21 +++++++++++++++++++++
 3 files changed, 32 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/serious-buses-learn.md
 create mode 100644 packages/gateway/src/getMaxConcurrency.ts

diff --git a/.changeset/serious-buses-learn.md b/.changeset/serious-buses-learn.md
new file mode 100644
index 000000000..d46ecd67b
--- /dev/null
+++ b/.changeset/serious-buses-learn.md
@@ -0,0 +1,5 @@
+---
+'@graphql-hive/gateway': patch
+---
+
+Respect available memory on forking the processes not just CPU
diff --git a/packages/gateway/src/cli.ts b/packages/gateway/src/cli.ts
index e1f8496db..c426297cc 100644
--- a/packages/gateway/src/cli.ts
+++ b/packages/gateway/src/cli.ts
@@ -25,6 +25,7 @@ import { DefaultLogger } from '@graphql-mesh/utils';
 import parseDuration from 'parse-duration';
 import { addCommands } from './commands/index';
 import { createDefaultConfigPaths } from './config';
+import { getMaxConcurrency } from './getMaxConcurrency';
 import type { ServerConfig } from './server';
 
 export type GatewayCLIConfig = (
@@ -178,9 +179,9 @@ export type AddCommand = (ctx: CLIContext, cli: CLI) => void;
 
 // we dont use `Option.default()` in the command definitions because we want the CLI options to
 // override the config file (with option defaults, config file will always be overwritten)
-const maxAvailableFork = Math.max(availableParallelism() - 1, 1);
+const maxFork = getMaxConcurrency();
 export const defaultOptions = {
-  fork: process.env['NODE_ENV'] === 'production' ? maxAvailableFork : 1,
+  fork: process.env['NODE_ENV'] === 'production' ? maxFork : 1,
   host:
     platform().toLowerCase() === 'win32' ||
     // is WSL?
@@ -200,7 +201,7 @@ let cli = new Command()
   .addOption(
     new Option(
       '--fork <count>',
-      `count of workers to spawn. uses "${maxAvailableFork}" (available parallelism) workers when NODE_ENV is "production", otherwise "1" (the main) worker (default: ${JSON.stringify(defaultOptions.fork)}`,
+      `count of workers to spawn. uses "${maxFork}" (available parallelism) workers when NODE_ENV is "production", otherwise "1" (the main) worker (default: ${JSON.stringify(defaultOptions.fork)}`,
     )
       .env('FORK')
       .argParser((v) => {
@@ -208,9 +209,9 @@ let cli = new Command()
         if (isNaN(count)) {
           throw new InvalidArgumentError('not a number.');
         }
-        if (count > maxAvailableFork) {
+        if (count > maxFork) {
           throw new InvalidArgumentError(
-            `exceedes number of available parallelism "${maxAvailableFork}".`,
+            `exceedes number of available parallelism "${maxFork}".`,
           );
         }
         return count;
diff --git a/packages/gateway/src/getMaxConcurrency.ts b/packages/gateway/src/getMaxConcurrency.ts
new file mode 100644
index 000000000..a5fb0f8dd
--- /dev/null
+++ b/packages/gateway/src/getMaxConcurrency.ts
@@ -0,0 +1,21 @@
+import { availableParallelism, freemem } from 'node:os';
+
+function getFreeMemInGb() {
+  return freemem() / 1024 ** 3;
+}
+
+function getMaxConcurrencyPerMem() {
+  return parseInt(String(getFreeMemInGb()));
+}
+
+function getMaxConcurrencyPerCpu() {
+  return availableParallelism();
+}
+
+export function getMaxConcurrency() {
+  const result = Math.min(getMaxConcurrencyPerMem(), getMaxConcurrencyPerCpu());
+  if (result < 1) {
+    return 1;
+  }
+  return result;
+}