From fa081e901414b4b062594120c9539b9e025dc1a5 Mon Sep 17 00:00:00 2001
From: Christopher Kolstad <chriswk@getunleash.ai>
Date: Tue, 20 Jun 2023 12:10:05 +0200
Subject: [PATCH] task: Make keepalive configurable via an environment variable
 (#4015)

As requested in
[Linear](https://linear.app/unleash/issue/2-1147/unleash-cloud-make-keepalive-configurable)
this PR makes the serverKeepAliveTimeout configurable via the
SERVER_KEEPALIVE_TIMEOUT environment variable. This was already
configurable when starting Unleash programmatically, but it's nice to
have as an env variable as well
---
 src/lib/__snapshots__/create-config.test.ts.snap     |  2 +-
 src/lib/create-config.ts                             | 11 +++++------
 website/docs/reference/deploy/configuring-unleash.md |  2 +-
 3 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/src/lib/__snapshots__/create-config.test.ts.snap b/src/lib/__snapshots__/create-config.test.ts.snap
index 928d6e63d7..d34c3f7bfe 100644
--- a/src/lib/__snapshots__/create-config.test.ts.snap
+++ b/src/lib/__snapshots__/create-config.test.ts.snap
@@ -171,7 +171,7 @@ exports[`should create default config 1`] = `
     "gracefulShutdownTimeout": 1000,
     "headersTimeout": 61000,
     "host": undefined,
-    "keepAliveTimeout": 60000,
+    "keepAliveTimeout": 15000,
     "pipe": undefined,
     "port": 4242,
     "secret": "super-secret",
diff --git a/src/lib/create-config.ts b/src/lib/create-config.ts
index b9212470ec..1de5dc3477 100644
--- a/src/lib/create-config.ts
+++ b/src/lib/create-config.ts
@@ -22,11 +22,7 @@ import {
 import { getDefaultLogProvider, LogLevel, validateLogProvider } from './logger';
 import { defaultCustomAuthDenyAll } from './default-custom-auth-deny-all';
 import { formatBaseUri } from './util/format-base-uri';
-import {
-    hoursToMilliseconds,
-    minutesToMilliseconds,
-    secondsToMilliseconds,
-} from 'date-fns';
+import { hoursToMilliseconds, secondsToMilliseconds } from 'date-fns';
 import EventEmitter from 'events';
 import {
     ApiTokenType,
@@ -170,7 +166,10 @@ const defaultServerOption: IServerOption = {
         process.env.ENABLE_HEAP_SNAPSHOT_ENPOINT,
         false,
     ),
-    keepAliveTimeout: minutesToMilliseconds(1),
+    keepAliveTimeout: parseEnvVarNumber(
+        process.env.SERVER_KEEPALIVE_TIMEOUT,
+        secondsToMilliseconds(15),
+    ),
     headersTimeout: secondsToMilliseconds(61),
     enableRequestLogger: false,
     gracefulShutdownEnable: parseEnvVarBoolean(
diff --git a/website/docs/reference/deploy/configuring-unleash.md b/website/docs/reference/deploy/configuring-unleash.md
index cfed6a75ff..c8e3895772 100644
--- a/website/docs/reference/deploy/configuring-unleash.md
+++ b/website/docs/reference/deploy/configuring-unleash.md
@@ -133,7 +133,7 @@ unleash.start(unleashOptions);
   - `refreshIntervalInMs` - how often (in milliseconds) front-end clients should refresh their data from the cache. Overridable with the `FRONTEND_API_REFRESH_INTERVAL_MS` environment variable.
 - **accessControlMaxAge** - You can configure the max-age of the Access-Control-Max-Age header. Defaults to 86400 seconds. Overridable with the `ACCESS_CONTROL_MAX_AGE` environment variable.
 - **responseTimeWithAppNameKillSwitch** - use this to disable metrics with app names. This is enabled by default but may increase the cardinality of metrics causing Unleash memory usage to grow if your app name is randomly generated (which is not recommended). Overridable with the `UNLEASH_RESPONSE_TIME_WITH_APP_NAME_KILL_SWITCH` environment variable.
-
+- **keepAliveTimeout** - Use this to tweak connection keepalive timeout in seconds. Useful for hosted situations where you need to make sure your connections are closed before terminating the instance. Defaults to `15`. Overridable with the `SERVER_KEEPALIVE_TIMEOUT` environment variable.
 You can also set the environment variable `ENABLED_ENVIRONMENTS` to a comma delimited string of environment names to override environments.
 
 ### Disabling Auto-Start {#disabling-auto-start}