From 26cfbd07cbd66c1d0cfa8d12ca94d61572cdadea Mon Sep 17 00:00:00 2001
From: Simon Larsen <simonlarsen@oneuptime.com>
Date: Tue, 12 Aug 2025 17:39:47 +0100
Subject: [PATCH] feat: Add server names hash tuning options to nginx
 configuration

---
 HelmChart/Public/oneuptime/templates/nginx.yaml |  8 ++++++++
 HelmChart/Public/oneuptime/values.yaml          |  3 +++
 Nginx/default.conf.template                     |  5 +++++
 Nginx/envsubst-on-templates.sh                  | 16 +++++++++++++++-
 4 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/HelmChart/Public/oneuptime/templates/nginx.yaml b/HelmChart/Public/oneuptime/templates/nginx.yaml
index 3634a8e7ec..0ba8ba5f40 100644
--- a/HelmChart/Public/oneuptime/templates/nginx.yaml
+++ b/HelmChart/Public/oneuptime/templates/nginx.yaml
@@ -111,6 +111,14 @@ spec:
               value: {{ $.Values.nginx.listenAddress | quote }}
             - name: NGINX_LISTEN_OPTIONS
               value: {{ $.Values.nginx.listenOptions | quote }}
+            {{- if $.Values.nginx.serverNamesHash.bucketSize }}
+            - name: SERVER_NAMES_HASH_BUCKET_SIZE
+              value: {{ $.Values.nginx.serverNamesHash.bucketSize | quote }}
+            {{- end }}
+            {{- if $.Values.nginx.serverNamesHash.maxSize }}
+            - name: SERVER_NAMES_HASH_MAX_SIZE
+              value: {{ $.Values.nginx.serverNamesHash.maxSize | quote }}
+            {{- end }}
             - name: ONEUPTIME_HTTP_PORT
               value: {{ $.Values.nginx.ports.http | quote }}
             - name: PORT
diff --git a/HelmChart/Public/oneuptime/values.yaml b/HelmChart/Public/oneuptime/values.yaml
index 94588aa3fe..930ad0131d 100644
--- a/HelmChart/Public/oneuptime/values.yaml
+++ b/HelmChart/Public/oneuptime/values.yaml
@@ -43,6 +43,9 @@ nginx:
   disableAutoscaler: false
   listenAddress: ""
   listenOptions: ""
+  serverNamesHash:
+    bucketSize: ""
+    maxSize: ""
   ports:
     http: 80
     https: 443
diff --git a/Nginx/default.conf.template b/Nginx/default.conf.template
index 42166bcbf4..170b97e76a 100644
--- a/Nginx/default.conf.template
+++ b/Nginx/default.conf.template
@@ -1,3 +1,8 @@
+## Hash tuning for many/long server names. Can be overridden via env vars.
+## Defaults are provided by envsubst-on-templates.sh if not set.
+server_names_hash_bucket_size ${SERVER_NAMES_HASH_BUCKET_SIZE};
+server_names_hash_max_size ${SERVER_NAMES_HASH_MAX_SIZE};
+
 upstream accounts {
     server ${SERVER_ACCOUNTS_HOSTNAME}:${ACCOUNTS_PORT} weight=10 max_fails=3 fail_timeout=30s;
 }
diff --git a/Nginx/envsubst-on-templates.sh b/Nginx/envsubst-on-templates.sh
index 3b6bb54479..efd884070b 100644
--- a/Nginx/envsubst-on-templates.sh
+++ b/Nginx/envsubst-on-templates.sh
@@ -25,8 +25,22 @@ auto_envsubst() {
     subdir=$(dirname "$relative_path")
     # create a subdirectory where the template file exists
     mkdir -p "$output_dir/$subdir"
+
+    # Make a temp copy to allow conditional line removal
+    tmpfile=$(mktemp)
+    cp "$template" "$tmpfile"
+
+    # If hash tuning envs are not set, remove their lines from the template
+    if [ -z "${SERVER_NAMES_HASH_BUCKET_SIZE}" ]; then
+      sed -i '/^[[:space:]]*server_names_hash_bucket_size[[:space:]]/d' "$tmpfile"
+    fi
+    if [ -z "${SERVER_NAMES_HASH_MAX_SIZE}" ]; then
+      sed -i '/^[[:space:]]*server_names_hash_max_size[[:space:]]/d' "$tmpfile"
+    fi
+
     echo "$ME: Running envsubst on $template to $output_path"
-    envsubst "$defined_envs" < "$template" > "$output_path"
+    envsubst "$defined_envs" < "$tmpfile" > "$output_path"
+    rm -f "$tmpfile"
   done
 }