Add support for configuring load balancing strategy

server/lib/traefik/getTraefikConfig.ts

@@ -30,6 +30,7 @@ import { buildWildcardTls } from "./certResolver";
 import { buildHostRule, appendPathMatch, computeRoutePriority } from "./rule";
 import {
     buildHttpLoadBalancerServers,
+    buildLoadBalancingStrategy,
     buildStickySessionCookie,
     buildTcpUdpLoadBalancerServers,
     buildStickySessionIp
@@ -93,6 +94,7 @@ export async function getTraefikConfig(
             domainId: resources.domainId,
             enabled: resources.enabled,
             stickySession: resources.stickySession,
+            loadBalancingStrategy: resources.loadBalancingStrategy,
             tlsServerName: resources.tlsServerName,
             setHostHeader: resources.setHostHeader,
             enableProxy: resources.enableProxy,
@@ -222,6 +224,7 @@ export async function getTraefikConfig(
                 domainId: row.domainId,
                 enabled: row.enabled,
                 stickySession: row.stickySession,
+                loadBalancingStrategy: row.loadBalancingStrategy,
                 tlsServerName: row.tlsServerName,
                 setHostHeader: row.setHostHeader,
                 enableProxy: row.enableProxy,
@@ -458,6 +461,9 @@ export async function getTraefikConfig(
             config_output.http.services![serviceName] = {
                 loadBalancer: {
                     servers: buildHttpLoadBalancerServers(targets),
+                    ...buildLoadBalancingStrategy(
+                        resource.loadBalancingStrategy
+                    ),
                     ...(resource.stickySession
                         ? buildStickySessionCookie(resource.ssl)
                         : {})

server/lib/traefik/loadBalancer.test.ts

@@ -2,6 +2,7 @@ import "@server/extendZod";
 import { assertEqualsObj } from "@test/assert";
 import {
     buildHttpLoadBalancerServers,
+    buildLoadBalancingStrategy,
     buildTcpUdpLoadBalancerServers
 } from "./loadBalancer";
 import type { TargetWithSite } from "./types";
@@ -75,6 +76,24 @@ function runTests() {
         );
     }
 
+    assertEqualsObj(
+        buildLoadBalancingStrategy("wrr"),
+        {},
+        "Default wrr strategy should be omitted"
+    );
+    assertEqualsObj(
+        buildLoadBalancingStrategy(null),
+        {},
+        "Missing strategy should be omitted"
+    );
+    for (const strategy of ["p2c", "hrw", "leasttime"]) {
+        assertEqualsObj(
+            buildLoadBalancingStrategy(strategy),
+            { strategy },
+            `${strategy} strategy should be emitted`
+        );
+    }
+
     console.log("All load balancer endpoint tests passed!");
 }
 

server/lib/traefik/loadBalancer.ts

@@ -63,6 +63,18 @@ export function buildHttpLoadBalancerServers(targets: TargetWithSite[]) {
         );
 }
 
+/**
+ * Build the loadBalancer.strategy for an HTTP-mode resource. Traefik defaults
+ * to wrr when strategy is omitted, so only emit it for the non-default
+ * strategies to keep the generated config unchanged for existing resources.
+ */
+export function buildLoadBalancingStrategy(strategy: string | null) {
+    if (!strategy || strategy === "wrr") {
+        return {};
+    }
+    return { strategy };
+}
+
 export function buildStickySessionCookie(ssl: boolean | null) {
     return {
         sticky: {