feat: Add multi-target load balancing support

Fixes #47.
- Added lua-resty-balancer to dependencies (Dockerfile & install.sh).
- Added 'targets' field to the Host model to hold additional targets.
- Updated the UI to allow inputting additional targets (IP:port).
- Updated targetinfo.lua to parse the additional targets and load balance between them and the primary target using resty.balancer.round_robin.

nodejs/models/host.js

@@ -28,6 +28,7 @@ class Host extends Table{
 		'host': {isRequired: true, type: 'string', min: 1, max: 500},
 		'ip': {isRequired: true, type: 'string', min: 3, max: 500},
 		'targetPort': {isRequired: true, type: 'number', min:0, max:65535},
+		'targets': {default: function(){return []}, isRequired: false, type: 'object'},
 		'forcessl': {isRequired: false, default: true, type: 'boolean'},
 		'targetssl': {isRequired: false, default: false, type: 'boolean'},
 

nodejs/utils/host_features.js

@@ -252,6 +252,7 @@ function normalizeHostFeatures(body){
 	if('sso_enabled' in body) body.sso_enabled = toBool(body.sso_enabled);
 	if('sso_allow_users' in body)  body.sso_allow_users  = parseAllowList(body.sso_allow_users);
 	if('sso_allow_groups' in body) body.sso_allow_groups = parseAllowList(body.sso_allow_groups);
+	if('targets' in body) body.targets = parseAllowList(body.targets);
 
 	if('ratelimit_rate' in body)  body.ratelimit_rate  = clampNumber(body.ratelimit_rate, 1, 1000000, 10);
 	if('ratelimit_burst' in body) body.ratelimit_burst = clampNumber(body.ratelimit_burst, 0, 1000000, 20);

nodejs/views/hosts.ejs

@@ -232,6 +232,7 @@
 		});
 
 		$f.find("textarea[name='req_headers']").val(hostFeatureHeadersToText(h.req_headers));
+		$f.find("textarea[name='targets']").val(hostFeatureListToText(h.targets));
 		$f.find("textarea[name='resp_headers']").val(hostFeatureHeadersToText(h.resp_headers));
 		$f.find("textarea[name='ip_allow']").val(hostFeatureListToText(h.ip_allow));
 		$f.find("textarea[name='ip_deny']").val(hostFeatureListToText(h.ip_deny));
@@ -632,6 +633,14 @@
 									<small class="field-help text-muted d-block">Whether the proxy talks to the target over HTTP or HTTPS. Independent of Incoming SSL above — clients can use HTTPS to reach the proxy while it still talks plain HTTP to the target, or vice versa.</small>
 								</div>
 							</div>
+
+							<hr>
+
+							<div class="form-group">
+								<label for="targets" class="form-label">Additional Targets (Load Balancing)</label>
+								<textarea name="targets" class="form-control" rows="2" placeholder="10.0.0.2:8080&#10;10.0.0.3:8080"></textarea>
+								<small class="field-help text-muted d-block">Add additional targets here (IP:port, one per line) to load balance across them using round-robin. The primary target above is always included.</small>
+							</div>
 						</div>
 
 						<!-- TLS & Wildcard -->