From 4fd790f7dd600c6bf0721fa70b8009c8ca1f97a8 Mon Sep 17 00:00:00 2001
From: Classic298 <27028174+Classic298@users.noreply.github.com>
Date: Sun, 21 Dec 2025 13:18:00 +0100
Subject: [PATCH] feat: Apply WEB_SEARCH_CONCURRENT_REQUESTS to all search
 engines using semaphore (#20070)

* sequential

* zero default

* fix
---
 backend/open_webui/config.py                  |  2 +-
 backend/open_webui/routers/retrieval.py       | 42 ++++++++++++++-----
 .../admin/Settings/WebSearch.svelte           | 29 +++++++------
 3 files changed, 49 insertions(+), 24 deletions(-)

diff --git a/backend/open_webui/config.py b/backend/open_webui/config.py
index cf2983d63f..c5ac40babd 100644
--- a/backend/open_webui/config.py
+++ b/backend/open_webui/config.py
@@ -2994,7 +2994,7 @@ WEB_SEARCH_DOMAIN_FILTER_LIST = PersistentConfig(
 WEB_SEARCH_CONCURRENT_REQUESTS = PersistentConfig(
     "WEB_SEARCH_CONCURRENT_REQUESTS",
     "rag.web.search.concurrent_requests",
-    int(os.getenv("WEB_SEARCH_CONCURRENT_REQUESTS", "10")),
+    int(os.getenv("WEB_SEARCH_CONCURRENT_REQUESTS", "0")),
 )
 
 
diff --git a/backend/open_webui/routers/retrieval.py b/backend/open_webui/routers/retrieval.py
index 43839d0107..89aabf5573 100644
--- a/backend/open_webui/routers/retrieval.py
+++ b/backend/open_webui/routers/retrieval.py
@@ -2103,16 +2103,38 @@ async def process_web_search(
             f"trying to web search with {request.app.state.config.WEB_SEARCH_ENGINE, form_data.queries}"
         )
 
-        search_tasks = [
-            run_in_threadpool(
-                search_web,
-                request,
-                request.app.state.config.WEB_SEARCH_ENGINE,
-                query,
-                user,
-            )
-            for query in form_data.queries
-        ]
+        # Use semaphore to limit concurrent requests based on WEB_SEARCH_CONCURRENT_REQUESTS
+        # 0 or None = unlimited (previous behavior), positive number = limited concurrency
+        # Set to 1 for sequential execution (rate-limited APIs like Brave free tier)
+        concurrent_limit = request.app.state.config.WEB_SEARCH_CONCURRENT_REQUESTS
+
+        if concurrent_limit:
+            # Limited concurrency with semaphore
+            semaphore = asyncio.Semaphore(concurrent_limit)
+
+            async def search_with_limit(query):
+                async with semaphore:
+                    return await run_in_threadpool(
+                        search_web,
+                        request,
+                        request.app.state.config.WEB_SEARCH_ENGINE,
+                        query,
+                        user,
+                    )
+
+            search_tasks = [search_with_limit(query) for query in form_data.queries]
+        else:
+            # Unlimited parallel execution (previous behavior)
+            search_tasks = [
+                run_in_threadpool(
+                    search_web,
+                    request,
+                    request.app.state.config.WEB_SEARCH_ENGINE,
+                    query,
+                    user,
+                )
+                for query in form_data.queries
+            ]
 
         search_results = await asyncio.gather(*search_tasks)
 
diff --git a/src/lib/components/admin/Settings/WebSearch.svelte b/src/lib/components/admin/Settings/WebSearch.svelte
index 588a5a6ac0..b2956fc729 100644
--- a/src/lib/components/admin/Settings/WebSearch.svelte
+++ b/src/lib/components/admin/Settings/WebSearch.svelte
@@ -630,19 +630,6 @@
 									/>
 								</div>
 							</div>
-						{:else if webConfig.WEB_SEARCH_ENGINE === 'ddgs' || webConfig.WEB_SEARCH_ENGINE === 'duckduckgo'}
-							<div class="w-full mb-2.5">
-								<div class=" self-center text-xs font-medium mb-1">
-									{$i18n.t('Concurrent Requests')}
-								</div>
-
-								<input
-									class="w-full rounded-lg py-2 px-4 text-sm bg-gray-50 dark:text-gray-300 dark:bg-gray-850 outline-hidden"
-									placeholder={$i18n.t('Concurrent Requests')}
-									bind:value={webConfig.WEB_SEARCH_CONCURRENT_REQUESTS}
-									required
-								/>
-							</div>
 						{:else if webConfig.WEB_SEARCH_ENGINE === 'external'}
 							<div class="mb-2.5 flex w-full flex-col">
 								<div>
@@ -692,6 +679,22 @@
 										required
 									/>
 								</div>
+
+								<div class="w-full">
+									<div class=" self-center text-xs font-medium mb-1">
+										<Tooltip content={$i18n.t('Limit concurrent search queries. 0 = unlimited (default). Set to 1 for sequential execution (recommended for APIs with strict rate limits like Brave free tier).')} placement="top-start">
+											{$i18n.t('Concurrent Requests')}
+										</Tooltip>
+									</div>
+
+									<input
+										class="w-full rounded-lg py-2 px-4 text-sm bg-gray-50 dark:text-gray-300 dark:bg-gray-850 outline-hidden"
+										placeholder={$i18n.t('Concurrent Requests')}
+										bind:value={webConfig.WEB_SEARCH_CONCURRENT_REQUESTS}
+										type="number"
+										min="0"
+									/>
+								</div>
 							</div>
 						</div>