Add LLM busy modes: wait (hang) or reject with Retry-After

LLM_BUSY_MODE=reject answers blocked LLM requests immediately with LLM_BUSY_STATUS (default 503, 429 works) and Retry-After, so routers like LiteLLM can cool down and retry instead of holding a hung connection. The default wait mode now also sends Retry-After when LLM_WAIT_TIMEOUT expires. Document the service account (LocalSystem default, NT SERVICE virtual-account hardening) and the Program Files / ProgramData install layout.
2026-09-20 21:43:03 +02:00
parent e363c9e4e4
commit bacb26772a
10 changed files with 291 additions and 3 deletions
@@ -2,6 +2,7 @@ package proxy

 import (
 	"bufio"
+	"context"
 	"fmt"
 	"io"
 	"net/http"
@@ -345,3 +346,108 @@ func TestPassThroughNoLock(t *testing.T) {
 		t.Fatalf("pass-through = %d %s", resp.StatusCode, body)
 	}
 }
+
+func TestLLMBusyReject(t *testing.T) {
+	f := newFakes(t)
+
+	lk := lock.New(nil)
+	if err := lk.AcquireImage(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	ollamaClient, err := ollama.New(f.ollama.URL, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	comfyClient, err := comfy.New(f.comfy.URL, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv, err := New(Config{
+		OllamaURL:      f.ollama.URL,
+		ComfyURL:       f.comfy.URL,
+		Lock:           lk,
+		Ollama:         ollamaClient,
+		Comfy:          comfyClient,
+		Metrics:        metrics.New(),
+		LLMWaitTimeout: 2 * time.Second,
+		LLMBusyMode:    "reject",
+		BusyRetryAfter: 17,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	front := httptest.NewServer(srv.OllamaHandler())
+	defer front.Close()
+
+	start := time.Now()
+	resp, err := http.Post(front.URL+"/api/chat", "application/json", strings.NewReader(`{}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	body, _ := io.ReadAll(resp.Body)
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusServiceUnavailable {
+		t.Fatalf("busy chat status = %d %s", resp.StatusCode, body)
+	}
+	if got := resp.Header.Get("Retry-After"); got != "17" {
+		t.Fatalf("Retry-After = %q", got)
+	}
+	if elapsed := time.Since(start); elapsed > time.Second {
+		t.Fatalf("reject was not immediate: %v", elapsed)
+	}
+
+	// After the image lock is released the next LLM request goes through.
+	lk.ReleaseImage()
+	resp, err = http.Post(front.URL+"/api/chat", "application/json", strings.NewReader(`{}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	resp.Body.Close()
+	if resp.StatusCode != 200 {
+		t.Fatalf("chat after release status = %d", resp.StatusCode)
+	}
+}
+
+func TestLLMBusyWaitTimeoutRetryAfter(t *testing.T) {
+	f := newFakes(t)
+
+	lk := lock.New(nil)
+	if err := lk.AcquireImage(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	defer lk.ReleaseImage()
+	ollamaClient, err := ollama.New(f.ollama.URL, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	comfyClient, err := comfy.New(f.comfy.URL, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv, err := New(Config{
+		OllamaURL:      f.ollama.URL,
+		ComfyURL:       f.comfy.URL,
+		Lock:           lk,
+		Ollama:         ollamaClient,
+		Comfy:          comfyClient,
+		Metrics:        metrics.New(),
+		LLMWaitTimeout: 50 * time.Millisecond,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	front := httptest.NewServer(srv.OllamaHandler())
+	defer front.Close()
+
+	resp, err := http.Post(front.URL+"/api/chat", "application/json", strings.NewReader(`{}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusServiceUnavailable {
+		t.Fatalf("timed-out chat status = %d", resp.StatusCode)
+	}
+	if got := resp.Header.Get("Retry-After"); got != "30" {
+		t.Fatalf("Retry-After = %q", got)
+	}
+}