Introduce new routing backend (#790)
This is a huge backend change that essentially started with rewriting the concurrency handling for processes and blew up to a refactor of the entire application. In short these are the improvements: **Better state and life cycle management:** Life cycle management of processes has always been the trickiest part of the code. Juggling mutex locks between multiple locations to reduce race conditions was complex. Too complex for my feeble brain to build a simple mental model around as llama-swap gained more features. All of that has been refactored. Most of the locks are gone, replaced with a single run() that owns all state changes. There is one place to start from now to understand and extend routing logic. The improved life cycle management makes it easier to implement more complex swap optimization strategies in the future like #727. **Collation of requests:** llama-swap previously handled requests and swapping in the order they came in. For example requests for models in this order ABCABC would result in 5 swaps. Now those requests are handled in this order AABBCC. The result is less time waiting for swap under a high churn request queue. This fixes #588 #612. A possible future enhancement is to support a starvation parameter so swap can be forced when models have been waiting too long. **Shared base implementation for groups and swap matrix:** During the refactor it became clear that much of the swapping logic was shared between these two implementations. That is not surprising considering the swap matrix was added many moons after groups. Now they share a common base and their specific swap strategies are implemented into the swapPlanner interface. Requests for bespoke or specific swapping scenarios is a common theme in the issues. Now users can implement whatever bespoke and weird swapping strategy they want in their own fork. Just ask your agent of choice to implement swapPlanner. I'll still remaining more conservative on what actually lands in core llama-swap and will continue to evaluate PRs if the changes is good for everyone or just one specific use case. **AI / Agentic Disclosure:** I paid very close attention to the low level swap concurrency design and implementation. It's important to keep that essential part reliable, boring and no surprises. Backwards compatibility was also maintained, even the one way non-exclusive group model loading behaviour that people have rightly pointed out be a weird design decision. With the underlying swap core done the web server, api and UI sitting on top were largely ported over with Claude Code and Opus 4.7 in multiple phases. If you're curious I kept the changes in docs/newrouter-todo.md. I did several passes to make sure things weren't left behind. However, even frontier LLMs at the time of this PR still make small decisions that don't make a lot of sense. They get shit wrong all the time, just in small subtle way. That said, there's likely to be some new bugs introduced with this massive refactor. I'm fairly confident that there's no major architectural flaws that would cause goal seeking agents to make dumb, ugly code decisions. For a little while the legacy llama-swap will be available under cmd/legacy/llama-swap. The plan is to eventually delete that entry point as well as the proxy package. On a bit of a personal note, this PR is exciting and a bit sad for me. I hand wrote much of the original code and this PR ultimately replaces much of it. While the old code served as a good reference for the agent to implement the new stuff it still a bit sad to eventually delete it all.
This commit is contained in:
Benson Wong
GitHub
@@ -0,0 +1,306 @@
|
||||
package main
|
||||
|
||||
import (
|
||||
"context"
|
||||
"encoding/json"
|
||||
"flag"
|
||||
"fmt"
|
||||
"io"
|
||||
"log"
|
||||
"net/http"
|
||||
"os"
|
||||
"os/signal"
|
||||
"strings"
|
||||
"syscall"
|
||||
"time"
|
||||
|
||||
"github.com/tidwall/gjson"
|
||||
)
|
||||
|
||||
var loremWords = strings.Fields(
|
||||
"Lorem ipsum dolor sit amet consectetur adipiscing elit sed do eiusmod tempor " +
|
||||
"incididunt ut labore et dolore magna aliqua Ut enim ad minim veniam quis nostrud " +
|
||||
"exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat Duis aute " +
|
||||
"irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla " +
|
||||
"pariatur Excepteur sint occaecat cupidatat non proident sunt in culpa qui officia " +
|
||||
"deserunt mollit anim id est laborum Sed ut perspiciatis unde omnis iste natus error " +
|
||||
"sit voluptatem accusantium doloremque laudantium totam rem aperiam eaque ipsa quae " +
|
||||
"ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo " +
|
||||
"Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit",
|
||||
)
|
||||
|
||||
var (
|
||||
flagListen = flag.String("listen", "localhost:9898", "listen address")
|
||||
flagTokens = flag.Int("tokens", 1000, "number of tokens to return")
|
||||
flagTPS = flag.Float64("tps", 75, "tokens per second")
|
||||
flagLoad = flag.String("load", "0s", "simulated load duration (e.g. 2s, 500ms)")
|
||||
)
|
||||
|
||||
type chunkDelta struct {
|
||||
Role string `json:"role,omitempty"`
|
||||
Content string `json:"content,omitempty"`
|
||||
}
|
||||
|
||||
type chunkChoice struct {
|
||||
Index int `json:"index"`
|
||||
Delta chunkDelta `json:"delta"`
|
||||
FinishReason *string `json:"finish_reason"`
|
||||
}
|
||||
|
||||
type chatChunk struct {
|
||||
ID string `json:"id"`
|
||||
Object string `json:"object"`
|
||||
Created int64 `json:"created"`
|
||||
Model string `json:"model"`
|
||||
Choices []chunkChoice `json:"choices"`
|
||||
}
|
||||
|
||||
type completionMessage struct {
|
||||
Role string `json:"role"`
|
||||
Content string `json:"content"`
|
||||
}
|
||||
|
||||
type completionChoice struct {
|
||||
Index int `json:"index"`
|
||||
Message completionMessage `json:"message"`
|
||||
FinishReason string `json:"finish_reason"`
|
||||
}
|
||||
|
||||
type completionUsage struct {
|
||||
PromptTokens int `json:"prompt_tokens"`
|
||||
CompletionTokens int `json:"completion_tokens"`
|
||||
TotalTokens int `json:"total_tokens"`
|
||||
}
|
||||
|
||||
type chatCompletion struct {
|
||||
ID string `json:"id"`
|
||||
Object string `json:"object"`
|
||||
Created int64 `json:"created"`
|
||||
Model string `json:"model"`
|
||||
Choices []completionChoice `json:"choices"`
|
||||
Usage completionUsage `json:"usage"`
|
||||
}
|
||||
|
||||
func loremText(n int) string {
|
||||
words := make([]string, n)
|
||||
for i := range words {
|
||||
words[i] = loremWords[i%len(loremWords)]
|
||||
}
|
||||
return strings.Join(words, " ")
|
||||
}
|
||||
|
||||
func sendChunk(w http.ResponseWriter, content string, finishReason *string) error {
|
||||
chunk := chatChunk{
|
||||
ID: "chatcmpl-fake",
|
||||
Object: "chat.completion.chunk",
|
||||
Created: time.Now().Unix(),
|
||||
Model: "fake-model",
|
||||
Choices: []chunkChoice{
|
||||
{
|
||||
Index: 0,
|
||||
Delta: chunkDelta{Content: content},
|
||||
FinishReason: finishReason,
|
||||
},
|
||||
},
|
||||
}
|
||||
data, err := json.Marshal(chunk)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
_, err = fmt.Fprintf(w, "data: %s\n\n", data)
|
||||
return err
|
||||
}
|
||||
|
||||
// startLoading runs the countdown log and closes ready when loadDur elapses.
|
||||
// If loadDur is zero, ready is closed immediately.
|
||||
func startLoading(loadDur time.Duration) <-chan struct{} {
|
||||
ready := make(chan struct{})
|
||||
if loadDur == 0 {
|
||||
close(ready)
|
||||
return ready
|
||||
}
|
||||
go func() {
|
||||
deadline := time.Now().Add(loadDur)
|
||||
log.Printf("loading... %s remaining", loadDur.Round(time.Second))
|
||||
ticker := time.NewTicker(time.Second)
|
||||
defer ticker.Stop()
|
||||
timer := time.NewTimer(loadDur)
|
||||
for {
|
||||
select {
|
||||
case <-timer.C:
|
||||
close(ready)
|
||||
log.Printf("ready")
|
||||
return
|
||||
case <-ticker.C:
|
||||
if rem := time.Until(deadline).Round(time.Second); rem > 0 {
|
||||
log.Printf("loading... %s remaining", rem)
|
||||
}
|
||||
}
|
||||
}
|
||||
}()
|
||||
return ready
|
||||
}
|
||||
|
||||
func healthHandler(ready <-chan struct{}) http.HandlerFunc {
|
||||
return func(w http.ResponseWriter, r *http.Request) {
|
||||
select {
|
||||
case <-ready:
|
||||
w.WriteHeader(http.StatusOK)
|
||||
default:
|
||||
w.WriteHeader(http.StatusServiceUnavailable)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func chatHandler(ready <-chan struct{}) http.HandlerFunc {
|
||||
return func(w http.ResponseWriter, r *http.Request) {
|
||||
if r.Method != http.MethodPost {
|
||||
http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
|
||||
return
|
||||
}
|
||||
|
||||
body, err := io.ReadAll(r.Body)
|
||||
if err != nil {
|
||||
http.Error(w, "failed to read body", http.StatusBadRequest)
|
||||
return
|
||||
}
|
||||
|
||||
streaming := gjson.GetBytes(body, "stream").Bool()
|
||||
ctx := r.Context()
|
||||
|
||||
select {
|
||||
case <-ready:
|
||||
case <-ctx.Done():
|
||||
return
|
||||
}
|
||||
|
||||
tokens := *flagTokens
|
||||
tps := *flagTPS
|
||||
if tps <= 0 {
|
||||
tps = 1
|
||||
}
|
||||
|
||||
if !streaming {
|
||||
delay := time.Duration(float64(tokens) / tps * float64(time.Second))
|
||||
select {
|
||||
case <-time.After(delay):
|
||||
case <-ctx.Done():
|
||||
return
|
||||
}
|
||||
text := loremText(tokens)
|
||||
resp := chatCompletion{
|
||||
ID: "chatcmpl-fake",
|
||||
Object: "chat.completion",
|
||||
Created: time.Now().Unix(),
|
||||
Model: "fake-model",
|
||||
Choices: []completionChoice{
|
||||
{
|
||||
Index: 0,
|
||||
Message: completionMessage{Role: "assistant", Content: text},
|
||||
FinishReason: "stop",
|
||||
},
|
||||
},
|
||||
Usage: completionUsage{
|
||||
PromptTokens: 0,
|
||||
CompletionTokens: tokens,
|
||||
TotalTokens: tokens,
|
||||
},
|
||||
}
|
||||
w.Header().Set("Content-Type", "application/json")
|
||||
json.NewEncoder(w).Encode(resp)
|
||||
return
|
||||
}
|
||||
|
||||
w.Header().Set("Content-Type", "text/event-stream")
|
||||
w.Header().Set("Cache-Control", "no-cache")
|
||||
w.Header().Set("Connection", "keep-alive")
|
||||
|
||||
flusher, ok := w.(http.Flusher)
|
||||
if !ok {
|
||||
http.Error(w, "streaming not supported", http.StatusInternalServerError)
|
||||
return
|
||||
}
|
||||
|
||||
// Send role delta first
|
||||
first := chatChunk{
|
||||
ID: "chatcmpl-fake",
|
||||
Object: "chat.completion.chunk",
|
||||
Created: time.Now().Unix(),
|
||||
Model: "fake-model",
|
||||
Choices: []chunkChoice{
|
||||
{Index: 0, Delta: chunkDelta{Role: "assistant"}},
|
||||
},
|
||||
}
|
||||
if data, err := json.Marshal(first); err == nil {
|
||||
fmt.Fprintf(w, "data: %s\n\n", data)
|
||||
flusher.Flush()
|
||||
}
|
||||
|
||||
interval := time.Duration(float64(time.Second) / tps)
|
||||
ticker := time.NewTicker(interval)
|
||||
defer ticker.Stop()
|
||||
|
||||
stop := "stop"
|
||||
for i := 0; i < tokens; i++ {
|
||||
select {
|
||||
case <-ctx.Done():
|
||||
return
|
||||
case <-ticker.C:
|
||||
}
|
||||
|
||||
word := loremWords[i%len(loremWords)]
|
||||
if i < tokens-1 {
|
||||
if err := sendChunk(w, word+" ", nil); err != nil {
|
||||
return
|
||||
}
|
||||
} else {
|
||||
if err := sendChunk(w, word, &stop); err != nil {
|
||||
return
|
||||
}
|
||||
}
|
||||
flusher.Flush()
|
||||
}
|
||||
|
||||
fmt.Fprintf(w, "data: [DONE]\n\n")
|
||||
flusher.Flush()
|
||||
}
|
||||
}
|
||||
|
||||
func main() {
|
||||
flag.Parse()
|
||||
|
||||
loadDur, err := time.ParseDuration(*flagLoad)
|
||||
if err != nil {
|
||||
log.Fatalf("invalid -load value %q: %v", *flagLoad, err)
|
||||
}
|
||||
|
||||
ready := startLoading(loadDur)
|
||||
|
||||
mux := http.NewServeMux()
|
||||
mux.HandleFunc("/health", healthHandler(ready))
|
||||
mux.HandleFunc("/v1/chat/completions", chatHandler(ready))
|
||||
|
||||
srv := &http.Server{
|
||||
Addr: *flagListen,
|
||||
Handler: mux,
|
||||
}
|
||||
|
||||
go func() {
|
||||
log.Printf("listening on %s (tokens=%d tps=%.1f load=%s)",
|
||||
*flagListen, *flagTokens, *flagTPS, loadDur)
|
||||
if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
|
||||
log.Fatalf("server error: %v", err)
|
||||
}
|
||||
}()
|
||||
|
||||
quit := make(chan os.Signal, 1)
|
||||
signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
|
||||
<-quit
|
||||
|
||||
log.Println("shutting down...")
|
||||
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
|
||||
defer cancel()
|
||||
if err := srv.Shutdown(ctx); err != nil {
|
||||
log.Printf("shutdown error: %v", err)
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user