automc: operator UI on AUTOMC_UI_BINDING
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Adds a separate HTTP server (not the upstream API on :25590) for the
operator dashboard. Single-page UI with two panes:
  * routes table — current pg-synced mappings, polled every 2s
  * logs — SSE stream backed by a logrus hook + 500-entry ring buffer

Opt-in via AUTOMC_UI_BINDING (e.g. ":8082"); unset = no-op, behaves
exactly like upstream. Designed to live behind server-manager's
/infra/mc-router/* reverse-proxy.

Patch is internal/automc-only, same fork philosophy as the rest —
upstream files stay verbatim.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
2026-06-10 18:03:48 +02:00
parent 004ee6dbfd
commit e2ce0453fa
4 changed files with 394 additions and 0 deletions
+116
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@@ -0,0 +1,116 @@
package automc
import (
"fmt"
"sync"
"time"
"github.com/sirupsen/logrus"
)
// LogEntry is the structured shape pushed to UI subscribers via SSE.
type LogEntry struct {
Time time.Time `json:"time"`
Level string `json:"level"`
Msg string `json:"msg"`
Attrs string `json:"attrs,omitempty"`
}
// LogBus is a fan-out buffer for logrus entries: a ring of the last N
// entries (replayed on connect) + live broadcast to current subscribers.
// Identical model to the one in svc-proxy/internal/httpsrv — kept local to
// avoid a cross-repo dep on the fork.
type LogBus struct {
cap int
mu sync.RWMutex
ring []LogEntry
next int
full bool
listeners map[chan LogEntry]struct{}
}
func NewLogBus(capacity int) *LogBus {
if capacity <= 0 {
capacity = 500
}
return &LogBus{
cap: capacity,
ring: make([]LogEntry, capacity),
listeners: map[chan LogEntry]struct{}{},
}
}
func (b *LogBus) Push(e LogEntry) {
b.mu.Lock()
b.ring[b.next] = e
b.next = (b.next + 1) % b.cap
if b.next == 0 {
b.full = true
}
subs := make([]chan LogEntry, 0, len(b.listeners))
for ch := range b.listeners {
subs = append(subs, ch)
}
b.mu.Unlock()
for _, ch := range subs {
select {
case ch <- e:
default:
}
}
}
func (b *LogBus) Backlog() []LogEntry {
b.mu.RLock()
defer b.mu.RUnlock()
if !b.full {
out := make([]LogEntry, b.next)
copy(out, b.ring[:b.next])
return out
}
out := make([]LogEntry, 0, b.cap)
out = append(out, b.ring[b.next:]...)
out = append(out, b.ring[:b.next]...)
return out
}
func (b *LogBus) Subscribe() chan LogEntry {
ch := make(chan LogEntry, 32)
b.mu.Lock()
b.listeners[ch] = struct{}{}
b.mu.Unlock()
return ch
}
func (b *LogBus) Unsubscribe(ch chan LogEntry) {
b.mu.Lock()
delete(b.listeners, ch)
b.mu.Unlock()
close(ch)
}
// logrusBusHook adapts the LogBus to logrus's Hook interface. Registered
// globally from Wire() so every upstream log emission is captured.
type logrusBusHook struct{ bus *LogBus }
func (h *logrusBusHook) Levels() []logrus.Level {
return logrus.AllLevels
}
func (h *logrusBusHook) Fire(e *logrus.Entry) error {
var attrs string
for k, v := range e.Data {
if attrs != "" {
attrs += " "
}
attrs += fmt.Sprintf("%s=%v", k, v)
}
h.bus.Push(LogEntry{
Time: e.Time,
Level: e.Level.String(),
Msg: e.Message,
Attrs: attrs,
})
return nil
}
+150
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<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>mc-router</title>
<style>
:root {
--bg: #0f1115; --panel: #161922; --panel-2: #1c2030;
--border: #2a2f42; --text: #d6d9e0; --muted: #7a8194;
--accent: #6aa9ff;
--err: #f87171; --warn: #fbbf24; --info: #93c5fd; --dbg: #6b7280;
}
* { box-sizing: border-box; }
body {
margin: 0; padding: 0;
font: 13px/1.4 ui-monospace, "JetBrains Mono", Menlo, Consolas, monospace;
background: var(--bg); color: var(--text);
display: grid; grid-template-rows: auto 1fr 1fr; height: 100vh;
}
header {
padding: 10px 16px; border-bottom: 1px solid var(--border);
background: var(--panel);
display: flex; justify-content: space-between; align-items: center;
}
h1 { margin: 0; font-size: 14px; font-weight: 600; letter-spacing: 0.5px; }
h1 .meta { color: var(--muted); margin-left: 12px; font-weight: normal; }
.status { color: var(--muted); font-size: 12px; }
.status.ok { color: #4ade80; }
.status.err { color: var(--err); }
section { padding: 12px 16px; overflow: auto; border-bottom: 1px solid var(--border); }
section h2 {
margin: 0 0 10px; font-size: 12px; text-transform: uppercase;
letter-spacing: 0.7px; color: var(--muted); font-weight: 600;
display: flex; justify-content: space-between; align-items: center;
}
section h2 .clear {
background: transparent; color: var(--muted); border: 1px solid var(--border);
padding: 2px 8px; cursor: pointer; font: inherit; border-radius: 3px;
}
section h2 .clear:hover { color: var(--text); border-color: var(--accent); }
table { width: 100%; border-collapse: collapse; }
th, td {
text-align: left; padding: 6px 10px;
border-bottom: 1px solid var(--border);
font-variant-numeric: tabular-nums;
}
th { color: var(--muted); font-weight: 500; font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; }
tbody tr:hover { background: var(--panel-2); }
.empty { color: var(--muted); padding: 20px; text-align: center; }
pre.logbox { margin: 0; white-space: pre-wrap; word-break: break-word; max-height: 100%; }
.log-line { padding: 1px 0; }
.log-line .ts { color: var(--muted); margin-right: 8px; }
.log-line .lvl { margin-right: 6px; font-weight: 600; }
.log-line.lvl-debug .lvl { color: var(--dbg); }
.log-line.lvl-info .lvl { color: var(--info); }
.log-line.lvl-warning .lvl, .log-line.lvl-warn .lvl { color: var(--warn); }
.log-line.lvl-error .lvl { color: var(--err); }
.log-line .attrs { color: var(--muted); margin-left: 8px; }
</style>
</head>
<body>
<header>
<h1>mc-router <span class="meta" id="meta">— connecting…</span></h1>
<span class="status" id="status">log stream: connecting</span>
</header>
<section class="routes">
<h2><span>Routes <span id="route-count" style="color:var(--muted);"></span></span></h2>
<table>
<thead>
<tr>
<th>Server address (host)</th>
<th>Backend</th>
</tr>
</thead>
<tbody id="route-rows"></tbody>
</table>
<div id="route-empty" class="empty">no routes registered</div>
</section>
<section class="logs">
<h2>
<span>Logs</span>
<button class="clear" onclick="document.getElementById('logbox').innerHTML=''">clear</button>
</h2>
<pre class="logbox" id="logbox"></pre>
</section>
<script>
async function refreshRoutes() {
try {
const r = await fetch('/api/routes');
const j = await r.json();
const rows = document.getElementById('route-rows');
const empty = document.getElementById('route-empty');
const count = document.getElementById('route-count');
rows.innerHTML = '';
if (!j.routes || j.routes.length === 0) {
empty.style.display = '';
count.textContent = '';
} else {
empty.style.display = 'none';
count.textContent = '(' + j.routes.length + ')';
for (const r of j.routes) {
const tr = document.createElement('tr');
tr.innerHTML = '<td>' + r.server_address + '</td><td>' + r.backend + '</td>';
rows.appendChild(tr);
}
}
document.getElementById('meta').textContent = '— ' + j.routes.length + ' routes';
} catch (e) {
document.getElementById('meta').textContent = '— api error';
}
}
setInterval(refreshRoutes, 2000);
refreshRoutes();
function startLogStream() {
const status = document.getElementById('status');
const box = document.getElementById('logbox');
const es = new EventSource('/api/logs');
es.onopen = () => { status.textContent = 'log stream: live'; status.className = 'status ok'; };
es.onerror = () => { status.textContent = 'log stream: reconnecting'; status.className = 'status err'; };
es.onmessage = ev => {
let e;
try { e = JSON.parse(ev.data); } catch { return; }
const ts = e.time ? e.time.split('T')[1].split('.')[0] : '';
const div = document.createElement('div');
const lvl = (e.level || 'info').toLowerCase();
div.className = 'log-line lvl-' + lvl;
div.innerHTML =
'<span class="ts">' + ts + '</span>' +
'<span class="lvl">' + (e.level || 'info') + '</span>' +
(e.msg || '') +
(e.attrs ? '<span class="attrs">' + e.attrs + '</span>' : '');
box.appendChild(div);
const parent = box.parentElement;
if (parent.scrollHeight - parent.scrollTop - parent.clientHeight < 60) {
parent.scrollTop = parent.scrollHeight;
}
while (box.children.length > 1000) box.removeChild(box.firstChild);
};
}
startLogStream();
</script>
</body>
</html>
+119
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package automc
import (
"context"
"embed"
"encoding/json"
"errors"
"fmt"
"io"
"io/fs"
"net/http"
"sort"
"time"
"github.com/itzg/mc-router/server"
"github.com/sirupsen/logrus"
)
//go:embed static/*
var staticFS embed.FS
// startUI starts a separate HTTP server on uiBinding serving the operator
// dashboard (embedded index.html), an SSE log feed, and a JSON snapshot of
// the current route table. The upstream JSON API on API_BINDING is left
// untouched so existing tooling keeps working.
func startUI(ctx context.Context, uiBinding string, bus *LogBus) {
mux := http.NewServeMux()
sub, err := fs.Sub(staticFS, "static")
if err != nil {
logrus.WithError(err).Error("automc ui: embed misconfigured")
return
}
mux.Handle("GET /", http.FileServer(http.FS(sub)))
mux.HandleFunc("GET /api/routes", routesSnapshotHandler)
mux.HandleFunc("GET /api/logs", sseLogsHandler(bus))
srv := &http.Server{
Addr: uiBinding,
Handler: mux,
ReadHeaderTimeout: 5 * time.Second,
}
go func() {
<-ctx.Done()
shutCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
_ = srv.Shutdown(shutCtx)
}()
go func() {
logrus.WithField("binding", uiBinding).Info("automc: ui server listening")
if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
logrus.WithError(err).Error("automc ui server failed")
}
}()
}
// RouteSnapshot is one row of the routes table the UI renders. Same shape as
// the upstream /routes JSON but flatter — the UI doesn't need both backend
// and scalingTarget shown separately.
type RouteSnapshot struct {
ServerAddress string `json:"server_address"`
Backend string `json:"backend"`
}
func routesSnapshotHandler(w http.ResponseWriter, _ *http.Request) {
mappings := server.Routes.GetMappings()
out := make([]RouteSnapshot, 0, len(mappings))
for addr, backend := range mappings {
out = append(out, RouteSnapshot{ServerAddress: addr, Backend: backend})
}
sort.Slice(out, func(i, j int) bool { return out[i].ServerAddress < out[j].ServerAddress })
w.Header().Set("Content-Type", "application/json")
_ = json.NewEncoder(w).Encode(map[string]any{
"routes": out,
"at": time.Now(),
})
}
func sseLogsHandler(bus *LogBus) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/event-stream")
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("Connection", "keep-alive")
w.Header().Set("X-Accel-Buffering", "no")
flusher, ok := w.(http.Flusher)
if !ok {
http.Error(w, "streaming unsupported", http.StatusInternalServerError)
return
}
for _, e := range bus.Backlog() {
writeSSEEvent(w, e)
}
flusher.Flush()
ch := bus.Subscribe()
defer bus.Unsubscribe(ch)
hb := time.NewTicker(30 * time.Second)
defer hb.Stop()
for {
select {
case <-r.Context().Done():
return
case e := <-ch:
writeSSEEvent(w, e)
flusher.Flush()
case <-hb.C:
_, _ = io.WriteString(w, ":hb\n\n")
flusher.Flush()
}
}
}
}
func writeSSEEvent(w io.Writer, e LogEntry) {
fmt.Fprintf(w, "data: {\"time\":%q,\"level\":%q,\"msg\":%q,\"attrs\":%q}\n\n",
e.Time.Format(time.RFC3339Nano), e.Level, e.Msg, e.Attrs)
}
+9
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@@ -20,5 +20,14 @@ func Wire(ctx context.Context) error {
s := newSyncer(dsn, waker) s := newSyncer(dsn, waker)
go s.run(ctx) go s.run(ctx)
logrus.Info("automc: pg route sync started") logrus.Info("automc: pg route sync started")
// Operator UI on a separate port — upstream's API_BINDING stays
// JSON-only and untouched. Enable by setting AUTOMC_UI_BINDING (e.g.
// ":8082"); leave unset to skip and behave exactly like upstream.
if uiBinding := os.Getenv("AUTOMC_UI_BINDING"); uiBinding != "" {
bus := NewLogBus(500)
logrus.AddHook(&logrusBusHook{bus: bus})
startUI(ctx, uiBinding, bus)
}
return nil return nil
} }