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Add per-listener connection limits

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Configurable maximum concurrent connections per listener. When the
limit is reached, new connections are closed immediately after accept.
0 means unlimited (default, preserving existing behavior).

Config: Listener gains max_connections field, validated non-negative.

DB: Migration 3 adds listeners.max_connections column.
UpdateListenerMaxConns method for runtime changes via gRPC.
CreateListener updated to persist max_connections on seed.

Server: ListenerState/ListenerData gain MaxConnections. Limit checked
in serve() after Accept but before handleConn — if ActiveConnections
>= MaxConnections, connection is closed and the accept loop continues.
SetMaxConnections method for runtime updates.

Proto: SetListenerMaxConnections RPC added. ListenerStatus gains
max_connections field. Generated code regenerated.

gRPC server: SetListenerMaxConnections implements write-through
(DB first, then in-memory update). GetStatus includes max_connections.

Client: SetListenerMaxConnections method, MaxConnections in
ListenerStatus.

Tests: DB CRUD and UpdateListenerMaxConns, server connection limit
enforcement (accept 2, reject 3rd, close one, accept again), gRPC
SetListenerMaxConnections round-trip with DB persistence, not-found
error handling.

Also updates PROJECT_PLAN.md with phases 6-8 and PROGRESS.md with
tracking for the new features.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
kyle
2026-03-25 16:42:53 -07:00
co-authored by Claude Opus 4.6
parent 5bc8f4fc8e
commit 564e0a9c67
16 changed files with 595 additions and 102 deletions
Download Patch File Download Diff File Expand all files Collapse all files
internal/db/db_test.go
+50 -11
View File
@@ -41,7 +41,7 @@ func TestIsEmpty(t *testing.T) {
t.Fatal("expected empty database")
}
if _, err := store.CreateListener(":443", false); err != nil {
if _, err := store.CreateListener(":443", false, 0); err != nil {
t.Fatalf("create listener: %v", err)
}
@@ -57,7 +57,7 @@ func TestIsEmpty(t *testing.T) {
func TestListenerCRUD(t *testing.T) {
store := openTestDB(t)
id, err := store.CreateListener(":443", false)
id, err := store.CreateListener(":443", false, 0)
if err != nil {
t.Fatalf("create: %v", err)
}
@@ -103,7 +103,7 @@ func TestListenerCRUD(t *testing.T) {
func TestListenerProxyProtocol(t *testing.T) {
store := openTestDB(t)
id, err := store.CreateListener(":443", true)
id, err := store.CreateListener(":443", true, 0)
if err != nil {
t.Fatalf("create: %v", err)
}
@@ -120,13 +120,52 @@ func TestListenerProxyProtocol(t *testing.T) {
}
}
func TestListenerMaxConnections(t *testing.T) {
store := openTestDB(t)
id, err := store.CreateListener(":443", false, 5000)
if err != nil {
t.Fatalf("create: %v", err)
}
l, err := store.GetListenerByAddr(":443")
if err != nil {
t.Fatalf("get: %v", err)
}
if l.MaxConnections != 5000 {
t.Fatalf("max_connections = %d, want 5000", l.MaxConnections)
}
// Update max connections.
if err := store.UpdateListenerMaxConns(id, 10000); err != nil {
t.Fatalf("update: %v", err)
}
l, err = store.GetListenerByAddr(":443")
if err != nil {
t.Fatalf("get after update: %v", err)
}
if l.MaxConnections != 10000 {
t.Fatalf("max_connections = %d, want 10000", l.MaxConnections)
}
// Set to 0 (unlimited).
if err := store.UpdateListenerMaxConns(id, 0); err != nil {
t.Fatalf("update to 0: %v", err)
}
l, _ = store.GetListenerByAddr(":443")
if l.MaxConnections != 0 {
t.Fatalf("max_connections = %d, want 0", l.MaxConnections)
}
}
func TestListenerDuplicateAddr(t *testing.T) {
store := openTestDB(t)
if _, err := store.CreateListener(":443", false); err != nil {
if _, err := store.CreateListener(":443", false, 0); err != nil {
t.Fatalf("first create: %v", err)
}
if _, err := store.CreateListener(":443", false); err == nil {
if _, err := store.CreateListener(":443", false, 0); err == nil {
t.Fatal("expected error for duplicate addr")
}
}
@@ -134,7 +173,7 @@ func TestListenerDuplicateAddr(t *testing.T) {
func TestRouteCRUD(t *testing.T) {
store := openTestDB(t)
listenerID, err := store.CreateListener(":443", false)
listenerID, err := store.CreateListener(":443", false, 0)
if err != nil {
t.Fatalf("create listener: %v", err)
}
@@ -177,7 +216,7 @@ func TestRouteCRUD(t *testing.T) {
func TestRouteL7Fields(t *testing.T) {
store := openTestDB(t)
listenerID, _ := store.CreateListener(":443", false)
listenerID, _ := store.CreateListener(":443", false, 0)
_, err := store.CreateRoute(listenerID, "api.example.com", "127.0.0.1:8080", "l7",
"/certs/api.crt", "/certs/api.key", false, true)
@@ -214,7 +253,7 @@ func TestRouteL7Fields(t *testing.T) {
func TestRouteDuplicateHostname(t *testing.T) {
store := openTestDB(t)
listenerID, _ := store.CreateListener(":443", false)
listenerID, _ := store.CreateListener(":443", false, 0)
if _, err := store.CreateRoute(listenerID, "example.com", "127.0.0.1:8443", "l4", "", "", false, false); err != nil {
t.Fatalf("first create: %v", err)
}
@@ -226,7 +265,7 @@ func TestRouteDuplicateHostname(t *testing.T) {
func TestRouteCascadeDelete(t *testing.T) {
store := openTestDB(t)
listenerID, _ := store.CreateListener(":443", false)
listenerID, _ := store.CreateListener(":443", false, 0)
store.CreateRoute(listenerID, "a.example.com", "127.0.0.1:8443", "l4", "", "", false, false)
store.CreateRoute(listenerID, "b.example.com", "127.0.0.1:9443", "l4", "", "", false, false)
@@ -373,7 +412,7 @@ func TestSeed(t *testing.T) {
func TestSnapshot(t *testing.T) {
store := openTestDB(t)
store.CreateListener(":443", false)
store.CreateListener(":443", false, 0)
dest := filepath.Join(t.TempDir(), "backup.db")
if err := store.Snapshot(dest); err != nil {
@@ -432,7 +471,7 @@ func TestMigrationV2Upgrade(t *testing.T) {
}
// Insert a listener and route with defaults to verify new columns work.
lid, err := store.CreateListener(":443", false)
lid, err := store.CreateListener(":443", false, 0)
if err != nil {
t.Fatalf("create listener: %v", err)
}