feat: add deterministic allocation policy

2026-09-11 08:23:45 +00:00 · 2026-08-31 20:43:56 +01:00
parent 9810ee543f
commit 2b8bce5e4b
3 changed files with 200 additions and 1 deletions
@@ -0,0 +1,85 @@
+package domain
+
+import (
+	"errors"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestAllocatorFiltersAndAtomicallyClaimsCompatibleReadyServer(t *testing.T) {
+	a, err := NewAllocator([]ReadyServer{
+		{ServerID: "server-b", Region: "EU", Build: "build-1", Protocol: 1, Transport: "enet", State: ServerReady},
+		{ServerID: "server-a", Region: "NA", Build: "build-1", Protocol: 1, Transport: "enet", State: ServerReady},
+		{ServerID: "server-c", Region: "EU", Build: "build-2", Protocol: 1, Transport: "enet", State: ServerReady},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	request := AllocationRequest{AllocationID: "allocation-1", MatchID: "match-1", Region: "EU", Build: "build-1", Protocol: 1, Transport: "enet"}
+	got, err := a.Allocate(request, time.Unix(1000, 0))
+	if err != nil || got.ServerID != "server-b" || got.State != ServerAllocated {
+		t.Fatalf("allocation = %+v err=%v", got, err)
+	}
+	if _, err := a.Allocate(AllocationRequest{AllocationID: "allocation-2", MatchID: "match-2", Region: "EU", Build: "build-1", Protocol: 1, Transport: "enet"}, time.Unix(1001, 0)); !errors.Is(err, ErrNoCapacity) {
+		t.Fatalf("claimed server was reused: %v", err)
+	}
+}
+
+func TestAllocatorIsIdempotentAndRejectsConflictingReplay(t *testing.T) {
+	a, _ := NewAllocator([]ReadyServer{{ServerID: "server-1", Region: "EU", Build: "build-1", Protocol: 1, Transport: "steam_sdr", State: ServerReady}})
+	request := AllocationRequest{AllocationID: "allocation-1", MatchID: "match-1", Region: "EU", Build: "build-1", Protocol: 1, Transport: "steam_sdr"}
+	first, err := a.Allocate(request, time.Unix(1000, 0))
+	if err != nil {
+		t.Fatal(err)
+	}
+	replay, err := a.Allocate(request, time.Unix(2000, 0))
+	if err != nil || replay != first {
+		t.Fatalf("replay = %+v err=%v", replay, err)
+	}
+	request.MatchID = "match-2"
+	if _, err := a.Allocate(request, time.Unix(2000, 0)); !errors.Is(err, ErrConflict) {
+		t.Fatalf("conflicting replay = %v", err)
+	}
+}
+
+func TestAllocatorRejectsInvalidServerAndNoCompatibleCapacity(t *testing.T) {
+	if _, err := NewAllocator([]ReadyServer{{ServerID: "server-1", Region: "EU", Build: "build-1", Protocol: 1, Transport: "udp", State: ServerReady}}); !errors.Is(err, ErrAllocationInput) {
+		t.Fatalf("invalid server accepted: %v", err)
+	}
+	a, _ := NewAllocator(nil)
+	if _, err := a.Allocate(AllocationRequest{AllocationID: "a", MatchID: "m", Region: "EU", Build: "b", Protocol: 1, Transport: "enet"}, time.Unix(1000, 0)); !errors.Is(err, ErrNoCapacity) {
+		t.Fatalf("empty allocator error = %v", err)
+	}
+}
+
+func TestAllocatorConcurrentClaimsCannotDoubleAllocateOneServer(t *testing.T) {
+	a, _ := NewAllocator([]ReadyServer{{ServerID: "server-1", Region: "EU", Build: "build-1", Protocol: 1, Transport: "enet", State: ServerReady}})
+	requests := []AllocationRequest{
+		{AllocationID: "allocation-a", MatchID: "match-a", Region: "EU", Build: "build-1", Protocol: 1, Transport: "enet"},
+		{AllocationID: "allocation-b", MatchID: "match-b", Region: "EU", Build: "build-1", Protocol: 1, Transport: "enet"},
+	}
+	var wg sync.WaitGroup
+	results := make(chan error, len(requests))
+	for _, request := range requests {
+		wg.Add(1)
+		go func(request AllocationRequest) {
+			defer wg.Done()
+			_, err := a.Allocate(request, time.Unix(1000, 0))
+			results <- err
+		}(request)
+	}
+	wg.Wait()
+	close(results)
+	wins := 0
+	for err := range results {
+		if err == nil {
+			wins++
+		} else if !errors.Is(err, ErrNoCapacity) {
+			t.Fatalf("unexpected concurrent claim error: %v", err)
+		}
+	}
+	if wins != 1 {
+		t.Fatalf("concurrent claims succeeded %d times", wins)
+	}
+}