[proxy] Add middleware snapshot revisions (#8114)

Version middleware snapshots so callers can reject stale policies. Existing Rebuild callers remain supported.

Validation: middleware race tests and scoped lint passed.

proxy/internal/middleware/manager_revision_test.go

@@ -0,0 +1,230 @@
+package middleware
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+const revisionTestMiddlewareID = "revision_test"
+
+type revisionTestFactory struct {
+	builds atomic.Int64
+}
+
+func (f *revisionTestFactory) ID() string {
+	return revisionTestMiddlewareID
+}
+
+func (f *revisionTestFactory) New(_ []byte) (Middleware, error) {
+	f.builds.Add(1)
+	return revisionTestMiddleware{}, nil
+}
+
+type revisionTestMiddleware struct{}
+
+func (revisionTestMiddleware) ID() string                     { return revisionTestMiddlewareID }
+func (revisionTestMiddleware) Version() string                { return "test" }
+func (revisionTestMiddleware) Slot() Slot                     { return SlotOnRequest }
+func (revisionTestMiddleware) AcceptedContentTypes() []string { return nil }
+func (revisionTestMiddleware) MetadataKeys() []string         { return nil }
+func (revisionTestMiddleware) MutationsSupported() bool       { return false }
+func (revisionTestMiddleware) Invoke(context.Context, *Input) (*Output, error) {
+	return &Output{Decision: DecisionAllow}, nil
+}
+func (revisionTestMiddleware) Close() error { return nil }
+
+func newRevisionTestManager(t *testing.T) (*Manager, *revisionTestFactory) {
+	t.Helper()
+	factory := &revisionTestFactory{}
+	registry := NewRegistry()
+	require.NoError(t, registry.Register(factory))
+	manager := NewManager(1, nil, nil)
+	manager.SetResolver(NewResolver(registry))
+	return manager, factory
+}
+
+func revisionTestBinding(serviceID, pathID string) PathTargetBinding {
+	return PathTargetBinding{
+		ServiceID: serviceID,
+		PathID:    pathID,
+		Specs: []Spec{{
+			ID:      revisionTestMiddlewareID,
+			Slot:    SlotOnRequest,
+			Enabled: true,
+		}},
+	}
+}
+
+func TestManagerRebuildSnapshotRevisionLookup(t *testing.T) {
+	manager, _ := newRevisionTestManager(t)
+	binding := revisionTestBinding("service", "/")
+
+	revision1, err := manager.RebuildSnapshot("service", []PathTargetBinding{binding})
+	require.NoError(t, err)
+	require.NotZero(t, revision1)
+	chain1, match := manager.ChainForRevision("service", "/", revision1)
+	require.True(t, match)
+	require.NotNil(t, chain1)
+
+	revision2, err := manager.RebuildSnapshot("service", []PathTargetBinding{binding})
+	require.NoError(t, err)
+	assert.NotEqual(t, revision1, revision2)
+	chain2, match := manager.ChainForRevision("service", "/", revision2)
+	require.True(t, match)
+	require.NotNil(t, chain2)
+	assert.NotSame(t, chain1, chain2)
+
+	stale, match := manager.ChainForRevision("service", "/", revision1)
+	assert.False(t, match)
+	assert.Nil(t, stale)
+	zero, match := manager.ChainForRevision("service", "/", 0)
+	assert.False(t, match)
+	assert.Nil(t, zero)
+}
+
+func TestManagerRebuildSnapshotTracksChainlessTransitions(t *testing.T) {
+	manager, _ := newRevisionTestManager(t)
+
+	chainlessRevision, err := manager.RebuildSnapshot("service", nil)
+	require.NoError(t, err)
+	chain, match := manager.ChainForRevision("service", "/", chainlessRevision)
+	assert.True(t, match)
+	assert.Nil(t, chain)
+
+	chainRevision, err := manager.RebuildSnapshot("service", []PathTargetBinding{
+		revisionTestBinding("service", "/"),
+	})
+	require.NoError(t, err)
+	_, match = manager.ChainForRevision("service", "/", chainlessRevision)
+	assert.False(t, match)
+	chain, match = manager.ChainForRevision("service", "/", chainRevision)
+	assert.True(t, match)
+	assert.NotNil(t, chain)
+
+	chainlessRevision2, err := manager.RebuildSnapshot("service", nil)
+	require.NoError(t, err)
+	_, match = manager.ChainForRevision("service", "/", chainRevision)
+	assert.False(t, match)
+	chain, match = manager.ChainForRevision("service", "/", chainlessRevision2)
+	assert.True(t, match)
+	assert.Nil(t, chain)
+}
+
+func TestManagerInvalidateMiddlewarePreservesServiceRevision(t *testing.T) {
+	manager, factory := newRevisionTestManager(t)
+	revision, err := manager.RebuildSnapshot("service", []PathTargetBinding{
+		revisionTestBinding("service", "/"),
+	})
+	require.NoError(t, err)
+	chain1, match := manager.ChainForRevision("service", "/", revision)
+	require.True(t, match)
+	require.NotNil(t, chain1)
+
+	manager.InvalidateMiddleware(revisionTestMiddlewareID)
+
+	chain2, match := manager.ChainForRevision("service", "/", revision)
+	require.True(t, match)
+	require.NotNil(t, chain2)
+	assert.NotSame(t, chain1, chain2)
+	assert.EqualValues(t, 2, factory.builds.Load())
+}
+
+func TestManagerInvalidateRemovesRevisionAndReaddDoesNotReuseIt(t *testing.T) {
+	manager, _ := newRevisionTestManager(t)
+	revision1, err := manager.RebuildSnapshot("service", nil)
+	require.NoError(t, err)
+
+	manager.Invalidate("service")
+	_, match := manager.ChainForRevision("service", "/", revision1)
+	assert.False(t, match)
+
+	revision2, err := manager.RebuildSnapshot("service", nil)
+	require.NoError(t, err)
+	assert.NotEqual(t, revision1, revision2)
+	_, match = manager.ChainForRevision("service", "/", revision2)
+	assert.True(t, match)
+
+	manager.InvalidateAll()
+	_, match = manager.ChainForRevision("service", "/", revision2)
+	assert.False(t, match)
+
+	revision3, err := manager.RebuildSnapshot("service", nil)
+	require.NoError(t, err)
+	assert.NotEqual(t, revision1, revision3)
+	assert.NotEqual(t, revision2, revision3)
+}
+
+func TestManagerRebuildSnapshotRejectsMismatchedBindingBeforeMutation(t *testing.T) {
+	manager, _ := newRevisionTestManager(t)
+	binding := revisionTestBinding("service", "/")
+	revision1, err := manager.RebuildSnapshot("service", []PathTargetBinding{binding})
+	require.NoError(t, err)
+	chain1, match := manager.ChainForRevision("service", "/", revision1)
+	require.True(t, match)
+
+	invalid := revisionTestBinding("other-service", "/replacement")
+	revision, err := manager.RebuildSnapshot("service", []PathTargetBinding{invalid})
+	require.Error(t, err)
+	assert.Zero(t, revision)
+	chainAfter, match := manager.ChainForRevision("service", "/", revision1)
+	assert.True(t, match)
+	assert.Same(t, chain1, chainAfter)
+
+	revision2, err := manager.RebuildSnapshot("service", nil)
+	require.NoError(t, err)
+	assert.Equal(t, revision1+1, revision2, "a rejected rebuild must not consume a revision")
+}
+
+func TestManagerConcurrentRebuildSnapshotRevisionsAreUnique(t *testing.T) {
+	manager, _ := newRevisionTestManager(t)
+	const rebuilds = 64
+
+	start := make(chan struct{})
+	revisions := make(chan Revision, rebuilds)
+	errors := make(chan error, rebuilds)
+	var wg sync.WaitGroup
+	for range rebuilds {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			<-start
+			revision, err := manager.RebuildSnapshot("service", nil)
+			if err != nil {
+				errors <- err
+				return
+			}
+			revisions <- revision
+		}()
+	}
+	close(start)
+	wg.Wait()
+	close(errors)
+	close(revisions)
+
+	for err := range errors {
+		require.NoError(t, err)
+	}
+	seen := make(map[Revision]struct{}, rebuilds)
+	for revision := range revisions {
+		require.NotZero(t, revision)
+		_, duplicate := seen[revision]
+		assert.False(t, duplicate, "each successful rebuild must receive a fresh revision")
+		seen[revision] = struct{}{}
+	}
+	require.Len(t, seen, rebuilds)
+
+	matches := 0
+	for revision := range seen {
+		chain, match := manager.ChainForRevision("service", "/", revision)
+		assert.Nil(t, chain)
+		if match {
+			matches++
+		}
+	}
+	assert.Equal(t, 1, matches, "only the current immutable table revision may match")
+}