satellite/nodeselection: improve annotation composability

We would like to make it easier to accept multiple annotations.

Examples:
```
country("GB") && annotation(...)
annotated(annotated(X,...),...)
```

Change-Id: I92e622e8b985b314dadddf83b17976c245eb2069

satellite/nodeselection/filter.go

@@ -15,10 +15,50 @@ type NodeFilter interface {
 	MatchInclude(node *SelectedNode) bool
 }
 
+// NodeFilterWithAnnotation is a NodeFilter with additional annotations.
+type NodeFilterWithAnnotation interface {
+	NodeFilter
+	GetAnnotation(name string) string
+}
+
+// Annotation can be used as node filters in 'XX && annotation('...')' like struct.
+type Annotation struct {
+	Key   string
+	Value string
+}
+
+// MatchInclude implements NodeFilter.
+func (a Annotation) MatchInclude(node *SelectedNode) bool {
+	return true
+}
+
+// GetAnnotation implements NodeFilterWithAnnotation.
+func (a Annotation) GetAnnotation(name string) string {
+	if a.Key == name {
+		return a.Value
+	}
+	return ""
+}
+
+var _ NodeFilterWithAnnotation = Annotation{}
+
 // AnnotatedNodeFilter is just a NodeFilter with additional annotations.
 type AnnotatedNodeFilter struct {
 	Filter      NodeFilter
-	Annotations map[string]string
+	Annotations []Annotation
+}
+
+// GetAnnotation implements NodeFilterWithAnnotation.
+func (a AnnotatedNodeFilter) GetAnnotation(name string) string {
+	for _, a := range a.Annotations {
+		if a.Key == name {
+			return a.Value
+		}
+	}
+	if annotated, ok := a.Filter.(NodeFilterWithAnnotation); ok {
+		return annotated.GetAnnotation(name)
+	}
+	return ""
 }
 
 // MatchInclude implements NodeFilter.
@@ -27,35 +67,27 @@ func (a AnnotatedNodeFilter) MatchInclude(node *SelectedNode) bool {
 }
 
 // WithAnnotation adds annotations to a NodeFilter.
-func WithAnnotation(filter NodeFilter, name string, value string) NodeFilter {
-	if anf, ok := filter.(AnnotatedNodeFilter); ok {
-		anf.Annotations[name] = value
-		return anf
-	}
+func WithAnnotation(filter NodeFilter, name string, value string) NodeFilterWithAnnotation {
 	return AnnotatedNodeFilter{
 		Filter: filter,
-		Annotations: map[string]string{
-			name: value,
+		Annotations: []Annotation{
+			{
+				Key:   name,
+				Value: value,
+			},
 		},
 	}
 }
 
 // GetAnnotation retrieves annotation from AnnotatedNodeFilter.
 func GetAnnotation(filter NodeFilter, name string) string {
-	if annotated, ok := filter.(AnnotatedNodeFilter); ok {
-		return annotated.Annotations[name]
-	}
-	if filters, ok := filter.(NodeFilters); ok {
-		for _, filter := range filters {
-			if annotated, ok := filter.(AnnotatedNodeFilter); ok {
-				return annotated.Annotations[name]
-			}
-		}
+	if annotated, ok := filter.(NodeFilterWithAnnotation); ok {
+		return annotated.GetAnnotation(name)
 	}
 	return ""
 }
 
-var _ NodeFilter = AnnotatedNodeFilter{}
+var _ NodeFilterWithAnnotation = AnnotatedNodeFilter{}
 
 // NodeFilters is a collection of multiple node filters (all should vote with true).
 type NodeFilters []NodeFilter
@@ -94,7 +126,20 @@ func (n NodeFilters) WithExcludedIDs(ds []storj.NodeID) NodeFilters {
 	return append(n, ExcludedIDs(ds))
 }
 
-var _ NodeFilter = NodeFilters{}
+// GetAnnotation implements NodeFilterWithAnnotation.
+func (n NodeFilters) GetAnnotation(name string) string {
+	for _, filter := range n {
+		if annotated, ok := filter.(NodeFilterWithAnnotation); ok {
+			value := annotated.GetAnnotation(name)
+			if value != "" {
+				return value
+			}
+		}
+	}
+	return ""
+}
+
+var _ NodeFilterWithAnnotation = NodeFilters{}
 
 // CountryFilter can select nodes based on the condition of the country code.
 type CountryFilter struct {

satellite/nodeselection/filter_test.go

@@ -55,6 +55,20 @@ func TestCriteria_ExcludedNodeNetworks(t *testing.T) {
 	}))
 }
 
+func TestAnnotations(t *testing.T) {
+	k := WithAnnotation(NodeFilters{}, "foo", "bar")
+	require.Equal(t, "bar", k.GetAnnotation("foo"))
+
+	k = NodeFilters{WithAnnotation(NodeFilters{}, "foo", "bar")}
+	require.Equal(t, "bar", k.GetAnnotation("foo"))
+
+	k = Annotation{
+		Key:   "foo",
+		Value: "bar",
+	}
+	require.Equal(t, "bar", k.GetAnnotation("foo"))
+}
+
 func TestCriteria_Geofencing(t *testing.T) {
 	eu := NodeFilters{}.WithCountryFilter(location.NewSet(EuCountries...))
 	us := NodeFilters{}.WithCountryFilter(location.NewSet(location.UnitedStates))

satellite/overlay/placement.go

@@ -151,15 +151,16 @@ func (d *ConfigurablePlacementRule) AddPlacementFromString(definitions string) e
 			}
 			return res, nil
 		},
-		"annotated": func(filter nodeselection.NodeFilter, kv map[string]string) (nodeselection.AnnotatedNodeFilter, error) {
+		"annotated": func(filter nodeselection.NodeFilter, kv ...nodeselection.Annotation) (nodeselection.AnnotatedNodeFilter, error) {
 			return nodeselection.AnnotatedNodeFilter{
 				Filter:      filter,
 				Annotations: kv,
 			}, nil
 		},
-		"annotation": func(key string, value string) (map[string]string, error) {
-			return map[string]string{
-				key: value,
+		"annotation": func(key string, value string) (nodeselection.Annotation, error) {
+			return nodeselection.Annotation{
+				Key:   key,
+				Value: value,
 			}, nil
 		},
 		"exclude": func(filter nodeselection.NodeFilter) (nodeselection.NodeFilter, error) {

satellite/overlay/placement_test.go

@@ -166,16 +166,47 @@ func TestPlacementFromString(t *testing.T) {
 		}))
 
 	})
-	t.Run("annotated", func(t *testing.T) {
-		p := NewPlacementRules()
-		err := p.AddPlacementFromString(`11:annotated(country("GB"),annotation("autoExcludeSubnet","off"))`)
-		require.NoError(t, err)
-		filters := p.placements[storj.PlacementConstraint(11)]
-		require.True(t, filters.MatchInclude(&nodeselection.SelectedNode{
-			CountryCode: location.UnitedKingdom,
-		}))
+	t.Run("annotation usage", func(t *testing.T) {
+		t.Run("normal", func(t *testing.T) {
+			t.Parallel()
+			p := NewPlacementRules()
+			err := p.AddPlacementFromString(`11:annotated(country("GB"),annotation("autoExcludeSubnet","off"))`)
+			require.NoError(t, err)
+			filters := p.placements[storj.PlacementConstraint(11)]
+			require.True(t, filters.MatchInclude(&nodeselection.SelectedNode{
+				CountryCode: location.UnitedKingdom,
+			}))
 
-		require.Equal(t, nodeselection.GetAnnotation(filters, "autoExcludeSubnet"), "off")
+			require.Equal(t, nodeselection.GetAnnotation(filters, "autoExcludeSubnet"), "off")
+		})
+		t.Run("with &&", func(t *testing.T) {
+			t.Parallel()
+			p := NewPlacementRules()
+			err := p.AddPlacementFromString(`11:country("GB") && annotation("foo","bar") && annotation("bar","foo")`)
+			require.NoError(t, err)
+
+			filters := p.placements[storj.PlacementConstraint(11)]
+			require.True(t, filters.MatchInclude(&nodeselection.SelectedNode{
+				CountryCode: location.UnitedKingdom,
+			}))
+			require.Equal(t, "bar", nodeselection.GetAnnotation(filters, "foo"))
+			require.Equal(t, "foo", nodeselection.GetAnnotation(filters, "bar"))
+			require.Equal(t, "", nodeselection.GetAnnotation(filters, "kossuth"))
+		})
+		t.Run("chained", func(t *testing.T) {
+			t.Parallel()
+			p := NewPlacementRules()
+			err := p.AddPlacementFromString(`11:annotated(annotated(country("GB"),annotation("foo","bar")),annotation("bar","foo"))`)
+			require.NoError(t, err)
+			filters := p.placements[storj.PlacementConstraint(11)]
+			require.True(t, filters.MatchInclude(&nodeselection.SelectedNode{
+				CountryCode: location.UnitedKingdom,
+			}))
+
+			require.Equal(t, "bar", nodeselection.GetAnnotation(filters, "foo"))
+			require.Equal(t, "foo", nodeselection.GetAnnotation(filters, "bar"))
+			require.Equal(t, "", nodeselection.GetAnnotation(filters, "kossuth"))
+		})
 
 	})
 	t.Run("exclude", func(t *testing.T) {