Cleanup channels

pkg/subscribe/handler.go

@@ -33,26 +33,7 @@ func Handler(apiContext *types.APIContext) error {
 	return err
 }
 
-func handler(apiContext *types.APIContext) error {
-	c, err := upgrader.Upgrade(apiContext.Response, apiContext.Request, nil)
-	if err != nil {
-		return err
-	}
-	defer c.Close()
-
-	cancelCtx, cancel := context.WithCancel(apiContext.Request.Context())
-	apiContext.Request = apiContext.Request.WithContext(cancelCtx)
-
-	go func() {
-		for {
-			if _, _, err := c.NextReader(); err != nil {
-				cancel()
-				c.Close()
-				break
-			}
-		}
-	}()
-
+func getMatchingSchemas(apiContext *types.APIContext) []*types.Schema {
 	apiVersions := apiContext.Request.URL.Query()["apiVersions"]
 	resourceTypes := apiContext.Request.URL.Query()["resourceTypes"]
 
@@ -69,11 +50,35 @@ func handler(apiContext *types.APIContext) error {
 		}
 	}
 
+	return schemas
+}
+
+func handler(apiContext *types.APIContext) error {
+	schemas := getMatchingSchemas(apiContext)
 	if len(schemas) == 0 {
 		return httperror.NewAPIError(httperror.NotFound, "no resources types matched")
 	}
 
-	readerGroup, ctx := errgroup.WithContext(apiContext.Request.Context())
+	c, err := upgrader.Upgrade(apiContext.Response, apiContext.Request, nil)
+	if err != nil {
+		return err
+	}
+	defer c.Close()
+
+	cancelCtx, cancel := context.WithCancel(apiContext.Request.Context())
+	readerGroup, ctx := errgroup.WithContext(cancelCtx)
+	apiContext.Request = apiContext.Request.WithContext(ctx)
+
+	go func() {
+		for {
+			if _, _, err := c.NextReader(); err != nil {
+				cancel()
+				c.Close()
+				break
+			}
+		}
+	}()
+
 	events := make(chan map[string]interface{})
 	for _, schema := range schemas {
 		streamStore(ctx, readerGroup, apiContext, schema, events)

store/transform/transform.go

@@ -1,6 +1,9 @@
 package transform
 
-import "github.com/rancher/norman/types"
+import (
+	"github.com/rancher/norman/types"
+	"github.com/rancher/norman/types/convert"
+)
 
 type TransformerFunc func(apiContext *types.APIContext, data map[string]interface{}) (map[string]interface{}, error)
 
@@ -36,18 +39,13 @@ func (t *Store) Watch(apiContext *types.APIContext, schema *types.Schema, opt *t
 		return t.StreamTransformer(apiContext, c)
 	}
 
-	result := make(chan map[string]interface{})
-	go func() {
-		for item := range c {
-			item, err := t.Transformer(apiContext, item)
-			if err == nil && item != nil {
-				result <- item
-			}
+	return convert.Chan(c, func(data map[string]interface{}) map[string]interface{} {
+		item, err := t.Transformer(apiContext, data)
+		if err != nil {
+			return nil
 		}
-		close(result)
-	}()
-
-	return result, nil
+		return item
+	}), nil
 }
 
 func (t *Store) List(apiContext *types.APIContext, schema *types.Schema, opt *types.QueryOptions) ([]map[string]interface{}, error) {

store/wrapper/wrapper.go

@@ -3,6 +3,7 @@ package wrapper
 import (
 	"github.com/rancher/norman/httperror"
 	"github.com/rancher/norman/types"
+	"github.com/rancher/norman/types/convert"
 )
 
 func Wrap(store types.Store) types.Store {
@@ -42,20 +43,11 @@ func (s *StoreWrapper) Watch(apiContext *types.APIContext, schema *types.Schema,
 		return nil, err
 	}
 
-	result := make(chan map[string]interface{})
-	go func() {
-		for item := range c {
-			item = apiContext.FilterObject(&types.QueryOptions{
-				Conditions: apiContext.SubContextAttributeProvider.Query(apiContext, schema),
-			}, item)
-			if item != nil {
-				result <- item
-			}
-		}
-		close(result)
-	}()
-
-	return result, nil
+	return convert.Chan(c, func(data map[string]interface{}) map[string]interface{} {
+		return apiContext.FilterObject(&types.QueryOptions{
+			Conditions: apiContext.SubContextAttributeProvider.Query(apiContext, schema),
+		}, data)
+	}), nil
 }
 
 func (s *StoreWrapper) Create(apiContext *types.APIContext, schema *types.Schema, data map[string]interface{}) (map[string]interface{}, error) {

types/convert/convert.go

@@ -10,6 +10,20 @@ import (
 	"unicode"
 )
 
+func Chan(c <-chan map[string]interface{}, f func(map[string]interface{}) map[string]interface{}) chan map[string]interface{} {
+	result := make(chan map[string]interface{})
+	go func() {
+		for data := range c {
+			modified := f(data)
+			if modified != nil {
+				result <- modified
+			}
+		}
+		close(result)
+	}()
+	return result
+}
+
 func Singular(value interface{}) interface{} {
 	if slice, ok := value.([]string); ok {
 		if len(slice) == 0 {