github.com/timstclair/heapster@v0.20.0-alpha1/Godeps/_workspace/src/k8s.io/kubernetes/pkg/watch/json/decoder.go (about) 1 /* 2 Copyright 2014 The Kubernetes Authors All rights reserved. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package json 18 19 import ( 20 "encoding/json" 21 "fmt" 22 "io" 23 24 "k8s.io/kubernetes/pkg/runtime" 25 "k8s.io/kubernetes/pkg/watch" 26 ) 27 28 // Decoder implements the watch.Decoder interface for io.ReadClosers that 29 // have contents which consist of a series of watchEvent objects encoded via JSON. 30 // It will decode any object registered in the supplied codec. 31 type Decoder struct { 32 r io.ReadCloser 33 decoder *json.Decoder 34 codec runtime.Codec 35 } 36 37 // NewDecoder creates an Decoder for the given writer and codec. 38 func NewDecoder(r io.ReadCloser, codec runtime.Codec) *Decoder { 39 return &Decoder{ 40 r: r, 41 decoder: json.NewDecoder(r), 42 codec: codec, 43 } 44 } 45 46 // Decode blocks until it can return the next object in the writer. Returns an error 47 // if the writer is closed or an object can't be decoded. 48 func (d *Decoder) Decode() (watch.EventType, runtime.Object, error) { 49 var got WatchEvent 50 if err := d.decoder.Decode(&got); err != nil { 51 return "", nil, err 52 } 53 switch got.Type { 54 case watch.Added, watch.Modified, watch.Deleted, watch.Error: 55 default: 56 return "", nil, fmt.Errorf("got invalid watch event type: %v", got.Type) 57 } 58 59 obj, err := d.codec.Decode(got.Object.RawJSON) 60 if err != nil { 61 return "", nil, fmt.Errorf("unable to decode watch event: %v", err) 62 } 63 return got.Type, obj, nil 64 } 65 66 // Close closes the underlying r. 67 func (d *Decoder) Close() { 68 d.r.Close() 69 }