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Merge pull request #24 from brendandburns/watch
Implement Watch
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/* | ||
Copyright 2019 The Kubernetes Authors. | ||
Licensed under the Apache License, Version 2.0 (the "License"); | ||
you may not use this file except in compliance with the License. | ||
You may obtain a copy of the License at | ||
http://www.apache.org/licenses/LICENSE-2.0 | ||
Unless required by applicable law or agreed to in writing, software | ||
distributed under the License is distributed on an "AS IS" BASIS, | ||
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
See the License for the specific language governing permissions and | ||
limitations under the License. | ||
*/ | ||
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// Note: the example only works with the code within the same release/branch. | ||
package main | ||
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import ( | ||
"context" | ||
"fmt" | ||
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"github.com/kubernetes-client/go/kubernetes/client" | ||
"github.com/kubernetes-client/go/kubernetes/config" | ||
) | ||
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func main() { | ||
c, err := config.LoadKubeConfig() | ||
if err != nil { | ||
panic(err.Error()) | ||
} | ||
cl := client.NewAPIClient(c) | ||
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watch := client.WatchClient{ | ||
Cfg: c, | ||
Client: cl, | ||
Path: "/api/v1/namespaces", | ||
MakerFn: func() interface{} { return &client.V1Namespace{} }, | ||
} | ||
if resultChan, errChan, err := watch.Connect(context.Background()); err != nil { | ||
panic(err) | ||
} else { | ||
for obj := range resultChan { | ||
fmt.Printf("%s\n%#v\n", obj.Type, obj.Object) | ||
} | ||
for err := range errChan { | ||
fmt.Printf("ERROR: %#v", err) | ||
} | ||
fmt.Printf("Closed!\n") | ||
} | ||
} |
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package client | ||
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import ( | ||
"bufio" | ||
"context" | ||
"encoding/json" | ||
"fmt" | ||
"io" | ||
"strings" | ||
) | ||
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// Result is a watch result | ||
type Result struct { | ||
Type string | ||
Object interface{} | ||
} | ||
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// WatchClient is a client for Watching the Kubernetes API | ||
type WatchClient struct { | ||
Cfg *Configuration | ||
Client *APIClient | ||
Path string | ||
MakerFn func() interface{} | ||
} | ||
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// Connect initiates a watch to the server. TODO: support watch from resource version | ||
func (w *WatchClient) Connect(ctx context.Context) (<-chan *Result, <-chan error, error) { | ||
url := w.Cfg.Scheme + "://" + w.Cfg.Host + w.Path + "?watch=true" | ||
req, err := w.Client.prepareRequest(ctx, url, "GET", nil, nil, nil, nil, "", []byte{}) | ||
if err != nil { | ||
return nil, nil, err | ||
} | ||
res, err := w.Client.callAPI(req) | ||
if err != nil { | ||
return nil, nil, err | ||
} | ||
if res.StatusCode != 200 { | ||
return nil, nil, fmt.Errorf("Error connecting watch (%d: %s)", res.StatusCode, res.Status) | ||
} | ||
resultChan := make(chan *Result, 1) | ||
errChan := make(chan error, 1) | ||
processWatch(res.Body, w.MakerFn, resultChan, errChan) | ||
return resultChan, errChan, nil | ||
} | ||
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func processWatch(stream io.Reader, makerFn func() interface{}, resultChan chan<- *Result, errChan chan<- error) { | ||
scanner := bufio.NewScanner(stream) | ||
go func() { | ||
defer close(resultChan) | ||
defer close(errChan) | ||
for scanner.Scan() { | ||
watchObj, err := decode(scanner.Text(), makerFn) | ||
if err != nil { | ||
errChan <- err | ||
return | ||
} | ||
if watchObj != nil { | ||
resultChan <- watchObj | ||
} | ||
} | ||
if err := scanner.Err(); err != nil { | ||
errChan <- err | ||
} | ||
}() | ||
} | ||
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func decode(line string, makerFn func() interface{}) (*Result, error) { | ||
if len(line) == 0 { | ||
return nil, nil | ||
} | ||
// TODO: support protocol buffer encoding? | ||
decoder := json.NewDecoder(strings.NewReader(line)) | ||
result := &Result{} | ||
for decoder.More() { | ||
name, err := decoder.Token() | ||
if err != nil { | ||
return nil, err | ||
} | ||
if name == "type" { | ||
token, err := decoder.Token() | ||
if err != nil { | ||
return nil, err | ||
} | ||
var ok bool | ||
result.Type, ok = token.(string) | ||
if !ok { | ||
return nil, fmt.Errorf("Error casting %v to string", token) | ||
} | ||
} | ||
if name == "object" { | ||
obj := makerFn() | ||
if err := decoder.Decode(&obj); err != nil { | ||
return nil, err | ||
} | ||
result.Object = obj | ||
return result, nil | ||
} | ||
} | ||
return nil, nil | ||
} |
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package client | ||
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import ( | ||
"context" | ||
"net/http" | ||
"net/http/httptest" | ||
"net/url" | ||
"strings" | ||
"testing" | ||
) | ||
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func makerFn() interface{} { return &V1Namespace{} } | ||
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type staticHandler struct { | ||
Code int | ||
Body string | ||
} | ||
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func (s *staticHandler) ServeHTTP(res http.ResponseWriter, req *http.Request) { | ||
res.WriteHeader(s.Code) | ||
res.Write([]byte(s.Body)) | ||
} | ||
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func TestFullError(t *testing.T) { | ||
server := httptest.NewServer(&staticHandler{ | ||
Code: 404, | ||
Body: `{"type":"ADDED","object":{"kind":"Namespace","apiVersion":"v1","metadata":{"name":"kube-system","selfLink":"/api/v1/namespaces/kube-system","uid":"164931a7-3d75-11e9-a0a0-2683b9459238","resourceVersion":"227","creationTimestamp":"2019-03-03T05:27:50Z","annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"v1\",\"kind\":\"Namespace\",\"metadata\":{\"annotations\":{},\"name\":\"kube-system\",\"namespace\":\"\"}}\n"}},"spec":{"finalizers":["kubernetes"]},"status":{"phase":"Active"}}}\n`, | ||
}) | ||
defer server.Close() | ||
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u, err := url.Parse(server.URL) | ||
if err != nil { | ||
t.Errorf("unexpected error: %v", err) | ||
} | ||
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cfg := &Configuration{} | ||
cfg.Host = u.Host | ||
cfg.Scheme = u.Scheme | ||
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watch := WatchClient{ | ||
Cfg: cfg, | ||
Client: NewAPIClient(cfg), | ||
MakerFn: makerFn, | ||
} | ||
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if _, _, err := watch.Connect(context.Background()); err == nil { | ||
t.Error("unexpected nil error") | ||
} | ||
} | ||
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func TestFull(t *testing.T) { | ||
server := httptest.NewServer(&staticHandler{ | ||
Code: 200, | ||
Body: `{"type":"ADDED","object":{"kind":"Namespace","apiVersion":"v1","metadata":{"name":"kube-system","selfLink":"/api/v1/namespaces/kube-system","uid":"164931a7-3d75-11e9-a0a0-2683b9459238","resourceVersion":"227","creationTimestamp":"2019-03-03T05:27:50Z","annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"v1\",\"kind\":\"Namespace\",\"metadata\":{\"annotations\":{},\"name\":\"kube-system\",\"namespace\":\"\"}}\n"}},"spec":{"finalizers":["kubernetes"]},"status":{"phase":"Active"}}}\n`, | ||
}) | ||
defer server.Close() | ||
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u, err := url.Parse(server.URL) | ||
if err != nil { | ||
t.Errorf("unexpected error: %v", err) | ||
} | ||
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cfg := &Configuration{} | ||
cfg.Host = u.Host | ||
cfg.Scheme = u.Scheme | ||
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watch := WatchClient{ | ||
Cfg: cfg, | ||
Client: NewAPIClient(cfg), | ||
MakerFn: makerFn, | ||
} | ||
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resultChan, errChan, err := watch.Connect(context.Background()) | ||
if err != nil { | ||
t.Errorf("unexpected error: %v", err) | ||
} | ||
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out := []*Result{} | ||
outErrs := []error{} | ||
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for r := range resultChan { | ||
out = append(out, r) | ||
} | ||
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for e := range errChan { | ||
outErrs = append(outErrs, e) | ||
} | ||
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if len(out) != 1 { | ||
t.Errorf("unexpected results: %v", out) | ||
t.FailNow() | ||
} | ||
for ix, val := range []string{"ADDED"} { | ||
if out[ix].Type != val { | ||
t.Errorf("unexpected value (%d): %v", ix, out[ix]) | ||
} | ||
} | ||
if len(outErrs) != 0 { | ||
t.Errorf("unexpected errors: %v", outErrs) | ||
} | ||
} | ||
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func TestDecode(t *testing.T) { | ||
line := `{"type":"ADDED","object":{"kind":"Namespace","apiVersion":"v1","metadata":{"name":"kube-system","selfLink":"/api/v1/namespaces/kube-system","uid":"164931a7-3d75-11e9-a0a0-2683b9459238","resourceVersion":"227","creationTimestamp":"2019-03-03T05:27:50Z","annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"v1\",\"kind\":\"Namespace\",\"metadata\":{\"annotations\":{},\"name\":\"kube-system\",\"namespace\":\"\"}}\n"}},"spec":{"finalizers":["kubernetes"]},"status":{"phase":"Active"}}}` | ||
result, err := decode(line, makerFn) | ||
if err != nil { | ||
t.Errorf("Unexpected non-nil: %v", err) | ||
} | ||
if result.Type != "ADDED" { | ||
t.Errorf("Unexpected event type: %s expected 'ADDED'", result.Type) | ||
} | ||
ns, ok := result.Object.(*V1Namespace) | ||
if !ok { | ||
t.Errorf("Cast failed: %v", result.Object) | ||
} | ||
if ns.Kind != "Namespace" || ns.Metadata.Name != "kube-system" { | ||
t.Errorf("Unexpected value %#v", *ns) | ||
} | ||
} | ||
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func TestMultiDecode(t *testing.T) { | ||
lines := ` | ||
{"type":"ADDED","object":{"kind":"Namespace","apiVersion":"v1","metadata":{"name":"kube-system","selfLink":"/api/v1/namespaces/kube-system","uid":"164931a7-3d75-11e9-a0a0-2683b9459238","resourceVersion":"227","creationTimestamp":"2019-03-03T05:27:50Z","annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"v1\",\"kind\":\"Namespace\",\"metadata\":{\"annotations\":{},\"name\":\"kube-system\",\"namespace\":\"\"}}\n"}},"spec":{"finalizers":["kubernetes"]},"status":{"phase":"Active"}}} | ||
{"type":"MODIFIED","object":{"kind":"Namespace","apiVersion":"v1","metadata":{"name":"kube-system-2","selfLink":"/api/v1/namespaces/kube-system","uid":"164931a7-3d75-11e9-a0a0-2683b9459238","resourceVersion":"227","creationTimestamp":"2019-03-03T05:27:50Z","annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"v1\",\"kind\":\"Namespace\",\"metadata\":{\"annotations\":{},\"name\":\"kube-system\",\"namespace\":\"\"}}\n"}},"spec":{"finalizers":["kubernetes"]},"status":{"phase":"Active"}}} | ||
{"type":"DELETED","object":{"kind":"Namespace","apiVersion":"v1","metadata":{"name":"kube-system-3","selfLink":"/api/v1/namespaces/kube-system","uid":"164931a7-3d75-11e9-a0a0-2683b9459238","resourceVersion":"227","creationTimestamp":"2019-03-03T05:27:50Z","annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"v1\",\"kind\":\"Namespace\",\"metadata\":{\"annotations\":{},\"name\":\"kube-system\",\"namespace\":\"\"}}\n"}},"spec":{"finalizers":["kubernetes"]},"status":{"phase":"Active"}}} | ||
` | ||
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results := make(chan *Result) | ||
errs := make(chan error) | ||
processWatch(strings.NewReader(lines), makerFn, results, errs) | ||
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out := []*Result{} | ||
outErrs := []error{} | ||
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for r := range results { | ||
out = append(out, r) | ||
} | ||
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for e := range errs { | ||
outErrs = append(outErrs, e) | ||
} | ||
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if len(out) != 3 { | ||
t.Errorf("unexpected results: %v", out) | ||
} | ||
for ix, val := range []string{"ADDED", "MODIFIED", "DELETED"} { | ||
if out[ix].Type != val { | ||
t.Errorf("unexpected value (%d): %v", ix, out[ix]) | ||
} | ||
} | ||
if len(outErrs) != 0 { | ||
t.Errorf("unexpected errors: %v", outErrs) | ||
} | ||
} |