github.com/uber/kraken@v0.1.4/tools/bin/puller/notification.go (about)

     1  // Copyright (c) 2016-2019 Uber Technologies, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  package main
    15  
    16  import (
    17  	"encoding/json"
    18  	"net/http"
    19  	"os"
    20  	"time"
    21  
    22  	"github.com/docker/distribution/notifications"
    23  
    24  	"github.com/uber/kraken/utils/log"
    25  )
    26  
    27  const (
    28  	baseManifestQuery = "http://%s/v2/%s/manifests/%s"
    29  	baseLayerQuery    = "http://%s/v2/%s/blobs/%s"
    30  	transferTimeout   = 120 * time.Second
    31  	localSource       = "localhost:5051"
    32  	tempDir           = "/tmp/kraken/tmp/puller/"
    33  )
    34  
    35  // HealthHandler tells haproxy we'fre still alive
    36  func HealthHandler(w http.ResponseWriter, request *http.Request) {
    37  	w.Header().Set("Content-Type", "text/plain")
    38  	w.Write([]byte("OK"))
    39  }
    40  
    41  // NotificationHandler receives docker push notification
    42  type NotificationHandler struct {
    43  	queue     chan uint8
    44  	useDocker bool
    45  }
    46  
    47  // NewNotificationHandler creates a new Notifaction
    48  func NewNotificationHandler(maxChanSize int, useDocker bool) (*NotificationHandler, error) {
    49  	if err := os.MkdirAll(tempDir, 0775); err != nil {
    50  		return nil, err
    51  	}
    52  	return &NotificationHandler{
    53  		queue:     make(chan byte, maxChanSize),
    54  		useDocker: useDocker,
    55  	}, nil
    56  }
    57  
    58  // Handler handles messages defined in http://godoc.org/github.com/docker/distribution/notifications.
    59  func (n *NotificationHandler) Handler(w http.ResponseWriter, r *http.Request) {
    60  	log.Debugf("notification received")
    61  	decoder := json.NewDecoder(r.Body)
    62  	var envelope notifications.Envelope
    63  
    64  	if err := decoder.Decode(&envelope); err != nil {
    65  		log.With("err", err).Error("cannot decode envelope")
    66  		return
    67  	}
    68  	for _, event := range envelope.Events {
    69  		if event.Action == notifications.EventActionPush {
    70  			url := event.Target.URL
    71  			repo := event.Target.Repository
    72  			tag := event.Target.Tag
    73  			digest := guessDigest(url, repo)
    74  			if len(digest) == 0 {
    75  				log.Debugf("non tag push action: target.URL: '%s', target.Repository: '%s'", url, repo)
    76  			} else {
    77  				select {
    78  				case n.queue <- 'c':
    79  					time.Sleep(2 * time.Second)
    80  					go func() {
    81  						PullImage(localSource, repo, tag, n.useDocker)
    82  						<-n.queue
    83  					}()
    84  				default:
    85  					// drop if queue full
    86  					log.Infof("queue full. drop %s:%s", repo, tag)
    87  				}
    88  			}
    89  		}
    90  	}
    91  
    92  	w.Header().Set("Content-Type", "application/json")
    93  	resString := "OK"
    94  	w.Write([]byte(resString))
    95  }