add slack notification cli flag

actions/notify_slack.go

@@ -0,0 +1,92 @@
+package actions
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/mozillazg/request"
+)
+
+// SlackNotifier is used to make the https requests to a specified slack
+// webhook URL
+type SlackNotifier struct {
+	slackURL string
+	identity string
+}
+
+const (
+	slackMessageStartup = "Watchtower startup"
+	slackMessageError   = "Some errors while checking and redeployment (Please check logs):"
+	slackMessageSuccess = "Successfully redeployed images:"
+)
+
+// NewSlackNotifier instantiates a new SlackNotifier with an URL and an identifier which will
+// be prepended to each message it sends
+func NewSlackNotifier(slackURL, identity string) *SlackNotifier {
+	identity = strings.Trim(identity, " ")
+
+	if len(identity) != 0 {
+		identity = fmt.Sprintf("[%s]: ", identity)
+	}
+
+	return &SlackNotifier{
+		slackURL: slackURL,
+		identity: identity,
+	}
+}
+
+func (s SlackNotifier) sendNotification(json map[string]interface{}) {
+	c := new(http.Client)
+	req := request.NewRequest(c)
+	req.Json = json
+	_, err := req.Post(s.slackURL)
+
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+
+// NotifyStartup sends a startup message to slack
+func (s SlackNotifier) NotifyStartup() {
+	s.sendNotification(map[string]interface{}{
+		"text": fmt.Sprintf("%s%s", s.identity, slackMessageStartup),
+	})
+}
+
+func buildAttachment(items []string, title, color string) map[string]interface{} {
+
+	var fields []map[string]string
+
+	for _, item := range items {
+		fields = append(fields, map[string]string{"value": item, "short": "false"})
+	}
+
+	return map[string]interface{}{
+		"fallback": title + strings.Join(items, ", "),
+		"color":    color,
+		"title":    title,
+		"fields":   fields,
+	}
+}
+
+// NotifyContainerUpdate sends a Message after updating containers which yielded either success or errors or both
+func (s SlackNotifier) NotifyContainerUpdate(successfulContainers, errorMessages []string) {
+
+	var attachments []map[string]interface{}
+
+	if len(successfulContainers) != 0 {
+		attachments = append(attachments, buildAttachment(successfulContainers, slackMessageSuccess, "good"))
+	}
+
+	if len(errorMessages) != 0 {
+		attachments = append(attachments, buildAttachment(errorMessages, slackMessageError, "danger"))
+	}
+
+	// add a pretext to the first attachment
+	attachments[0]["pretext"] = s.identity
+
+	s.sendNotification(map[string]interface{}{
+		"attachments": attachments,
+	})
+}

actions/update.go

@@ -1,6 +1,7 @@
 package actions
 
 import (
+	"fmt"
 	"math/rand"
 	"time"
 
@@ -34,12 +35,18 @@ func containerFilter(names []string) container.Filter {
 // used to start those containers have been updated. If a change is detected in
 // any of the images, the associated containers are stopped and restarted with
 // the new image.
-func Update(client container.Client, names []string, cleanup bool, noRestart bool) error {
+func Update(client container.Client, names []string, cleanup bool, noRestart bool) ([]string, []string, error) {
 	log.Info("Checking containers for updated images")
 
+	// helper vars for notification
+	var (
+		updatedContainers []string
+		errorMessages     []string
+	)
+
 	containers, err := client.ListContainers(containerFilter(names))
 	if err != nil {
-		return err
+		return updatedContainers, errorMessages, err
 	}
 
 	for i, container := range containers {
@@ -48,13 +55,14 @@ func Update(client container.Client, names []string, cleanup bool, noRestart boo
 			log.Infof("Unable to update container %s. Proceeding to next.", containers[i].Name())
 			log.Debug(err)
 			stale = false
+			errorMessages = append(errorMessages, fmt.Sprintf("Unable to update container %s: %v", container.Details(), err))
 		}
 		containers[i].Stale = stale
 	}
 
 	containers, err = container.SortByDependencies(containers)
 	if err != nil {
-		return err
+		return updatedContainers, errorMessages, err
 	}
 
 	checkDependencies(containers)
@@ -70,6 +78,7 @@ func Update(client container.Client, names []string, cleanup bool, noRestart boo
 		if container.Stale {
 			if err := client.StopContainer(container, waitTime); err != nil {
 				log.Error(err)
+				errorMessages = append(errorMessages, fmt.Sprintf("Unable to stop container %s: %v", container.Details(), err))
 			}
 		}
 	}
@@ -84,6 +93,7 @@ func Update(client container.Client, names []string, cleanup bool, noRestart boo
 			if container.IsWatchtower() {
 				if err := client.RenameContainer(container, randName()); err != nil {
 					log.Error(err)
+					errorMessages = append(errorMessages, fmt.Sprintf("Unable to rename container %s: %v", container.Details(), err))
 					continue
 				}
 			}
@@ -91,16 +101,19 @@ func Update(client container.Client, names []string, cleanup bool, noRestart boo
 			if !noRestart {
 				if err := client.StartContainer(container); err != nil {
 					log.Error(err)
+					errorMessages = append(errorMessages, fmt.Sprintf("Unable to restart container %s: %v", container.Details(), err))
 				}
 			}
 
 			if cleanup {
 				client.RemoveImage(container)
 			}
+
+			updatedContainers = append(updatedContainers, container.Details())
 		}
 	}
 
-	return nil
+	return updatedContainers, errorMessages, nil
 }
 
 func checkDependencies(containers []container.Container) {

container/container.go

@@ -64,6 +64,12 @@ func (c Container) ImageName() string {
 	return imageName
 }
 
+// Details returns the name of the Docker image as defined in ImageName
+// together with the name of the container
+func (c Container) Details() string {
+	return fmt.Sprintf("%s (%s)", c.ImageName(), c.Name())
+}
+
 // Links returns a list containing the names of all the containers to which
 // this container is linked.
 func (c Container) Links() []string {

glide.lock

@@ -1,10 +1,12 @@
-hash: 9ddd729b207d71ce16ae9a0282ac87a046b9161ac4f15b108e86a03367172516
+hash: 79bf30c3a98ecbe4c7668765f0033f5e487836d2011b21bcd219d321ace35f13
-updated: 2017-01-24T20:45:43.1914053+01:00
+updated: 2017-02-07T15:03:18.178257775+01:00
 imports:
 - name: github.com/Azure/go-ansiterm
   version: 388960b655244e76e24c75f48631564eaefade62
   subpackages:
   - winterm
+- name: github.com/bitly/go-simplejson
+  version: aabad6e819789e569bd6aabf444c935aa9ba1e44
 - name: github.com/davecgh/go-spew
   version: 6d212800a42e8ab5c146b8ace3490ee17e5225f9
   subpackages:
@@ -101,7 +103,7 @@ imports:
 - name: github.com/docker/libtrust
   version: 9cbd2a1374f46905c68a4eb3694a130610adc62a
 - name: github.com/golang/protobuf
-  version: 1f49d83d9aa00e6ce4fc8258c71cc7786aec968a
+  version: f7137ae6b19afbfd61a94b746fda3b3fe0491874
   subpackages:
   - proto
 - name: github.com/gorilla/context
@@ -114,16 +116,17 @@ imports:
   version: f4e566c536cf69158e808ec28ef4182a37fdc981
 - name: github.com/Microsoft/go-winio
   version: 24a3e3d3fc7451805e09d11e11e95d9a0a4f205e
+- name: github.com/mozillazg/request
+  version: 052232e32456da4751d789b61e89aba4a07a7e25
 - name: github.com/opencontainers/runc
-  version: 2f7393a47307a16f8cee44a37b262e8b81021e3e
+  version: b263a43430ac6996a4302b891688544225197294
-  repo: https://github.com/docker/runc.git
   subpackages:
   - libcontainer/configs
   - libcontainer/devices
   - libcontainer/system
   - libcontainer/user
 - name: github.com/opencontainers/runtime-spec
-  version: 1c7c27d043c2a5e513a44084d2b10d77d1402b8c
+  version: 794ca7ac88234607f9d2c76da8a6e9bbbade8cb9
   subpackages:
   - specs-go
 - name: github.com/pkg/errors
@@ -135,10 +138,9 @@ imports:
 - name: github.com/robfig/cron
   version: 9585fd555638e77bba25f25db5c44b41f264aeb7
 - name: github.com/Sirupsen/logrus
-  version: d26492970760ca5d33129d2d799e34be5c4782eb
+  version: c078b1e43f58d563c74cebe63c85789e76ddb627
 - name: github.com/spf13/cobra
-  version: a3c09249f1a24a9d951f2738fb9b9256b8b42fa5
+  version: 35136c09d8da66b901337c6e86fd8e88a1a255bd
-  repo: https://github.com/dnephin/cobra.git
 - name: github.com/spf13/pflag
   version: dabebe21bf790f782ea4c7bbd2efc430de182afd
 - name: github.com/stretchr/objx
@@ -157,7 +159,7 @@ imports:
   - tar/asm
   - tar/storage
 - name: golang.org/x/net
-  version: 2beffdc2e92c8a3027590f898fe88f69af48a3f8
+  version: ""
   repo: https://github.com/tonistiigi/net.git
   subpackages:
   - context
@@ -166,6 +168,7 @@ imports:
   - http2/hpack
   - internal/timeseries
   - proxy
+  - publicsuffix
   - trace
 - name: golang.org/x/sys
   version: 8f0908ab3b2457e2e15403d3697c9ef5cb4b57a9

glide.yaml

@@ -26,3 +26,5 @@ import:
   - context
 - package: github.com/robfig/cron
   version: 9585fd555638e77bba25f25db5c44b41f264aeb7
+- package: github.com/mozillazg/request
+  version: v0.8.0

main.go

@@ -27,6 +27,7 @@ var (
 	scheduleSpec  string
 	cleanup       bool
 	noRestart     bool
+	slackNotifier *actions.SlackNotifier
 )
 
 func init() {
@@ -82,6 +83,15 @@ func main() {
 			Name:  "debug",
 			Usage: "enable debug mode with verbose logging",
 		},
+		cli.StringFlag{
+			Name:  "slack-hook-url",
+			Usage: "the url for sending slack webhooks to",
+		},
+		cli.StringFlag{
+			Name:  "slack-message-identification",
+			Usage: "specify a string which will be used to identify the messages comming from this watchtower instance. Default if omitted is \"watchtower\"",
+			Value: "watchtower",
+		},
 	}
 
 	if err := app.Run(os.Args); err != nil {
@@ -108,6 +118,9 @@ func before(c *cli.Context) error {
 	cleanup = c.GlobalBool("cleanup")
 	noRestart = c.GlobalBool("no-restart")
 
+	slackURL := c.GlobalString("slack-hook-url")
+	slackPrefix := c.GlobalString("slack-message-identification")
+
 	// configure environment vars for client
 	err := envConfig(c)
 	if err != nil {
@@ -115,6 +128,12 @@ func before(c *cli.Context) error {
 	}
 
 	client = container.NewClient(!c.GlobalBool("no-pull"))
+
+	if len(slackURL) != 0 {
+		slackNotifier = actions.NewSlackNotifier(slackURL, slackPrefix)
+		slackNotifier.NotifyStartup()
+	}
+
 	return nil
 }
 
@@ -135,9 +154,14 @@ func start(c *cli.Context) error {
 			select {
 			case v := <-tryLockSem:
 				defer func() { tryLockSem <- v }()
-				if err := actions.Update(client, names, cleanup, noRestart); err != nil {
+				updatedContainers, errorMessages, err := actions.Update(client, names, cleanup, noRestart)
+				if err != nil {
 					fmt.Println(err)
 				}
+				if slackNotifier != nil && (len(updatedContainers) != 0 || len(errorMessages) != 0) {
+					slackNotifier.NotifyContainerUpdate(updatedContainers, errorMessages)
+
+				}
 			default:
 				log.Debug("Skipped another update already running.")
 			}