Add support for Telegram (#10)

* Add support for Telegram in chat package

* Replace ioutil.ReadFile with os.ReadFile

* Document use of Telegram as notification destination

* Make Telegram message more compact

* Simplify Dockerfile

* Use master tag by default for images

Dockerfile

@@ -8,10 +8,10 @@ RUN apk update && \
     mkdir -p "/build"
 
 WORKDIR /build
-COPY go.mod go.sum /build/
+COPY go.mod go.sum .
 RUN go mod download
 
-COPY . /build/
+COPY . .
 RUN CGO_ENABLED=0 GOOS=linux GOARCH=${ARCH} go build -a --installsuffix cgo --ldflags="-s" -o informer
 
 FROM alpine

README.md

@@ -34,6 +34,20 @@ metadata:
 
 You should use the Bot User OAuth Access Token as `token`. It can be copied from the Slack App admin interface after registering a new Slack API App and enabling the Bot feature.
 
+##### If you use Telegram, use
+
+```yaml
+apiVersion: v1
+data:
+  chatId: <chat-id>
+  token: <bot-token>
+kind: ConfigMap
+metadata:
+  name: telegram-informer-cfg
+```
+
+Extracting the chat ID in Telegram can be slightly finicky. The easiest way I've found is using the ID exposed in the URLs when using the web.telegram.org frontend.
+
 This step is required to create a valid configuration for our crash informer.
 
 ### Step 2: Deploy the informer
@@ -43,6 +57,9 @@ kubectl apply -f manifests/mattermost-informer.yaml
 
 # If you use Slack
 kubectl apply -f manifests/slack-informer.yaml
+
+# If you use Telegram
+kubectl apply -f manifests/telegram-informer.yaml
 ```
 
 You may want to update the `namespace` references, since the informer only watches a given namespace.

manifests/mattermost-informer.yaml

@@ -48,7 +48,7 @@ spec:
       serviceAccountName: crash-informer
       containers:
       - name: informer
-        image: ghcr.io/lnsp/k8s-crash-informer:v0.2.1
+        image: ghcr.io/lnsp/k8s-crash-informer:master
         imagePullPolicy: Always
         env:
           - name: MATTERMOST_CHANNEL

manifests/slack-informer.yaml

@@ -48,7 +48,7 @@ spec:
       serviceAccountName: crash-informer
       containers:
       - name: informer
-        image: ghcr.io/lnsp/k8s-crash-informer:v0.2.1
+        image: ghcr.io/lnsp/k8s-crash-informer:master
         imagePullPolicy: Always
         env:
           - name: SLACK_CHANNEL

manifests/telegram-informer.yaml

@@ -0,0 +1,69 @@
+kind: Role
+apiVersion: rbac.authorization.k8s.io/v1
+metadata:
+  name: crash-informer
+  namespace: default
+rules:
+- apiGroups: [""]
+  resources: ["pods", "pods/log", "replicationcontrollers"]
+  verbs: ["get", "watch", "list"]
+- apiGroups: ["apps", "extensions"]
+  resources: ["replicasets", "deployments"]
+  verbs: ["get", "watch", "list"]
+---
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: crash-informer
+  namespace: default
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: crash-informer
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: crash-informer
+subjects:
+  - kind: ServiceAccount
+    name: crash-informer
+    namespace: default
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: telegram-informer
+  namespace: default
+spec:
+  selector:
+    matchLabels:
+      app: telegram-informer
+  template:
+    metadata:
+      labels:
+        app: telegram-informer
+    spec:
+      restartPolicy: Always
+      serviceAccountName: crash-informer
+      containers:
+      - name: informer
+        image: ghcr.io/lnsp/k8s-crash-informer:master
+        imagePullPolicy: Always
+        env:
+          - name: TELEGRAM_CHATID
+            valueFrom:
+              configMapKeyRef:
+                name: telegram-informer-cfg
+                key: chatId
+          - name: TELEGRAM_TOKEN
+            valueFrom:
+              configMapKeyRef:
+                name: telegram-informer-cfg
+                key: token
+          - name: INFORMER_TYPE
+            value: telegram
+        resources:
+          limits:
+            memory: "128Mi"
+            cpu: "100m"

pkg/chat/chat.go

@@ -2,7 +2,10 @@ package chat
 
 import (
 	"fmt"
+	"strings"
+	"unicode/utf16"
 
+	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
 	"github.com/kelseyhightower/envconfig"
 	"github.com/mattermost/mattermost-server/v6/model"
 	"github.com/slack-go/slack"
@@ -84,6 +87,8 @@ func NewClientFromEnv() (Client, error) {
 		client, err = NewMattermostClientFromEnv()
 	case "slack":
 		client, err = NewSlackClientFromEnv()
+	case "telegram":
+		client, err = NewTelegramClientFromEnv()
 	default:
 		err = fmt.Errorf("unknown client type: %s", cfg.Type)
 	}
@@ -163,3 +168,78 @@ func NewSlackClientFromEnv() (*SlackClient, error) {
 		Channel: cfg.Channel,
 	}, nil
 }
+
+type TelegramConfig struct {
+	Token  string
+	ChatID int64
+}
+
+type TelegramClient struct {
+	chat tgbotapi.Chat
+	bot  *tgbotapi.BotAPI
+}
+
+func (client *TelegramClient) Send(note *CrashNotification) {
+	// Generate text
+	type entityMarker struct {
+		Type    string
+		Content string
+	}
+	contents := []entityMarker{
+		{"bold", note.Title},
+		{"", note.Message},
+		{"bold", "Logs"},
+		{"pre", note.Logs},
+		{"bold", "Reason"},
+		{"pre", note.Reason},
+	}
+	// Generate text
+	cleartext := []string{}
+	for _, c := range contents {
+		cleartext = append(cleartext, c.Content)
+	}
+	// Get all joined groups
+	message := tgbotapi.NewMessage(client.chat.ID, strings.Join(cleartext, "\n"))
+	offset := 0
+	// Generate list of entities
+	for _, c := range contents {
+		length := len(utf16.Encode([]rune(c.Content)))
+		if c.Type != "" {
+			message.Entities = append(message.Entities, tgbotapi.MessageEntity{
+				Type:   c.Type,
+				Offset: offset,
+				Length: length,
+			})
+		}
+		offset += length + 1
+	}
+	_, err := client.bot.Send(message)
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+
+// NewTelegramClientFromEnv instantiates and configures a Telegram client.
+func NewTelegramClientFromEnv() (*TelegramClient, error) {
+	var cfg TelegramConfig
+	if err := envconfig.Process("telegram", &cfg); err != nil {
+		return nil, err
+	}
+	bot, err := tgbotapi.NewBotAPI(cfg.Token)
+	if err != nil {
+		return nil, fmt.Errorf("init bot: %w", err)
+	}
+	// Get chat to verify
+	chat, err := bot.GetChat(tgbotapi.ChatInfoConfig{
+		ChatConfig: tgbotapi.ChatConfig{
+			ChatID: cfg.ChatID,
+		},
+	})
+	if err != nil {
+		return nil, fmt.Errorf("get chat: %w", err)
+	}
+	return &TelegramClient{
+		chat: chat,
+		bot:  bot,
+	}, nil
+}

pkg/utils/utils.go

@@ -2,14 +2,14 @@ package utils
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 )
 
 const namespaceFilePath = "/var/run/secrets/kubernetes.io/serviceaccount/namespace"
 
 // Namespace returns the namespace this pod is running in.
 func Namespace() (string, error) {
-	nsfile, err := ioutil.ReadFile(namespaceFilePath)
+	nsfile, err := os.ReadFile(namespaceFilePath)
 	if err != nil {
 		return "", fmt.Errorf("could not read namespace: %v", err)
 	}