feature/slack notifications

.github/workflows/sync-oncall.yml

@@ -34,4 +34,5 @@ jobs:
           cd synconcall
           ./synconcall --config=../dev.oncall \
             --group=dev-oncall@bytebase.com --admin-user=d@bytebase.com \
-            --slack-group=S0AAPDZBNQL
+            --slack-group=S0AAPDZBNQL \
+            --slack-channel=C08CMEAP63T

synconcall/SLACK_SETUP.md

@@ -22,6 +22,7 @@ To sync on-call rotations to a Slack User Group, you need a **Slack User OAuth T
      - `usergroups:write` (To add/remove members)
      - `users:read`       (To look up user details)
      - `users:read.email` (To look up users by email)
+     - `chat:write`       (To post notification messages)
 
      > [!IMPORTANT]  
      > **DO NOT** select scopes starting with `admin.` (e.g., `admin.usergroups:write`). These require an Enterprise Grid plan and will cause installation errors. Ensure you select the standard `usergroups:write`.
@@ -32,11 +33,30 @@ To sync on-call rotations to a Slack User Group, you need a **Slack User OAuth T
    - Allow the permissions.
    - Copy the **User OAuth Token**. It should start with `xoxp-`.
 
+## Finding IDs
+
+### Finding User Group ID
+1. Open Slack on desktop.
+2. Go to **People & User Groups** in the sidebar.
+3. Click on the desired User Group (e.g., `@dev-oncall`).
+4. Click the **...** (three dots) menu near the top right of the group card.
+5. Select **Copy ID**. It usually starts with `S` (e.g., `S0123456789`).
+
+### Finding Channel ID
+1. Open the desired channel in Slack.
+2. Click on the **channel name** in the header to open details.
+3. Scroll to the bottom of the "About" tab.
+4. You will see **Channel ID**. It usually starts with `C` (e.g., `C0123456789`).
+
 ## Usage
 
 Run the tool with your new token:
 
 ```bash
 export SLACK_TOKEN="xoxp-your-token-here"
-go run ./synconcall --config=dev.oncall --slack-group=S0AAPDZBNQL
+# Sync + Notify
+go run ./synconcall \
+    --config=dev.oncall \
+    --slack-group=S0AAPDZBNQL \
+    --slack-channel=C012345ABC
 ```

synconcall/go.mod

@@ -2,7 +2,11 @@ module github.com/bytebase/oncall/synconcall
 
 go 1.25.6
 
-require google.golang.org/api v0.262.0
+require (
+	github.com/slack-go/slack v0.17.3
+	golang.org/x/oauth2 v0.34.0
+	google.golang.org/api v0.262.0
+)
 
 require (
 	cloud.google.com/go/auth v0.18.1 // indirect
@@ -17,15 +21,13 @@ require (
 	github.com/googleapis/enterprise-certificate-proxy v0.3.11 // indirect
 	github.com/googleapis/gax-go/v2 v2.16.0 // indirect
 	github.com/gorilla/websocket v1.5.3 // indirect
-	github.com/slack-go/slack v0.17.3 // indirect
 	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0 // indirect
 	go.opentelemetry.io/otel v1.39.0 // indirect
 	go.opentelemetry.io/otel/metric v1.39.0 // indirect
 	go.opentelemetry.io/otel/trace v1.39.0 // indirect
 	golang.org/x/crypto v0.47.0 // indirect
 	golang.org/x/net v0.49.0 // indirect
-	golang.org/x/oauth2 v0.34.0 // indirect
 	golang.org/x/sys v0.40.0 // indirect
 	golang.org/x/text v0.33.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20260120174246-409b4a993575 // indirect

synconcall/go.sum

@@ -15,6 +15,8 @@ github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
 github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
 github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
+github.com/go-test/deep v1.1.1 h1:0r/53hagsehfO4bzD2Pgr/+RgHqhmf+k1Bpse2cTu1U=
+github.com/go-test/deep v1.1.1/go.mod h1:5C2ZWiW0ErCdrYzpqxLbTX7MG14M9iiw8DgHncVwcsE=
 github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
 github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=

synconcall/main.go

@@ -23,6 +23,7 @@ func main() {
 	// Slack flags
 	slackGroup := flag.String("slack-group", "", "Slack User Group ID to sync")
 	slackToken := flag.String("slack-token", "", "Slack API Token (can also be set via SLACK_TOKEN env var)")
+	slackChannel := flag.String("slack-channel", "", "Slack Channel ID to notify on changes")
 
 	showHelp := flag.Bool("help", false, "Show usage information")
 
@@ -42,6 +43,22 @@ func main() {
 	}
 
 	syncPerformed := false
+	anyChanges := false
+	var currentRotation *Rotation
+
+	// Initialize Slack Client if needed (for sync or notifications)
+	var slackClient *SlackClient
+	token := *slackToken
+	if token == "" {
+		token = os.Getenv("SLACK_TOKEN")
+	}
+
+	if token != "" {
+		slackClient = NewSlackClient(token)
+	} else if *slackGroup != "" || *slackChannel != "" {
+		fmt.Fprintf(os.Stderr, "Error: Slack token is required via --slack-token or SLACK_TOKEN env var for Slack sync or notifications\n")
+		os.Exit(1)
+	}
 
 	// Google Group Sync
 	if *groupEmail != "" {
@@ -77,10 +94,16 @@ func main() {
 			os.Exit(1)
 		}
 
-		if err := runSync(*configPath, *groupEmail, googleClient); err != nil {
+		changed, rot, err := runSync(*configPath, *groupEmail, googleClient)
+		if err != nil {
 			fmt.Fprintf(os.Stderr, "Error: Google Group sync failed - %v\n", err)
 			os.Exit(1)
 		}
+		if changed {
+			anyChanges = true
+		}
+		currentRotation = rot
+
 		fmt.Printf("--- Google Group Sync Completed ---\n\n")
 	}
 
@@ -89,20 +112,17 @@ func main() {
 		syncPerformed = true
 		fmt.Println("--- Starting Slack Sync ---")
 
-		token := *slackToken
-		if token == "" {
-			token = os.Getenv("SLACK_TOKEN")
-		}
-		if token == "" {
-			fmt.Fprintf(os.Stderr, "Error: Slack token is required via --slack-token or SLACK_TOKEN env var\n")
-			os.Exit(1)
-		}
-		slackClient := NewSlackClient(token)
+		// slackClient is already initialized above
 
-		if err := runSync(*configPath, *slackGroup, slackClient); err != nil {
+		changed, rot, err := runSync(*configPath, *slackGroup, slackClient)
+		if err != nil {
 			fmt.Fprintf(os.Stderr, "Error: Slack sync failed - %v\n", err)
 			os.Exit(1)
 		}
+		if changed {
+			anyChanges = true
+		}
+		currentRotation = rot // Either sync source provides valid rotation
 		fmt.Printf("--- Slack Sync Completed ---\n\n")
 	}
 
@@ -111,9 +131,33 @@ func main() {
 		printUsage()
 		os.Exit(1)
 	}
+
+	// Send notification if configured and changes were made
+	if anyChanges && slackClient != nil && *slackChannel != "" && currentRotation != nil {
+
+		fmt.Printf("--- Sending Notification ---\n")
+
+		primaryMention := currentRotation.Primary
+		if id, err := slackClient.GetUserIDByEmail(primaryMention); err == nil {
+			primaryMention = fmt.Sprintf("<@%s>", id)
+		}
+
+		secondaryMention := currentRotation.Secondary
+		if id, err := slackClient.GetUserIDByEmail(secondaryMention); err == nil {
+			secondaryMention = fmt.Sprintf("<@%s>", id)
+		}
+
+		msg := fmt.Sprintf("On-call rotation update.\n\nCurrent on-call:\n• Primary: %s\n• Secondary: %s",
+			primaryMention, secondaryMention)
+
+		fmt.Printf("Sending notification to channel %s...\n", *slackChannel)
+		if err := slackClient.PostMessage(*slackChannel, msg); err != nil {
+			fmt.Fprintf(os.Stderr, "Warning: Failed to send Slack notification: %v\n", err)
+		}
+	}
 }
 
-func runSync(configPath string, groupEmail string, client GroupsClient) error {
+func runSync(configPath string, groupEmail string, client GroupsClient) (bool, *Rotation, error) {
 	fmt.Printf("Reading schedule from: %s\n", configPath)
 
 	// Get current time
@@ -122,12 +166,12 @@ func runSync(configPath string, groupEmail string, client GroupsClient) error {
 	// Parse schedule and find current rotation
 	rotations, err := ParseSchedule(configPath)
 	if err != nil {
-		return err
+		return false, nil, err
 	}
 
 	currentRotation, err := FindCurrentRotation(rotations, now)
 	if err != nil {
-		return err
+		return false, nil, err
 	}
 
 	fmt.Printf("Current rotation: %s - Primary: %s, Secondary: %s\n",
@@ -140,30 +184,29 @@ func runSync(configPath string, groupEmail string, client GroupsClient) error {
 
 	result, err := Sync(groupEmail, configPath, client, now)
 	if err != nil {
-		return err
+		return false, nil, err
 	}
 
 	// Report results
 	if len(result.Removed) == 0 && len(result.Added) == 0 {
 		fmt.Println("  No changes needed.")
+		return false, currentRotation, nil
 	} else {
 		for _, member := range result.Removed {
 			fmt.Printf("  Removed: %s\n", member)
 		}
 		for _, member := range result.Added {
 			fmt.Printf("  Added: %s\n", member)
 		}
+		return true, currentRotation, nil
 	}
-
-	fmt.Println("Sync completed successfully.")
-	return nil
 }
 
 func printUsage() {
 	fmt.Fprintf(os.Stderr, `synconcall - Sync oncall rotation to Google Group or Slack User Group
 
 Usage:
-  synconcall --config=<path> [--group=<email> --admin-user=<email>] [--slack-group=<id> --slack-token=<token>]
+  synconcall --config=<path> [--group=<email> --admin-user=<email>] [--slack-group=<id> --slack-token=<token>] [--slack-channel=<channel_id>]
 
 Required Flags:
   --config string
@@ -181,6 +224,8 @@ Slack Flags:
         Slack User Group ID to sync
   --slack-token string
         Slack API Token (can also be set via SLACK_TOKEN env var)
+  --slack-channel string
+        Slack Channel ID to notify on changes
 
 Optional Flags:
   --help

synconcall/slack.go

@@ -132,3 +132,21 @@ func (c *SlackClient) RemoveMember(groupID, memberEmail string) error {
 
 	return nil
 }
+
+// PostMessage sends a message to a Slack channel
+func (c *SlackClient) PostMessage(channelID, message string) error {
+	_, _, err := c.client.PostMessage(channelID, slack.MsgOptionText(message, false))
+	if err != nil {
+		return fmt.Errorf("failed to post message to slack channel %s: %w", channelID, err)
+	}
+	return nil
+}
+
+// GetUserIDByEmail resolves an email to a Slack User ID
+func (c *SlackClient) GetUserIDByEmail(email string) (string, error) {
+	user, err := c.client.GetUserByEmail(email)
+	if err != nil {
+		return "", fmt.Errorf("failed to get user by email %s: %w", email, err)
+	}
+	return user.ID, nil
+}