feat(slack): add support for thread replies and message updates (#187)

docs/services/slack.md

@@ -206,3 +206,42 @@ template.app-sync-failed: |
 ```
 
 The message is sent according to the `deliveryPolicy` string field under the `slack` field. The available modes are `Post` (default), `PostAndUpdate`, and `Update`. The `PostAndUpdate` and `Update` settings require `groupingKey` to be set.
+
+### Thread Replies and Message Updates
+
+You can explicitly control thread replies and message updates using the `threadTs` and `updateTs` fields:
+
+#### Reply to a Specific Thread
+
+Use `threadTs` to post a message as a reply in a specific Slack thread. This is useful when you want to reply to a particular message thread based on a timestamp you already know (e.g., from a previous notification or external system).
+
+```yaml
+template.app-deploy-status: |
+  message: |
+    Deployment completed for {{.app.metadata.name}}.
+  slack:
+    threadTs: "1234567890.123456"  # Reply to this specific thread
+```
+
+The `threadTs` value should be the timestamp of the parent message in the thread. When set, the message will be posted as a reply in that thread, regardless of the `groupingKey` or `deliveryPolicy` settings.
+
+#### Update a Specific Message
+
+Use `updateTs` to update a specific existing message. This is useful when you want to update a particular message based on its timestamp (e.g., to update a deployment status message).
+
+```yaml
+template.app-deploy-update: |
+  message: |
+    Deployment status: {{.app.status.operationState.phase}}
+  slack:
+    updateTs: "1234567890.123456"  # Update this specific message
+```
+
+The `updateTs` value should be the timestamp of the message you want to update. When set, the existing message will be updated with the new content, regardless of the `groupingKey` or `deliveryPolicy` settings.
+
+**Important Notes:**
+- `threadTs` and `updateTs` are mutually exclusive - only use one at a time
+- Both fields support template expressions, allowing dynamic values from your notification context
+- When either field is set, it overrides the normal `groupingKey` and `deliveryPolicy` behavior
+- Only messages posted by the authenticated bot user can be updated
+- To update a message, you need the original message's timestamp (which can be obtained from the Slack API response or stored externally)

go.mod

@@ -23,7 +23,7 @@ require (
 	github.com/opsgenie/opsgenie-go-sdk-v2 v1.2.23
 	github.com/prometheus/client_golang v1.21.0
 	github.com/sirupsen/logrus v1.9.3
-	github.com/slack-go/slack v0.16.0
+	github.com/slack-go/slack v0.17.3
 	github.com/spf13/cast v1.7.1
 	github.com/spf13/cobra v1.9.1
 	github.com/stretchr/testify v1.10.0
@@ -75,7 +75,7 @@ require (
 	github.com/google/s2a-go v0.1.9 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.3.4 // indirect
 	github.com/googleapis/gax-go/v2 v2.14.1 // indirect
-	github.com/gorilla/websocket v1.5.0 // indirect
+	github.com/gorilla/websocket v1.5.3 // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
 	github.com/huandu/xstrings v1.5.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect

go.sum

@@ -102,8 +102,8 @@ github.com/go-openapi/swag v0.23.0 h1:vsEVJDUo2hPJ2tu0/Xc+4noaxyEffXNIs3cOULZ+Gr
 github.com/go-openapi/swag v0.23.0/go.mod h1:esZ8ITTYEsH1V2trKHjAN8Ai7xHb8RV+YSZ577vPjgQ=
 github.com/go-task/slim-sprig/v3 v3.0.0 h1:sUs3vkvUymDpBKi3qH1YSqBQk9+9D/8M2mN1vB6EwHI=
 github.com/go-task/slim-sprig/v3 v3.0.0/go.mod h1:W848ghGpv3Qj3dhTPRyJypKRiqCdHZiAzKg9hl15HA8=
-github.com/go-test/deep v1.0.4 h1:u2CU3YKy9I2pmu9pX0eq50wCgjfGIt539SqR7FbHiho=
-github.com/go-test/deep v1.0.4/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
+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/gobuffalo/envy v1.7.0/go.mod h1:n7DRkBerg/aorDM8kbduw5dN3oXGswK5liaSCx4T5NI=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
@@ -127,7 +127,6 @@ github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMyw
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
@@ -154,9 +153,8 @@ github.com/gopackage/ddp v0.0.0-20170117053602-652027933df4 h1:4EZlYQIiyecYJlUbV
 github.com/gopackage/ddp v0.0.0-20170117053602-652027933df4/go.mod h1:lEO7XoHJ/xNRBCxrn4h/CEB67h0kW1B0t4ooP2yrjUA=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/gorilla/websocket v1.4.0/go.mod h1:E7qHFY5m1UJ88s3WnNqhKjPHQ0heANvMoAMk2YaljkQ=
-github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
-github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
-github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=
+github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/gregdel/pushover v1.3.1 h1:4bMLITOZ15+Zpi6qqoGqOPuVHCwSUvMCgVnN5Xhilfo=
 github.com/gregdel/pushover v1.3.1/go.mod h1:EcaO66Nn1StkpEm1iKtBTV3d2A16SoMsVER1PthX7to=
 github.com/hashicorp/go-cleanhttp v0.5.0/go.mod h1:JpRdi6/HCYpAwUzNwuwqhbovhLtngrth3wmdIIUrZ80=
@@ -261,8 +259,8 @@ github.com/shopspring/decimal v1.4.0/go.mod h1:gawqmDU56v4yIKSwfBSFip1HdCCXN8/+D
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
-github.com/slack-go/slack v0.16.0 h1:khp/WCFv+Hb/B/AJaAwvcxKun0hM6grN0bUZ8xG60P8=
-github.com/slack-go/slack v0.16.0/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
+github.com/slack-go/slack v0.17.3 h1:zV5qO3Q+WJAQ/XwbGfNFrRMaJ5T/naqaonyPV/1TP4g=
+github.com/slack-go/slack v0.17.3/go.mod h1:X+UqOufi3LYQHDnMG1vxf0J8asC6+WllXrVrhl8/Prk=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
 github.com/smartystreets/goconvey v0.0.0-20190731233626-505e41936337/go.mod h1:syvi0/a8iFYH4r/RixwvyeAJjdLS9QV7WQ/tjFTllLA=
 github.com/sony/sonyflake v1.0.0 h1:MpU6Ro7tfXwgn2l5eluf9xQvQJDROTBImNCfRXn/YeM=

pkg/services/slack.go

@@ -28,6 +28,8 @@ type SlackNotification struct {
 	GroupingKey     string                   `json:"groupingKey"`
 	NotifyBroadcast bool                     `json:"notifyBroadcast"`
 	DeliveryPolicy  slackutil.DeliveryPolicy `json:"deliveryPolicy"`
+	ThreadTS        string                   `json:"threadTs,omitempty"`
+	UpdateTS        string                   `json:"updateTs,omitempty"`
 }
 
 func (n *SlackNotification) GetTemplater(name string, f texttemplate.FuncMap) (Templater, error) {
@@ -54,6 +56,16 @@ func (n *SlackNotification) GetTemplater(name string, f texttemplate.FuncMap) (T
 		return nil, err
 	}
 
+	threadTS, err := texttemplate.New(name).Funcs(f).Parse(n.ThreadTS)
+	if err != nil {
+		return nil, err
+	}
+
+	updateTS, err := texttemplate.New(name).Funcs(f).Parse(n.UpdateTS)
+	if err != nil {
+		return nil, err
+	}
+
 	return func(notification *Notification, vars map[string]interface{}) error {
 		if notification.Slack == nil {
 			notification.Slack = &SlackNotification{}
@@ -88,6 +100,18 @@ func (n *SlackNotification) GetTemplater(name string, f texttemplate.FuncMap) (T
 		}
 		notification.Slack.GroupingKey = groupingKeyData.String()
 
+		var threadTSData bytes.Buffer
+		if err := threadTS.Execute(&threadTSData, vars); err != nil {
+			return err
+		}
+		notification.Slack.ThreadTS = threadTSData.String()
+
+		var updateTSData bytes.Buffer
+		if err := updateTS.Execute(&updateTSData, vars); err != nil {
+			return err
+		}
+		notification.Slack.UpdateTS = updateTSData.String()
+
 		notification.Slack.NotifyBroadcast = n.NotifyBroadcast
 		notification.Slack.DeliveryPolicy = n.DeliveryPolicy
 		return nil
@@ -187,6 +211,8 @@ func (s *slackService) Send(notification Notification, dest Destination) error {
 		slackNotification.GroupingKey,
 		slackNotification.NotifyBroadcast,
 		slackNotification.DeliveryPolicy,
+		slackNotification.ThreadTS,
+		slackNotification.UpdateTS,
 		msgOptions,
 	)
 }

pkg/util/slack/client.go

@@ -121,7 +121,48 @@ func (c *threadedClient) setThreadTimestamp(recipient string, groupingKey string
 	thread[groupingKey] = ts
 }
 
-func (c *threadedClient) SendMessage(ctx context.Context, recipient string, groupingKey string, broadcast bool, policy DeliveryPolicy, options []sl.MsgOption) error {
+func (c *threadedClient) SendMessage(ctx context.Context, recipient string, groupingKey string, broadcast bool, policy DeliveryPolicy, threadTS string, updateTS string, options []sl.MsgOption) error {
+	// Validate that threadTS and updateTS are mutually exclusive
+	if threadTS != "" && updateTS != "" {
+		return errors.New("threadTS and updateTS are mutually exclusive; only one may be set")
+	}
+	// If explicit updateTS is provided, update that specific message and return
+	if updateTS != "" {
+		_, _, err := SendMessageRateLimited(
+			c.Client,
+			ctx,
+			c.Limiter,
+			c.getChannelID(recipient),
+			sl.MsgOptionUpdate(updateTS),
+			sl.MsgOptionAsUser(true),
+			sl.MsgOptionCompose(options...),
+		)
+		return err
+	}
+
+	// If explicit threadTS is provided, post as a reply in that thread and return
+	if threadTS != "" {
+		options = append(options, sl.MsgOptionTS(threadTS))
+		_, channelID, err := SendMessageRateLimited(
+			c.Client,
+			ctx,
+			c.Limiter,
+			recipient,
+			sl.MsgOptionPost(),
+			buildPostOptions(broadcast, options),
+		)
+		if err != nil {
+			return err
+		}
+
+		c.lock.Lock()
+		c.ChannelIDs[recipient] = channelID
+		c.lock.Unlock()
+
+		return nil
+	}
+
+	// Otherwise, use the existing groupingKey + policy logic
 	ts := c.getThreadTimestamp(recipient, groupingKey)
 	if groupingKey != "" && ts != "" {
 		options = append(options, sl.MsgOptionTS(ts))