MG-853 - Add Slack output integration (#315)

* add slack integration

Signed-off-by: ianmuchyri <ianmuchiri8@gmail.com>

* allow support for multiple message options

Signed-off-by: ianmuchyri <ianmuchiri8@gmail.com>

* add message to slack struct

Signed-off-by: ianmuchyri <ianmuchiri8@gmail.com>

* update template name

Signed-off-by: ianmuchyri <ianmuchiri8@gmail.com>

* group postgres and slack

Signed-off-by: ianmuchyri <ianmuchiri8@gmail.com>

---------

Signed-off-by: ianmuchyri <ianmuchiri8@gmail.com>

go.mod

@@ -45,6 +45,7 @@ require (
 )
 
 require (
+	github.com/slack-go/slack v0.17.3 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 )

go.sum

@@ -442,6 +442,8 @@ github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6Mwd
 github.com/sirupsen/logrus v1.6.0/go.mod h1:7uNnSEd1DgxDLC74fIahvMZmmYsHGZGEOFrfsX/uA88=
 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 v0.17.3 h1:zV5qO3Q+WJAQ/XwbGfNFrRMaJ5T/naqaonyPV/1TP4g=
+github.com/slack-go/slack v0.17.3/go.mod h1:X+UqOufi3LYQHDnMG1vxf0J8asC6+WllXrVrhl8/Prk=
 github.com/smarty/assertions v1.16.0 h1:EvHNkdRA4QHMrn75NZSoUQ/mAUXAYWfatfB01yTCzfY=
 github.com/smarty/assertions v1.16.0/go.mod h1:duaaFdCS0K9dnoM50iyek/eYINOZ64gbh1Xlf6LG7AI=
 github.com/smartystreets/goconvey v1.8.1 h1:qGjIddxOk4grTu9JPOU31tVfq3cNdBlNa5sSznIX1xY=

re/handlers.go

@@ -103,14 +103,14 @@ func (re *re) handleOutput(ctx context.Context, o Runnable, r Rule, msg *messagi
 	case *outputs.Email:
 		o.Emailer = re.email
 		return o.Run(ctx, msg, val)
-	case *outputs.Postgres:
-		return o.Run(ctx, msg, val)
 	case *outputs.ChannelPublisher:
 		o.RePubSub = re.rePubSub
 		return o.Run(ctx, msg, val)
 	case *outputs.SenML:
 		o.WritersPub = re.writersPub
 		return o.Run(ctx, msg, val)
+	case *outputs.Postgres, *outputs.Slack:
+		return o.Run(ctx, msg, val)
 	default:
 		return fmt.Errorf("unknown output type: %T", o)
 	}

re/outputs/outputs.go

@@ -26,16 +26,18 @@ const (
 	SaveSenMLType
 	EmailType
 	SaveRemotePgType
+	SlackType
 )
 
 var (
-	scriptKindToString = [...]string{"channels", "alarms", "save_senml", "email", "save_remote_pg"}
+	scriptKindToString = [...]string{"channels", "alarms", "save_senml", "email", "save_remote_pg", "slack"}
 	stringToScriptKind = map[string]OutputType{
 		"channels":       ChannelsType,
 		"alarms":         AlarmsType,
 		"save_senml":     SaveSenMLType,
 		"email":          EmailType,
 		"save_remote_pg": SaveRemotePgType,
+		"slack":          SlackType,
 	}
 )
 

re/outputs/slack.go

@@ -0,0 +1,72 @@
+// Copyright (c) Abstract Machines
+// SPDX-License-Identifier: Apache-2.0
+
+package outputs
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"text/template"
+
+	"github.com/absmach/supermq/pkg/messaging"
+	"github.com/slack-go/slack"
+)
+
+type Slack struct {
+	Token     string `json:"token"`
+	ChannelID string `json:"channel_id"`
+	Message   string `json:"message"`
+}
+
+func (s *Slack) Run(ctx context.Context, msg *messaging.Message, val any) error {
+	templData := templateVal{
+		Message: msg,
+		Result:  val,
+	}
+
+	tmpl, err := template.New("slack").Parse(s.Message)
+	if err != nil {
+		return err
+	}
+
+	var output bytes.Buffer
+	if err := tmpl.Execute(&output, templData); err != nil {
+		return err
+	}
+
+	mapping := output.String()
+
+	var message slack.Msg
+	if err := json.Unmarshal([]byte(mapping), &message); err != nil {
+		return err
+	}
+
+	slackClient := slack.New(s.Token)
+
+	var opts []slack.MsgOption
+
+	if message.Text != "" {
+		opts = append(opts, slack.MsgOptionText(message.Text, false))
+	}
+	if len(message.Attachments) > 0 {
+		opts = append(opts, slack.MsgOptionAttachments(message.Attachments...))
+	}
+	if len(message.Blocks.BlockSet) > 0 {
+		opts = append(opts, slack.MsgOptionBlocks(message.Blocks.BlockSet...))
+	}
+	_, _, err = slackClient.PostMessage(s.ChannelID, opts...)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (s *Slack) MarshalJSON() ([]byte, error) {
+	return json.Marshal(map[string]any{
+		"type":       SlackType.String(),
+		"token":      s.Token,
+		"channel_id": s.ChannelID,
+		"message":    s.Message,
+	})
+}

re/rule.go

@@ -50,6 +50,7 @@ var outputRegistry = map[outputs.OutputType]func() Runnable{
 	outputs.SaveRemotePgType: func() Runnable { return &outputs.Postgres{} },
 	outputs.ChannelsType:     func() Runnable { return &outputs.ChannelPublisher{} },
 	outputs.SaveSenMLType:    func() Runnable { return &outputs.SenML{} },
+	outputs.SlackType:        func() Runnable { return &outputs.Slack{} },
 }
 
 type Rule struct {