feat: add slack webhook

internal/hook/discordhook.go

@@ -25,7 +25,7 @@ func (h *Hook) doDiscord(cmd *v1.Hook_ActionDiscord, vars HookVars, output io.Wr
 
 	requestBytes, _ := json.Marshal(request)
 
-	fmt.Fprintf(output, "Sending Discord message to %s\n---- payload ----", cmd.ActionDiscord.GetWebhookUrl())
+	fmt.Fprintf(output, "Sending Discord message to %s\n---- payload ----\n", cmd.ActionDiscord.GetWebhookUrl())
 	output.Write(requestBytes)
 
 	_, err = post(cmd.ActionDiscord.GetWebhookUrl(), "application/json", bytes.NewReader(requestBytes))

internal/hook/hook.go

@@ -155,6 +155,8 @@ func (h *Hook) Do(event v1.Hook_Condition, vars HookVars, output io.Writer) erro
 		return h.doDiscord(action, vars, output)
 	case *v1.Hook_ActionGotify:
 		return h.doGotify(action, vars, output)
+	case *v1.Hook_ActionSlack:
+		return h.doSlack(action, vars, output)
 	default:
 		return fmt.Errorf("unknown hook action: %v", action)
 	}

internal/hook/slackhook.go

@@ -0,0 +1,33 @@
+package hook
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+
+	v1 "github.com/garethgeorge/backrest/gen/go/v1"
+)
+
+func (h *Hook) doSlack(cmd *v1.Hook_ActionSlack, vars HookVars, output io.Writer) error {
+	payload, err := h.renderTemplateOrDefault(cmd.ActionSlack.GetTemplate(), defaultTemplate, vars)
+	if err != nil {
+		return fmt.Errorf("template rendering: %w", err)
+	}
+
+	type Message struct {
+		Text string `json:"text"`
+	}
+
+	request := Message{
+		Text: "Backrest Notification\n" + payload, // leading newline looks better in discord.
+	}
+
+	requestBytes, _ := json.Marshal(request)
+
+	fmt.Fprintf(output, "Sending Slack message to %s\n---- payload ----\n", cmd.ActionSlack.GetWebhookUrl())
+	output.Write(requestBytes)
+
+	_, err = post(cmd.ActionSlack.GetWebhookUrl(), "application/json", bytes.NewReader(requestBytes))
+	return err
+}

proto/v1/config.proto

@@ -72,6 +72,7 @@ message Hook {
     Webhook action_webhook = 101 [json_name="actionWebhook"];
     Discord action_discord = 102 [json_name="actionDiscord"];
     Gotify action_gotify = 103 [json_name="actionGotify"];
+    Slack action_slack = 104 [json_name="actionSlack"];
   }
 
   message Command {
@@ -93,6 +94,11 @@ message Hook {
     string template = 100 [json_name="template"]; // template for the webhook payload.
     string title_template = 101 [json_name="titleTemplate"]; // template for the webhook title.
   }
+
+  message Slack {
+    string webhook_url = 1 [json_name="webhookUrl"];
+    string template = 2 [json_name="template"]; // template for the webhook payload.
+  }
 }
 
 message Auth {