Add bindings/templating to the Slack Notifier (#134)

* add bindings/templating to the Slack Notifier

slack/main.go

@@ -15,8 +15,10 @@
 package main
 
 import (
+	"bytes"
 	"context"
 	"fmt"
+	"text/template"
 
 	"github.com/GoogleCloudPlatform/cloud-build-notifiers/lib/notifiers"
 	log "github.com/golang/glog"
@@ -35,12 +37,14 @@ func main() {
 }
 
 type slackNotifier struct {
-	filter notifiers.EventFilter
-
+	filter     notifiers.EventFilter
+	tmpl       *template.Template
 	webhookURL string
+	br         notifiers.BindingResolver
+	tmplView   *notifiers.TemplateView
 }
 
-func (s *slackNotifier) SetUp(ctx context.Context, cfg *notifiers.Config, _ string, sg notifiers.SecretGetter, _ notifiers.BindingResolver) error {
+func (s *slackNotifier) SetUp(ctx context.Context, cfg *notifiers.Config, blockKitTemplate string, sg notifiers.SecretGetter, br notifiers.BindingResolver) error {
 	prd, err := notifiers.MakeCELPredicate(cfg.Spec.Notification.Filter)
 	if err != nil {
 		return fmt.Errorf("failed to make a CEL predicate: %w", err)
@@ -60,32 +64,47 @@ func (s *slackNotifier) SetUp(ctx context.Context, cfg *notifiers.Config, _ stri
 		return fmt.Errorf("failed to get token secret: %w", err)
 	}
 	s.webhookURL = wu
+	tmpl, err := template.New("blockkit_template").Parse(blockKitTemplate)
+	s.tmpl = tmpl
+	s.br = br
 
 	return nil
 }
 
 func (s *slackNotifier) SendNotification(ctx context.Context, build *cbpb.Build) error {
+
 	if !s.filter.Apply(ctx, build) {
 		return nil
 	}
 
 	log.Infof("sending Slack webhook for Build %q (status: %q)", build.Id, build.Status)
-	msg, err := s.writeMessage(build)
+
+	bindings, err := s.br.Resolve(ctx, nil, build)
+	if err != nil {
+		return fmt.Errorf("failed to resolve bindings: %w", err)
+	}
+
+	s.tmplView = &notifiers.TemplateView{
+		Build:  &notifiers.BuildView{Build: build},
+		Params: bindings,
+	}
+
+	msg, err := s.writeMessage()
+
 	if err != nil {
 		return fmt.Errorf("failed to write Slack message: %w", err)
 	}
 
 	return slack.PostWebhook(s.webhookURL, msg)
 }
 
-func (s *slackNotifier) writeMessage(build *cbpb.Build) (*slack.WebhookMessage, error) {
-	txt := fmt.Sprintf(
-		"Cloud Build (%s, %s): %s",
-		build.ProjectId,
-		build.Id,
-		build.Status,
-	)
+func (s *slackNotifier) writeMessage() (*slack.WebhookMessage, error) {
+	build := s.tmplView.Build
+	_, err := notifiers.AddUTMParams(build.LogUrl, notifiers.ChatMedium)
 
+	if err != nil {
+		return nil, fmt.Errorf("failed to add UTM params: %w", err)
+	}
 	var clr string
 	switch build.Status {
 	case cbpb.Build_SUCCESS:
@@ -96,20 +115,16 @@ func (s *slackNotifier) writeMessage(build *cbpb.Build) (*slack.WebhookMessage,
 		clr = "warning"
 	}
 
-	logURL, err := notifiers.AddUTMParams(build.LogUrl, notifiers.ChatMedium)
-	if err != nil {
-		return nil, fmt.Errorf("failed to add UTM params: %w", err)
+	var buf bytes.Buffer
+	if err := s.tmpl.Execute(&buf, s.tmplView); err != nil {
+		return nil, err
 	}
+	var blocks slack.Blocks
 
-	atch := slack.Attachment{
-		Text:  txt,
-		Color: clr,
-		Actions: []slack.AttachmentAction{{
-			Text: "View Logs",
-			Type: "button",
-			URL:  logURL,
-		}},
+	err = blocks.UnmarshalJSON(buf.Bytes())
+	if err != nil {
+		return nil, fmt.Errorf("failed to unmarshal templating JSON: %w", err)
 	}
 
-	return &slack.WebhookMessage{Attachments: []slack.Attachment{atch}}, nil
+	return &slack.WebhookMessage{Attachments: []slack.Attachment{{Color: clr}}, Blocks: &blocks}, nil
 }

slack/main_test.go

@@ -2,36 +2,94 @@ package main
 
 import (
 	"testing"
+	"text/template"
 
+	"github.com/GoogleCloudPlatform/cloud-build-notifiers/lib/notifiers"
 	"github.com/google/go-cmp/cmp"
 	"github.com/slack-go/slack"
 	cbpb "google.golang.org/genproto/googleapis/devtools/cloudbuild/v1"
 )
 
 func TestWriteMessage(t *testing.T) {
 	n := new(slackNotifier)
-	b := &cbpb.Build{
+
+	blockKitTemplate := `[
+		{
+		  "type": "section",
+		  "text": {
+			"type": "mrkdwn",
+			"text": "Build Status: {{.Build.Status}}"
+		  }
+		},
+		{
+		  "type": "divider"
+		},
+		{
+		  "type": "section",
+		  "text": {
+			"type": "mrkdwn",
+			"text": "View Build Logs"
+		  },
+		  "accessory": {
+			"type": "button",
+			"text": {
+			  "type": "plain_text",
+			  "text": "Logs"
+			},
+			"value": "click_me_123",
+			"url": "{{.Build.LogUrl}}",
+			"action_id": "button-action"
+		  }
+		}
+	  ]`
+
+	tmpl, err := template.New("blockkit_template").Parse(blockKitTemplate)
+	if err != nil {
+		t.Fatalf("failed to parse template: %v", err)
+	}
+	n.tmpl = tmpl
+	n.tmplView = &notifiers.TemplateView{Build: &notifiers.BuildView{Build: &cbpb.Build{
 		ProjectId: "my-project-id",
 		Id:        "some-build-id",
 		Status:    cbpb.Build_SUCCESS,
 		LogUrl:    "https://some.example.com/log/url?foo=bar",
-	}
+	}}}
 
-	got, err := n.writeMessage(b)
+	got, err := n.writeMessage()
 	if err != nil {
 		t.Fatalf("writeMessage failed: %v", err)
 	}
 
 	want := &slack.WebhookMessage{
-		Attachments: []slack.Attachment{{
-			Text:  "Cloud Build (my-project-id, some-build-id): SUCCESS",
-			Color: "good",
-			Actions: []slack.AttachmentAction{{
-				Text: "View Logs",
-				Type: "button",
-				URL:  "https://some.example.com/log/url?foo=bar&utm_campaign=google-cloud-build-notifiers&utm_medium=chat&utm_source=google-cloud-build",
-			}},
-		}},
+		Attachments: []slack.Attachment{{Color: "good"}},
+		Blocks: &slack.Blocks{
+			BlockSet: []slack.Block{
+				&slack.SectionBlock{
+					Type: "section",
+					Text: &slack.TextBlockObject{
+						Type: "mrkdwn",
+						Text: "Build Status: SUCCESS",
+					},
+				},
+				&slack.DividerBlock{
+					Type: "divider",
+				},
+				&slack.SectionBlock{
+					Type: "section",
+					Text: &slack.TextBlockObject{
+						Type: "mrkdwn",
+						Text: "View Build Logs",
+					},
+					Accessory: &slack.Accessory{ButtonElement: &slack.ButtonBlockElement{
+						Type:     "button",
+						Text:     &slack.TextBlockObject{Type: "plain_text", Text: "Logs"},
+						ActionID: "button-action",
+						URL:      "https://some.example.com/log/url?foo=bar",
+						Value:    "click_me_123",
+					}},
+				},
+			},
+		},
 	}
 
 	if diff := cmp.Diff(got, want); diff != "" {

slack/slack.json

@@ -0,0 +1,30 @@
+[
+    {
+      "type": "section",
+      "text": {
+        "type": "mrkdwn",
+        "text": "Cloud Build {{.Build.ProjectId}} {{.Build.Id}} {{.Build.Status}}"
+      }
+    },
+    {
+      "type": "divider"
+    },
+    {
+      "type": "section",
+      "text": {
+        "type": "mrkdwn",
+        "text": "View Build Logs"
+      },
+      "accessory": {
+        "type": "button",
+        "text": {
+          "type": "plain_text",
+          "text": "Logs"
+        },
+        "value": "click_me_123",
+        "url": "{{.Build.LogUrl}}",
+        "action_id": "button-action"
+      }
+    }
+  ]
+