From ec3dbaa847230f9c4c6aae2ef19102afdc1c571a Mon Sep 17 00:00:00 2001
From: Yaniv Brener <brener.yaniv@gmail.com>
Date: Mon, 5 Jun 2023 10:27:23 -0700
Subject: [PATCH] Added a template function 'replace' to BlockKitTemplate
 parser, which lets user replace substrings in the template (#161)

Co-authored-by: Yaniv Brener <ybrener@beyond12.org>
---
 slack/README.md    |  3 +++
 slack/main.go      |  8 +++++++-
 slack/main_test.go | 13 +++++++++----
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/slack/README.md b/slack/README.md
index 7886ca03..eb836e86 100644
--- a/slack/README.md
+++ b/slack/README.md
@@ -27,3 +27,6 @@ gcloud run deploy service-name \
    --no-allow-unauthenticated \
    --update-env-vars=CONFIG_PATH=config-path,PROJECT_ID=project-id
 ```
+## Slack BlockKit Template Functions
+- The `replace` function allows replacement of substrings in any {{template variables}} in the .json Slack template. (For example, the variable `.Build.FailureInfo.Detail` contains double quotes, which breaks the BlockKitTemplate parsing.)
+   - Usage: `{{replace .Build.FailureInfo.Detail "\"" "'"}}`
\ No newline at end of file
diff --git a/slack/main.go b/slack/main.go
index de82c6f5..76e16aad 100644
--- a/slack/main.go
+++ b/slack/main.go
@@ -19,6 +19,7 @@ import (
 	"context"
 	"fmt"
 	"text/template"
+	"strings"
 
 	"github.com/GoogleCloudPlatform/cloud-build-notifiers/lib/notifiers"
 	log "github.com/golang/glog"
@@ -64,7 +65,12 @@ func (s *slackNotifier) SetUp(ctx context.Context, cfg *notifiers.Config, blockK
 		return fmt.Errorf("failed to get token secret: %w", err)
 	}
 	s.webhookURL = wu
-	tmpl, err := template.New("blockkit_template").Parse(blockKitTemplate)
+	tmpl, err := template.New("blockkit_template").Funcs(template.FuncMap{
+		"replace": func(s, old, new string) string {
+			return strings.ReplaceAll(s, old, new)
+		},
+	}).Parse(blockKitTemplate)
+
 	s.tmpl = tmpl
 	s.br = br
 
diff --git a/slack/main_test.go b/slack/main_test.go
index 227ef30e..dcbb4a79 100644
--- a/slack/main_test.go
+++ b/slack/main_test.go
@@ -3,6 +3,7 @@ package main
 import (
 	"testing"
 	"text/template"
+	"strings"
 
 	"github.com/GoogleCloudPlatform/cloud-build-notifiers/lib/notifiers"
 	"github.com/google/go-cmp/cmp"
@@ -37,13 +38,17 @@ func TestWriteMessage(t *testing.T) {
 			  "text": "Logs"
 			},
 			"value": "click_me_123",
-			"url": "{{.Build.LogUrl}}",
+			"url": "{{replace .Build.LogUrl "\"" "'"}}",
 			"action_id": "button-action"
 		  }
 		}
 	  ]`
 
-	tmpl, err := template.New("blockkit_template").Parse(blockKitTemplate)
+	tmpl, err := template.New("blockkit_template").Funcs(template.FuncMap{
+		"replace": func(s, old, new string) string {
+			return strings.ReplaceAll(s, old, new)
+		},
+	}).Parse(blockKitTemplate)
 	if err != nil {
 		t.Fatalf("failed to parse template: %v", err)
 	}
@@ -52,7 +57,7 @@ func TestWriteMessage(t *testing.T) {
 		ProjectId: "my-project-id",
 		Id:        "some-build-id",
 		Status:    cbpb.Build_SUCCESS,
-		LogUrl:    "https://some.example.com/log/url?foo=bar",
+		LogUrl:    "https://some.example.com/log/url?foo=bar\"",
 	}}}
 
 	got, err := n.writeMessage()
@@ -85,7 +90,7 @@ func TestWriteMessage(t *testing.T) {
 							Type:     "button",
 							Text:     &slack.TextBlockObject{Type: "plain_text", Text: "Logs"},
 							ActionID: "button-action",
-							URL:      "https://some.example.com/log/url?foo=bar",
+							URL:      "https://some.example.com/log/url?foo=bar'",
 							Value:    "click_me_123",
 						}},
 					},