linkify the URL in HTTP failure messages as a Slack hyperlink

Transforms 'request for "<URL>"' into Slack mrkdwn <URL|request>, so the
failure line renders the word 'request' as a clickable link instead of
showing the raw URL in quotes.

monitoring/src/main/java/org/thingsboard/monitoring/data/notification/ServiceFailureNotification.java

@@ -19,6 +19,8 @@ import lombok.Getter;
 import org.apache.commons.lang3.exception.ExceptionUtils;
 
 import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 @Getter
 public class ServiceFailureNotification implements Notification {
@@ -46,9 +48,24 @@ public class ServiceFailureNotification implements Notification {
             errorMsg = error.getClass().getSimpleName();
         }
         errorMsg = stripResponseBody(errorMsg);
+        errorMsg = linkifyRequestUrl(errorMsg);
         return String.format("%s - Failure: %s (number of subsequent failures: %s)", serviceKey, errorMsg, failuresCount);
     }
 
+    private static final Pattern REQUEST_URL_PATTERN = Pattern.compile("request for \"(https?://[^\"\\s]+)\"");
+
+    static String linkifyRequestUrl(String msg) {
+        if (msg == null) {
+            return null;
+        }
+        Matcher m = REQUEST_URL_PATTERN.matcher(msg);
+        if (!m.find()) {
+            return msg;
+        }
+        // Slack mrkdwn link: <url|label>
+        return m.replaceAll("<$1|request>");
+    }
+
     static String stripResponseBody(String msg) {
         if (msg == null) {
             return null;

monitoring/src/test/java/org/thingsboard/monitoring/data/notification/ServiceFailureNotificationTest.java

@@ -53,6 +53,25 @@ class ServiceFailureNotificationTest {
         assertThat(ServiceFailureNotification.stripResponseBody(null)).isNull();
     }
 
+    @Test
+    void linkifyReplacesRequestForUrlWithSlackMrkdwnLink() {
+        String msg = "503 Service Temporarily Unavailable on POST request for \"https://qa-tb-pe-lts43.iot-private.cloud/api/auth/login\"";
+
+        assertThat(ServiceFailureNotification.linkifyRequestUrl(msg))
+                .isEqualTo("503 Service Temporarily Unavailable on POST <https://qa-tb-pe-lts43.iot-private.cloud/api/auth/login|request>");
+    }
+
+    @Test
+    void linkifyLeavesMessagesWithoutRequestUrlUntouched() {
+        String msg = "Connection refused";
+        assertThat(ServiceFailureNotification.linkifyRequestUrl(msg)).isEqualTo(msg);
+    }
+
+    @Test
+    void linkifyHandlesNull() {
+        assertThat(ServiceFailureNotification.linkifyRequestUrl(null)).isNull();
+    }
+
     @Test
     void shortNameUsesShortNameProviderWhenAvailable() {
         ShortNameProvider provider = () -> "MQTT";