add env var and use proxy if exists

Author: RoiGlinik

src/robusta/core/model/env_vars.py

@@ -73,6 +73,7 @@ def load_bool(env_var, default: bool):
 
 SLACK_REQUEST_TIMEOUT = int(os.environ.get("SLACK_REQUEST_TIMEOUT", 90))
 SLACK_TABLE_COLUMNS_LIMIT = int(os.environ.get("SLACK_TABLE_COLUMNS_LIMIT", 3))
+SLACK_PROXY_URL = os.environ.get("SLACK_PROXY_URL")  # proxy endpoint "https://api.robusta.dev/integrations/slack/postmessage"
 DISCORD_TABLE_COLUMNS_LIMIT = int(os.environ.get("DISCORD_TABLE_COLUMNS_LIMIT", 4))
 RSA_KEYS_PATH = os.environ.get("RSA_KEYS_PATH", "/etc/robusta/auth")
 

src/robusta/integrations/slack/sender.py

@@ -20,6 +20,7 @@
     HOLMES_ENABLED,
     SLACK_REQUEST_TIMEOUT,
     SLACK_TABLE_COLUMNS_LIMIT,
+    SLACK_PROXY_URL,
 )
 from robusta.core.reporting.base import Emojis, EnrichmentType, Finding, FindingStatus, LinkType
 from robusta.core.reporting.blocks import (
@@ -77,21 +78,26 @@ def __init__(self, slack_token: str, account_id: str, cluster_name: str, signing
             ssl=ssl_context,
             timeout=SLACK_REQUEST_TIMEOUT,
             retry_handlers=all_builtin_retry_handlers(),
+            proxy=SLACK_PROXY_URL
         )
+        if SLACK_PROXY_URL:
+            logging.info(f"Slack client configured to use proxy: {SLACK_PROXY_URL}")
+
         self.registry = registry
         self.signing_key = signing_key
         self.account_id = account_id
         self.cluster_name = cluster_name
         self.is_preview = is_preview
         self.disable_holmes_note = disable_holmes_note
 
-        if slack_token not in self.verified_api_tokens:
-            try:
-                self.slack_client.auth_test()
-                self.verified_api_tokens.add(slack_token)
-            except SlackApiError as e:
-                logging.error(f"Cannot connect to Slack API: {e}")
-                raise e
+        if SLACK_PROXY_URL is None:
+            if slack_token not in self.verified_api_tokens:
+                try:
+                    self.slack_client.auth_test()
+                    self.verified_api_tokens.add(slack_token)
+                except SlackApiError as e:
+                    logging.error(f"Cannot connect to Slack API: {e}")
+                    raise e
 
     def __slack_preview_sanitize_string(self, text: str) -> str:
         """