MS Teams: Auto-detect Power Automate and disable file attachments (#1995)

* Fix MS Teams sink to respect send_svg parameter

The MS Teams sink was embedding base64-encoded images in the Adaptive Card
payload, causing 'payload too large' errors with Power Automate webhooks
(which have a strict 28KB limit).

Other sinks (Slack, Discord, Jira, Zulip, etc.) already check the send_svg
parameter to filter out images, but MS Teams was missing this check.

Changes:
- Pass send_svg parameter from MsTeamsSink to MsTeamsSender
- Filter image FileBlocks when send_svg=False using is_image() helper
- Add documentation for the send_svg setting

Fixes #1994

* Add docstring to send_finding_to_ms_teams for CI coverage

* Add send_files parameter to MS Teams sink to handle 28KB limit

Replace the incorrectly used send_svg parameter with send_files:
- send_svg was designed only for SVG files (see commit e354c48)
- MS Teams 28KB limit affects all file types, not just SVGs
- Follow existing pattern from Telegram, Pushover, YaMessenger sinks

Changes:
- Add send_files: bool = True to MsTeamsSinkParams
- Update sender.py to filter all files when send_files is False
- Remove incorrect is_image import from sender.py
- Add docstring to write_finding for CodeRabbit coverage
- Update documentation with new parameter name

* Auto-detect Power Automate URLs and disable file attachments

- Change send_files from bool to Optional[bool] with None default
- Add _is_power_automate_url() helper to detect Power Automate webhooks
- Auto-disable files for Power Automate URLs (*.api.powerplatform.com)
- Keep files enabled for legacy webhooks (*.webhook.office.com)
- Explicit send_files: true/false always overrides auto-detection
- Update documentation with auto-detection behavior

Author: philslab-ninja

docs/configuration/sinks/ms-teams.rst

@@ -93,4 +93,35 @@ For example:
      - ms_teams_sink:
         name: main_ms_teams_sink
         webhook_url: teams-incoming-webhook
-        prefer_redirect_to_platform: false
+        prefer_redirect_to_platform: false
+
+File Attachments
+-------------------------------------------------------------------
+
+MS Teams Power Automate workflow webhooks have a strict 28KB payload size limit.
+Robusta automatically detects Power Automate URLs and disables file attachments
+to avoid exceeding this limit.
+
+**Auto-detection behavior:**
+
+- Power Automate URLs (``*.api.powerplatform.com``): files disabled by default
+- Legacy webhook URLs (``*.webhook.office.com``): files enabled by default
+
+**Override auto-detection:**
+
+You can explicitly control file attachments using the ``send_files`` parameter:
+
+.. code-block:: yaml
+
+     sinksConfig:
+     - ms_teams_sink:
+        name: main_ms_teams_sink
+        webhook_url: teams-incoming-webhook
+        send_files: true   # Force enable files (override auto-detection)
+        # send_files: false  # Force disable files
+
+.. note::
+
+    When ``send_files`` is false (or auto-detected as false for Power Automate),
+    all file attachments (images, logs, graphs, etc.) will not be included in
+    the MS Teams message. Text-based content will still be sent normally.

src/robusta/core/sinks/msteams/msteams_sink.py

@@ -12,6 +12,12 @@ def __init__(self, sink_config: MsTeamsSinkConfigWrapper, registry):
         self.sink_config = sink_config.ms_teams_sink
 
     def write_finding(self, finding: Finding, platform_enabled: bool):
+        """Write a finding to the MS Teams channel via webhook.
+
+        Args:
+            finding: The finding to send to MS Teams.
+            platform_enabled: Whether the Robusta platform is enabled for enhanced links.
+        """
         MsTeamsSender.send_finding_to_ms_teams(
             self.webhook_url,
             finding,
@@ -20,4 +26,5 @@ def write_finding(self, finding: Finding, platform_enabled: bool):
             self.account_id,
             self.webhook_override,
             self.sink_config.prefer_redirect_to_platform,
+            self.sink_config.send_files,
         )

src/robusta/core/sinks/msteams/msteams_sink_params.py

@@ -10,6 +10,7 @@
 class MsTeamsSinkParams(SinkBaseParams):
     webhook_url: str
     webhook_override: Optional[str] = None
+    send_files: Optional[bool] = None  # Auto-detect: False for Power Automate, True for legacy
 
     @classmethod
     def _get_sink_type(cls):

src/robusta/integrations/msteams/sender.py

@@ -1,4 +1,5 @@
 import logging
+from typing import Optional
 
 from robusta.core.reporting import (
     BaseBlock,
@@ -18,6 +19,15 @@
 from robusta.integrations.msteams.msteams_msg import MsTeamsMsg
 
 
+def _is_power_automate_url(url: str) -> bool:
+    """Check if URL is a Power Automate workflow webhook (has 28KB payload limit).
+
+    Power Automate URLs contain '.api.powerplatform.com' or '/powerautomate/'.
+    Legacy connector URLs use '*.webhook.office.com' and don't have the 28KB limit.
+    """
+    return ".api.powerplatform.com" in url or "/powerautomate/" in url
+
+
 class MsTeamsSender:
     @classmethod
     def __to_ms_teams(cls, block: BaseBlock, msg: MsTeamsMsg):
@@ -61,15 +71,40 @@ def send_finding_to_ms_teams(
         account_id: str,
         webhook_override: str,
         prefer_redirect_to_platform: bool,
+        send_files: Optional[bool] = None,
     ):
+        """Send a finding to MS Teams via webhook.
+
+        Args:
+            webhook_url: The MS Teams webhook URL.
+            finding: The finding to send.
+            platform_enabled: Whether the Robusta platform is enabled.
+            cluster_name: The name of the cluster.
+            account_id: The Robusta account ID.
+            webhook_override: Optional webhook URL override pattern.
+            prefer_redirect_to_platform: Whether to prefer platform links over Prometheus.
+            send_files: Whether to include file attachments. None (default) auto-detects
+                based on webhook URL: disabled for Power Automate (28KB limit), enabled
+                for legacy webhooks. Explicit True/False overrides auto-detection.
+        """
         webhook_url = MsTeamsWebhookUrlTransformer.template(
             webhook_override=webhook_override, default_webhook_url=webhook_url, annotations=finding.subject.annotations
         )
+
+        # Auto-detect send_files based on webhook URL if not explicitly set
+        if send_files is None:
+            send_files = not _is_power_automate_url(webhook_url)
+
         msg = MsTeamsMsg(webhook_url, prefer_redirect_to_platform)
         msg.write_title_and_desc(platform_enabled, finding, cluster_name, account_id)
 
         for enrichment in finding.enrichments:
             files_blocks, other_blocks = cls.__split_block_to_files_and_all_the_rest(enrichment)
+
+            # Filter out all files when send_files is False to avoid 28KB payload limit
+            if not send_files:
+                files_blocks = []
+
             for block in other_blocks:
                 cls.__to_ms_teams(block, msg)