New custom slack sink, slack_sink_preview (#1789)

* WIP

* Update sender.py

* Update sender.py

* Update sender.py

* Update sender.py

* Update sender.py

* Update sender.py

* Update sender.py

* Update sender.py

* incorporate feedback from igor

* add templating

* remove unused code

* add logs

* simplify code - always use jinja

* add legacy option

* bugfix sending to slack

* fixing template

* refactoring code

* saving progress

* added tests

* refactoring changes

* misc changes

* changess

* working version

* refactor send finding to slack

* added space

* removing unneeded code atm

* refactor

* fixing

* docs update

* updated tests

* bugfixes and header support

* fixed mentions

* added channel override test

rename

test preview

pytest fix

test fix

test fix

update slack_utils

pytest changes

attempting to debug slack test

fixing pytest preview sink

* refactoring, removing useless changes

* refactoring sender

* remove unneeded code

* added additional features

added hide_buttons,
added hide_enrichments
does not show description on custom template

* changed manual tests

* add aggregation key

* pr changes

* added fingerprint to template

---------

Co-authored-by: avi robusta <avi@robusta.dev>
Co-authored-by: arik <alon.arik@gmail.com>

Author: 3 people

docs/configuration/sinks/slack.rst

@@ -181,3 +181,118 @@ your own. This is not recommended for most companies due to the added complexity
 
     When using a custom Slack app, callback buttons are not supported due to complexities in how Slack handles incoming
     messages. :ref:`Contact us if you need assistance. <Getting Support>`
+
+
+Message Templating
+-------------------------------------------------------------------
+
+Slack messages can be customized using Jinja2 templates. Robusta includes default templates that match the standard format, but you can override them for custom formatting.
+
+To use custom templates change your `slack_sink` to `slack_sink_preview`, and add your templates to the ``slack_custom_templates`` parameter:
+
+.. code-block:: yaml
+
+   sinksConfig:
+   - slack_sink_preview:
+       api_key: xoxb-198...
+       name: preview_slack_sink
+       slack_channel: demo-slack-preview
+       slack_custom_templates:
+         custom_template.j2: |-
+           {
+              "type": "header",
+              "text": {
+                "type": "plain_text",
+                "text": "Custom Alert Format:\n {{ status_emoji }} [{{ status_text }}] {{ title }}",
+                "emoji": true
+              }
+            }
+
+            {
+              "type": "section",
+              "text": {
+                "type": "mrkdwn",
+                "text": "{{ status_emoji }} *[{{ status_text }}] {{ title }}*{% if mention %} {{ mention }}{% endif %}"
+              }
+            }
+
+            {
+              "type": "divider"
+            }
+
+            {
+              "type": "section",
+              "fields": [
+                {
+                  "type": "mrkdwn",
+                  "text": "*Type:* {{ alert_type }}"
+                },
+                {
+                  "type": "mrkdwn",
+                  "text": "*Severity:* {{ severity_emoji }} {{ severity }}"
+                },
+                {
+                  "type": "mrkdwn",
+                  "text": "*Cluster:* {{ cluster_name }}"
+                }
+                {% if resource_text %}
+                ,
+                {
+                  "type": "mrkdwn",
+                  "text": "*Resource:*\\n{{ resource_text }}"
+                }
+                {% endif %}
+              ]
+            }
+
+            {
+              "type": "section",
+              "text": {
+                "type": "mrkdwn",
+                "text": "{% if labels %}*Labels:*\\n\\n{% for key, value in labels.items() %}• *{{ key }}*: {{ value }}\\n\\n{% endfor %}{% else %}*Labels:* _None_{% endif %}"
+              }
+            }
+
+Templates use Slack's Block Kit format and must generate valid JSON. Each template block is separated by double newlines (``\n\n``).
+
+Available template variables:
+
++-----------------------------+-------------------------------------------------------------+
+| Variable                    | Description                                                 |
++=============================+=============================================================+
+| ``title``                   | The alert title                                             |
++-----------------------------+-------------------------------------------------------------+
+| ``description``             | The alert description                                       |
++-----------------------------+-------------------------------------------------------------+
+| ``status_text``             | "Firing" or "Resolved"                                      |
++-----------------------------+-------------------------------------------------------------+
+| ``status_emoji``            | "⚠️" (for firing) or "✅" (for resolved)                    |
++-----------------------------+-------------------------------------------------------------+
+| ``severity``                | Alert severity (e.g., "Warning", "Critical")                |
++-----------------------------+-------------------------------------------------------------+
+| ``severity_emoji``          | Emoji for the severity level                                |
++-----------------------------+-------------------------------------------------------------+
+| ``alert_type``              | "Alert", "K8s Event", or "Notification"                     |
++-----------------------------+-------------------------------------------------------------+
+| ``cluster_name``            | The name of the cluster                                     |
++-----------------------------+-------------------------------------------------------------+
+| ``investigate_uri``         | URI for investigation                                       |
++-----------------------------+-------------------------------------------------------------+
+| ``resource_text``           | Resource identifier (e.g., "Pod/namespace/name")            |
++-----------------------------+-------------------------------------------------------------+
+| ``subject_kind``            | The Kubernetes resource kind (e.g., "Pod", "Deployment")    |
++-----------------------------+-------------------------------------------------------------+
+| ``subject_namespace``       | The Kubernetes namespace                                    |
++-----------------------------+-------------------------------------------------------------+
+| ``subject_name``            | The name of the Kubernetes resource                         |
++-----------------------------+-------------------------------------------------------------+
+| ``resource_emoji``          | Emoji for the resource type                                 |
++-----------------------------+-------------------------------------------------------------+
+| ``mention``                 | Any @mentions extracted from the title                      |
++-----------------------------+-------------------------------------------------------------+
+| ``labels``                  | Kubernetes labels on the subject resource (dict)            |
++-----------------------------+-------------------------------------------------------------+
+| ``annotations``             | Kubernetes annotations on the subject resource (dict)       |
++-----------------------------+-------------------------------------------------------------+
+| ``fingerprint``             | The unique identifier for the alert                         |
++-----------------------------+-------------------------------------------------------------+

src/robusta/core/model/runner_config.py

@@ -18,6 +18,7 @@
 from robusta.core.sinks.rocketchat.rocketchat_sink_params import RocketchatSinkConfigWrapper
 from robusta.core.sinks.servicenow.servicenow_sink_params import ServiceNowSinkConfigWrapper
 from robusta.core.sinks.slack.slack_sink_params import SlackSinkConfigWrapper
+from robusta.core.sinks.slack.preview.slack_sink_preview_params import SlackSinkPreviewConfigWrapper
 from robusta.core.sinks.mail.mail_sink_params import MailSinkConfigWrapper
 from robusta.core.sinks.telegram.telegram_sink_params import TelegramSinkConfigWrapper
 from robusta.core.sinks.victorops.victorops_sink_params import VictoropsConfigWrapper
@@ -55,6 +56,7 @@ class RunnerConfig(BaseModel):
             Union[
                 RobustaSinkConfigWrapper,
                 SlackSinkConfigWrapper,
+                SlackSinkPreviewConfigWrapper,
                 DataDogSinkConfigWrapper,
                 KafkaSinkConfigWrapper,
                 MsTeamsSinkConfigWrapper,

src/robusta/core/sinks/sink_factory.py

@@ -22,6 +22,8 @@
 from robusta.core.sinks.sink_base import SinkBase
 from robusta.core.sinks.sink_config import SinkConfigBase
 from robusta.core.sinks.slack import SlackSink, SlackSinkConfigWrapper
+from robusta.core.sinks.slack.preview.slack_sink_preview_params import SlackSinkPreviewConfigWrapper
+from robusta.core.sinks.slack.preview.slack_sink_preview import SlackSinkPreview
 from robusta.core.sinks.telegram import TelegramSink, TelegramSinkConfigWrapper
 from robusta.core.sinks.victorops import VictoropsConfigWrapper, VictoropsSink
 from robusta.core.sinks.webex import WebexSink, WebexSinkConfigWrapper
@@ -35,6 +37,7 @@
 class SinkFactory:
     __sink_config_mapping: Dict[Type[SinkConfigBase], Type[SinkBase]] = {
         SlackSinkConfigWrapper: SlackSink,
+        SlackSinkPreviewConfigWrapper: SlackSinkPreview,
         RocketchatSinkConfigWrapper: RocketchatSink,
         RobustaSinkConfigWrapper: RobustaSink,
         MsTeamsSinkConfigWrapper: MsTeamsSink,

src/robusta/core/sinks/slack/__init__.py

@@ -1,2 +1,5 @@
+from robusta.core.sinks.slack.slack_sink_params import SlackSinkParams, SlackSinkConfigWrapper
 from robusta.core.sinks.slack.slack_sink import SlackSink
-from robusta.core.sinks.slack.slack_sink_params import SlackSinkConfigWrapper, SlackSinkParams
+
+# to prevent circular imports in SlackSender, SlackSinkParams and SlackSinkPreviewParams
+__all__ = ["SlackSink", "SlackSinkParams", "SlackSinkConfigWrapper"]

src/robusta/core/sinks/slack/preview/slack_sink_preview.py

@@ -0,0 +1,10 @@
+from robusta.core.sinks.slack.preview.slack_sink_preview_params import SlackSinkPreviewConfigWrapper, SlackSinkPreviewParams
+from robusta.core.sinks.slack.slack_sink import SlackSink
+
+
+class SlackSinkPreview(SlackSink):
+    params: SlackSinkPreviewParams
+
+    def __init__(self, sink_config: SlackSinkPreviewConfigWrapper, registry):
+        super().__init__(sink_config, registry, is_preview=True)
+

src/robusta/core/sinks/slack/preview/slack_sink_preview_params.py

@@ -0,0 +1,34 @@
+from robusta.core.sinks.sink_base_params import SinkBaseParams
+from robusta.core.sinks.sink_config import SinkConfigBase
+from robusta.core.sinks.slack.slack_sink_params import SlackSinkParams
+from typing import Optional, Dict
+from pydantic import validator
+
+
+class SlackSinkPreviewParams(SlackSinkParams):
+    #TODO: improve the SlackSinkPreviewParams so the slack_custom_templates can be defined once globally and
+    # only a template name needs to be passed to each channel in the config
+    slack_custom_templates: Optional[Dict[str, str]] = None  # Template name -> custom template content
+    hide_buttons: bool = False
+    hide_enrichments: bool = False
+
+
+    @validator('slack_custom_templates')
+    def check_one_item(cls, v):
+        if v is not None and len(v) != 1:
+            raise ValueError("slack_custom_templates must contain exactly one key-value pair")
+        return v
+
+    def get_custom_template(self) -> Optional[str]:
+        """Get the custom template if defined"""
+        if not self.slack_custom_templates:
+            return None
+
+        return next(iter(self.slack_custom_templates.values()))
+
+
+class SlackSinkPreviewConfigWrapper(SinkConfigBase):
+    slack_sink_preview: SlackSinkPreviewParams
+
+    def get_params(self) -> SinkBaseParams:
+        return self.slack_sink_preview

src/robusta/core/sinks/slack/slack_sink.py

@@ -10,12 +10,13 @@
 class SlackSink(SinkBase):
     params: SlackSinkParams
 
-    def __init__(self, sink_config: SlackSinkConfigWrapper, registry):
-        super().__init__(sink_config.slack_sink, registry)
-        self.slack_channel = sink_config.slack_sink.slack_channel
-        self.api_key = sink_config.slack_sink.api_key
+    def __init__(self, sink_config: SlackSinkConfigWrapper, registry, is_preview=False):
+        slack_sink_params = sink_config.get_params()
+        super().__init__(slack_sink_params, registry)
+        self.slack_channel = slack_sink_params.slack_channel
+        self.api_key = slack_sink_params.api_key
         self.slack_sender = slack_module.SlackSender(
-            self.api_key, self.account_id, self.cluster_name, self.signing_key, self.slack_channel
+            self.api_key, self.account_id, self.cluster_name, self.signing_key, self.slack_channel, is_preview
         )
         self.registry.subscribe("replace_callback_with_string", self)
 

src/robusta/core/sinks/slack/templates/header.j2

@@ -0,0 +1,36 @@
+{# Default template for Slack message headers #}
+{# This creates a JIRA-style header with title and context blocks #}
+
+{# First create the title block with status #}
+{
+  "type": "section",
+  "text": {
+    "type": "mrkdwn",
+    "text": "{{ status_emoji }} *[{{ status_text }}] {% if platform_enabled and include_investigate_link %}<{{ investigate_uri }}|{{ title }}>{% else %}{{ title }}{% endif %}*{% if mention %} {{ mention }}{% endif %}"
+  }
+}
+
+{# Then create the context block with metadata #}
+{
+  "type": "context",
+  "elements": [
+    {
+      "type": "mrkdwn", 
+      "text": ":bell: Type: {{ alert_type }}"
+    },
+    {
+      "type": "mrkdwn",
+      "text": "{{ severity_emoji }} Severity: {{ severity }}"
+    },
+    {
+      "type": "mrkdwn",
+      "text": ":globe_with_meridians: Cluster: {{ cluster_name }}"
+    }
+    {% if resource_text %}
+    ,{
+      "type": "mrkdwn",
+      "text": "{{ resource_emoji }} Resource: {{ resource_text }}"
+    }
+    {% endif %}
+  ]
+}

src/robusta/core/sinks/slack/templates/template_loader.py

@@ -0,0 +1,95 @@
+import json
+import logging
+import os
+from typing import Any, Dict, List
+
+from jinja2 import Environment, FileSystemLoader, Template, select_autoescape
+
+# Get the directory where our templates are stored
+TEMPLATE_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)))
+
+
+class SlackTemplateLoader:
+    """
+    Loads and renders Jinja2 templates for Slack messages.
+    """
+
+    def __init__(self):
+        """Initialize the template environment."""
+        self.env = Environment(
+            loader=FileSystemLoader(TEMPLATE_DIR),
+            autoescape=select_autoescape(["html", "xml"]),
+            trim_blocks=True,
+            lstrip_blocks=True,
+        )
+        # Cache for templates
+        self._templates: Dict[str, Template] = {}
+
+    def get_template(self, template_name: str) -> Template:
+        """
+        Get a template by name, loading from file if not already cached.
+
+        Args:
+            template_name: The name of the template file (e.g., "header.j2")
+
+        Returns:
+            A Jinja2 Template object
+        """
+        if template_name not in self._templates:
+            try:
+                self._templates[template_name] = self.env.get_template(template_name)
+            except Exception as e:
+                logging.error(f"Error loading template {template_name}: {e}")
+                # Return a simple default template as fallback
+                return Template("Template loading error")
+
+        return self._templates[template_name]
+
+    def render_to_blocks(self, template: Template, context: Dict[str, Any]) -> List[Dict[str, Any]]:
+        """
+        Render a Jinja2 Template object using the provided context and parse the result as JSON to get Slack blocks.
+        Args:
+            template: A Jinja2 Template object
+            context: Dictionary of variables to pass to the template
+        Returns:
+            List of Slack block objects (dictionaries)
+        """
+        try:
+            rendered = template.render(**context)
+            blocks = []
+            for block_str in rendered.strip().split("\n\n"):
+                if not block_str.strip():
+                    continue
+                try:
+                    # Try to parse as JSON, but if it fails, log and skip
+                    block = json.loads(block_str)
+                    blocks.append(block)
+                except json.JSONDecodeError as e:
+                    logging.exception(f"Error parsing JSON from template output: {e}")
+                    logging.warning(f"Problematic JSON (repr): {repr(block_str)}")
+                    continue  # Skip this block and continue
+                except Exception as e:
+                    logging.error(f"Unexpected error parsing block: {e}")
+                    logging.warning(f"Problematic JSON (repr): {repr(block_str)}")
+                    continue
+            return blocks
+        except Exception as e:
+            logging.error(f"Error rendering template: {e}")
+            return []
+
+    def render_custom_template_to_blocks(self, custom_template: str, context: Dict[str, Any]) -> List[Dict[str, Any]]:
+        try:
+            template = Template(custom_template)
+            return self.render_to_blocks(template, context)
+        except Exception as e:
+            logging.error(f"Error rendering custom template: {e}")
+            return self.render_default_template_to_blocks(context)
+
+    def render_default_template_to_blocks(self, context: Dict[str, Any]) -> List[Dict[str, Any]]:
+        DEFAULT_TEMPLATE_NAME="header.j2"
+        template = self.get_template(DEFAULT_TEMPLATE_NAME)
+        return self.render_to_blocks(template, context)
+
+
+# Singleton instance
+template_loader = SlackTemplateLoader()