Slack Integration

Provides patterns for sending notifications and messages to Slack.

Webhook Messages

import requests
from typing import Dict, List, Optional

def send_slack_message(webhook_url: str, message: str) -> bool:
    """
    Send simple message via Slack webhook.

    Usage:
        send_slack_message(
            webhook_url="https://hooks.slack.com/services/xxx/yyy/zzz",
            message="New invoice processed: INV-001"
        )
    """
    payload = {"text": message}
    response = requests.post(webhook_url, json=payload)
    return response.status_code == 200

def send_slack_block_message(webhook_url: str, blocks: List[Dict]) -> bool:
    """
    Send formatted block message.

    Usage:
        blocks = [
            {"type": "header", "text": {"type": "plain_text", "text": "Invoice Alert"}},
            {"type": "section", "text": {"type": "mrkdwn", "text": "*INV-001* is ready"}}
        ]
        send_slack_block_message(webhook_url, blocks)
    """
    payload = {"blocks": blocks}
    response = requests.post(webhook_url, json=payload)
    return response.status_code == 200

Invoice Notification Blocks

def create_invoice_notification_blocks(
    invoice_number: str,
    amount: float,
    vendor: str,
    due_date: str,
    status: str = "pending"
) -> List[Dict]:
    """
    Create formatted invoice notification blocks.

    Usage:
        blocks = create_invoice_notification_blocks(
            invoice_number="INV-001",
            amount=1500.00,
            vendor="Acme Corp",
            due_date="2024-02-15",
            status="approved"
        )
        send_slack_block_message(webhook_url, blocks)
    """
    status_emoji = {
        "pending": ":hourglass:",
        "approved": ":white_check_mark:",
        "paid": ":moneybag:",
        "overdue": ":warning:",
        "rejected": ":x:"
    }.get(status, ":page_facing_up:")

    return [
        {
            "type": "header",
            "text": {
                "type": "plain_text",
                "text": f"{status_emoji} Invoice Notification"
            }
        },
        {
            "type": "section",
            "fields": [
                {"type": "mrkdwn", "text": f"*Invoice:*\n{invoice_number}"},
                {"type": "mrkdwn", "text": f"*Amount:*\n${amount:,.2f}"},
                {"type": "mrkdwn", "text": f"*Vendor:*\n{vendor}"},
                {"type": "mrkdwn", "text": f"*Due Date:*\n{due_date}"},
            ]
        },
        {
            "type": "context",
            "elements": [
                {"type": "mrkdwn", "text": f"Status: *{status.upper()}*"}
            ]
        }
    ]

Batch Summary Notification

def create_batch_summary_blocks(
    title: str,
    total_invoices: int,
    total_amount: float,
    breakdown: Dict[str, int]
) -> List[Dict]:
    """
    Create summary notification for batch processing.

    Usage:
        blocks = create_batch_summary_blocks(
            title="Daily Invoice Processing Complete",
            total_invoices=25,
            total_amount=45000.00,
            breakdown={"processed": 23, "errors": 2}
        )
    """
    breakdown_text = "\n".join(f"- {k}: {v}" for k, v in breakdown.items())

    return [
        {
            "type": "header",
            "text": {"type": "plain_text", "text": title}
        },
        {
            "type": "section",
            "text": {
                "type": "mrkdwn",
                "text": f"*Total Invoices:* {total_invoices}\n*Total Amount:* ${total_amount:,.2f}"
            }
        },
        {"type": "divider"},
        {
            "type": "section",
            "text": {
                "type": "mrkdwn",
                "text": f"*Breakdown:*\n{breakdown_text}"
            }
        }
    ]

Alert with Actions

def create_approval_request_blocks(
    invoice_number: str,
    amount: float,
    vendor: str,
    approver_id: str
) -> List[Dict]:
    """
    Create invoice approval request with action buttons.

    Note: Action buttons require Slack app integration, not just webhooks.
    """
    return [
        {
            "type": "header",
            "text": {"type": "plain_text", "text": ":page_facing_up: Approval Required"}
        },
        {
            "type": "section",
            "text": {
                "type": "mrkdwn",
                "text": f"<@{approver_id}> - Invoice *{invoice_number}* requires your approval."
            }
        },
        {
            "type": "section",
            "fields": [
                {"type": "mrkdwn", "text": f"*Amount:*\n${amount:,.2f}"},
                {"type": "mrkdwn", "text": f"*Vendor:*\n{vendor}"}
            ]
        },
        {
            "type": "actions",
            "elements": [
                {
                    "type": "button",
                    "text": {"type": "plain_text", "text": "Approve"},
                    "style": "primary",
                    "value": f"approve_{invoice_number}"
                },
                {
                    "type": "button",
                    "text": {"type": "plain_text", "text": "Reject"},
                    "style": "danger",
                    "value": f"reject_{invoice_number}"
                }
            ]
        }
    ]

Error Notifications

def send_error_notification(
    webhook_url: str,
    error_type: str,
    error_message: str,
    context: Dict = None
):
    """Send error notification to Slack."""
    context_text = ""
    if context:
        context_text = "\n".join(f"- {k}: {v}" for k, v in context.items())

    blocks = [
        {
            "type": "header",
            "text": {"type": "plain_text", "text": ":rotating_light: Error Alert"}
        },
        {
            "type": "section",
            "text": {
                "type": "mrkdwn",
                "text": f"*Error Type:* {error_type}\n*Message:* {error_message}"
            }
        }
    ]

    if context_text:
        blocks.append({
            "type": "section",
            "text": {"type": "mrkdwn", "text": f"*Context:*\n{context_text}"}
        })

    send_slack_block_message(webhook_url, blocks)

Helper Script

Use helper.py for the SlackNotifier class with error handling and retry logic.