Automate Slack Notifications with Graphs Using Cloud Run Functions and Cloud Scheduler

import os
import matplotlib.pyplot as plt
from google.cloud import bigquery
from datetime import datetime, timedelta
import io
import pytz
from slack_sdk import WebClient
from slack_sdk.errors import SlackApiError

def create_weekly_total_sessions_chart(_):
    SLACK_TOKEN = os.environ.get('SLACK_API_TOKEN')
    SLACK_CHANNEL_ID = os.environ.get('SLACK_CHANNEL_ID')

    client = bigquery.Client()

    # Calculate the date range for the last 7 days
    jst = pytz.timezone('Asia/Tokyo')
    today = datetime.now(jst)
    start_date = (today - timedelta(days=7)).strftime('%Y-%m-%d')
    end_date = (today - timedelta(days=1)).strftime('%Y-%m-%d')

    query = f"""
        SELECT 
            DATE(created_at) AS date,
            COUNT(DISTINCT session_id) AS unique_sessions
        FROM `<project>.<dataset>.summary_all`
        WHERE created_at BETWEEN '{start_date} 00:00:00' AND '{end_date} 23:59:59'
        GROUP BY date
        ORDER BY date;
    """

    query_job = client.query(query)
    results = query_job.result()

    # Prepare data for the graph
    dates = []
    session_counts = []
    for row in results:
        dates.append(row['date'].strftime('%Y-%m-%d'))
        session_counts.append(row['unique_sessions'])

    # Generate the graph
    plt.figure()
    plt.plot(dates, session_counts, marker='o')
    plt.title('Unique Session Counts (Last 7 Days)')
    plt.xlabel('Date')
    plt.ylabel('Unique Sessions')
    plt.xticks(rotation=45)
    plt.tight_layout()

    # Save the graph as an image
    image_binary = io.BytesIO()
    plt.savefig(image_binary, format='png')
    image_binary.seek(0)

    # Send the graph to Slack
    client = WebClient(token=SLACK_TOKEN)
    try:
        response = client.files_upload_v2(
            channel=SLACK_CHANNEL_ID,
            file_uploads=[{
                "file": image_binary,
                "filename": "unique_sessions.png",
                "title": "Unique Session Counts (Last 7 Days)"
            }],
            initial_comment="Here are the session counts for the last 7 days!"
        )
    except SlackApiError as e:
        return f"Error uploading file: {e.response['error']}"

    return "Success"

functions-framework==3.*
google-cloud-bigquery
matplotlib
slack_sdk
pytz

gcloud functions add-invoker-policy-binding create-weekly-total-sessions-chart \
      --region="asia-northeast1" \
      --member="MEMBER_NAME"