Connect and query from a BigQuery database via a Google Cloud Function (Python)

Question

I have

1. A google Cloud Function (main.py + requirements.txt)
2. A bigQuery Database
3. Working query

Can someone help me with a link/tutorial/code to connect to this bigquery database using my Google Cloud Function in Python and simply query some data from the database and display it.

I tried the https://cloud.google.com/bigquery/docs/reference/libraries but it was related to connecting to big query from a normal deployment and not a Google Cloud Function.

This is what I have so far. It is deploying without an error, but upon testing, it is giving a 500 error

main.py (sample public query

from google.cloud import bigquery

def query_stackoverflow(request):
 client = bigquery.Client()
 query_job = client.query(
    """
    SELECT
      CONCAT(
        'https://stackguides.com/questions/',
        CAST(id as STRING)) as url,
      view_count
    FROM `bigquery-public-data.stackoverflow.posts_questions`
    WHERE tags like '%google-bigquery%'
    ORDER BY view_count DESC
    LIMIT 10"""
)

results = query_job.result()  # Waits for job to complete.
return Response("{'message':'successfully connected'}", status=200, mimetype='application/json')

requirements.txt

google-cloud-bigquery

Error log:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<title>500 Internal Server Error</title>
<h1>Internal Server Error</h1>
<p>The server encountered an internal error and was unable to complete your 
request. Either the server is overloaded or there is an error in the 
application.</p>

Answer 1

1. Create a service account and grant the necessary role.

gcloud iam service-accounts create connect-to-bigquery
gcloud projects add-iam-policy-binding your-project --member="serviceAccount:[email protected]" --role="roles/owner"

2. Create a cloud function using using the service account you just created as identity

3. Edit the main.py and requirements.txt

4. Deploy and Test the function

SUCCESS!