Get Meeting Link

We need get_meeting_link.py in our scripts folder. This script will fetch a meeting link from DynamoDB based on which row contains the EC2's instance ID.

Here are a few important pieces:

Initial Configuration

METADATA_URL = "http://169.254.169.254/latest/meta-data/instance-id"
TABLE_NAME = "elephant-meetings"
AWS_REGION = "us-west-2"

# --- Set the output file path ---
OUTPUT_DIR = r"C:\scripts\meeting"
OUTPUT_METADATA_PATH = os.path.join(OUTPUT_DIR, "metadata.env")

• Static local variables defining where the metadata is, the name of the DynamoDB table, and the region
• 169.254.169.254 is the Instance Metadata Service (IMDS)
  • EC2 instances can call it to find out information about themselves from AWS (cool as heck)

DynamoDB Scan

try:
    dynamodb = boto3.resource('dynamodb', region_name=AWS_REGION)
    table = dynamodb.Table(TABLE_NAME)

    # Scan for the EC2 ID in either teacher or student field
    response = table.scan(
        FilterExpression=(
            boto3.dynamodb.conditions.Attr('teacher_ec2_id').eq(instance_id) | 
            boto3.dynamodb.conditions.Attr('student_ec2_id').eq(instance_id)
        )
    )

• This is where we scan for the instance id within DynamoDB

Role Detection and Metadata Extraction

role = None
if item.get('teacher_ec2_id') == instance_id:
    role = 'teacher'
elif item.get('student_ec2_id') == instance_id:
    role = 'student'

# 2. Extract Data (Use safe defaults if keys are missing)
metadata = {
    "MEETING_URL": item.get('jitsi_url', 'URL_NOT_FOUND'),
    "USER_ROLE": role,
    # *** FIX: Use 'id' (Primary Key) instead of 'session_id' ***
    "SESSION_ID": item.get('id', 'ID_NOT_FOUND'),
    "TEACHER_NAME": item.get('teacher_name', 'UnknownTeacher'),
    "STUDENT_NAME": item.get('student_name', 'UnknownStudent'),
}

• In the case that there's a match (there should be), we initialize the "role" variable
• Assign the role to either "teacher" or "student"
• Then write the metadata.env file
• By knowing the session_id and the role, we know exactly where to store the link to the uploaded data

Awesome - Jitsi Meeting Provisioning

The meeting URL will be used to dynamically determine our Jitsi meeting room. Fun fact about Jitsi: meetings are provisioned on the fly, meaning that we don't need to send any HTTP request saying "hey Jitsi, spin me up a meeting". You can go to meet.jitsi.com/vancouveriscool and it will just be there. Kinda sick.

Write Metadata File

try:
    # Ensure the directory exists
    os.makedirs(OUTPUT_DIR, exist_ok=True)

    # Write the new .env file
    with open(OUTPUT_METADATA_PATH, 'w') as f:
        for key, value in metadata.items():
            # Write in strict KEY=VALUE format (no spaces)
            f.write(f"{key}={value}\n")

• os is the library that allows the function to interact with the environment it is running in. We're creating the metadata.env file in the location we defined above and writing all the items.

Testing - Script Requirements

Test this script. The only requirement is that you need a row in DynamoDB with a session_id and the EC2's ID in either the teacher_ec2_id or student_ec2_id column. You can manually put this in easily, which is the upside to DynamoDB.