This assumes you are familar with the basic configurations needed to connect to Amazon Web Services (AWS) using Python boto3. If not, check out my article Python (Scripting) - Getting Started with Amazon Web Services (AWS) boto3.

Here is the minimal boilerplate code without any error handling to invoke the Lambda Function named "my-lambda-function".

#!/usr/bin/python3
import boto3

client = boto3.client('lambda')
response = client.invoke(
        FunctionName="my-lambda-function"
        )

print(response)

Here is a more practical example, with try/except/else error handling.

#!/usr/bin/python3
import boto3
import sys

try:
  client = boto3.client('lambda')
except Exception as exception:
  print(exception)
  sys.exit(1)

try:
  response = client.invoke(
        FunctionName="my-lambda-function"
        )
except Exception as exception:
  print(exception)
else:
  print(f"response = {response}")

Which should return something like this.

{
  'ResponseMetadata': {
    'RequestId': '68560a0e-df18-4ed0-9241-fea5b6932a07', 
    'HTTPStatusCode': 200, 
    'HTTPHeaders': {
      'date': 'Sat, 27 Apr 2024 05:16:46 GMT', 
      'content-type': 'application/json', 
      'content-length': '53', 
      'connection': 'keep-alive', 
      'x-amzn-requestid': '68560a0e-df18-4ed0-9241-fea5b6932a07', 
      'x-amzn-remapped-content-length': '0', 
      'x-amz-executed-version': '$LATEST', 
      'x-amzn-trace-id': 'root=1-662c8a3e-700ece1869e8ebf66b3434cc;parent=6662bc5c53ab48f1;sampled=0;lineage=458c89d0:0'
    }, 
    'RetryAttempts': 0
  }, 
  'StatusCode': 200, 
  'ExecutedVersion': '$LATEST', 
  'Payload': <botocore.response.StreamingBody object at 0x7f6deb2e5f40>
}

Notice in this example that the response has 'Payload': <botocore.response.StreamingBody object at 0x7f6deb2e5f40>. Here is one way to parse the payload.

print(response['Payload'].read().decode('utf-8'))

Which should then return something like this.

{"statusCode": 200, "body": "\"Hello from Lambda!\""}