This page explains how to set up an AWS Lambda function to send logs from an S3 bucket to Axiom. The Lambda function triggers when a new log file is uploaded to an S3 bucket, processes the log data, and sends it to Axiom. To determine the best method to send data from different AWS services, see Send data from AWS to Axiom.

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Prerequisites

  • Create an AWS account with permissions to create and manage S3 buckets, Lambda functions, and IAM roles. For more information, see the AWS documentation.

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Package the requests module

Before creating the Lambda function, package the requests module so it can be used in the function:
  1. Create a new directory.
  2. Install the requests module into the current directory using pip.
  3. Zip the contents of the directory.
  4. Add your Lambda function file to the zip file.

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Create AWS Lambda function

Create a Lambda function with Python runtime and upload the packaged zip file containing the requests module and your function code below: 
import os
import json
import boto3
import requests
import csv
import io
import ndjson

def lambda_handler(event, context):
    # Extract the bucket name and object key from the event
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']

    try:
        # Fetch the log file from S3
        s3 = boto3.client('s3')
        obj = s3.get_object(Bucket=bucket, Key=key)
    except Exception as e:
        print(f"Error fetching from S3: {str(e)}")
        raise e

    # Read the log data from the S3 object
    log_data = obj['Body'].read().decode('utf-8')

    # Determine the file format and parse accordingly
    file_extension = os.path.splitext(key)[1].lower()

    if file_extension == '.csv':
        csv_data = csv.DictReader(io.StringIO(log_data))
        json_logs = list(csv_data)
    elif file_extension == '.txt' or file_extension == '.log':
        log_lines = log_data.strip().split("\n")
        json_logs = [{'message': line} for line in log_lines]
    elif file_extension == '.ndjson' or file_extension == '.jsonl':
        json_logs = ndjson.loads(log_data)
    else:
        print(f"Unsupported file format: {file_extension}")
        return

    # Prepare Axiom API request
    dataset_name = os.environ['DATASET_NAME']
    axiom_api_url = f"https://api.axiom.co/v1/datasets/{dataset_name}/ingest"
    api_token = os.environ['API_TOKEN']
    axiom_headers = {
        "Authorization": f"Bearer {api_token}",
        "Content-Type": "application/json"
    }

    # Send logs to Axiom
    for log in json_logs:
        try:
            response = requests.post(axiom_api_url, headers=axiom_headers, json=log)
            if response.status_code != 200:
                print(f"Failed to send log to Axiom: {response.text}")
        except Exception as e:
            print(f"Error sending to Axiom: {str(e)}. Log: {log}")

    print(f"Processed {len(json_logs)} log entries")
In the environment variables section of the Lambda function configuration, add the following environment variables:
  • DATASET_NAME is the name of the Axiom dataset where you want to send data.
  • API_TOKEN is the Axiom API token you have generated. For added security, store the API token in an environment variable

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Configure S3 to trigger Lambda

In the Amazon S3 console, select the bucket where your log files are stored. Go to the properties tab, find the event notifications section, and create an event notification. Select All object create events as the event type and choose the Lambda function you created earlier as the destination. For more information, see the AWS documentation.

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Upload a test log file

Ensure the log file you upload to the S3 bucket is in the correct format, such as JSON or newline-delimited JSON (NDJSON) or CSV. Here’s an example: 
[
   {
     "_time":"2021-02-04T03:11:23.222Z",
     "data":{"key1":"value1","key2":"value2"}
   },
   {
     "data":{"key3":"value3"},
     "attributes":{"key4":"value4"}
   },
   {
     "tags": {
       "server": "aws",
       "source": "wordpress"
     }
   }
 ]
After uploading a test log file to your S3 bucket, the Lambda function automatically processes the log data and sends it to Axiom. In Axiom, go to the Datasets tab and select the dataset you specified in the Lambda function. You now see your logs from your IoT devices in Axiom.