Lambda funtion for comparing photos and publishing back to IoT

aws-rekognition-with-iot

from __future__ import print_function

import boto3
from decimal import Decimal
import json
import urllib

print('Loading function')

rekognition = boto3.client('rekognition')
iot = boto3.client('iot-data')


# --------------- Helper Functions to call Rekognition APIs ------------------

def compare_faces(bucket, key, key_target, threshold=80):
	response = rekognition.compare_faces(
	    SourceImage={
			"S3Object": {
				"Bucket": bucket,
				"Name": key,
			}
		},
		TargetImage={
			"S3Object": {
				"Bucket": bucket,
				"Name": key_target,
			}
		},
	    SimilarityThreshold=threshold,
	)
	return response['SourceImageFace'], response['FaceMatches']

# --------------- Main handler ------------------


def lambda_handler(event, context):
    print("Received event: " + json.dumps(event, indent=2))
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = urllib.unquote_plus(event['Records'][0]['s3']['object']['key'].encode('utf8'))
    key_target = "target/" + key
    try:
        response = compare_faces(bucket, key, key_target)
        print(response)
        mypayload = json.dumps(response)
        iotResponse = iot.publish(
            topic="rekognition/result",
            qos=1,
            payload=mypayload)
        print(iotResponse)
        return iotResponse
    except Exception as e:
        print(e)
        print("Error processing object {} from bucket {}. ".format(key, bucket) +
              "Make sure your object and bucket exist and your bucket is in the same region as this function.")
        raise e