AWS/LambdaExamples

2021 - Coursera course
Bash script to upload python lambda in zip file
```
   1 import boto3
   2 import subprocess
   3 
   4 client = boto3.client('lambda')
   5 ROLE = 'arn:' + subprocess.getoutput('aws iam list-roles | grep role/lab4 | cut -f3- -d : | cut  --complement -c 44,45')
   6 BUCKET = subprocess.getoutput('aws s3api list-buckets --query "Buckets[].Name" | grep s3bucket | tr -d "," | xargs')
   7 
   8 
   9 response = client.create_function(
  10     FunctionName='get_reviews',
  11     Runtime='python3.8',
  12     Role=ROLE,
  13     Handler='get_reviews_code.lambda_handler',
  14     Code={
  15         'S3Bucket': BUCKET,
  16         'S3Key': 'get_reviews.zip'
  17     }
  18    
  19 )
  20 
  21 print ("DONE")
```

Python lambda example from course

APIGW setup, Integration mapping template, Content-Type application/json

{

    "product_id_str": "$input.params().querystring.get('product_id')"

}

Test ApiGW Method Execution, "Query Strings {get_reviews}"
```
product_id=TESTID
```

API GW Integration response Header Mappings

Response header	Mapping value
Access-Control-Allow-Headers	'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token'
Access-Control-Allow-Methods	'GET'
Access-Control-Allow-Origin	'*'

Python lambda code

   1 import boto3
   2 import json
   3 import re 
   4 
   5 def lambda_handler(event, context):
   6     product_id_str = event['product_id_str']
   7     S3_BUCKET = 'aws-tc-largeobjects'
   8     S3_FILE = 'DEV-AWS-MO-Building_2.0/my_json_lines.jsonl'
   9 
  10     s3 = boto3.client('s3')
  11 
  12     r = s3.select_object_content(
  13             Bucket=S3_BUCKET,
  14             Key=S3_FILE,
  15             ExpressionType='SQL',
  16             Expression="select s.review_headline, s.review_body, s.star_rating from s3object[*] s where s.product_id = '" + product_id_str + "'",
  17             InputSerialization={'JSON': {"Type": "Lines"}},
  18             OutputSerialization={'JSON': {}}
  19     )
  20     
  21     all_reviews_list = []
  22     helper_format_str = ""
  23     for event in r['Payload']:
  24         if 'Records' in event:
  25             helper_format_str = event['Records']['Payload'].decode('utf-8')
  26             helper_format_str = helper_format_str.replace("review_headline", "review_headline_str").replace("review_body", "review_body_str")
  27             all_reviews_list = helper_format_str.splitlines()
  28             
  29     result_list = []
  30     for review_chunk in all_reviews_list:
  31         result_list.append(json.loads(review_chunk))
  32     
  33     return {
  34         "product_id_str" : product_id_str,
  35         "reviews_arr": result_list
  36     }

lambda python, checking and extracting info from Bearer token

   1 import json
   2 import base64
   3 
   4 def lambda_handler(event, context):
   5     token_str = ""
   6     ipv4_str = ""
   7     decoded = {}
   8     return_me = {}
   9     name_str = ""
  10     extract_str = ""
  11     cell_str = ""
  12     return_me["message_str"] =  "Report processing, check your phone shortly"
  13     if "Authorization" in json.dumps(event):
  14         #i.e we are at the website and have a valid Bearer token passed
  15         token_str = event["params"]["header"]["Authorization"]
  16         extract_str = token_str.replace("Bearer ", "").strip().split(".")[1]
  17         extract_str += '=' * (-len(extract_str) % 4)
  18         decoded = json.loads(base64.b64decode(extract_str))
  19         cell_str = decoded["phone_number"]
  20         name_str = decoded["cognito:username"]
  21         ipv4_str = event["params"]["header"]["X-Forwarded-For"]
  22         return_me["cell_str"] = cell_str
  23         return_me["name_str"] = name_str
  24         return_me["name_str"] = decoded["cognito:username"]
  25         return_me["ipv4_str"] = ipv4_str
  26         return_me["message_str"] = "Report Processing"
  27     return return_me