Classes
07 - Lambda Functions
Part 1

API Gateway

API

We will add an API service. Thus, every time there is a call to the API endpoint, whether through the browser or an application, the Lambda function will be triggered.

This will be the schematic drawing:

Create API

Question 1

import boto3
import os
from dotenv import load_dotenv
import random
import string


load_dotenv()

lambda_function_name = "" # Example: sayHello_<INSPER_USERNAME>
api_gateway_name = "" # Example: api_hello_<INSPER_USERNAME>"

id_num = "".join(random.choices(string.digits, k=7))

api_gateway = boto3.client(
    "apigatewayv2",
    aws_access_key_id=os.getenv("AWS_ACCESS_KEY_ID"),
    aws_secret_access_key=os.getenv("AWS_SECRET_ACCESS_KEY"),
    region_name=os.getenv("AWS_REGION"),
)

lambda_function = boto3.client(
    "lambda",
    aws_access_key_id=os.getenv("AWS_ACCESS_KEY_ID"),
    aws_secret_access_key=os.getenv("AWS_SECRET_ACCESS_KEY"),
    region_name=os.getenv("AWS_REGION"),
)

lambda_function_get = lambda_function.get_function(FunctionName=lambda_function_name)

print(lambda_function_get)

api_gateway_create = api_gateway.create_api(
    Name=api_gateway_name,
    ProtocolType="HTTP",
    Version="1.0",
    RouteKey="ANY /", # Here you can change to GET POST and provide route like "GET /hello"
    Target=lambda_function_get["Configuration"]["FunctionArn"],
)

api_gateway_permissions = lambda_function.add_permission(
    FunctionName=lambda_function_name,
    StatementId="api-gateway-permission-statement-" + id_num,
    Action="lambda:InvokeFunction",
    Principal="apigateway.amazonaws.com",
)

print("API Endpoint:", api_gateway_create["ApiEndpoint"])

Question 2

Show APIs

To list the APIs registered in the account, use:

Without paginationWith pagination

import boto3
import os
from dotenv import load_dotenv

load_dotenv()

api_gateway = boto3.client(
    "apigatewayv2",
    aws_access_key_id=os.getenv("AWS_ACCESS_KEY_ID"),
    aws_secret_access_key=os.getenv("AWS_SECRET_ACCESS_KEY"),
    region_name=os.getenv("AWS_REGION"),
)

response = api_gateway.get_apis(MaxResults="2000")

# Show APIs name and endpoint
print("APIs:")
for api in response["Items"]:
    print(f"- {api['Name']} ({api['ApiEndpoint']})")

If you have many APIs, you may need to paginate through the results:

import boto3
import os
from dotenv import load_dotenv

load_dotenv(override=True)

api_gateway = boto3.client(
    "apigatewayv2",
    aws_access_key_id=os.getenv("AWS_ACCESS_KEY_ID"),
    aws_secret_access_key=os.getenv("AWS_SECRET_ACCESS_KEY"),
    region_name=os.getenv("AWS_REGION"),
)

apis = []
next_token = None

while True:
    if next_token:
        response = api_gateway.get_apis(MaxResults="100", NextToken=next_token)
    else:
        response = api_gateway.get_apis(MaxResults="100")

    apis.extend(response.get("Items", []))

    next_token = response.get("NextToken")
    if not next_token:
        break

print(f"You have {len(apis)} APIs\n")

# Show APIs name and endpoint
if apis:
    print("APIs:")
    for api in apis:
        print(f"- {api['Name']} ({api['ApiEndpoint']})")

Question 3

Tip: How to delete an API

To delete an API, you can use the following code:

Warning

More then one API with the same name may exist.

APIs are identified by their unique IDs!

"""Deletes the first REST API found with the specified name."""
import boto3
import os
from dotenv import load_dotenv

load_dotenv(override=True)

# Provide the name of the API to delete. E.g., "api_hello_<YOUR_INSPER_USERNAME>"
api_name = ""

if not api_name:
    raise ValueError("No API name provided!")

api_gateway = boto3.client(
    "apigateway",
    aws_access_key_id=os.getenv("AWS_ACCESS_KEY_ID"),
    aws_secret_access_key=os.getenv("AWS_SECRET_ACCESS_KEY"),
    region_name=os.getenv("AWS_REGION"),
)

# List all APIs with pagination
apis = []
position = None

while True:
    if position:
        response = api_gateway.get_rest_apis(limit=100, position=position)
    else:
        response = api_gateway.get_rest_apis(limit=100)

    apis.extend(response.get("items", []))
    position = response.get("position")

    if not position:
        break

# Find API by name
target_api = next((api for api in apis if api["name"] == api_name), None)

if not target_api:
    print(f"REST API with name '{api_name}' not found.")
else:
    api_id = target_api["id"]
    try:
        api_gateway.delete_rest_api(restApiId=api_id)
        print(f"REST API '{api_name}' (ID: {api_id}) deleted successfully.")
    except Exception as e:
        print("Error while deleting REST API:", str(e))

Practicing

Question 4