AWS Certified Developer - Associate (DVA-C01)

An IAM User is a persistent identity for a person or service, with long-term credentials. An IAM Role is a temporary set of permissions that can be assumed by trusted entities (users, services, or accounts) to grant temporary access to AWS resources, often used for cross-account access or granting permissions to EC2 instances or Lambda functions.

1. S3 Standard: General-purpose storage for frequently accessed data, high durability and availability.
2. S3 Intelligent-Tiering: Automatically moves data between two access tiers (frequent and infrequent) based on access patterns.
3. S3 Standard-IA (Infrequent Access): For data accessed less frequently but requires rapid access when needed.
4. S3 Glacier: Low-cost archive storage for data accessed rarely, with retrieval times from minutes to hours.

1. Synchronous invocation: The client waits for the Lambda function to process the event and return a response. Examples: API Gateway, Load Balancers.
2. Asynchronous invocation: The client sends the event to Lambda and doesn't wait for a response. Lambda queues the event and retries on failure. Examples: S3 event notifications, SNS, SQS.

1. Partition Key: A hash attribute that determines the logical partition where data is stored. It ensures uniqueness for each item within that partition.
2. Sort Key: An optional range attribute that, combined with the Partition Key, forms a composite primary key. It allows for efficient querying of items within the same partition based on a range or specific value.

1. IAM Authorizer: Uses AWS Identity and Access Management (IAM) roles and policies to control access.
2. Cognito User Pool Authorizer: Integrates with Amazon Cognito User Pools to authenticate users and provide JWTs for authorization.
3. Lambda Authorizer (formerly Custom Authorizer): A Lambda function that you provide to perform custom authentication and authorization logic, returning an IAM policy.

The Visibility Timeout is the period during which a message is hidden from other consumers after it has been received by one consumer. This prevents multiple consumers from processing the same message simultaneously. If the message is not deleted within this timeout, it becomes visible again and can be processed by another consumer.

The "fan-out" pattern involves publishing a message to an SNS topic, which then delivers copies of that message to multiple subscribed endpoints simultaneously. These endpoints can include SQS queues, Lambda functions, HTTP/S endpoints, email addresses, or SMS messages, enabling parallel processing or multi-channel notifications.

1. User Pools: Provide user directories for sign-up, sign-in, and user management. They handle authentication and issue JSON Web Tokens (JWTs).
2. Identity Pools (Federated Identities): Provide temporary AWS credentials to authenticated (or unauthenticated) users, allowing them to access other AWS services. They bridge your user pool or other identity providers to AWS IAM.