Npm Amazon Web Services Libraries

When are AWS libraries useful?

AWS libraries are beneficial when building applications with AWS (Amazon Web Services). They allow the integration of various services provided by AWS like S3 for storage, DynamoDB for NoSQL database, Lambda for serverless computing, and many more. The need for these libraries arises when developers prefer not to manually code the connectivity and functionality of these services, situate API endpoints, and handle data transformations.

In terms of npm (Node package manager), with its extensive library of pre-built packages, using AWS libraries helps to leverage the power and functionality of AWS services within a NodeJS application more efficiently. They streamline the process of using AWS services by providing handy, pre-configured and pre-coded functions to interact with AWS.

What functionalities do AWS libraries usually have?

AWS libraries offer a broad range of functionalities specific to the services they provide access to. Below are some of the most common functionalities:

1. AWS SDK: AWS SDKs simplify use of AWS services in your applications, including AWS databases, storage, messaging, and other services. They provide pre-configured functions for interacting with these services making the application development process faster and less error-prone.

2. Data Storage and Retrieval: Libraries like AWS S3 (Simple Storage Service) provide methods for storing and retrieving any amount of data, at any time, from anywhere on the web.

3. Computing Power: Libraries like AWS EC2 (Elastic Compute Cloud) or Lambda, offer computing power when needed and accordingly scale back when not in use.

4. Database Access: AWS libraries provide seamless access to databases like Amazon RDS (Relational Database Service), DynamoDB, and others. These libraries wrap the complexity of direct DB interactions.

5. Messaging and Notification Services: AWS libraries provide functionality for sending and receiving notifications and messages in various formats.

6. Security and Access Control: AWS libraries aid in incorporating Amazon's robust security mechanisms into your application, often via AWS IAM (Identity and Access Management).

Gotchas/Pitfalls to Look Out For

1. Versioning: Always verify the version of the AWS library installed as the function signatures and capabilities can drastically differ between versions, potentially leading to unexpected behavior.

2. Hidden Costs: AWS services are not free and excessive use can lead to high expenditure. Therefore, monitor the usage pattern carefully.

3. Learning Curve: The sheer number of services and libraries can be overwhelming for any developer. Proper planning and resource mapping are needed.

4. Region Speficication: Some AWS libraries require the region to be explicitly specified. Forgetting to set this may result in surprising outcomes.

5. Dependency Conflicts: Mixing different AWS libraries or using them with other packages sometimes lead to dependency conflicts. Always check the compatibility before using them together.

6. Security: You should not hard-code credentials in your application. AWS libraries offer ways to supply credentials securely, but it's up to the developer to ensure that this is done properly.