AWS Lambda

An event driven computing service

for dynamic applications

Server Free Backend

  • You don’t have to configure, launch, or monitor EC2 instances.
  • You don’t have to install any operating systems or language environments.
  • You don’t need to think about scale or fault tolerance 
  • You don’t need to request or reserve capacity. 

Freshly created Function

  • A freshly created function is ready and able to handle tens of thousands of requests per hour.
  • Absolutely no incremental effort on your part.
  • Very cost-effective.
  • Each event is processed individually so thousands of functions can run in parallel and performance remains consistently high regardless of the frequency of events.

Runs within milliseconds of events

  • Runs your code in response to events.
  • Automatically manages the compute resources for you, making it easy to build applications that respond quickly to new information.
  • Starts running your code within milliseconds of an event such as an image upload, in-app activity, website click, or output from a connected device.

Pay only for requests served

  • Pay only for the requests served and the compute time required to run your code. 
  • Billing is metered in increments of 100 milliseconds, making it cost-effective and easy to scale automatically from a few requests per day to thousands per second.
  • First 1 million requests per month are free
  • $0.20 per 1 million requests thereafter ($0.0000002 per request)

Associate Lambda w/resources

  • After uploading, you associate your function with specific AWS resources
    • a particular S3 bucket,
    • DynamoDB table, or
    • Kinesis stream. 
  • Lambda will then arrange to route events (generally signifying that the resource has changed) to your function.

Trigger: change in resource 

  • When a resource changes, Lambda will execute any functions that are associated with it.
  • It will launch and manage compute resources as needed in order to keep up with incoming requests.
  • It will shut them down if they are no longer needed.

  • Lambda is accessible from the

    •  AWS Management Console,

    • the AWS SDKs and

    • the AWS Command Line Interface (CLI).

  • The Lambda APIs can be used to connect existing code editors and other development tools to Lambda.

Lambda programming model

  • The function has access (via a parameter supplied along with the POST) to a JSON data structure.
  • This structure contains detailed information about the change (or other event) that caused the function to be activated.
  • Lambda will activate additional copies of function as needed in order to keep pace with changes.
  • The functions cannot store durable state on the compute instance and should use S3 or DynamoDB instead. 

Node.js & AWS SDK

  • Your code can make use of just about any functionality that is intrinsic to Node.js and to the underlying Linux environment.
  • It can also use the AWS SDK for JavaScript in Node.js to make calls to other AWS services.
  • The context information that you supply for each function specifies a maximum execution time for the function.
  • This is typically set fairly low (you can do a lot of work in a couple of seconds) but can be set to up 60 seconds as your needs dictate.

Lambda Runtime Environment

  • The context information that you supply for each function specifies a maximum execution time for the function.
  • This is typically set fairly low (you can do a lot of work in a couple of seconds) but can be set to up 60 seconds as your needs dictate.
  • Lambda uses multiple IAM roles to manage access to your functions and your AWS resources.
    • invocation role gives Lambda permission to run a particular function.
    • execution role gives a function permission to access specific AWS resources.
  • You can use distinct roles for each function in order to implement a fine-grained set of permissions.
     

Analytics Data

  • Lambda monitors the execution of each function and stores request
  • The metrics are retained for 30 days and can be viewed in the Console.

Memory, CPU, I/O

  • The context information for a function specifies the amount of memory needed to run it.

  • You can set this to any desired value between 128 MB and 1 GB.

  • The memory setting also determines the amount of

    • CPU power,

    • network bandwidth, and

    • I/O bandwidth that are made available to the function.

Processes, Storage, Network

  • Each invocation of a function can make use of
    • up to 256 processes or threads.
    • up to 512 MB of local storage
    • up to 1,024 file descriptors
    • up to 10 simultaneous outbound network connections.
  • Lambda imposes a set of administrative limits on each AWS account.
  • During the preview, you can have up to 25 invocation requests underway simultaneously.
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