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
  • count,
  • latency,
  • availability, and
  • error rate metrics in Amazon CloudWatch.
• 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.