Serverless Architectures - 0 views
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Serverless was first used to describe applications that significantly or fully depend on 3rd party applications / services (‘in the cloud’) to manage server-side logic and state.
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‘rich client’ applications (think single page web apps, or mobile apps) that use the vast ecosystem of cloud accessible databases (like Parse, Firebase), authentication services (Auth0, AWS Cognito), etc.
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‘(Mobile) Backend as a Service’
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Serverless can also mean applications where some amount of server-side logic is still written by the application developer but unlike traditional architectures is run in stateless compute containers that are event-triggered, ephemeral (may only last for one invocation), and fully managed by a 3rd party.
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‘Functions as a service
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AWS Lambda is one of the most popular implementations of FaaS at present,
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A good example is Auth0 - they started initially with BaaS ‘Authentication as a Service’, but with Auth0 Webtask they are entering the FaaS space.
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a typical ecommerce app
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a backend data-processing service
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with zero administration.
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FaaS offerings do not require coding to a specific framework or library.
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Horizontal scaling is completely automatic, elastic, and managed by the provider
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Functions in FaaS are triggered by event types defined by the provider.
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a FaaS-supported message broker
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from a deployment-unit point of view FaaS functions are stateless.
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allowed the client direct access to a subset of our database
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deleted the authentication logic in the original application and have replaced it with a third party BaaS service
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The client is in fact well on its way to becoming a Single Page Application.
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implement a FaaS function that responds to http requests via an API Gateway
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port the search code from the Pet Store server to the Pet Store Search function
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replaced a long lived consumer application with a FaaS function that runs within the event driven context
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server applications - is a key difference when comparing with other modern architectural trends like containers and PaaS
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the only code that needs to change when moving to FaaS is the ‘main method / startup’ code, in that it is deleted, and likely the specific code that is the top-level message handler (the ‘message listener interface’ implementation), but this might only be a change in method signature
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With FaaS you need to write the function ahead of time to assume parallelism
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Most providers also allow functions to be triggered as a response to inbound http requests, typically in some kind of API gateway
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you should assume that for any given invocation of a function none of the in-process or host state that you create will be available to any subsequent invocation.
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FaaS functions are either naturally stateless
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store state across requests or for further input to handle a request.
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certain classes of long lived task are not suited to FaaS functions without re-architecture
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if you were writing a low-latency trading application you probably wouldn’t want to use FaaS systems at this time
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An API Gateway is an HTTP server where routes / endpoints are defined in configuration and each route is associated with a FaaS function.
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API Gateway will allow mapping from http request parameters to inputs arguments for the FaaS function
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API Gateways may also perform authentication, input validation, response code mapping, etc.
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the Serverless Framework makes working with API Gateway + Lambda significantly easier than using the first principles provided by AWS.
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Apex - a project to ‘Build, deploy, and manage AWS Lambda functions with ease.'
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'Serverless' to mean the union of a couple of other ideas - 'Backend as a Service' and 'Functions as a Service'.
