Evidently L2

This is a fork of https://github.com/aws/aws-cdk-rfcs/issues/428 implemention (https://github.com/ljuti/aws-cdk/tree/construct/aws-evidently/packages/%40aws-cdk/aws-evidently)

Core Constructs

Project

A Project is an AWS Evidently project where you group and track features, launches and experiments.

Feature

A Feature is an AWS Evidently feature, a set of behaviour in your application that you wish to launch or test.

Launch

A Launch is an AWS Evidently launch which you use to schedule or incrementally release a feature.

Experiment

An Experiment is an AWS Evidently experiment that helps you make feature design decisions based on evidence and data.

API Walkthrough with a Use Case Example

In an AWS News Blog article, author @sebsto demonstrates how to use AWS Evidently with a web application example.

Let's see how we would use the construct library to replace AWS Console tasks of the example.

1. Create a Project

   import * as evidently from 'aws-cdk-lib/aws_evidently';
   
   const project = new evidently.Project(this, 'GuestbookWebApp', {
   projectName: 'AWSNewsBlog',
   description: 'AWSNewsBlogDemo',
   });

2. Add a Feature

   const editable = new evidently.Variation({
   variationName: 'editable',
   valueType: VariationObjectValueType.BOOLEAN,
   value: true,
   });
          
   const readonly = new evidently.Variation({
   variationName: 'readonly',
   valueType: VariationObjectValueType.BOOLEAN,
   value: false,
   });
   
   const feature = new evidently.Feature(this, 'EditableGuestbook', {
   project: project,
   featureName: 'Editing',
   variations: [
       editable,
       readonly,
   ],
   entityOverrides: [
       new EntityOverride({
       entityId: 'seb',
       variation: editable,
       });
   ],
   });

3. Create a Launch

   const editableGroup = new evidently.LaunchGroup({
   groupName: 'Editable',
   feature: feature,
   variation: editable,
   });
   const readonlyGroup = new evidently.LaunchGroup({
   groupName: 'Readonly',
   feature: feature,
   variation: readonly,
   });
   
   const launchConfiguration = new StepConfig({
   groupsToWeight: [
       {
       group: editableGroup,
       splitWeight: SplitWeight.50_PCT,
       }
   ],
   startTime: <timestamp>,
   });
   
   const launch = new evidently.Launch(this, 'EditableGuestbook', {
   launchName: 'EditableGuestbook',
   description: 'Launch the editable guest book feature',
   groups: [
       editableGroup,
       readonlyGroup,
   ],
   scheduledSplitsConfig: [launchConfiguration],
   });

4. Start an Experiment

   const goal = new evidently.MetricGoal({
   desiredChange: MetricGoalDesiredChange.INCREASE,
   entityIdKey: 'user',
   eventPattern: 'eventbridge-pattern',
   metricName: 'Edits',
   valueKey: 'edits',
   });
   
   const treatmentOne = new evidently.Treatment({
   feature: feature,
   treatmentName: 'editing',
   variation: editable,
   });
   
   const treatmentTwo = new evidently.Treatment({
   feature: feature,
   treatmentName: 'readonly',
   variation: readonly,
   });
   
   const config = new evidently.OnlineAbConfig({
   controlTreatmentName: treatmentOne.treatmentName,
   treatmentWeights: [
       new evidently.TreatmentToWeight({
       splitWeight: 20000,
       treatment: treatmentOne,
       }),
       new evidently.TreatmentToWeight({
       splitWeight: 80000,
       treatment: treatmentTwo,
       }),
   ],
   });
   
   const experiment = new evidently.Experiment({
   project: project,
   experimentName: 'EditableGuestBook',
   metricGoals: [goal],
   onlineAbConfig: config,
   treatments: [
       treatmentOne,
       treatmentTwo,
   ],
   });

More

• If using feature flags in a web app, I strongly recommend looking at @sebsto example to deal with unauthenticated role and cognito ;)
• DOn't forget to grant permissions to your role used to be able to leverage aws-sdk V3 and BatchEvaluateFeatureCommand and EvaluateFeatureCommand to get the feature flags values. For instance in your cdk code :

  this.unauthenticatedRole.attachInlinePolicy(
  		new Policy(this, "EvidentlyPolicy", {
  			statements: [
  				new PolicyStatement({
  					actions: [
  						"evidently:EvaluateFeature",
  						"evidently:BatchEvaluateFeature",
  					],
  					resources: [
  						`arn:aws:evidently:${Stack.of(this).region}:${Stack.of(this).account}:project/${this.featureFlagStore.project.projectName}/feature/*`,
  					],
  					effect: Effect.ALLOW,
  				}),
  			],
  		})
  	);
      ```
  

Credits

@ljuti