New serverless pattern - dynamodb-lambda-elasticache #1735
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| This project contains an event-driven microservices design pattern that is influenced by the [CQRS Pattern](https://microservices.io/patterns/data/cqrs.html). | ||
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| This pattern will write data into a DDB table and then create a stream from it. Lambda is then used to process the change events in the database and replicate the data in Elasticache for faster reads.. |
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| Once you have run `sam deploy --guided` mode once and saved arguments to a configuration file (samconfig.toml), you can use `sam deploy` in future to use these defaults. | ||
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| 1. Note the outputs from the SAM deployment process. These contain the resource names and/or ARNs which are used for testing. |
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Error: Unable to upload artifact OrderPublisher referenced by CodeUri parameter of OrderPublisher resource.
Parameter CodeUri of resource OrderPublisher refers to a file or folder that does not exist /serverless-patterns/dynamodb-lambda-elasticache/OrderPublisher
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| ## Testing | ||
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| Invoke the OrderPublisher lambda function with the following payload, which will create the new order in the DynamoDB table. Note the order id received as a response from the Lambda function, which can be used to query the order data. |
| {"cliendId":"123456789","productId":"abc-def-ghi"} | ||
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| Invoke the OrderQueryService lambda function with the following payload. Replace the ```<order-id>``` with the Order Id returned by the previous Lambda function, to view the order details fetched from the Elasticache. |
| ## Cleanup | ||
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| 1. Delete the stack | ||
| ```bash |
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| # CQRS pattern with Amazon DynamoDB, AWS Lambda and Amazon Elasticache for Redis | |||
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| This project contains an event-driven microservices design pattern that is influenced by the [CQRS Pattern](https://microservices.io/patterns/data/cqrs.html). | |||
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im just dont know how this pattern makes it faster than a normal read to DynamoDB. Have you tested that? DynamoDB has a single milisecond performance and doesnt need to be behind a VPC to work. It would be great to get this pattern backed by some data before creating it
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This pattern focuses on microservices architecture use-cases where each microservice owns one or more sub-domains and a database dedicated to the domain. Due to this architecture pattern, it's no longer starightforward to implement queries and join data from multiple services. For example, for ordering service, each service is responsible for different writes like create-order service. And to "get order order details" we might need to join from multiple tables like order, payment, customer details etc. Since both reading and writing have different approaches, we can employ different strategies for each operation. CQRS (Command and Query Responsibility Segregation) uses “separation of concern” principle to separate the read database from the write database.
Commands perform mutation operations such as “create order” or “update order”. Queries perform ready-only operations such as “Get order details”. By this isolation, we can design purpose-built database based on the usage requirement. With the CQRS pattern, we could implement multiple denormalised views that make the application scalable and performant by simplifying the command query models because of its separation of concern principle.
In this pattern we are using DynamoDB for the high-performant writes and Elasticache for building materialised views for the application reads
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all review comments have been addressed |
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Getting an error when doing sam deploy |
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@mavi888 just checking if you have performed a Maven build before doing sam deploy? If not, you would have to run the command "mvn clean install" to build the project which will create the jar file in the target folder, which can then be deployed using sam |
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@mavi888 could you please provide an ETA for the code review, since its open since 3 weeks and is blocking our other tasks that are dependent on this repo. Thanks |
| * [Create an AWS account](https://portal.aws.amazon.com/gp/aws/developer/registration/index.html) if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources. | ||
| * [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html) installed and configured | ||
| * [Git Installed](https://git-scm.com/book/en/v2/Getting-Started-Installing-Git) | ||
| * [AWS Serverless Application Model](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-install.html) (AWS SAM) installed |
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java and maven should be listed here
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Just run the maven clean build and Im getting an error Make sure that all the prerequistes are listed, maybe im missing something. |
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@mavi888 it seems to be an issue with the Java version. the compiler version is 11, as mentioned in the pom. can we have a working session, so we can resolve all issues in a single go? |
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Unfortunately we don't have the resources to help troubleshoot this. Patterns should be simple, low-code, IaC frameworks to connect services. I would recommend submitting this as a pattern instead if you are able to fix the issues. |
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Closing this PR, as we have published as a repo instead |
Issue #1734, if available:
Description of changes:
New serverless pattern submission for implementing CQRS pattern using AWS serverless services
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