Babashka backend
This section will take you through the basics of Babashka backend.
You will
- Generate a scaffold project for your code
- Target the
babashkainteractive runtime so that we can edit Clojure code in AWS - Locally test the code in Docker
- Deploy the project to AWS
:information_source: Full project source can be find here
- We'll generate our first project using the
holy-lambdaproject template. This will create a project tree with all the necessary resources to get us started.
clojure -X:new :template holy-lambda :name com.company/example-lambda :output holy-lambda-example
-
Go into the the project directory
cd holy-lambda-exampleYou should see following project structure:
$$ tree . . ├── bb.edn ├── deps.edn ├── Dockerfile ├── README.md ├── resources │ └── native-agents-payloads │ └── 1.edn ├── src │ └── com │ └── company │ └── example_lambda │ └── core.cljc └── template.yml 6 directories, 7 files -
Visit the following link and click deploy. Now you should be redirected to
AWS Lambda Functiondashboard. Scroll down and click deploy! Wait few seconds. Now you should be redirected toAWS Lambda Applications dashboard. Wait few more seconds, so thatCloudformationcan finish the deployment.:warning: Guide supports Babashka backend version >= 0.5.1
You should see the following image
-
Copy the
Physical IDand put it intemplate.yml. Make sure to includeCodeUriin the function properties and remove the globalCodeUriset inParameters.AWSTemplateFormatVersion: '2010-09-09' Transform: AWS::Serverless-2016-10-31 Description: > Example basic lambda using `holy-lambda` micro library Parameters: Runtime: Type: String Default: provided Timeout: Type: Number Default: 40 MemorySize: Type: Number Default: 128 Entrypoint: Type: String Default: com.company.example-lambda.core Globals: Function: Runtime: !Ref Runtime Timeout: !Ref Timeout MemorySize: !Ref MemorySize Environment: Variables: HL_ENTRYPOINT: !Ref Entrypoint Resources: BabashkaDepsLayer: Type: AWS::Serverless::LayerVersion Properties: LayerName: BabashkaDepsLayer ContentUri: ./.holy-lambda/bb-clj-deps ExampleLambdaFunction: Type: AWS::Serverless::Function Properties: FunctionName: ExampleLambdaFunction Handler: com.company.example-lambda.core.ExampleLambda CodeUri: src Events: HelloEvent: Type: HttpApi Properties: ApiId: !Ref ServerlessHttpApi Path: / Method: GET Layers: - <HERE_PUT_PHISICAL_ID> - !Ref BabashkaDepsLayer ... -
Run
hl:babashka:syncto download all necessary dependencies. -
Try to invoke the function using
AWS SAM CLI
```bash
sam local invoke ExampleLambdaFunction
```
> :information_source: The first invocation is rather slow locally since AWS SAM has to download runtime image for babashka. Subsequent invocations are much faster.
**After some time you should see the following output**
```bash
Skip pulling image and use local one: samcli/lambda:provided-91cd3f3acab2b3d207d6211b4.
Mounting <PATH> as /var/task:ro,delegated inside runtime container
START RequestId: 5dc1e421-69c9-462c-9f90-f0e840426ad8 Version: $LATEST
{"statusCode":200,"headers":{"content-type":"text/plain; charset=utf-8"},"body":"Hello world. Babashka is a sweet friend of mine! Babashka version: 0.6.2"}
END RequestId: 5dc1e421-69c9-462c-9f90-f0e840426ad8
REPORT RequestId: 5dc1e421-69c9-462c-9f90-f0e840426ad8
Init Duration: 0.22 ms Duration: 75.82 ms Billed Duration: 100 ms Memory Size: 128 MB Max Memory Used: 128 MB
```
> :information_source: Highly recommend to check the official AWS SAM docs and play with other commands e.g. `sam local start-api`
Deployment
Having successfully run the Lambda locally, we can now deploy to AWS.
Run the following command:
sam deploy --guided
Default settings should be sufficient. Press enter for parameters and answer the questions as provided below
Configuring SAM deploy
======================
Looking for config file [samconfig.toml] : Not found
Setting default arguments for 'sam deploy'
=========================================
Stack Name [sam-app]:
AWS Region [eu-central-1]:
Parameter Timeout [40]:
Parameter MemorySize [128]:
Parameter Entrypoint [com.company.example-lambda.core]:
#Shows you resources changes to be deployed and require a 'Y' to initiate deploy
Confirm changes before deploy [y/N]: y
#SAM needs permission to be able to create roles to connect to the resources in your template
Allow SAM CLI IAM role creation [Y/n]: y
ExampleLambdaFunction may not have authorization defined, Is this okay? [y/N]: y
Save arguments to configuration file [Y/n]: y
SAM configuration file [samconfig.toml]:
SAM configuration environment [default]:
Looking for resources needed for deployment:
Creating the required resources...
Successfully created!
Managed S3 bucket: <DEPLOYMENT_BUCKET>
A different default S3 bucket can be set in samconfig.toml
Saved arguments to config file
Running 'sam deploy' for future deployments will use the parameters saved above.
The above parameters can be changed by modifying samconfig.toml
Learn more about samconfig.toml syntax at
https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-config.html
Uploading to sam-app/6e50bf307281c6662526db069ce8daec 713 / 713 (100.00%)
Deploying with following values
===============================
Stack name : sam-app
Region : eu-central-1
Confirm changeset : True
Deployment s3 bucket : <DEPLOYMENT_BUCKET>
Capabilities : ["CAPABILITY_IAM"]
Parameter overrides : {"Runtime": "provided", "Timeout": "40", "MemorySize": "128", "Entrypoint": "com.company.example-lambda.core"}
Signing Profiles : {}
Initiating deployment
=====================
Uploading to sam-app/<TEMPLATE_HASH>.template 1480 / 1480 (100.00%)
Waiting for changeset to be created..
CloudFormation stack changeset
---------------------------------------------------------------------------------------------------------------------------------------------------------
Operation LogicalResourceId ResourceType Replacement
---------------------------------------------------------------------------------------------------------------------------------------------------------
+ Add ExampleLambdaFunctionHelloEventPermi AWS::Lambda::Permission N/A
ssion
+ Add ExampleLambdaFunctionRole AWS::IAM::Role N/A
+ Add ExampleLambdaFunction AWS::Lambda::Function N/A
+ Add ServerlessHttpApiApiGatewayDefaultSt AWS::ApiGatewayV2::Stage N/A
age
+ Add ServerlessHttpApi AWS::ApiGatewayV2::Api N/A
---------------------------------------------------------------------------------------------------------------------------------------------------------
Changeset created successfully. <CHANGESET_ARN>
Previewing CloudFormation changeset before deployment
======================================================
Deploy this changeset? [y/N]: y
Now AWS SAM will deploy the application and link the provided layers with AWS Lambda function.
2021-09-13 12:14:30 - Waiting for stack create/update to complete
CloudFormation events from changeset
---------------------------------------------------------------------------------------------------------------------------------------------------------
ResourceStatus ResourceType LogicalResourceId ResourceStatusReason
---------------------------------------------------------------------------------------------------------------------------------------------------------
CREATE_IN_PROGRESS AWS::IAM::Role ExampleLambdaFunctionRole -
CREATE_IN_PROGRESS AWS::IAM::Role ExampleLambdaFunctionRole Resource creation Initiated
CREATE_COMPLETE AWS::IAM::Role ExampleLambdaFunctionRole -
CREATE_IN_PROGRESS AWS::Lambda::Function ExampleLambdaFunction -
CREATE_IN_PROGRESS AWS::Lambda::Function ExampleLambdaFunction Resource creation Initiated
CREATE_COMPLETE AWS::Lambda::Function ExampleLambdaFunction -
CREATE_IN_PROGRESS AWS::ApiGatewayV2::Api ServerlessHttpApi -
CREATE_COMPLETE AWS::ApiGatewayV2::Api ServerlessHttpApi -
CREATE_IN_PROGRESS AWS::ApiGatewayV2::Api ServerlessHttpApi Resource creation Initiated
CREATE_IN_PROGRESS AWS::Lambda::Permission ExampleLambdaFunctionHelloEventPermi Resource creation Initiated
ssion
CREATE_IN_PROGRESS AWS::ApiGatewayV2::Stage ServerlessHttpApiApiGatewayDefaultSt -
age
CREATE_IN_PROGRESS AWS::Lambda::Permission ExampleLambdaFunctionHelloEventPermi -
ssion
CREATE_COMPLETE AWS::ApiGatewayV2::Stage ServerlessHttpApiApiGatewayDefaultSt -
age
CREATE_IN_PROGRESS AWS::ApiGatewayV2::Stage ServerlessHttpApiApiGatewayDefaultSt Resource creation Initiated
age
CREATE_COMPLETE AWS::Lambda::Permission ExampleLambdaFunctionHelloEventPermi -
ssion
CREATE_COMPLETE AWS::CloudFormation::Stack sam-app -
---------------------------------------------------------------------------------------------------------------------------------------------------------
CloudFormation outputs from deployed stack
----------------------------------------------------------------------------------------------------------------------------------------------------------
Outputs
----------------------------------------------------------------------------------------------------------------------------------------------------------
Key ExampleLambdaEndpoint
Description Endpoint for ExampleLambdaFunction
Value https://<ENDPOINT>
----------------------------------------------------------------------------------------------------------------------------------------------------------
Successfully created/updated stack - sam-app in eu-central-1
Congratulations. You can now check your API running by clicking on Serverless HttpApi URL, that is the output of sam deploy --guided.
Edit code in AWS Lambda (Babashka)
-
Sign in to the AWS Console
-
Select the region where your lambda has been deployed.
-
Go to
Lambdaconsole and select our deployed function.
-
You can now edit the source code, deploy the function and interactively develop your application on the cloud.
Let's try out interactive Clojure editing from the AWS Lambda code editor. We're going to change the welcome string.
Select code.cljc and replace the existing say-hello and ExampleLambda functions with the following:
(defn say-hello
[]
#?(:bb (str "Wow. Live edits :O"))
:clj "Hello world"))
When you make edits, you need to deploy the changes:
Select the Deploy button.
Now when you run the ExampleTestEvent test event, you'll see the new output response:
That's interactive code editing, in Clojure, in AWS Lambda!
:warning: Any changes that are made directly in the editor will be overwritten with the new deployment. Remember to copy any necessary changes made back to the code base.
:information_source: Interactive editing is only available with the Babashka backend.
Conclusion
In this guide, we've covered many of the basics with holy-lambda. We've covered quite a lot actually, so well done for getting this far!
We created a holy-lambda project based on the Babashka backend to allow interactive code editing in AWS. We demonstrated the power of interactive editing by enhancing our code with custom message.
We hope you enjoy using Clojure in AWS Lambdas using holy-lambda
Clean up
The resources created in this guide incur minimal AWS costs when they're not being executed.
If you prefer to completely remove the resources using the following command to tear down and delete the application stack:
sam delete
Output
Are you sure you want to delete the stack sam-app in the region eu-central-1 ? [y/N]: y
Are you sure you want to delete the folder sam-app in S3 which contains the artifacts? [y/N]: y
- Deleting S3 object with key sam-app/<OBJECT_KEY>
- Deleting S3 object with key sam-app/<OBJECT_KEY>.template
- Deleting Cloudformation stack sam-app
Deleted successfully
Can you improve this documentation? These fine people already did:
Karol Wójcik & lowecgEdit on GitHub
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