Hi guys I’m so sorry if this sounds stupid but I’m still getting familiar with aws, so I don’t know how everything works yet. The thing is I created a react app with amplify and a graphql through amplify Cli and then I created a lambda function to be triggered every time something is added to the table/collection and I would like to develop locally, because right now every time I change the lambda function I have to re deploy it. Can you guys help me? I’m sorry if it doesn’t make sense
You should look into mocking and testing, for example: https://aws.amazon.com/blogs/aws/new-local-mocking-and-testing-with-the-amplify-cli/
You can also get DynamoDB Local as well as run Lambda locally with SAM.
Related
I'm currently using lambda function which is invoked using Aws Lex. It was working normally and I didn't modify any of its configuration and out of nowhere it stopped working and I keep getting this error.
/opt/sls-sdk-node/exec-wrapper.sh: does not exist
Can anyone please explain what is an exec-wrapper.sh and how is it possible for it to suddenly disappear? And how can I solve this problem?
This looks to be an error stemming from the Serverless framework rather than an issue with Lex itself. Did you perhaps upgrade any of the SLS dependencies?
It turned out that after removing the serverless framework, there were some configurations (exec-wrapper.sh) that were not removed and needed to be removed manually from lambda using the aws console
edit: Turns out the solution is in the docs. I had bog standard normal 'sam' installed but I needed what they call the 'public preview version' AKA 'sam-beta-cdk'. With this installed the API can be started locally with sam-betacdk start-api and works well. While I appreciate the answers which suggest that development should be done using purely TDD I feel there is also value in this more interactive, manual mode as it permits quicker exploration of the problem space.
I'm trying to build my first app with CDK + Typescript using API Gateway, Lambdas and DynamoDB. I have built a couple of Lambdas and deployed them and they work fine live on the web. However I don't want a minute long deploy cycle and various associated AWS costs as part of my workflow. What I want is to be able to test my API locally.
I have struggled to find docs on how to do this. Amazon seem to recommend using the SAM CLI here so that is what I've been trying.
The docs claim running sam local xyz runs cdk synth to make a "could assembly" in ./aws-sam/build but I see no evidence of this. Instead what I get is a complaint that sam could not find a 'template.yml'. So I manually run cdk synth > template.yml which creates one in the root folder. Then I run sam local start-api and it seems happy to start up.
Then I try and hit my test lambda using CURL: curl 'http://127.0.0.1:3000/test' I get {"message":"Internal server error"} and a huge ugly stack trace in the console that is running sam local start-api
The lambda is this...
exports.handler = async function() {
console.log("WooHoo! Test handler ran")
return {statusCode: 200, headers: {"Content-Type": "application/json"}, body: "Test handler ran!"}
}
Start of the huge ugly stack trace...
Mounting /home/user/code/image-cache/asset.beeaa749e012b5921018077f0a5e4fc3ab271ef1c191bd12a82aa9a92148782e as /var/task:ro,delegated inside runtime container
START RequestId: 99f53642-b294-4ce5-a1b4-8c967db80ce1 Version: $LATEST
2021-09-15T12:33:37.086Z undefined ERROR Uncaught Exception {"errorType":"Runtime.ImportModuleError","errorMessage":"Error: Cannot find module 'test'\nRequire stack:\n- /var/runtime/UserFunction.js\n- /var/runtime/index.js","stack":["Runtime.ImportModuleError: Error: Cannot find module 'test'","Require stack:","- /var/runtime/UserFunction.js","- /var/runtime/index.js"," at _loadUserApp (/var/runtime/UserFunction.js:100:13)"," at Object.module.exports.load (/var/runtime/UserFunction.js:140:17)",
The end of the huge ugly stack trace...
Invalid lambda response received: Lambda response must be valid json
So it would seem sam local start-api can't find test and throws and error which means the API gateway doesn't get a valid 'lambda response'. So far this has not helped me chase down the problem :/ It certainly seems aware that test is a route, as trying to hit other endpoints gives the classic {"message":"Missing Authentication Token"} but it chokes hard trying to fulfill it despite me having both functions/test.ts and the compiled functions/test.js present.
I have the test route and handler defined in my CDK stack definition like so...
const testLambda = new lambda.Function(this, "testLambdaHandler", {
runtime: lambda.Runtime.NODEJS_14_X,
code: lambda.Code.fromAsset("functions"),
handler: "test.handler"
})
api.root
.resourceForPath("test")
.addMethod("GET", new apigateway.LambdaIntegration(testLambda))
I considered posting my template.yml but that is even longer than the big ugly error message so I haven't.
So I have three questions (well actually a million but I don't want to be too cheeky!)
Is this actually the canonical way of locally testing apps made with CDK
If so, where am I going wrong?
If not, what is the better/proper way?
Lambda handlers are just functions. They do not need any special environment to function - they are called at a specific point in the Lambda Invocation process, and provided an event (a json object) and a context (another json object)
You can (and should!) unit test them just like any other individual function in your language/testing framework.
As #Lucasz mentioned, you should rely on the fact that, if set up properly, API gateway and Lambda will interact the same way every time. Once you have run one end to end test and you know that the basics work, any further implementation can be done trough unit testing
There are numerous libraries for mocking AWS service calls in unit testing, and there are plenty of good practice work arounds for the services that are more difficult to mock (ie: its difficult to mock a Lambda call from inside another lambda - but if you wrap that lambda call in its own function, you can mock the function itself to return whatever you want it to - and this is good practice for testing as well!)
using jest, in a coded unit test, you can call the lambda handler, give it stubbed or mocked event json, as well as a context json (probably just blank as youre not using it) and the lambda handler will act just like any other function with two parameters you've ever written, including returning what you want it to return.
You must be doing something wrong with your file directory. Where is your index.js located? If you generate the template.json, is the directory correct?
Also in what directory do you execute the Sam local command?
The thing with testing your serverless application is you don't have to test your full application. You need to count on AWS that API gateway, dynamodb and lambda is perfectly working.
The only thing you need to test is the logic you implemented.
In here you make sure your function prints out something and returns a 200. That's all you have to do.
Look into 'jest' for testing js.
If you want to test cdk you should into https://docs.aws.amazon.com/cdk/latest/guide/testing.html
Also "running Aws locally" is not good practice. it's never the same as how it's running in real life aka the cloud. You use plugins for this, tools for that... Local is not the same as in the cloud.
If you have any more questions, feel free to ask.
I want to make a bot that makes other bots on Telegram platform. I want to use AWS infrastructure, look like their Lamdba functions are perfect fit, pay for them only when they are active. In my concept, each bot equal to one lambda function, and they all share the same codebase.
At the starting point, I thought to make each new Lambda function programmatically, but this will bring me problems later I think, like need to attach many services programmatically via AWS SDK: Gateway API, DynamoDB. But the main problem, how I will update the codebase for these 1000+ functions later? I think that bash script is a bad idea here.
So, I moved forward and found SAM (AWS Serverless Application Model) and CloudFormatting, which should help me I guess. But I can't understand the concept. I can make a stack with all the required resources, but how will I make new bots from this one stack? Or should I build a template and make new stacks for each new bot programmatically via AWS SDK from this template?
Next, how to update them later? For example, I want to update all bots that have version 1.1 to version 1.2. How I will replace them? Should I make a new stack or can I update older ones? I don't see any options in UI of CloudFormatting or any related methods in AWS SDK for that.
Thanks
But the main problem, how I will update the codebase for these 1000+ functions later?
You don't. You use lambda alias. This allows you to fully decouple your lambda versions from your clients. This works because you are using an alias of your function in your client's code (or api gateway). The alias is fixed and does not change.
However, alias is like a pointer - it can point to different versions of your lambda function. Therefore, when you publish a new lambda version you just point alias to it. Its fully transparent from your clients and their alias does not require any change.
I agree with #Marcin. Also it would be worth checking serverless? Seems like you are still experimenting so most likely you are deploying using bash scripts with AWS SDK/SAM commands. This is fine but once you start getting the gist of what your architecture looks like, I think you will appreciate what serverless can offer. You can deploy/teardown cloudformation stacks in matter of seconds. Also you can use serverless-offline so that you can have a local build of your AWS lambda architecture on your local machine.
All this has saved me hours of grunt work.
Long time stack overflow lurker and fist time poster.
I've started a new project using AWS lambdas and have found the learning curve particularly steep coming from a background of developing desktop applications.
When developing desktop applications it's easy to create a test environment locally. I know it's possible to test lambda functions locally and I've been able to do this for simple cases.
The lambda functions I'm using interact a lot with other AWS services (S3, Aurora, etc). Also, the final solution will include around 15 lambda functions linked via a step function.
I want to know if it's possible to create a separate test environment to the live production environment for the entire step function. This would allow me to perform system tests before deploying to production.
I've looked into AWS codepipeline as a possible solution but I'm not sure if this would allow me to create a seperate test environment before deploying to production.
Any help would be greatly appreciated.
Thanks!
I am currently developing an AppSync based API in a domain driven manner, so we need to put a function to an already created Pipeline Resolver. Does anybody know if there is there any chance doing this via CloudFormation without using a custom resource?
Thanks in advance, Sven
Terraform can do this neatly if you can build this pull request yourself or vote in this issue to get it merged into a public release.
The new syntax is described here.
The build process is actually quite simple. It took me about 30 min end-to-end.
Install GoLang.
Clone the repo with the changes and sync it with the main (upstream) repo.
Make sure you cloned it into go\src\github.com\terraform-providers\terraform-provider-aws folder.
Run go build from go\src\github.com\terraform-providers\terraform-provider-aws
Replace .terraform\plugins\...\terraform-provider-aws-* executable with the one you compiled.
Run terraform init
Test by trying to import a function terraform import aws_appsync_function.example xxxxx-yyyyy
I hope the pull request gets merged by the time you read this.