AWS backend deployment - reactjs

Question

I deployed a React App on AWS with amplify. Now I developed an express backend which communicates with the React frontend.
Now I am wondering if there is a way to host the backend within the same project as the react app on AWS using amplify. So hosting the whole Fullstack App with amplify.
I have read a lot about hosting backend with amplify. But from the documentation it looks like that I can only use the backend-services provided by aws using Amplify CLI and not my own express backend.
Does anyone have experience with hosting their own express backend using Amplify?
As I do not have much experience with cloud-hosting at all, I would be very thankful for some help :)
Best regards from Germany
Jan

Answer 1

Usually, on Amplify you use AppSync for the backend.
This way you have your full-stack on Amplify
With the API you can easily add the basic operations of an API, and customize the more specific ones using lambdas.
But if you still need to host your own, you can add a lambda function for your backend, check this article about running ExpressJS on a lambda.
If you add it via Amplify-CLI (amplify function add) you can see it on the Amplify Console, including logs and other details about it.
I'll go through both scenarios in more detail below:
Custom operations with AppSync
In case you decide to use DynamoDB/AppSync with GraphQL interface you can define your custom operations on the GraphQL Schema.
i.e:
Create a lambda function MyCustomOperation
Define the operation, input and the return you want from your operation (you can use Javascript)
On your GraphQL schema use the #function directive to associate the function to the query desired
type Query {
myCustomQuery(input: String): String #function(name: "MyCustomOperation-${env}")
}
See more details here
Express Backend
In case you need your full backend
To add it to your Amplify project you can create a lambda function
amplify function add and select the template Serverless express function (Integration with Amazon API Gateway), the documentation has more details.
It will give your API endpoint, which you provide on the next step.
You can now manually set it on the configuration as informed here
Amplify.configure({
// OPTIONAL - if your API requires authentication
Auth: {
// REQUIRED - Amazon Cognito Identity Pool ID
identityPoolId: 'XX-XXXX-X:XXXXXXXX-XXXX-1234-abcd-1234567890ab',
// REQUIRED - Amazon Cognito Region
region: 'XX-XXXX-X',
// OPTIONAL - Amazon Cognito User Pool ID
userPoolId: 'XX-XXXX-X_abcd1234',
// OPTIONAL - Amazon Cognito Web Client ID (26-char alphanumeric string)
userPoolWebClientId: 'a1b2c3d4e5f6g7h8i9j0k1l2m3',
},
API: {
endpoints: [
{
name: "MyAPIGatewayAPI",
endpoint: "https://1234567890-abcdefgh.amazonaws.com"
},
{
name: "MyCustomCloudFrontApi",
endpoint: "https://api.my-custom-cloudfront-domain.com",
}
]
}
});
Then you just need to adjust the lambda function with the code you already have for the backend.