Upload image to AWS S3 using AppSync when data source is Lambda Function

Question

I am trying to upload images to my S3 bucket when sending chat messages to my Aurora Database using AppSync with Lambda configured as it's data source.

My resolver for the mutation is:

{
    "version": "2017-02-28",
    "operation": "Invoke",
    "payload": {
        "field": "createMessage",
        "arguments":  $utils.toJson($context.arguments)
    }
}

The messages are being saved correctly in the database however the S3 image data files are not being saved in my S3 bucket. I believe I have configured everything correctly except for the resolver which I am not sure about.

So are you uploading the image to S3 via your lambda function? — Lisa M Shon, Aug 13 '18 at 15:52
What I was asking is if you had a lambda resolver that uploads to s3. Or are you using the AWS SDK to do this? — Lisa M Shon, Aug 14 '18 at 20:30
I’m using the aws sdk for that. The app sync client handles the upload from the graph ql schema — alionthego, Aug 15 '18 at 05:12

score 2 · Answer 1 · answered Aug 14 '18 at 06:57

Uploading files with AppSync when data source is lambda is basically the same as for every other data source and it does not depend on resolvers.

Just make sure you have your credentials for complex objects set up (JS example using Amplify library for authorization):

import { Auth } from 'aws-amplify'
const client = new AWSAppSyncClient({
    url: /*your endpoint*/,
    region: /*your region*/,
    complexObjectsCredentials: () => Auth.currentCredentials(),
})

And also you need to provide S3 complex object as an input type for your mutation:

input S3ObjectInput {
    bucket: String!
    key: String!
    region: String!
    localUri: String
    mimeType: String
}

Everything else will work just fine even with lambda data source. Here you can find more information related to your question(in that example dynamoDB is used but it is basically the same for lambda: https://stackoverflow.com/a/50218870/9359164

Upload image to AWS S3 using AppSync when data source is Lambda Function

1 Answers1