S3 - Getting metadata from Post S3 Upload lambda function - amazon-web-services

Question

I'm generating a presigned URL using s3.getSignedUrl('putObject', params) and for my params
var params = {
Bucket: bucketName,
Key: photoId + "-" + photoNumber + "-of-" + numberImages + ".jpeg",
Expires: signedUrlExpireSeconds,
ContentType: contentType,
Metadata : { testkey1 : "hello" }
};
I'm trying to receive the Metadata in my S3 successful upload lambda function, however it's not appearing. Anyone know why? The upload is successful and for my printed logs, I'm receiving everything but the metadata tag in the event:
console.log(event);
"Records": [
{
"eventVersion": "2.1",
"eventSource": "aws:s3",
"awsRegion": "us-east-1",
"eventTime": "2020-01-15T06:51:57.171Z",
"eventName": "ObjectCreated:Put",
"userIdentity": {
"principalId":
},
"requestParameters": {
"sourceIPAddress":
},
"responseElements": {
"x-amz-request-id": "4C32689CE5B70A82",
"x-amz-id-2": "AS0f97RHlLW2DF6tVfRwbTeoEpk2bEne/0LrWqHpLJRHY5GMBjy/NQOHqYAMhd2JjiiUcuw0nUTMJS8pDAch1Abc5xzzWVMv"
},
"s3": {
"s3SchemaVersion": "1.0",
"configurationId": "9a9a755e-e809-4dbf-abf8-3450aaa208ed",
"bucket": {
"name": ,
"ownerIdentity": {
"principalId": "A3SZPXLS03IWBG"
},
"arn":
},
"object": {
"key": "BcGMYe-1-of-1.jpeg",
"size": 19371,
"eTag": "45c719f2f6b5349cc360db9a13d0cee4",
"sequencer": "005E1EB6921E08F7E4"
}
}
}
]

Answer 1

This is s3 event message structure. the message structure originally doesn't contain metadata.
You need to get metadata in the lambda function in person.
You would get metadata through s3 head-object command with the bucket-name and object-key in the event received.
{
"Records":[
{
"eventVersion":"2.2",
"eventSource":"aws:s3",
"awsRegion":"us-west-2",
"eventTime":The time, in ISO-8601 format, for example, 1970-01-01T00:00:00.000Z, when Amazon S3 finished processing the request,
"eventName":"event-type",
"userIdentity":{
"principalId":"Amazon-customer-ID-of-the-user-who-caused-the-event"
},
"requestParameters":{
"sourceIPAddress":"ip-address-where-request-came-from"
},
"responseElements":{
"x-amz-request-id":"Amazon S3 generated request ID",
"x-amz-id-2":"Amazon S3 host that processed the request"
},
"s3":{
"s3SchemaVersion":"1.0",
"configurationId":"ID found in the bucket notification configuration",
"bucket":{
"name":"bucket-name",
"ownerIdentity":{
"principalId":"Amazon-customer-ID-of-the-bucket-owner"
},
"arn":"bucket-ARN"
},
"object":{
"key":"object-key",
"size":object-size,
"eTag":"object eTag",
"versionId":"object version if bucket is versioning-enabled, otherwise null",
"sequencer": "a string representation of a hexadecimal value used to determine event sequence,
only used with PUTs and DELETEs"
}
},
"glacierEventData": {
"restoreEventData": {
"lifecycleRestorationExpiryTime": "The time, in ISO-8601 format, for example, 1970-01-01T00:00:00.000Z, of Restore Expiry",
"lifecycleRestoreStorageClass": "Source storage class for restore"
}
}
}
]
}