DynamoDB item creation using a aws_dynamodb_table_item resource

[hashibot]

This issue was originally opened by @drieselliott as hashicorp/terraform#11773. It was migrated here as part of the provider split. The original body of the issue is below.

---

Hi,

It would be nice to have a 'aws_dynamodb_table_item' resource that allows you to write configuration entries to DynamoDB tables when provisioning an environment. It should support both the DynamoDB JSON and the normal JSON format.

resource "aws_dynamodb_table_item" "configuration_item" {
    table = "${aws_dynamodb_table.configuration_table.name}"
    format = "json"
    item = <<EOF
       //Some JSON content
EOF
}

table: The table name
format: Either 'json' or 'dynamodb' for 'normal json' or 'dynamodb json'
item: The item to insert into the table (either as inline content or template)

This is very useful in serverless applications that use DynamoDb as their configuration store and Terraform to provision everything. Otherwise you need to rely on a separate non-terraform script to upload your configuration entries.

Thanks for considering this.

Dries

[galadriel2143]

Started a PR to implement this feature. Functionality is complete, but needs tests (not sure if someone can help with this but would be appreciated) and there are a few questions I would have before it gets merged back in.

• Behavior on update: Should it force attributes back to the ones specified in the resource definition of they don't match? I think this would be fine based on how terraform handles attributes on other resources.
• Behavior on externally removed item: Recreate, leave alone, or hard fail? Recreating when it's missing seems to fall in line with other resources.
• Output values: Currently I'm returning the range attribute value, hash attribute value, and the "query key", which contains both and can be used in a DDB query to get the object if necessary. Is there anything else that should be returned, or maybe we shouldn't return these at all...
• Query setup: I have the range_key and hash_key names specified on the resource. These probably could be determined by querying the table metadata, but that would add more HTTP calls, and specifying them on the resource theoretically offers some protection from the key schema changing in an unexpected way.
• Value comparison: Doing a deep equal on the item returned from DynamoDB (type map[string]*dynamodb.AttributeValue). It seems to work correctly, but are there any potential problems with this? I'm only projecting the attributes that exist in the item definition, so that way any additional attributes don't constantly trigger false positives.

Example:

resource "aws_dynamodb_table_item" "configuration_item" {
    table_name = "testy"
    hash_key = "hello"
    range_key = "getsorty"
    item = <<EOF
{
    "hello": { "S": "helloworld"},
    "getsorty": { "N": "100" },
    "othervalue": { "N": "900" },
}
EOF
}

output "query_key" {
    value = "${aws_dynamodb_table_item.configuration_item.query_key}"
}

output "table_name" {
    value = "${aws_dynamodb_table_item.configuration_item.table_name}"
}

Computed outputs:

    range_value = "{\"N\": \"100\" }"
    hash_value = "{\"S\": \"helloworld\" }"
    query_key = <<EOF
    {
        "hello": { "S": "helloworld" },
        "getsorty": {"N": "100" }
    }
    EOF

One possible usage of outputs:

terraform output query_key | xargs -d'\n' aws dynamodb --table-name "$(terraform output table_name)" --key

[galadriel2143]

@drieselliott @radeksimko Do you have any comments on this?

[jantman]

Is there any movement on this? This would be an extremely useful feature for us...

[ccgagnon]

+1 It would be very useful feature for us too.

[galadriel2143]

@jantman @ccagnon Are either of you familiar with Terraform's test suite, and/or want to take a crack at it? Do you see anything that needs to be improved with my code? Please let me know.

[galadriel2143]

@ccgagnon

[galadriel2143]

Our team is very eager to have this merged in as well. Currently we're using the resources from a separate provider plugin.

[jantman]

Unfortunately I'm not familiar with Terraform's test suite, or even Go in general...

[galadriel2143]

@jantman I wasn't very familiar with Go either before I wrote this. Gogland is a pretty useful IDE if you need some assistance. I wouldn't recommend developing on Windows though.

[ccgagnon]

@galadriel2143 I am not familiar with Terraform's test suite, but I know go. I can take a look and try it.

[nikhil-p]

Any update on this? Need this feature soon.

[queeno]

I would like to get this feature in terraform asap as well

[tskotov]

+1 for this resource.

[bflad]

This has been released in terraform-provider-aws version 1.9.0. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!