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listtags

This package contains a code generator to consistently handle the various AWS Go SDK service implementations for listing resource tags. Not all AWS Go SDK services that support tagging are generated in this manner.

To run this code generator, execute go generate ./... from the root of the repository. The general workflow for the generator is:

  • Generate Go file contents via template from local variables and functions
  • Go format file contents
  • Write file contents to list_tags_gen.go file

Example Output

// AmplifyListTags lists amplify service tags.
// The identifier is typically the Amazon Resource Name (ARN), although
// it may also be a different identifier depending on the service.
func AmplifyListTags(conn *amplify.Amplify, identifier string) (KeyValueTags, error) {
    input := &amplify.ListTagsForResourceInput{
        ResourceArn: aws.String(identifier),
    }

    output, err := conn.ListTagsForResource(input)

    if err != nil {
        return New(nil), err
    }

    return AmplifyKeyValueTags(output.Tags), nil
}

Implementing a New Generated Service

Requirements

Before a new service can be added to the generator, the new service must:

  • Have the KeyValueTags conversion functions implemented for the AWS Go SDK service type/map. See also the servicetags generator README.
  • Implement a function for listing resource tags (e.g. ListTagsforResource)
  • Have the service included in aws/internal/keyvaluetags/service_generation_customizations.go, if not present the following compilation error will be seen:
2019/09/03 09:22:21 error executing template: template: listtags:19:41: executing "listtags" at <ClientType>: error calling ClientType: unrecognized ServiceClientType: acmpca

Once the service has met all the requirements, in main.go:

  • Add import for new service, e.g. "github.com/aws/aws-sdk-go/service/athena"
  • Add service name to serviceNames, e.g. athena
  • Run go generate ./... (or make gen) from the root of the repository to regenerate the code
  • Run go test ./... (or make test) from the root of the repository to ensure the generated code compiles
  • (Optional) Customize the service generation, if necessary (see below)

Customizations

By default, the generator creates a {SERVICE}ListTags() function with the following structs and function calls:

  • {SERVICE}.ListTagsForResourceInput struct with ResourceArn field for calling ListTagsForResource() API call

If these do not match the actual AWS Go SDK service implementation, the generated code will compile with errors. See the sections below for certain errors and how to handle them.

ServiceListTagsFunction

Given the following compilation error:

./list_tags_gen.go:183:12: undefined: backup.ListTagsForResourceInput
./list_tags_gen.go:187:21: conn.ListTagsForResource undefined (type *backup.Backup has no field or method ListTagsForResource)

The function for listing resource tags must be updated. Add an entry within the ServiceListTagsFunction() function of the generator to customize the naming of the ListTagsForResource() function and matching ListTagsForResourceInput struct. In the above case:

case "backup":
    return "ListTags"

ServiceListTagsInputIdentifierField

Given the following compilation error:

./list_tags_gen.go:1118:3: unknown field 'ResourceArn' in struct literal of type transfer.ListTagsForResourceInput

The field name to identify the resource for tag listing must be updated. Add an entry within the ServiceListTagsInputIdentifierField() function of the generator to customize the naming of the ResourceArn field for the list tags input struct. In the above case:

case "transfer":
    return "Arn"

ServiceListTagsOutputTagsField

Given the following compilation error:

./list_tags_gen.go:206:38: output.Tags undefined (type *cloudhsmv2.ListTagsOutput has no field or method Tags)

The field name of the tags from the tag listing must be updated. Add an entry within the ServiceListTagsOutputTagsField() function of the generator to customize the naming of the Tags field for the list tags output struct. In the above case:

case "cloudhsmv2":
    return "TagList"