Module tags

Type-safe operations on AWS tags.

Overview

This basic data structure of this module is the TagList struct. It contains a list of untyped AWS tags. It implements TryFrom and Into for the relevant Tag types in the aws_sdk_* crates. In itself, that is not too interesting, as the tag values are still just String.

To get typed tags, there is a Tags macro. Applied to a struct, it adds methods to create a struct instance for an instance TagList, and turn a struct instance back into a TagList:

use aws_lib::tags::{Tags, TagList, RawTag};

#[Tags]
struct MyTags {
   tag1: String,
   tag2: bool,
   tag3: Option<bool>,
}

let tags = TagList::from_vec(vec![
  RawTag::new("tag1".to_owned(), "foo".to_owned()),
  RawTag::new("tag2".to_owned(), "true".to_owned()),
]);

let parsed = MyTags::from_tags(tags).unwrap();

assert!(parsed.tag1 == "foo");
assert!(parsed.tag2);
assert!(parsed.tag3.is_none());

Using custom tag types

By default, encoding and decoding of tags is supported for String and bool values.

• String is encoded as-is
• bool is encoded as true and false

In case you have your own type T you want to encode in a tag, there are two strategies:

• serde, which requires T to implement Serialize and Deserialize.
• manual, which requires T to impelemnt two traits:
  • impl TryFrom<RawTagValue> for T: How to (fallibly) create a T from the value of an tag
  • impl From<T> for RawTagValue: How to turn T back into the value of a tag. This cannot fail.

There is a Tag derive macro that selects the strategy, which can then be used in a struct that is using #[Tags]:

use aws_lib::tags::{Tag, Tags};

#[derive(Tag, Debug, Clone, PartialEq, Eq)]
#[tag(translate = transparent)]
struct MyTag(String);

#[Tags]
struct MyTags {
   foo: MyTag,
}

Structs

RawTag

RawTagValue

Tag

A tag generic over its containing value type.

TagKey

TagList

TranslateManual

Enums

ParseTagAwsError

ParseTagError

Like ParseTagValueError, but contains potential additional information about the tag key.

ParseTagValueError

ParseTagsError

Errors that can happen when parsing a set of tags.

Traits

TagValue

TranslatableManual

Translator

Attribute Macros

Tags

Derive Macros

Tag