AWS SDK for Zig

NOTE: THIS SDK IS CURRENTLY UNUSABLE FOR S3 AND 15 OTHER SERVICES WITHOUT A PROXY. SEE LIMITATIONS SECTION BELOW

Current executable size for the demo is 980k after compiling with -Doptimize=ReleaseSmall in x86_linux, and will vary based on services used. Tested targets:

• x86_64-linux
• riscv64-linux
• aarch64-linux
• x86_64-windows
• arm-linux
• aarch64-macos
• x86_64-macos

Tested targets are built, but not continuously tested, by CI.

Building

zig build should work. It will build the code generation project, fetch model files from upstream AWS Go SDK v2, run the code generation, then build the main project with the generated code. Testing can be done with zig test.

Using

This is designed for use with the Zig 0.11 package manager, and exposes a module called "aws". Set up build.zig.zon and add the dependency/module to your project as normal and the package manager should do its thing. A full example can be found in /example.

Configuring the module and/or Running the demo

This library mimics the aws c libraries for it's work, so it operates like most other 'AWS things'. /src/main.zig gives you a handful of examples for working with services. For local testing or alternative endpoints, there's no real standard, so there is code to look for AWS_ENDPOINT_URL environment variable that will supersede all other configuration.

Other branches

The default branch is fully functional but requires TLS 1.3. Until AWS Services support TLS 1.3 at the end of 2023, the 0.9.0 branch may be of use. More details below in limitations. This branch overall is superior, as is the 0.11 compiler, but if you need a service that doesn't support TLS 1.3 and you need it right away, feel free to use that branch. Note I do not intend to update code in the 0.9.0 branch, but will accept PRs.

An old branch based on aws-crt exists for posterity, and supports x86_64 linux. The old branch is deprecated, so if there are issues you see that work correctly in the aws-crt branch, please file an issue. I can't think of a reason to use this branch any more. I do not intend to entertain PRs on this branch, but reach out if you think it is important.

Limitations

The zig 0.11 HTTP client supports TLS 1.3 only. This, IMHO, is a reasonable restriction given its introduction 5 years ago, but is inflicting some short term pain on this project as AWS has not yet fully implemented the protocol. AWS has committed to TLS 1.3 support across all services by the end of 2023, but many (most) services as of August 28th have not yet been upgraded. Proxy support has been added, so to get to the services that do not yet support TLS 1.3, you can use something like mitmproxy to proxy those requests. Of course, this is not a good production solution...

WebIdentityToken is not yet implemented.

TODO List:

• Json parsing is based on a fork of the 0.9.0 (maybe earlier?) json parser. This needs a re-visit. Note also that a json.zig file is embedded/copied from the codegen project, so that also needs a second look.
• Take a look to see about compilation speed. With codegen caching this is reasonable, but still takes longer than needed.
• Upgrade the model files. This is a simple tasks, but I'd like the first item on this list to be completed first.
• Implement sigv4a signing
• Implement jitter/exponential backoff
• Implement timeouts and other TODO's in the code
• Add option to cache signature keys

Compiler wishlist/watchlist:

• comptime allocations so we can read files, etc (or is there another way)

Services without TLS 1.3 support (11 services out of 255 total)

NOTE ON S3: For me, S3 is currently intermittently available using TLS 1.3, so it appears deployments are in progress.

cloudsearch
data.iot
dax
elasticache
models.lex
opsworks
personalize-runtime
runtime.lex
runtime-v2-lex
s3
support

Dependency tree

No dependencies:

• aws_authentication: base structure for credentials (only one type)
• aws_http_base: contains basic structures for http requests/results
• case: provides functions to change casing
• date: provides limited date manipulation functions
• http_client_17015_issue: zig 0.11 http client, with changes
• json: custom version of earlier stdlib json parser
• xml: custom xml parser library
• url: custom url encoding

aws_credentials: Allows credential handling aws_authentication

aws_http: http_client_17015_issue aws_http_base aws_signing

aws_signing: handles signing of http requests aws_http_base aws_authentication date

aws: main usage point for libraries aws_http json url case date servicemodel xml_shaper aws_credentials aws_authentication

main: main entrypoint for demo executable aws

servicemodel: Provides access to all aws service generated models all generated model files

xml_shaper: Manages interface from xml to in memory structures xml date