aws-sdk-for-zig/README.md

AWS SDK for Zig (zig native branch)

This SDK currently supports all AWS services except EC2 and S3. These two services only support XML, and zig 0.9.0 and master both trigger compile errors while incorporating the XML parser in conjunction with a process to fill the types. S3 also requires some plumbing tweaks in the signature calculation. Examples of usage are in src/main.zig.

Current executable size for the demo is 953k (90k of which is the AWS PEM file) after compiling with -Drelease-safe and stripping the executable after compilation. This is for x86_linux. 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, run the code generation, then build the main project with the generated code.

First time build should use zig build -Dfetch to fetch dependent packages (zfetch and friends).

Running

This library mimics the aws c libraries for it's work, so it operates like most other 'AWS things'. 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. Note that an alternative endpoint may require passing in a client option to specify an different TLS root certificate (pass null to disable certificate verification).

The old branch exists for posterity, and supports x86_64 linux. This branch is recommended moving forward.

Limitations

There are many nuances of AWS V4 signature calculation. S3 is not supported because it uses many of these test cases. WebIdentityToken is not yet implemented.

TODO List:

• To work around compiler issues, the best option may be to convert from Xml to json, then parse from there. This will be pursued first. It may need to wait for zig 0.10.0 when self-hosted compiler is likely to be completed (zig 0.10.0 eta May 2022) discovered. If we need to wait, S3, EC2 and other restXml protocols will be blocked.
• Implement AWS restXml protocol. Includes S3. Total service count 4. This may be blocked due to the same issue as EC2.
• Implement AWS EC2 query protocol. Includes EC2. Total service count 1. This may be blocked on a compiler bug, though has not been tested with zig 0.9.0. More details and llvm ir log can be found in the XML branch.
• 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:

• Merge PR to allow stripping -static
• comptime allocations so we can read files, etc (or is there another way)