## Summary
- add one strict `BUZZ_S3_ADDRESSING_STYLE=path|virtual` setting shared
by media and Git/CAS storage
- preserve path-style defaults for bundled Compose/Helm MinIO while
supporting Railway's virtual-hosted bucket contract
- fail startup on invalid or non-Unicode values before dependency
connection, and validate the Helm value with the same two choices
- document operator mappings and why endpoint and bucket remain separate
for routing and SigV4 signing
## Best-practice rationale
AWS documents both URL forms and favors virtual-hosted addressing for
S3, while compatibility endpoints such as the bundled MinIO deployment
can require path style. `rust-s3` defaults to virtual/subdomain
addressing and provides `with_path_style()` for the explicit
compatibility case.
Some providers buckets only support as virtual-hosted bucket styles.
This PR therefore uses one explicit, provider-neutral switch rather than
endpoint heuristics or fallback behavior, while retaining `path` as
Buzz's backward-compatible default.
Sources:
-
https://docs.aws.amazon.com/AmazonS3/latest/userguide/VirtualHosting.html
- https://docs.rs/rust-s3/0.37.0/s3/bucket/struct.Bucket.html
- https://docs.railway.com/storage-buckets#url-style
-
https://github.com/minio/minio/blob/master/docs/config/README.md#domain
## Validation
- `cargo fmt --all`
- `cargo check --workspace --all-targets`
- targeted `buzz-media` and `buzz-relay` parsing/client-construction
tests for defaults, strict errors, and both URL styles
- Helm unittest: 45/45 passed
- Compose config/render validation passed
- local MinIO path-mode relay startup passed the Git A3 conformance
probe and became ready
- unreachable object storage failed startup and readiness never opened
- push hooks completed the broader Rust and desktop suites successfully
---------
Signed-off-by: npub122y0pqkertljmedu303rl0aqrj3w8pvu43t6jxm6875lzg6f2pwqegc3xc <5288f082d91aff2de5bc8be23fbfa01ca2e3859cac57a91b7a3fa9f12349505c@buzz.block.builderlab.xyz>
Signed-off-by: Kalvin Chau <kalvin@block.xyz>
Co-authored-by: npub122y0pqkertljmedu303rl0aqrj3w8pvu43t6jxm6875lzg6f2pwqegc3xc <5288f082d91aff2de5bc8be23fbfa01ca2e3859cac57a91b7a3fa9f12349505c@buzz.block.builderlab.xyz>
