Sample
tower 0.5.3: Handle Tower 0.5 middleware composition ordering, poll_ready reservation and clone invalidation traps, buffer-timeout-loadshed queue interactions, Steer head-of-line blocking, and in-place retry policy mutation
Verified sample for cargo tower 0.5.3: Handle Tower 0.5 middleware composition ordering, poll_ready reservation and clone invalidation traps…
sha256:70cb8cec09e074888556da7097e94d68ad979b471ca30473f3e2662c391dd7fd
This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured.
How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people.
MIT-0
Execution evidence
The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.
- Evidence basis
- Signed contract pass
- Verification receipts
- 2
- Signing keys that built it
- 2
Declared environment
rust linux x64 rust rust cargo
Verification-run environments
| Environment | Contract | Stages | Run |
|---|---|---|---|
| rust 1 · linux alpine/x64 · docker ed25519:d91480838ac982c9 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · cargo@1 |
2026-08-16 |
| rust 1 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · cargo@1 |
2026-08-18 |
Case
HOW- Goal
- Handle Tower 0.5 middleware composition ordering, poll_ready reservation and clone invalidation traps, buffer-timeout-loadshed queue interactions, Steer head-of-line blocking, and in-place retry policy mutation
- Packages
- Symbols
-
- tower::builder::ServiceBuilder
- tower::Service
- tower::ServiceExt
- tower::load_shed::LoadShed
- tower::limit::ConcurrencyLimit
- tower::buffer::Buffer
- tower::timeout::Timeout
- tower::steer::Steer
- tower::retry::Policy
- Environment
- rust
- Created
- 2026-08-16T09:19:45Z
Contract
- assert ServiceBuilder applies layers top-to-bottom where the first registered layer executes outermost on request and innermost on response
- assert cloning a LoadShed service after readiness check resets is_ready to false and silently rejects calls with Overloaded on an idle service
- assert cloning a ConcurrencyLimit service after readiness check resets permit to None and panics on call without re-polling poll_ready
- assert placing Timeout outside Buffer bounds total queue-plus-execution latency and drops canceled requests before inner invocation
- assert placing Timeout inside Buffer bounds only inner execution time allowing unbounded queue delay
- assert placing LoadShed outside Buffer sheds callers on buffer saturation while LoadShed inside Buffer drops queued requests when inner is unready
- assert Steer blocks all routes when any single branch is unready causing head-of-line blocking across independent services
- assert Tower 0.5 retry Policy receives mutable references to request and result allowing in-place request modification across retry attempts
Files
- Cargo.lock
- Cargo.toml
- NOTES.md
- csx.json
- src/lib.rs
- tests/tower_traps.rs