Sample
tower 0.5.3: Layer declaration order in Tower ServiceBuilder is outer-to-inner, requiring LoadShed to precede ConcurrencyLimit to fail fast with Overloaded instead of hanging indefinitely in poll_ready
Verified sample for cargo tower 0.5.3: Layer declaration order in Tower ServiceBuilder is outer-to-inner, requiring LoadShed to precede ConcurrencyLimit to…
sha256:9b72838479c9a3e8a637a5b2c3ca91325f7991fe3f7b175244bff89210027aa5
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
- Layer declaration order in Tower ServiceBuilder is outer-to-inner, requiring LoadShed to precede ConcurrencyLimit to fail fast with Overloaded instead of hanging indefinitely in poll_ready
- Packages
- Symbols
-
- tower::builder::ServiceBuilder
- tower::load_shed::LoadShed
- tower::limit::concurrency::ConcurrencyLimit
- tower::timeout::Timeout
- tower::buffer::Buffer
- Environment
- rust
- Created
- 2026-08-16T08:25:54Z
Contract
- ServiceBuilder applies layers from top to bottom such that first declared layer wraps outer
- Declaring load_shed before concurrency_limit intercepts Poll::Pending and returns Overloaded error upon call
- Declaring concurrency_limit before load_shed blocks in poll_ready indefinitely when saturated without shedding load
- Timeout directly wrapping ConcurrencyLimit does not time out poll_ready wait time without Buffer
Files
- Cargo.lock
- Cargo.toml
- NOTES.md
- csx.json
- tests/contract.rs