cloud-sdk

no_std-first multi-provider cloud SDK for Rust.
Provider crates, explicit API domains, security-first release gates, and transport-free core types.

Crates.io | Docs.rs | Release Plan | Threat Model | Security

cloud-sdk

cloud-sdk is a no_std-first Rust workspace for cloud provider SDKs. The first provider crate is cloud-sdk-hetzner, covering the Hetzner Cloud and DNS APIs. The default crates have no network client, TLS stack, async runtime, filesystem, clock, or secret-storage dependency. Transport and serialization remain explicit boundaries: v0.15 defines a no-network contract and testkit, v0.16 adds an opt-in blocking rustls adapter, v0.17 adds an executor-neutral async contract and optional Tokio-backed adapter, and v0.14 added narrowly reviewed no_std Serde and caller-buffer sanitization. None changes the default provider graph.

The project target is a serious production-ready cloud-sdk foundation and Hetzner provider at 1.0.0, reached through small reviewed releases with test, security, dependency, and release evidence. Future provider crates can follow the same pattern, especially focused cloud and SaaS providers such as cloud-sdk-scaleway or cloud-sdk-ovh.

Cost And Production Warning

Cloud APIs can create, modify, and delete billable resources. This SDK is built with careful review, tests, security gates, and release checks, but no SDK can guarantee that it is free from mistakes or that every provider-side API behavior is risk-free.

Before running code against a real cloud account, review the exact operations, inputs, permissions, and provider pricing yourself. You are responsible for the infrastructure actions you execute and for any costs, downtime, data loss, or configuration changes caused by those actions. If you find an SDK mistake, please report it so it can be fixed.

Current Status

Status: v0.18.0 pagination and action polling implementation stop reached; pentest required. The latest published release is v0.17.0.

Implemented now:

Rust workspace pinned to stable 1.97.0.
MSRV policy for Rust 1.90.0 through 1.97.0.
Edition 2024 and workspace resolver 3.
cloud-sdk provider-neutral crate.
cloud-sdk-hetzner provider crate with focused internal modules.
Initial Hetzner API surface partition for Cloud, DNS, security, and Storage Box resources.
Provider-neutral blocking and runtime-neutral async transport contracts, plus a no_std deterministic mock testkit implementing both contracts.
Provider-neutral bounded pagination and action polling state machines with caller-owned page fetching, parsing, delay, timeout, and cancellation policy.
Validated rate-limit metadata propagation through blocking, async, and mock transports without hidden retries.
Optional hardened provider-neutral blocking and async reqwest/rustls transports, plus admitted guarded caller-buffer sanitization.
Local checks for formatting, linting, tests, no_std policy, modularity, and file length.
MIT OR Apache-2.0 license.
Security, implementation, release, modularity, supply-chain, and threat-model docs.
Official Hetzner Cloud/DNS and Storage Box spec source lock for v0.2.0.
Complete source-derived API matrix with 221 operations, owner modules, pagination, sorting, action behavior, deprecation status, and implementation status.
Local upstream lock validation for the pinned Hetzner spec URLs and hashes.
Hetzner API drift detection for added, removed, and changed operations and component schemas.
Core Hetzner request/response policy domains for endpoint paths, base URL selection, endpoint group base mapping, bounded query parameters, fixed-buffer percent encoding, labels, pagination, sorting, action status, API errors, and rate-limit metadata.
Read-only Hetzner catalog request primitives for locations, pricing, server types, load balancer types, ISOs, and public images.
Hetzner security request primitives for SSH key CRUD, certificate CRUD, and certificate retry action endpoints.
Hetzner server request primitives for server CRUD, metrics, and server action endpoint paths.
Hetzner server-adjacent request primitives for images, placement groups, primary IPs, and their v0.7 action paths.
Hetzner storage/IP request primitives for volumes, floating IPs, and their v0.8 action paths.
Hetzner Storage Box request primitives for boxes, box types, snapshots, subaccounts, Storage Box actions, and subaccount actions.
Hetzner Firewall request primitives for CRUD, resource application, and validated rule replacement.
Hetzner Network request primitives for CRUD, routes, subnets, range changes, and protection actions.
Hetzner Load Balancer request primitives for CRUD, metrics, services, targets, network attachment, reverse DNS, protection, algorithms, type changes, and public-interface actions.
Hetzner DNS Zone request primitives for CRUD, zonefile import/export, primary nameservers, TTL and protection actions, and action listing.
Hetzner DNS RRSet request primitives for CRUD, list filtering, TTL and protection actions, and bounded record mutations.
Optional no_std Serde boundary for size-checked RRSet request bodies and validated shared action/error response envelopes.

Not implemented yet:

No provider-level client that executes typed Hetzner request models end to end; v0.17 exposes reviewed provider-neutral blocking and async transports.
No token storage or secret manager integration.
No broad request/response serialization outside the reviewed RRSet and shared response boundary.
No automatic pagination stream; the explicit cursor requires callers to fetch and decode each page.
No automatic retries or sleeps; the action poller delegates delay, timeout, and cancellation decisions to caller policy.
No generated response model.
No live Hetzner API tests.
No non-Hetzner providers yet. Smaller focused cloud and SaaS providers such as Scaleway and OVH are better future fits than hyperscaler-scale APIs, but no non-Hetzner provider is a 1.0 deliverable.
No Robot Webservice support. Robot is planned after the Hetzner Cloud/DNS provider reaches 1.0.0, likely as a 1.1.0 track exposed through cloud-sdk-hetzner.

Trust Dashboard

Area	Status
License	`MIT OR Apache-2.0`
MSRV	Rust `1.90.0`
Pinned toolchain	Rust `1.97.0`
Default target	`no_std`
Default runtime dependencies	none in `cloud-sdk`; provider crates remain transport-free by default
Unsafe policy	first-party crates use `#![forbid(unsafe_code)]`
Default features	empty
Network defaults	none
Secret storage defaults	none
Release evidence	local gates, dependency policy, SBOM, pentest report before tags
Crate versions	tracked in `docs/CRATE_VERSION_MATRIX.md`
1.0 target	serious production-ready provider-neutral foundation plus Hetzner provider

Provider Roadmap

Provider	Target Version	Crate
`Hetzner Cloud`	1.0.0	`cloud-sdk-hetzner`
`Hetzner Robot`	1.1.0	planned in `cloud-sdk-hetzner`

Install

[dependencies]
cloud-sdk = "0.18.0"
cloud-sdk-hetzner = "0.16.0"

Provider-Neutral Example

use cloud_sdk::{ApiFamily, Method, Provider};

let provider = Provider::Hetzner;
let family = ApiFamily::Cloud;
let method = Method::Get;

assert_eq!(provider, Provider::Hetzner);
assert_eq!(family, ApiFamily::Cloud);
assert_eq!(method, Method::Get);

Transport Contract Example

use cloud_sdk::Method;
use cloud_sdk::transport::{RequestTarget, TransportRequest};

let Ok(target) = RequestTarget::new("/servers?page=1") else {
    return;
};
let request = TransportRequest::new(Method::Get, target);

assert_eq!(request.method(), Method::Get);
assert_eq!(request.target().as_str(), "/servers?page=1");
assert!(request.body().is_empty());

The core contracts perform no I/O and select no executor. Use cloud-sdk-testkit for deterministic blocking or async tests, or opt into cloud-sdk-reqwest/blocking-rustls or async-rustls for HTTPS.

Optional Blocking Transport

[dependencies]
cloud-sdk = "0.18.0"
cloud-sdk-reqwest = { version = "0.15.0", features = ["blocking-rustls"] }

use std::time::Duration;

use cloud_sdk::Method;
use cloud_sdk::transport::{BlockingTransport, RequestTarget, TransportRequest};
use cloud_sdk_reqwest::blocking::{
    BearerToken, BlockingClientBuilder, HttpsEndpoint, RequestTimeouts,
    UserAgent,
};

let Ok(endpoint) = HttpsEndpoint::new("https://api.hetzner.cloud/v1") else { return };
let Ok(token) = BearerToken::new("replace-with-scoped-token") else { return };
let Ok(user_agent) = UserAgent::new("my-service/1.0") else { return };
let Ok(timeouts) = RequestTimeouts::new(
    Duration::from_secs(30),
    Duration::from_secs(10),
) else { return };
let Ok(mut client) = BlockingClientBuilder::new(endpoint, token, user_agent, timeouts).build()
else { return };

let Ok(target) = RequestTarget::new("/servers?page=1") else { return };
let request = TransportRequest::new(Method::Get, target);
let mut response_body = [0_u8; 65_536];
let Ok(response) = client.send(request, &mut response_body) else { return };

assert!(response.status().is_success());

The production builder is HTTPS-only, requires explicit bounded timeouts and a user agent, uses rustls with TLS 1.2 minimum, and disables redirects, retries, proxies, referer generation, and response decompression. It forces HTTP/1 and the system resolver even if another dependency enables reqwest HTTP/2 or Hickory DNS. The caller owns token generation, scope, rotation, revocation, and cleanup of the original secret; the adapter clears only its own token and request-body storage.

Optional Async Transport

[dependencies]
cloud-sdk = "0.18.0"
cloud-sdk-reqwest = { version = "0.15.0", features = ["async-rustls"] }

use cloud_sdk::Method;
use cloud_sdk::transport::{AsyncTransport, RequestTarget, TransportRequest};

let Ok(target) = RequestTarget::new("/servers?page=1") else { return };
let request = TransportRequest::new(Method::Get, target);
let mut response_body = [0_u8; 65_536];
let Ok(response) = AsyncTransport::send(&mut client, request, &mut response_body).await
else { return };

assert!(response.status().is_success());

The async adapter requires an active Tokio executor because reqwest uses Tokio internally; the core trait and testkit remain executor-neutral. Responses are buffered only up to caller capacity and copied after complete success. Timeout, read failure, overflow, or cancellation leaves the caller buffer cleared.

Pagination Cursor Example

use cloud_sdk::pagination::{
    PageLimit, PageMetadata, PageNumber, PaginationCursor,
};

# fn main() -> Result<(), cloud_sdk::pagination::PaginationError> {
let first = PageNumber::new(1)?;
let second = PageNumber::new(2)?;
let limit = PageLimit::new(10)?;
let mut cursor = PaginationCursor::new(first, 25, limit)?;

assert_eq!(cursor.next_page()?, first);
let metadata = PageMetadata::new(
    first,
    25,
    None,
    Some(second),
    Some(second),
    Some(30),
)?;
let boundary = cursor.observe(metadata, 25, None)?;

assert!(!boundary.is_terminal());
assert_eq!(cursor.next_page()?, second);
# Ok(())
# }

The caller fetches and decodes each requested page, then passes only validated metadata and the decoded entry count to the cursor. Empty non-terminal pages, repeated pages, contradictory navigation, entries above per_page, mismatch with a supplied total, page-size or traversal-total changes, and the caller's hard page limit fail closed. Restart the traversal when provider metadata changes. Each accepted boundary preserves transport rate-limit metadata.

Action Polling Example

use core::time::Duration;
use cloud_sdk::action_polling::{
    ActionPollStep, ActionPoller, ActionUpdate, PollContext, PollDecision,
    PollPolicy,
};

struct FixedDelay;

impl PollPolicy for FixedDelay {
    type Error = ();

    fn decide(&mut self, _context: PollContext) -> Result<PollDecision, Self::Error> {
        Ok(PollDecision::Delay(Duration::from_secs(2)))
    }
}

let mut poller = ActionPoller::new();
let mut policy = FixedDelay;
let running = poller.observe(
    ActionUpdate::<()>::Running,
    25,
    None,
    &mut policy,
);
assert_eq!(running, Ok(ActionPollStep::Delay(Duration::from_secs(2))));

let complete = poller.observe(
    ActionUpdate::<()>::Success,
    100,
    None,
    &mut policy,
);
assert_eq!(complete, Ok(ActionPollStep::Complete));

Provider failures are returned as ActionPollStep::Failed(E) without being discarded. Running observations invoke caller policy, which must explicitly choose a nonzero delay, cancellation, or timeout; the SDK owns no clock, executor, sleep, retry count, or deadline.

Fixed Buffer Example

use cloud_sdk::buffer::write_query_u64;

# fn main() -> Result<(), ()> {
let mut output = [0u8; 8];
let mut len = 0;
let mut first = true;
write_query_u64(&mut output, &mut len, &mut first, "page", 0, ())?;

let query = output
    .get(..len)
    .and_then(|bytes| core::str::from_utf8(bytes).ok());
assert_eq!(query, Some("page=0"));
# Ok(())
# }

JSON String Example

use cloud_sdk::buffer::write_json_string;

# fn main() -> Result<(), ()> {
let mut output = [0u8; 48];
let mut len = 0;
write_json_string(&mut output, &mut len, "line\n\"quoted\"", ())?;

let value = output
    .get(..len)
    .and_then(|bytes| core::str::from_utf8(bytes).ok());
assert_eq!(value, Some("\"line\\n\\\"quoted\\\"\""));
# Ok(())
# }

Workspace Crates

Crate	Default `std`?	Purpose
`cloud-sdk`	no	Provider-neutral domains and shared SDK foundation.
`cloud-sdk-hetzner`	no	Main Hetzner documentation and provider crate with internal `cloud`, `dns`, `security`, and `storage` modules.
`cloud-sdk-reqwest`	no	Provider-neutral optional blocking and async reqwest/rustls transports; transport-free by default.
`cloud-sdk-testkit`	no	Provider-neutral blocking/async mock transport, response metadata fixtures, and adversarial corpus.
`cloud-sdk-sanitization`	no	Provider-neutral volatile caller-buffer cleanup and guarded secret buffers.

The workspace uses one primary crate per provider. Provider-specific API families remain modules inside that crate; reusable transport, testkit, serialization, and sanitization boundaries remain provider-neutral. Package names with another scoped suffix, such as cloud-sdk-ovh-reqwest or cloud-sdk-scaleway-dns, are rejected by release automation.

The root README documents the workspace and release process. Crate-local README files document the crate-specific role and examples. For Hetzner-specific usage, start with cloud-sdk-hetzner.

Hetzner endpoint modules live inside the provider crate:

crates/cloud-sdk-hetzner/src/
  actions.rs
  endpoint.rs
  labels.rs
  pagination.rs
  rate_limit.rs
  request.rs
  response.rs
  cloud/catalog.rs
  cloud/
  dns/
  security/
  storage/

API Scope

The first planning pass covers the Hetzner Cloud API reference at https://docs.hetzner.cloud/reference/cloud, including overview material for authentication, query parameters, errors, actions, labels, pagination, rate limiting, server metadata, sorting, and deprecation notices.

Robot Webservice support is intentionally post-1.0. It uses a different API shape, authentication model, and request encoding than the Cloud/DNS API. The planned direction is to expose it through cloud-sdk-hetzner after 1.0, without letting Robot-specific behavior weaken the default Cloud SDK design.

Endpoint groups scheduled for the SDK:

Area	Groups
Cross-resource	actions
Servers	servers, server actions, server types, images, image actions, ISOs, placement groups, primary IPs, primary IP actions
Storage	volumes, volume actions
IPs	floating IPs, floating IP actions
Network edge	firewalls, firewall actions, load balancers, load balancer actions, load balancer types, networks, network actions
DNS	zones, zone actions, zone RRSets, zone RRSet actions
Security	certificates, certificate actions, SSH keys
Storage Boxes	storage boxes, storage box actions, storage box subaccounts
Catalog and billing	locations, pricing

The v0.2.0 planning pass source-locked the official machine-readable specs:

Cloud and DNS: https://docs.hetzner.cloud/cloud.spec.json
Storage Boxes: https://docs.hetzner.cloud/hetzner.spec.json

docs/API_MATRIX.md tracks all 221 discovered operations. Deprecated operations remain listed for drift tracking, but are marked deferred-deprecated until the SDK has an explicit compatibility policy.

Before changing endpoint models, run:

scripts/check_hetzner_api_drift.py --fetch

That compares the current upstream specs with the locked operation and schema fingerprints in docs/API_FINGERPRINTS.tsv and docs/API_SCHEMA_FINGERPRINTS.tsv.

Do not refresh lock files directly from a drift report. First review the upstream changes and update the pinned spec hashes in the source-lock evidence. Then refresh the fingerprints during the reviewed source-lock pass:

scripts/check_hetzner_api_drift.py --fetch --write-lock --accept-lock-refresh

The write path verifies fetched spec bytes against the pinned SHA-256 values before overwriting the fingerprint files.

Rust Version Support

The minimum supported Rust version is Rust 1.90.0. Development uses the pinned stable Rust 1.97.0 until the toolchain policy is updated.

Compatibility verification matrix for current main:

Rust	Local Evidence
`1.90.0`	`cargo +1.90.0 check --workspace --all-features`
`1.91.0`	`cargo +1.91.0 check --workspace --all-features`
`1.92.0`	`cargo +1.92.0 check --workspace --all-features`
`1.93.0`	`cargo +1.93.0 check --workspace --all-features`
`1.94.0`	`cargo +1.94.0 check --workspace --all-features`
`1.95.0`	`cargo +1.95.0 check --workspace --all-features`
`1.96.0`	`cargo +1.96.0 check --workspace --all-features`
`1.96.1`	`cargo +1.96.1 check --workspace --all-features`
`1.97.0`	`scripts/checks.sh`

Checks

scripts/checks.sh
scripts/release_0_1_gate.sh
scripts/check_hetzner_upstream.sh --local-only
scripts/check_hetzner_api_drift.py --fetch
scripts/release_0_2_gate.sh
scripts/release_0_3_gate.sh
scripts/release_0_4_gate.sh
scripts/release_0_5_gate.sh
scripts/release_0_6_gate.sh
scripts/release_0_7_gate.sh
scripts/release_0_8_gate.sh
scripts/release_0_9_gate.sh
scripts/release_0_10_gate.sh
scripts/release_0_11_gate.sh
scripts/release_0_12_gate.sh
scripts/release_0_13_gate.sh
scripts/release_0_14_gate.sh

Name		Name	Last commit message	Last commit date
Latest commit History 110 Commits
.cargo		.cargo
.github		.github
crates		crates
docs		docs
release-notes		release-notes
sbom		sbom
scripts		scripts
security/pentest		security/pentest
tests/reqwest-feature-unification		tests/reqwest-feature-unification
.gitattributes		.gitattributes
.gitignore		.gitignore
CHANGELOG.md		CHANGELOG.md
Cargo.lock		Cargo.lock
Cargo.toml		Cargo.toml
LICENSE-APACHE		LICENSE-APACHE
LICENSE-MIT		LICENSE-MIT
README.md		README.md
SECURITY.md		SECURITY.md
deny.toml		deny.toml
release-crates.toml		release-crates.toml
rust-toolchain.toml		rust-toolchain.toml

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cloud-sdk

Cost And Production Warning

Current Status

Trust Dashboard

Provider Roadmap

Install

Provider-Neutral Example

Transport Contract Example

Optional Blocking Transport

Optional Async Transport

Pagination Cursor Example

Action Polling Example

Fixed Buffer Example

JSON String Example

Workspace Crates

API Scope

Rust Version Support

Checks

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cloud-sdk

Cost And Production Warning

Current Status

Trust Dashboard

Provider Roadmap

Install

Provider-Neutral Example

Transport Contract Example

Optional Blocking Transport

Optional Async Transport

Pagination Cursor Example

Action Polling Example

Fixed Buffer Example

JSON String Example

Workspace Crates

API Scope

Rust Version Support

Checks

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