# instant-acme: async, pure-Rust ACME client
[](https://docs.rs/instant-acme/)
[](https://crates.io/crates/instant-acme)
[](https://github.com/InstantDomain/instant-acme/actions?query=workflow%3ACI)
[](LICENSE-APACHE)
instant-acme is an async, pure-Rust ACME (RFC 8555) client.
instant-acme is used in production at [InstantDomain](https://instantdomain.com/) to help
us provision TLS certificates within seconds for our customers. instant-acme relies
on Tokio and rustls to implement the [RFC 8555](https://www.rfc-editor.org/rfc/rfc8555.html)
specification.
## Features
* Store/recover your account credentials by serializing/deserializing
* Fully async implementation with tracing support
* Support for processing multiple orders concurrently
* Uses hyper with rustls and Tokio for HTTP requests
* Uses *ring* for ECDSA signing
* Minimum supported Rust version: 1.51
## Limitations
* Only tested with DNS challenges against Let's Encrypt so far (staging and production)
* Only supports ECDSA keys for now
## Getting started
```rust
use std::time::Duration;
use rcgen::{Certificate, CertificateParams, DistinguishedName};
use tokio::time::sleep;
use tracing::{error, info};
use acme::{
Account, AuthorizationStatus, ChallengeType, Identifier, LetsEncrypt, NewAccount, NewOrder,
OrderStatus,
};
async fn provision(names: Vec<String>) -> anyhow::Result<()> {
// Create a new account. This will generate a fresh ECDSA key for you.
// Alternatively, restore an account from serialized credentials by
// using `Account::from_credentials()`.
let account = Account::create(
&NewAccount {
contact: &[],
terms_of_service_agreed: true,
only_return_existing: false,
},
LetsEncrypt::Staging.url(),
)
.await?;
// Create the ACME order based on the given domain names.
// Note that this only needs an `&Account`, so the library will let you
// process multiple orders in parallel for a single account.
let identifiers = names
.iter()
.map(|name| Identifier::Dns(name.into()))
.collect::<Vec<_>>();
let (mut order, state) = account
.new_order(&NewOrder {
identifiers: &identifiers,
})
.await
.unwrap();
info!("order state: {:#?}", state);
assert!(matches!(state.status, OrderStatus::Pending));
// Pick the desired challenge type and prepare the response.
let authorizations = order.authorizations(&state.authorizations).await.unwrap();
let mut challenges = Vec::with_capacity(authorizations.len());
for authz in &authorizations {
match authz.status {
AuthorizationStatus::Pending => {}
AuthorizationStatus::Valid => continue,
_ => todo!(),
}
// We'll use the DNS challenges for this example, but you could
// pick something else to use here.
let challenge = authz
.challenges
.iter()
.find(|c| c.r#type == ChallengeType::Dns01)
.ok_or_else(|| anyhow::anyhow!("no dns01 challenge found"))?;
let Identifier::Dns(identifier) = &authz.identifier;
// TODO: set up the challenge response here.
challenges.push((identifier, &challenge.url));
}
// Let the server know we're ready to accept the challenges.
for (_, url) in &challenges {
order.set_challenge_ready(url).await.unwrap();
}
// Exponentially back off until the order becomes ready or invalid.
let mut tries = 1u8;
let mut delay = Duration::from_millis(250);
let state = loop {
sleep(delay).await;
let state = order.state().await.unwrap();
if let OrderStatus::Ready | OrderStatus::Invalid = state.status {
info!("order state: {:#?}", state);
break state;
}
delay *= 2;
tries += 1;
match tries < 5 {
true => info!(?state, tries, "order is not ready, waiting {delay:?}"),
false => {
error!(?state, tries, "order is not ready");
return Err(anyhow::anyhow!("order is not ready"));
}
}
};
if state.status == OrderStatus::Invalid {
return Err(anyhow::anyhow!("order is invalid"));
}
let mut names = Vec::with_capacity(challenges.len());
for (identifier, _) in challenges {
names.push(identifier.to_owned());
}
// If the order is ready, we can provision the certificate.
// Use the rcgen library to create a Certificate Signing Request.
let mut params = CertificateParams::new(names.clone());
params.distinguished_name = DistinguishedName::new();
let cert = Certificate::from_params(params).unwrap();
let csr = cert.serialize_request_der()?;
// Finalize the order and print certificate chain, private key and account credentials.
let cert_chain_pem = order.finalize(&csr, &state.finalize).await.unwrap();
info!("certficate chain:\n\n{}", cert_chain_pem,);
info!("private key:\n\n{}", cert.serialize_private_key_pem());
info!(
"account credentials:\n\n{}",
serde_json::to_string_pretty(&account.credentials()).unwrap()
);
Ok(())
}
```