OpenBao Rust SDK

openbao is a secure, typed, async Rust SDK for OpenBao, the community-driven open source fork of Vault. It is designed for audited secret workflows: HTTPS by default, no redirect forwarding, strict path validation, secret-aware token types, and a small reviewed dependency surface.

The crate name on crates.io is openbao; Rust imports are lowercase:

use openbao::Client;

This README documents the 0.3.0 release candidate. 0.3.0 builds on the published 0.2.0 crate with Transit, audit device helpers, safe exact lease lookup, renew, and revoke helpers, plugin catalog operations, and a loopback-only OpenBao dev bootstrap helper.

The crate is dual-licensed under MIT or Apache-2.0.

Current Status

Implemented now:

• Async client with typestate authentication.
• Direct token authentication with secrecy::SecretString.
• AppRole login with secret-aware role ID, secret ID, token, and accessor handling.
• Token create, lookup, accessor lookup/list, renew, revoke, and revoke-self helpers.
• KV v2 read, write, CAS write, patch, list, latest delete, version read, version delete, undelete, destroy, metadata, and backend config helpers.
• KV v1 read, write, delete, and list helpers.
• Transit key create, read, list, delete, encrypt, decrypt, rewrap, data key, random, hash, HMAC, sign, and verify helpers.
• System health, seal status, and loopback-only dev bootstrap helpers.
• Secret and auth mount enable, list, read, tune, and disable helpers.
• Response wrapping lookup, wrap, unwrap, and rewrap helpers.
• ACL policy list, read, write, delete, and prefix list helpers.
• Capability checks for the caller token, an explicit token, or a token accessor.
• Audit device list, enable, disable, and hash helpers.
• Safe exact lease lookup, renew, and revoke helpers.
• Plugin catalog list, type-list, register, read, delete, and backend reload helpers.
• Raw JSON request escape hatch for endpoints that are not typed yet.
• Local TLS OpenBao Podman stack on 9940 and 9941.
• Real OpenBao integration test gate using the pinned OpenBao image.

Planned next:

• 0.4.0: PKI, Kubernetes auth, and TLS certificate auth.
• 0.5.0: database secrets, JWT/OIDC, and userpass.
• 0.6.0: SSH, TOTP, and explicitly gated production init/unseal/rekey/rotate APIs.
• 0.7.0: cubbyhole, identity, Kubernetes secrets, LDAP secrets, and RabbitMQ.
• 0.8.0: remaining auth methods and broader system backend automation.

See API Coverage and Release Plan for the road to 1.0.0.

Trust Dashboard

Area	Status
License	MIT OR Apache-2.0
Rust edition	2024
MSRV	Rust 1.95
Async runtime	Runtime-agnostic client; examples use Tokio
HTTP transport	reqwest with redirects disabled
Default TLS backend	Rustls
TLS floor	TLS 1.3 by default; TLS 1.2 requires explicit opt-in
Plain HTTP	Rejected by default; numeric loopback IPs only when explicitly enabled
Token storage	secrecy::SecretString
Unsafe policy	unsafe_code = "forbid"
Path validation	Rejects traversal, query/fragment injection, empty segments, controls, and trailing periods
Error posture	API error strings are bounded and sanitized before formatting
Dependency policy	cargo deny plus RustSec audit in the release gate
Release evidence	fmt, clippy, tests, docs, deny, audit, SBOM, and real OpenBao integration
Pentest gate	Required before tagging a release

Security details live in SECURITY.md. Release evidence and release sequencing live in release-notes and docs/RELEASE_PLAN.md.

Install

[dependencies]
openbao = "0.3"
secrecy = "0.10.3"
serde = { version = "1.0.228", features = ["derive"] }
tokio = { version = "1.52.3", features = ["macros", "rt-multi-thread"] }

Some advanced examples below name transport and JSON helper types directly:

[dependencies]
reqwest = { version = "0.13.4", default-features = false, features = ["rustls"] }
serde_json = "1.0.150"

The crate defaults to the common SDK surface:

[dependencies]
openbao = { version = "0.3", features = ["approle", "token", "kv1", "kv2", "transit", "sys", "rustls-tls"] }

For a smaller build, disable defaults and opt into only what the application uses:

[dependencies]
openbao = { version = "0.3", default-features = false, features = ["kv2", "sys", "rustls-tls"] }

Features

Feature	Default	Purpose
approle	yes	AppRole authentication helpers.
token	yes	Token lifecycle helpers.
kv1	yes	KV v1 secrets engine helpers.
kv2	yes	KV v2 secrets engine helpers.
transit	yes	Transit cryptography helpers.
sys	yes	System backend helpers.
rustls-tls	yes	Rustls transport configuration.
native-tls	no	Legacy native TLS support. Requires native-tls-acknowledged after audit.
native-tls-acknowledged	no	Explicit acknowledgment for audited native TLS builds.

Support Matrix

Client, Transport, And TLS

Capability	Status	Notes
Async client	Yes	Built on reqwest with a small public API surface.
Typestate auth	Yes	Separate unauthenticated and authenticated client states.
HTTPS by default	Yes	Plain HTTP is rejected unless loopback HTTP is explicitly enabled.
Redirect protection	Yes	Redirect following is disabled to avoid forwarding token headers.
TLS floor	Yes	TLS 1.3 minimum by default; audited legacy deployments can opt down to TLS 1.2.
Custom CA roots	Yes	Extra root certificates can be merged with the platform trust store.
Root-only trust stores	Yes	System roots can be bypassed by using only configured root certificates.
Connection timeout	Yes	5-second connection timeout by default; caller overrides are bounded.
User agent fingerprinting	Yes	Default user agent omits the exact crate version.
Namespace header	Yes	X-Vault-Namespace support for namespace-aware deployments.
Raw JSON requests	Yes	Escape hatch for endpoints that are not typed yet.

Authentication

Capability	Status	Notes
Direct token auth	Yes	Tokens are accepted as SecretString.
X-Vault-Token	Yes	Default documented OpenBao-compatible token header.
Bearer auth	Yes	Optional Authorization: Bearer header mode.
AppRole login	Yes	Role ID and secret ID are secret-aware; returned token is wrapped.
Token accessor handling	Yes	Accessors are treated as secret material.
Token lifecycle helpers	Yes	Lookup, accessor lookup/list, renew, revoke, revoke-self, and create helpers.
Kubernetes auth	Planned	Planned for 0.4.0.
TLS certificate auth	Planned	Planned for 0.4.0.
JWT/OIDC and userpass	Planned	Planned for 0.5.0.

Secret Engines

Capability	Status	Notes
KV v2 read/write	Yes	Typed serialization and deserialization.
KV v2 CAS write	Yes	Optional check-and-set version support.
KV v2 patch	Yes	JSON merge patch content type.
KV v2 list/delete versions	Yes	Metadata list, latest delete, soft delete, undelete, and destroy.
KV v2 metadata/config	Yes	Backend and per-key metadata helpers.
KV v1	Yes	Read, write, delete, and list helpers.
Transit	Yes	Key create/read/list/delete, encrypt, decrypt, rewrap, data key, random, hash, HMAC, sign, and verify.
PKI	Planned	Planned for 0.4.0.
Database credentials	Planned	Planned for 0.5.0.
SSH and TOTP	Planned	Planned for 0.6.0.
Identity and remaining engines	Planned	Planned for 0.7.0.

System Backend And Operations

Capability	Status	Notes
Health	Yes	Accepts OpenBao active, standby, sealed, and uninitialized health statuses.
Init status	Yes	Typed /sys/init status helper.
Seal status	Yes	Typed /sys/seal-status helper.
Dev bootstrap	Yes	Fresh numeric-loopback dev instances only; not for production or HSM/KMS deployments.
Mount management	Yes	Secret and auth mount enable/list/read/tune/disable helpers.
Response wrapping	Yes	Lookup, wrap, unwrap, and rewrap helpers.
Policies and capabilities	Yes	ACL policy helpers plus self/token/accessor capability checks.
Audit devices	Yes	Enable, list, disable, and audit hash helpers.
Lease helpers	Yes	Safe exact lookup, renew, and revoke; prefix/force/tidy operations are intentionally not exposed.
Plugin catalog	Yes	List, type-list, register, read, delete, and mounted backend reload helpers.
Production init, unseal, rekey, rotate	Planned	Explicit safety documentation in 0.6.0.
Quotas, metrics, namespaces	Planned	Planned in the 0.8.0 operations line.

Examples

Create a client from an existing token:

use openbao::{Client, Result};
use secrecy::SecretString;

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);

    let health = client.sys().health().await?;
    println!("openbao version: {}", health.version);
    Ok(())
}

Configure a stricter client with a namespace and root-only trust store:

use openbao::{Client, OpenBaoConfig, Result};
use reqwest::Certificate;
use secrecy::SecretString;

#[tokio::main]
async fn main() -> Result<()> {
    let ca_pem = std::fs::read("openbao-ca.pem")
        .map_err(|error| openbao::Error::InvalidTlsConfig(error.to_string()))?;
    let ca = Certificate::from_pem(&ca_pem)?;

    let config = OpenBaoConfig::new("https://bao.example.com:8200")?
        .namespace("admin/team-a")?
        .only_root_certificates(vec![ca])?;

    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::from_config(config)?.with_token(token);

    let seal = client.sys().seal_status().await?;
    println!("sealed: {}", seal.sealed);
    Ok(())
}

Authenticate with AppRole:

use openbao::{Client, Result};
use secrecy::SecretString;

#[tokio::main]
async fn main() -> Result<()> {
    let client = Client::new("https://bao.example.com:8200")?;
    let role_id = SecretString::from(std::env::var("APPROLE_ROLE_ID").unwrap_or_default());
    let secret_id = SecretString::from(std::env::var("APPROLE_SECRET_ID").unwrap_or_default());

    let (client, login) = client.login_approle(role_id, secret_id).await?;
    let health = client.sys().health().await?;

    let _token_accessor = login.accessor;
    println!("openbao version: {}", health.version);
    Ok(())
}

Write and read KV v2 data:

use openbao::{Client, Result};
use secrecy::SecretString;
use serde::{Deserialize, Serialize};

#[derive(Deserialize, Serialize)]
struct DatabaseCredentials {
    username: String,
    password: SecretString,
}

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);
    let kv = client.kv2("secret")?;

    kv.write(
        "production/database",
        DatabaseCredentials {
            username: "app".to_owned(),
            password: SecretString::from("change-me"),
        },
    )
    .await?;

    let secret = kv
        .read::<DatabaseCredentials>("production/database")
        .await?;

    println!("username: {}", secret.data.username);
    let _password_is_not_logged = secret.data.password;
    Ok(())
}

Use KV v2 check-and-set, patch, and version operations:

use openbao::secrets::kv2::{Kv2MetadataOptions, Kv2WriteOptions};
use openbao::{Client, Result};
use secrecy::SecretString;
use serde::Serialize;

#[derive(Serialize)]
struct Patch {
    password: SecretString,
}

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);
    let kv = client.kv2("secret")?;

    kv.write_with_options(
        "app/config",
        serde_json::json!({ "username": "app", "password": "first" }),
        Some(Kv2WriteOptions { cas: Some(0) }),
    )
    .await?;

    let second = kv
        .patch("app/config", Patch {
            password: SecretString::from("rotated"),
        })
        .await?;

    let _previous = kv
        .read_version::<serde_json::Value>("app/config", second.version - 1)
        .await?;
    kv.delete_versions("app/config", &[second.version - 1]).await?;
    kv.undelete_versions("app/config", &[second.version - 1]).await?;
    kv.destroy_versions("app/config", &[second.version - 1]).await?;

    kv.patch_metadata(
        "app/config",
        &Kv2MetadataOptions {
            max_versions: Some(10),
            cas_required: Some(true),
            delete_version_after: Some("24h".to_owned()),
            custom_metadata: None,
        },
    )
    .await?;

    Ok(())
}

Use a KV v1 mount:

use openbao::{Client, Result};
use secrecy::SecretString;
use serde::{Deserialize, Serialize};

#[derive(Deserialize, Serialize)]
struct Config {
    endpoint: String,
}

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);
    let kv = client.kv1("legacy-secret")?;

    kv.write("app/config", Config {
        endpoint: "https://api.example.com".to_owned(),
    })
    .await?;

    let config = kv.read::<Config>("app/config").await?;
    let keys = kv.list("app").await?;

    println!("endpoint: {}", config.endpoint);
    println!("keys: {}", keys.keys.len());
    Ok(())
}

Encrypt and decrypt through Transit:

use openbao::secrets::transit::{TransitDecryptRequest, TransitEncryptRequest};
use openbao::{Client, Result};
use secrecy::{ExposeSecret, SecretString};

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);
    let transit = client.transit("transit")?;

    let encrypted = transit
        .encrypt(
            "app-key",
            &TransitEncryptRequest {
                plaintext: SecretString::from("c2VjcmV0"),
                associated_data: None,
                context: None,
                key_version: None,
                nonce: None,
            },
        )
        .await?;

    let decrypted = transit
        .decrypt(
            "app-key",
            &TransitDecryptRequest {
                ciphertext: encrypted.ciphertext,
                associated_data: None,
                context: None,
                nonce: None,
            },
        )
        .await?;

    println!("plaintext length: {}", decrypted.plaintext.expose_secret().len());
    Ok(())
}

Create, inspect, renew, and revoke a child token:

use openbao::auth::token::TokenCreateRequest;
use openbao::{Client, Result};
use secrecy::SecretString;
use std::collections::BTreeMap;

#[tokio::main]
async fn main() -> Result<()> {
    let root_or_parent = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(root_or_parent);

    let child = client
        .token()
        .create(&TokenCreateRequest {
            policies: vec!["default".to_owned()],
            meta: BTreeMap::from([("owner".to_owned(), "example".to_owned())]),
            display_name: Some("example-child".to_owned()),
            ttl: Some("30m".to_owned()),
            explicit_max_ttl: Some("1h".to_owned()),
            renewable: Some(true),
            ..TokenCreateRequest::default()
        })
        .await?;

    let info = client.token().lookup(&child.client_token).await?;
    println!("renewable: {}", info.renewable);

    let _renewed = client.token().renew(&child.client_token, Some("15m")).await?;
    client.token().revoke_accessor(&child.accessor).await?;
    Ok(())
}

Enable and tune a KV v2 mount:

use openbao::sys::{LeaseDuration, MountConfig, MountEnableRequest};
use openbao::{Client, Result};
use secrecy::SecretString;
use std::collections::BTreeMap;

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);

    client
        .sys()
        .enable_mount(
            "apps",
            &MountEnableRequest {
                backend_type: "kv".to_owned(),
                description: Some("application secrets".to_owned()),
                config: Some(MountConfig {
                    default_lease_ttl: Some(LeaseDuration::Duration("30m".to_owned())),
                    max_lease_ttl: Some(LeaseDuration::Duration("2h".to_owned())),
                    ..MountConfig::default()
                }),
                options: BTreeMap::from([("version".to_owned(), "2".to_owned())]),
                local: None,
                seal_wrap: Some(true),
                external_entropy_access: None,
            },
        )
        .await?;

    let mounts = client.sys().list_mounts().await?;
    println!("mount count: {}", mounts.len());
    Ok(())
}

Wrap and unwrap JSON data:

use openbao::{Client, Result};
use secrecy::SecretString;
use serde::{Deserialize, Serialize};

#[derive(Deserialize, Serialize)]
struct WrappedPayload {
    nonce: String,
}

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);

    let wrap = client
        .sys()
        .wrapping_wrap("5m", &WrappedPayload {
            nonce: "one-time".to_owned(),
        })
        .await?;

    let payload = client
        .sys()
        .wrapping_unwrap::<WrappedPayload>(Some(&wrap.token))
        .await?;

    println!("payload nonce length: {}", payload.nonce.len());
    Ok(())
}

Write an ACL policy and check capabilities:

use openbao::sys::PolicyWriteRequest;
use openbao::{Client, Result};
use secrecy::SecretString;

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);

    client
        .sys()
        .write_policy(
            "app-read",
            &PolicyWriteRequest {
                policy: r#"path "secret/data/app" { capabilities = ["read"] }"#.to_owned(),
                expiration: None,
                ttl: None,
                cas: None,
                cas_required: None,
            },
        )
        .await?;

    let capabilities = client.sys().capabilities_self(["secret/data/app"]).await?;
    let _for_path = capabilities.by_path.get("secret/data/app");
    Ok(())
}

Enable an audit device and calculate an audit hash:

use openbao::sys::AuditEnableRequest;
use openbao::{Client, Result};
use secrecy::SecretString;
use std::collections::BTreeMap;

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);

    client
        .sys()
        .enable_audit_device(
            "file",
            &AuditEnableRequest {
                backend_type: "file".to_owned(),
                description: Some("local audit file".to_owned()),
                options: BTreeMap::from([(
                    "file_path".to_owned(),
                    "/var/log/openbao/audit.log".to_owned(),
                )]),
                local: None,
            },
        )
        .await?;

    let hash = client
        .sys()
        .audit_hash("file", &SecretString::from("known-secret-value"))
        .await?;

    println!("audit hash prefix: {}", hash.hash.split(':').next().unwrap_or(""));
    Ok(())
}

Look up and renew one exact lease:

use openbao::{Client, Result};
use secrecy::SecretString;

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let lease_id = SecretString::from(std::env::var("BAO_LEASE_ID").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);

    let lease = client.sys().lookup_lease(&lease_id).await?;
    if lease.renewable {
        let renewed = client.sys().renew_lease(&lease_id, Some(1800)).await?;
        println!("renewed lease seconds: {}", renewed.lease_duration);
    }

    Ok(())
}

Read and reload a plugin catalog entry:

use openbao::sys::{PluginReloadRequest, PluginType};
use openbao::{Client, Result};
use secrecy::SecretString;

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);

    let plugins = client.sys().list_plugins_by_type(PluginType::Secret).await?;
    if plugins.keys.iter().any(|name| name == "transit") {
        let _info = client
            .sys()
            .read_plugin(PluginType::Secret, "transit", None)
            .await?;
    }

    client
        .sys()
        .reload_plugin_backend(&PluginReloadRequest {
            plugin: Some("example-plugin".to_owned()),
            mounts: Vec::new(),
            scope: None,
        })
        .await?;

    Ok(())
}

Call an endpoint that is not typed yet:

use openbao::{Client, Result};
use reqwest::Method;
use secrecy::SecretString;
use serde_json::Value;

#[tokio::main]
async fn main() -> Result<()> {
    let token = SecretString::from(std::env::var("BAO_TOKEN").unwrap_or_default());
    let client = Client::new("https://bao.example.com:8200")?.with_token(token);

    let response: Value = client
        .request_json(Method::GET, "sys/internal/specs/openapi", Option::<&Value>::None)
        .await?;

    println!("openapi keys: {}", response.as_object().map_or(0, |object| object.len()));
    Ok(())
}

The raw request layer is intentionally low level. Prefer typed helpers when the crate supports an endpoint; use raw JSON to bridge missing OpenBao APIs while coverage grows.

Local OpenBao Dev Instance

The local dev stack uses Podman, TLS, a private CA, and loopback-only ports in the requested 994x range.

Prepare the rootless Podman volume and TLS assets without starting OpenBao:

scripts/openbao_dev.sh prepare

This project does not require a /srv directory tree for local development: raft data lives in a Podman-managed volume, and TLS material lives in the ignored deploy/podman/dev-state/ directory.

scripts/openbao_dev.sh up

Endpoints:

• API: https://127.0.0.1:9940
• Cluster: https://127.0.0.1:9941
• CA certificate: deploy/podman/dev-state/tls/dev-ca.crt

Initialize and unseal OpenBao using bao operator init and bao operator unseal, then export BAO_ADDR=https://127.0.0.1:9940 and BAO_CACERT=deploy/podman/dev-state/tls/dev-ca.crt.

For disposable local development, the crate can initialize and unseal a fresh numeric-loopback instance directly:

use openbao::{Client, OpenBaoConfig, Result, sys::DevBootstrapOptions};
use reqwest::Certificate;

#[tokio::main]
async fn main() -> Result<()> {
    let ca_pem = std::fs::read("deploy/podman/dev-state/tls/dev-ca.crt")
        .map_err(|error| openbao::Error::InvalidTlsConfig(error.to_string()))?;
    let ca = Certificate::from_pem(&ca_pem)?;

    let config = OpenBaoConfig::new("https://127.0.0.1:9940")?
        .only_root_certificates(vec![ca])?;
    let client = Client::from_config(config)?;

    let bootstrap = client
        .sys()
        .bootstrap_dev(&DevBootstrapOptions::single_key())
        .await?;

    let health = bootstrap.client.sys().health().await?;
    println!("initialized: {}, sealed: {}", health.initialized, health.sealed);
    Ok(())
}

bootstrap_dev is not a production initialization ceremony. It creates root and unseal material in process memory, uses Shamir keys, refuses non-loopback targets, and refuses already initialized servers. Do not use it with HSM/KMS auto-unseal, shared environments, or any instance that requires operator key ceremony.

Run the real OpenBao integration flow:

scripts/openbao_integration.sh

The integration script creates a fresh TLS dev instance, initializes and unseals it, stores the root token in a temporary 0600 file for the test process, and removes that file when the run exits.

Release Discipline

Run the normal local checks:

scripts/checks.sh

Run the current release gate:

scripts/release_0_3_gate.sh

Set OPENBAO_SKIP_INTEGRATION=1 only when Podman is unavailable; release candidate validation should run the integration gate.

No release tag should be cut unless the matching pentest report status is reviewed and recorded in the release notes.