kube_client/config/mod.rs
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//! Kubernetes configuration objects from `~/.kube/config`, `$KUBECONFIG`, or the [cluster environment](https://kubernetes.io/docs/tasks/access-application-cluster/access-cluster/#accessing-the-api-from-a-pod).
//!
//! # Usage
//! The [`Config`] has several constructors plus logic to infer environment.
//!
//! Unless you have issues, prefer using [`Config::infer`], and pass it to a [`Client`][crate::Client].
use std::{path::PathBuf, time::Duration};
use thiserror::Error;
mod file_config;
mod file_loader;
mod incluster_config;
use file_loader::ConfigLoader;
pub use file_loader::KubeConfigOptions;
pub use incluster_config::Error as InClusterError;
/// Failed to infer config
#[derive(Error, Debug)]
#[error("failed to infer config: in-cluster: ({in_cluster}), kubeconfig: ({kubeconfig})")]
pub struct InferConfigError {
in_cluster: InClusterError,
// We can only pick one source, but the kubeconfig failure is more likely to be a user error
#[source]
kubeconfig: KubeconfigError,
}
/// Possible errors when loading kubeconfig
#[derive(Error, Debug)]
pub enum KubeconfigError {
/// Failed to determine current context
#[error("failed to determine current context")]
CurrentContextNotSet,
/// Kubeconfigs with mismatching kind cannot be merged
#[error("kubeconfigs with mismatching kind cannot be merged")]
KindMismatch,
/// Kubeconfigs with mismatching api version cannot be merged
#[error("kubeconfigs with mismatching api version cannot be merged")]
ApiVersionMismatch,
/// Failed to load current context
#[error("failed to load current context: {0}")]
LoadContext(String),
/// Failed to load the cluster of context
#[error("failed to load the cluster of context: {0}")]
LoadClusterOfContext(String),
/// Failed to find named user
#[error("failed to find named user: {0}")]
FindUser(String),
/// Failed to find the path of kubeconfig
#[error("failed to find the path of kubeconfig")]
FindPath,
/// Failed to read kubeconfig
#[error("failed to read kubeconfig from '{1:?}': {0}")]
ReadConfig(#[source] std::io::Error, PathBuf),
/// Failed to parse kubeconfig YAML
#[error("failed to parse kubeconfig YAML: {0}")]
Parse(#[source] serde_yaml::Error),
/// The structure of the parsed kubeconfig is invalid
#[error("the structure of the parsed kubeconfig is invalid: {0}")]
InvalidStructure(#[source] serde_yaml::Error),
/// Cluster url is missing on selected cluster
#[error("cluster url is missing on selected cluster")]
MissingClusterUrl,
/// Failed to parse cluster url
#[error("failed to parse cluster url: {0}")]
ParseClusterUrl(#[source] http::uri::InvalidUri),
/// Failed to parse proxy url
#[error("failed to parse proxy url: {0}")]
ParseProxyUrl(#[source] http::uri::InvalidUri),
/// Failed to load certificate authority
#[error("failed to load certificate authority")]
LoadCertificateAuthority(#[source] LoadDataError),
/// Failed to load client certificate
#[error("failed to load client certificate")]
LoadClientCertificate(#[source] LoadDataError),
/// Failed to load client key
#[error("failed to load client key")]
LoadClientKey(#[source] LoadDataError),
/// Failed to parse PEM-encoded certificates
#[error("failed to parse PEM-encoded certificates: {0}")]
ParseCertificates(#[source] pem::PemError),
}
/// Errors from loading data from a base64 string or a file
#[derive(Debug, Error)]
pub enum LoadDataError {
/// Failed to decode base64 data
#[error("failed to decode base64 data: {0}")]
DecodeBase64(#[source] base64::DecodeError),
/// Failed to read file
#[error("failed to read file '{1:?}': {0}")]
ReadFile(#[source] std::io::Error, PathBuf),
/// No base64 data or file path was provided
#[error("no base64 data or file")]
NoBase64DataOrFile,
}
/// Configuration object detailing things like cluster URL, default namespace, root certificates, and timeouts.
///
/// # Usage
/// Construct a [`Config`] instance by using one of the many constructors.
///
/// Prefer [`Config::infer`] unless you have particular issues, and avoid manually managing
/// the data in this struct unless you have particular needs. It exists to be consumed by the [`Client`][crate::Client].
///
/// If you are looking to parse the kubeconfig found in a user's home directory see [`Kubeconfig`].
#[cfg_attr(docsrs, doc(cfg(feature = "config")))]
#[derive(Debug, Clone)]
pub struct Config {
/// The configured cluster url
pub cluster_url: http::Uri,
/// The configured default namespace
pub default_namespace: String,
/// The configured root certificate
pub root_cert: Option<Vec<Vec<u8>>>,
/// Set the timeout for connecting to the Kubernetes API.
///
/// A value of `None` means no timeout
pub connect_timeout: Option<std::time::Duration>,
/// Set the timeout for the Kubernetes API response.
///
/// A value of `None` means no timeout
pub read_timeout: Option<std::time::Duration>,
/// Set the timeout for the Kubernetes API request.
///
/// A value of `None` means no timeout
pub write_timeout: Option<std::time::Duration>,
/// Whether to accept invalid certificates
pub accept_invalid_certs: bool,
/// Stores information to tell the cluster who you are.
pub auth_info: AuthInfo,
/// Optional proxy URL. Proxy support requires the `socks5` feature.
pub proxy_url: Option<http::Uri>,
/// If set, apiserver certificate will be validated to contain this string
///
/// If not set, the `cluster_url` is used instead
pub tls_server_name: Option<String>,
}
impl Config {
/// Construct a new config where only the `cluster_url` is set by the user.
/// and everything else receives a default value.
///
/// Most likely you want to use [`Config::infer`] to infer the config from
/// the environment.
pub fn new(cluster_url: http::Uri) -> Self {
Self {
cluster_url,
default_namespace: String::from("default"),
root_cert: None,
connect_timeout: Some(DEFAULT_CONNECT_TIMEOUT),
read_timeout: Some(DEFAULT_READ_TIMEOUT),
write_timeout: Some(DEFAULT_WRITE_TIMEOUT),
accept_invalid_certs: false,
auth_info: AuthInfo::default(),
proxy_url: None,
tls_server_name: None,
}
}
/// Infer a Kubernetes client configuration.
///
/// First, a user's kubeconfig is loaded from `KUBECONFIG` or
/// `~/.kube/config`. If that fails, an in-cluster config is loaded via
/// [`Config::incluster`]. If inference from both sources fails, then an
/// error is returned.
///
/// [`Config::apply_debug_overrides`] is used to augment the loaded
/// configuration based on the environment.
pub async fn infer() -> Result<Self, InferConfigError> {
let mut config = match Self::from_kubeconfig(&KubeConfigOptions::default()).await {
Err(kubeconfig_err) => {
tracing::trace!(
error = &kubeconfig_err as &dyn std::error::Error,
"no local config found, falling back to local in-cluster config"
);
Self::incluster().map_err(|in_cluster| InferConfigError {
in_cluster,
kubeconfig: kubeconfig_err,
})?
}
Ok(success) => success,
};
config.apply_debug_overrides();
Ok(config)
}
/// Load an in-cluster Kubernetes client configuration using
/// [`Config::incluster_env`].
pub fn incluster() -> Result<Self, InClusterError> {
Self::incluster_env()
}
/// Load an in-cluster config using the `KUBERNETES_SERVICE_HOST` and
/// `KUBERNETES_SERVICE_PORT` environment variables.
///
/// A service account's token must be available in
/// `/var/run/secrets/kubernetes.io/serviceaccount/`.
///
/// This method matches the behavior of the official Kubernetes client
/// libraries and is the default for both TLS stacks.
pub fn incluster_env() -> Result<Self, InClusterError> {
let uri = incluster_config::try_kube_from_env()?;
Self::incluster_with_uri(uri)
}
/// Load an in-cluster config using the API server at
/// `https://kubernetes.default.svc`.
///
/// A service account's token must be available in
/// `/var/run/secrets/kubernetes.io/serviceaccount/`.
///
/// This behavior does not match that of the official Kubernetes clients,
/// but can be used as a consistent entrypoint in many clusters.
/// See <https://github.com/kube-rs/kube/issues/1003> for more info.
pub fn incluster_dns() -> Result<Self, InClusterError> {
Self::incluster_with_uri(incluster_config::kube_dns())
}
fn incluster_with_uri(cluster_url: http::uri::Uri) -> Result<Self, InClusterError> {
let default_namespace = incluster_config::load_default_ns()?;
let root_cert = incluster_config::load_cert()?;
Ok(Self {
cluster_url,
default_namespace,
root_cert: Some(root_cert),
connect_timeout: Some(DEFAULT_CONNECT_TIMEOUT),
read_timeout: Some(DEFAULT_READ_TIMEOUT),
write_timeout: Some(DEFAULT_WRITE_TIMEOUT),
accept_invalid_certs: false,
auth_info: AuthInfo {
token_file: Some(incluster_config::token_file()),
..Default::default()
},
proxy_url: None,
tls_server_name: None,
})
}
/// Create configuration from the default local config file
///
/// This will respect the `$KUBECONFIG` evar, but otherwise default to `~/.kube/config`.
/// You can also customize what context/cluster/user you want to use here,
/// but it will default to the current-context.
pub async fn from_kubeconfig(options: &KubeConfigOptions) -> Result<Self, KubeconfigError> {
let loader = ConfigLoader::new_from_options(options).await?;
Self::new_from_loader(loader).await
}
/// Create configuration from a [`Kubeconfig`] struct
///
/// This bypasses kube's normal config parsing to obtain custom functionality.
pub async fn from_custom_kubeconfig(
kubeconfig: Kubeconfig,
options: &KubeConfigOptions,
) -> Result<Self, KubeconfigError> {
let loader = ConfigLoader::new_from_kubeconfig(kubeconfig, options).await?;
Self::new_from_loader(loader).await
}
async fn new_from_loader(loader: ConfigLoader) -> Result<Self, KubeconfigError> {
let cluster_url = loader
.cluster
.server
.clone()
.ok_or(KubeconfigError::MissingClusterUrl)?
.parse::<http::Uri>()
.map_err(KubeconfigError::ParseClusterUrl)?;
let default_namespace = loader
.current_context
.namespace
.clone()
.unwrap_or_else(|| String::from("default"));
let accept_invalid_certs = loader.cluster.insecure_skip_tls_verify.unwrap_or(false);
let mut root_cert = None;
if let Some(ca_bundle) = loader.ca_bundle()? {
root_cert = Some(ca_bundle);
}
Ok(Self {
cluster_url,
default_namespace,
root_cert,
connect_timeout: Some(DEFAULT_CONNECT_TIMEOUT),
read_timeout: Some(DEFAULT_READ_TIMEOUT),
write_timeout: Some(DEFAULT_WRITE_TIMEOUT),
accept_invalid_certs,
proxy_url: loader.proxy_url()?,
auth_info: loader.user,
tls_server_name: loader.cluster.tls_server_name,
})
}
/// Override configuration based on environment variables
///
/// This is only intended for use as a debugging aid, and the specific variables and their behaviour
/// should **not** be considered stable across releases.
///
/// Currently, the following overrides are supported:
///
/// - `KUBE_RS_DEBUG_IMPERSONATE_USER`: A Kubernetes user to impersonate, for example: `system:serviceaccount:default:foo` will impersonate the `ServiceAccount` `foo` in the `Namespace` `default`
/// - `KUBE_RS_DEBUG_IMPERSONATE_GROUP`: A Kubernetes group to impersonate, multiple groups may be specified by separating them with commas
/// - `KUBE_RS_DEBUG_OVERRIDE_URL`: A Kubernetes cluster URL to use rather than the one specified in the config, useful for proxying traffic through `kubectl proxy`
pub fn apply_debug_overrides(&mut self) {
// Log these overrides loudly, to emphasize that this is only a debugging aid, and should not be relied upon in production
if let Ok(impersonate_user) = std::env::var("KUBE_RS_DEBUG_IMPERSONATE_USER") {
tracing::warn!(?impersonate_user, "impersonating user");
self.auth_info.impersonate = Some(impersonate_user);
}
if let Ok(impersonate_groups) = std::env::var("KUBE_RS_DEBUG_IMPERSONATE_GROUP") {
let impersonate_groups = impersonate_groups.split(',').map(str::to_string).collect();
tracing::warn!(?impersonate_groups, "impersonating groups");
self.auth_info.impersonate_groups = Some(impersonate_groups);
}
if let Ok(url) = std::env::var("KUBE_RS_DEBUG_OVERRIDE_URL") {
tracing::warn!(?url, "overriding cluster URL");
match url.parse() {
Ok(uri) => {
self.cluster_url = uri;
}
Err(err) => {
tracing::warn!(
?url,
error = &err as &dyn std::error::Error,
"failed to parse override cluster URL, ignoring"
);
}
}
}
}
/// Client certificate and private key in PEM.
pub(crate) fn identity_pem(&self) -> Option<Vec<u8>> {
self.auth_info.identity_pem().ok()
}
}
fn certs(data: &[u8]) -> Result<Vec<Vec<u8>>, pem::PemError> {
Ok(pem::parse_many(data)?
.into_iter()
.filter_map(|p| {
if p.tag() == "CERTIFICATE" {
Some(p.into_contents())
} else {
None
}
})
.collect::<Vec<_>>())
}
// https://github.com/kube-rs/kube/issues/146#issuecomment-590924397
const DEFAULT_CONNECT_TIMEOUT: Duration = Duration::from_secs(30);
const DEFAULT_READ_TIMEOUT: Duration = Duration::from_secs(295);
const DEFAULT_WRITE_TIMEOUT: Duration = Duration::from_secs(295);
// Expose raw config structs
pub use file_config::{
AuthInfo, AuthProviderConfig, Cluster, Context, ExecAuthCluster, ExecConfig, ExecInteractiveMode,
Kubeconfig, NamedAuthInfo, NamedCluster, NamedContext, NamedExtension, Preferences,
};
#[cfg(test)]
mod tests {
#[cfg(not(feature = "client"))] // want to ensure this works without client features
#[tokio::test]
async fn config_loading_on_small_feature_set() {
use super::Config;
let cfgraw = r#"
apiVersion: v1
clusters:
- cluster:
certificate-authority-data: aGVsbG8K
server: https://0.0.0.0:6443
name: k3d-test
contexts:
- context:
cluster: k3d-test
user: admin@k3d-test
name: k3d-test
current-context: k3d-test
kind: Config
preferences: {}
users:
- name: admin@k3d-test
user:
client-certificate-data: aGVsbG8K
client-key-data: aGVsbG8K
"#;
let file = tempfile::NamedTempFile::new().expect("create config tempfile");
std::fs::write(file.path(), cfgraw).unwrap();
std::env::set_var("KUBECONFIG", file.path());
let kubeconfig = Config::infer().await.unwrap();
assert_eq!(kubeconfig.cluster_url, "https://0.0.0.0:6443/");
}
}