Function validate_label_key

crates/openshell-server/src/grpc/validation.rs:386–485

Validate a label selector string format. Format: "key1=value1,key2=value2" Returns `INVALID_ARGUMENT` if the selector has invalid format. Validate a label key according to Kubernetes requirements. Label keys have an optional prefix and required name, separated by `/`: - Prefix (optional): DNS subdomain format, max 253 chars - Name (required): alphanumeric + `-._`, max 63 chars, must start/end wi

(key: &str)

///
/// See: <https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/>
pub(super) fn validate_label_key(key: &str) -> Result<(), Status> {
    if key.is_empty() {
        return Err(Status::invalid_argument("label key cannot be empty"));
    }

    if key.len() > 253 {
        return Err(Status::invalid_argument(format!(
            "label key exceeds 253 characters: '{key}'"
        )));
    }

    // Split into optional prefix and required name
    let (prefix, name) = if let Some((p, n)) = key.split_once('/') {
        (Some(p), n)
    } else {
        (None, key)
    };

    // Validate name segment (required, max 63 chars)
    if name.is_empty() {
        return Err(Status::invalid_argument(format!(
            "label key name segment cannot be empty: '{key}'"
        )));
    }

    if name.len() > 63 {
        return Err(Status::invalid_argument(format!(
            "label key name segment exceeds 63 characters: '{key}'"
        )));
    }

    // Name must contain only alphanumeric, hyphens, underscores, and dots
    if !name
        .chars()
        .all(|c| c.is_alphanumeric() || c == '-' || c == '_' || c == '.')
    {
        return Err(Status::invalid_argument(format!(
            "label key name segment contains invalid characters (must be alphanumeric, '-', '_', or '.'): '{key}'"
        )));
    }

    // Name must start and end with alphanumeric
    let first = name.chars().next().unwrap(); // safe: we checked !is_empty()
    let last = name.chars().last().unwrap();
    if !first.is_alphanumeric() {
        return Err(Status::invalid_argument(format!(
            "label key name segment must start with alphanumeric character: '{key}'"
        )));
    }
    if !last.is_alphanumeric() {
        return Err(Status::invalid_argument(format!(
            "label key name segment must end with alphanumeric character: '{key}'"
        )));
    }

    // Validate prefix if present (DNS subdomain format)
    if let Some(prefix) = prefix {
        if prefix.is_empty() {