Function validate_label_value

crates/openshell-server/src/grpc/validation.rs:496–533

Validate a label value according to Kubernetes requirements. Label values: - Can be empty (Kubernetes allows empty values) - Max 63 characters - If non-empty, must contain only alphanumeric, hyphens, underscores, and dots - If non-empty, must start and end with alphanumeric character See:

(value: &str)

///
/// See: <https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/>
pub(super) fn validate_label_value(value: &str) -> Result<(), Status> {
    // Empty values are allowed in Kubernetes
    if value.is_empty() {
        return Ok(());
    }

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

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

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

    Ok(())
}

/// Validate a label selector string format.
///