Function detect_driver

crates/openshell-core/src/config.rs:123–140

Auto-detect the appropriate compute driver based on the runtime environment. Priority order: Kubernetes → Podman → Docker. VM is never auto-detected (requires explicit `--drivers vm`). Returns the first driver where the environment check passes. Returns `None` if no compatible driver is found.

()

/// Returns the first driver where the environment check passes.
/// Returns `None` if no compatible driver is found.
pub fn detect_driver() -> Option<ComputeDriverKind> {
    // Kubernetes: check for KUBERNETES_SERVICE_HOST env var (set inside pods)
    if std::env::var_os("KUBERNETES_SERVICE_HOST").is_some() {
        return Some(ComputeDriverKind::Kubernetes);
    }

    // Podman: check for a reachable local API socket.
    if is_podman_available() {
        return Some(ComputeDriverKind::Podman);
    }

    // Docker: check if the CLI is available or a local Docker socket exists.
    if is_docker_available() {
        return Some(ComputeDriverKind::Docker);
    }

    None
}

/// Check if a binary is available on the system PATH.
fn is_binary_available(name: &str) -> bool {