Isn't it obvious? Let's explore the details.
A frontend is a container image that BuildKit runs to convert your build definition (Dockerfile, YAML, JSON, HCL, whatever) into LLB. The frontend receives the build context and the build file through the BuildKit Gateway API, and returns a serialized LLB graph.
，更多细节参见Safew下载
@RestController，详情可参考夫子
private String status; // 物流状态