KubernetesClient-C

KubernetesC-SDK

告诉编译器：

“这些函数是 C 写的，别给它们加花哨的 C++ 名字修饰，用纯 C 风格导出。”

extern "C" {
#include <kubernetes/config/kube_config.h>
#include <kubernetes/api/CoreV1API.h>
}

结构体之间的关系

这套结构的目的是：
让不同类型的 Kubernetes 对象（Pod、Service、Namespace等）都能用统一的链表容器 list_t 来保存，从而方便解析与遍历。

• v1_pod_list_t 只是“某一类对象”的容器（这里是 Pod）

• 而 list_t 是通用链表容器

• listEntry_t 是链表节点结构

---

​ 1️⃣ v1_pod_list_t

typedef struct v1_pod_list_t {char *api_version;          // 版本，如 "v1"list_t *items;              // 这里是一个链表，存放多个 v1_pod_t 对象char *kind;                 // 类型，如 "PodList"struct v1_list_meta_t *metadata; // 元数据，如继续分页的 tokenint _library_owned;         // 标记内存是否由库管理
} v1_pod_list_t;

​ 2️⃣ list_t（链表头）

typedef struct list_t {listEntry_t *firstEntry;  // 第一个节点listEntry_t *lastEntry;   // 最后一个节点long count;               // 节点数量
} list_t;

​ 3️⃣ listEntry_t（链表节点）

typedef struct listEntry_t {listEntry_t *nextListEntry;  // 指向下一个节点listEntry_t *prevListEntry;  // 指向上一个节点void *data;                  // 指向实际数据（这里是 v1_pod_t*）
} listEntry_t;

遍历宏的设计

#define list_ForEach(element, list) \for (element = (list != NULL) ? (list)->firstEntry : NULL; \element != NULL; \element = element->nextListEntry)

等价写法：

listEntry_t *element = list->firstEntry;
while (element != NULL) {...element = element->nextListEntry;
}

Creating API Clients

常见的连接方式有两种

1. 从kubeconfig 文件和使用集群内置配置，这是在 Kubernetes 集群之外运行应用程序时最常见的方法：

// Initialize variables
char *basePath = NULL;
sslConfig_t *sslConfig = NULL;
list_t *apiKeys = NULL;
apiClient_t *apiClient = NULL;// Load configuration from kubeconfig file (typically ~/.kube/config)
int rc = load_kube_config(&basePath, &sslConfig, &apiKeys, NULL);
if (rc != 0) {// Handle errorreturn -1;
}// Create API client with loaded configuration
apiClient = apiClient_create_with_base_path(basePath, sslConfig, apiKeys);
if (!apiClient) {// Handle errorreturn -1;
}// Use the API client...// Clean up resources
apiClient_free(apiClient);
free_client_config(basePath, sslConfig, apiKeys);
apiClient_unsetupGlobalEnv();

2. 使用集群内配置,在 Kubernetes Pod 中运行时，可以使用集群内配置，该配置会自动检测和使用服务帐户令牌

// Initialize variables
char *basePath = NULL;
sslConfig_t *sslConfig = NULL;
list_t *apiKeys = NULL;
apiClient_t *apiClient = NULL;// Load in-cluster configuration
int rc = load_incluster_config(&basePath, &sslConfig, &apiKeys);
if (rc != 0) {// Handle errorreturn -1;
}// Create API client with loaded configuration
apiClient = apiClient_create_with_base_path(basePath, sslConfig, apiKeys);
if (!apiClient) {// Handle errorreturn -1;
}// Use the API client...// Clean up resources
apiClient_free(apiClient);
free_client_config(basePath, sslConfig, apiKeys);
apiClient_unsetupGlobalEnv();

• basePath: The base URL of the Kubernetes API server
  basePath：Kubernetes API 服务器的基本 URL
• sslConfig: SSL/TLS configuration for secure connections
  sslConfig：用于安全连接的 SSL/TLS 配置
• dataReceived: Buffer containing the response data
  dataReceived：包含响应数据的缓冲区
• dataReceivedLen: Length of the received data
  dataReceivedLen：接收数据的长度
• response_code: HTTP response code from the last request
  response_code：上次请求的 HTTP 响应代码
• apiKeys_BearerToken: Authentication tokens for the API server
  apiKeys_BearerToken：API 服务器的身份验证令牌

面向对象设计

#include <iostream>
#include <string>extern "C"
{
#include <kubernetes/config/kube_config.h>
#include <kubernetes/api/CoreV1API.h>
}using namespace std;struct kube_params_t
{char *_basePath;sslConfig_t *_sslConfig;list_t *_apiKeys;kube_params_t() : _basePath(nullptr), _sslConfig(nullptr), _apiKeys(nullptr) {}~kube_params_t(){if (_basePath || _sslConfig || _apiKeys){free_client_config(_basePath, _sslConfig, _apiKeys);_basePath = nullptr;_sslConfig = nullptr;_apiKeys = nullptr;}}
};class K8sCluster
{
private:kube_params_t *_params;apiClient_t *_apiClient;bool _connected;void initClient(){int rc = load_kube_config(&_params->_basePath, &_params->_sslConfig, &_params->_apiKeys, nullptr);if (rc != 0){cerr << "Cannot to connected k8s" << endl;return;}_apiClient = apiClient_create_with_base_path(_params->_basePath, _params->_sslConfig, _params->_apiKeys);if (!_apiClient){cerr << "Create apiclient Failed" << endl;return;}_connected = true;}public:K8sCluster() : _params(new kube_params_t), _apiClient(nullptr), _connected(false) { initClient(); }K8sCluster(kube_params_t *params) : _params(params), _apiClient(nullptr), _connected(false){if (_params){initClient();}}~K8sCluster(){apiClient_free(_apiClient);delete _params;}void list_pod(const char *);bool isConnected() const { return _connected; }
};void K8sCluster::list_pod(const char *ns)
{if (!_apiClient){printf("[-] apiClient is null, cannot list pods.\n");return;}v1_pod_list_t *pod_list = CoreV1API_listNamespacedPod(_apiClient, (char *)ns, nullptr, nullptr, nullptr,nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,nullptr, nullptr);printf("HTTP response code = %ld\n", _apiClient->response_code);if (!pod_list){printf("Cannot get any pod.\n");return;}listEntry_t *listEntry = nullptr;v1_pod_t *pod = nullptr;list_ForEach(listEntry, pod_list->items){pod = static_cast<v1_pod_t *>(listEntry->data);if (pod && pod->metadata && pod->metadata->name)printf("  Pod: %s Namespace: %s\n", pod->metadata->name, pod->metadata->_namespace);}v1_pod_list_free(pod_list);
}int main()
{kube_params_t *params = new kube_params_t;K8sCluster info(params);const char *ns = "kube-system";info.list_pod(ns);apiClient_unsetupGlobalEnv();return 0;
}

CMake 编译文件配置

cmake_minimum_required(VERSION 3.16.3)
project(k8scon)
set(CXX_STANDARD 11)
set(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR}/bin)
# 如果 include 不在默认路径，还要加上
include_directories(/usr/local/include)
link_directories(/usr/local/lib)
add_executable(case case1.cc)
# 如果库在 /usr/local/lib 下
target_link_libraries(casekubernetes           # <-- 核心 SDKcurl                 # SDK 使用 libcurlssl                  # OpenSSLcrypto               # OpenSSLpthread              # 网络请求线程安全
)