Kubernetes-Client-C
KubernetesC-SDK
https://github.com/kubernetes-client/c
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 token
int _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
- 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 error
return -1;
}
// Create API client with loaded configuration
apiClient = apiClient_create_with_base_path(basePath, sslConfig, apiKeys);
if (!apiClient) {
// Handle error
return -1;
}
// Use the API client...
// Clean up resources
apiClient_free(apiClient);
free_client_config(basePath, sslConfig, apiKeys);
apiClient_unsetupGlobalEnv();
- 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 error
return -1;
}
// Create API client with loaded configuration
apiClient = apiClient_create_with_base_path(basePath, sslConfig, apiKeys);
if (!apiClient) {
// Handle error
return -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 URLsslConfig: 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(case
kubernetes # <-- 核心 SDK
curl # SDK 使用 libcurl
ssl # OpenSSL
crypto # OpenSSL
pthread # 网络请求线程安全
)
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