Merge pull request #242 from DanyT/feature/load-kubeconfig-from-memory

add support to load kubernetes configuration for memory buffer

examples/Makefile

@@ -2,6 +2,7 @@ all:
 	cd create_pod; make
 	cd list_pod_with_invalid_kubeconfig; make
 	cd list_pod; make
+	cd list_pod_buffer; make
 	cd list_pod_incluster; make
 	cd delete_pod; make
 	cd exec_provider; make
@@ -18,6 +19,7 @@ clean:
 	cd create_pod; make clean
 	cd list_pod_with_invalid_kubeconfig; make clean
 	cd list_pod; make clean
+	cd list_pod_buffer; make clean
 	cd list_pod_incluster; make clean
 	cd delete_pod; make clean
 	cd exec_provider; make clean
@@ -35,6 +37,7 @@ test:
 	kubectl wait --for=condition=ready --all pod -n default --timeout=60s
 	cd list_pod_with_invalid_kubeconfig; make test
 	cd list_pod; make test
+	cd list_pod_buffer; make test
 	cd delete_pod; make test
 	kubectl wait --for=delete pod/test-pod-6 -n default --timeout=120s
 	cd list_secret; make test
@@ -51,6 +54,7 @@ memcheck:
 	kubectl wait --for=condition=ready --all pod -n default --timeout=60s
 	cd list_pod_with_invalid_kubeconfig; make memcheck
 	cd list_pod; make memcheck
+	cd list_pod_buffer; make memcheck
 	cd delete_pod; make memcheck
 	kubectl wait --for=delete pod/test-pod-6 -n default --timeout=120s
 	cd list_secret; make memcheck

examples/list_pod_buffer/.gitignore

@@ -0,0 +1 @@
+list_pod_buffer_bin

examples/list_pod_buffer/CMakeLists.txt

@@ -0,0 +1,4 @@
+find_package(${pkgName} CONFIG REQUIRED COMPONENTS ${pkgName})
+
+add_executable(list_pod_buffer main.c)
+target_link_libraries(list_pod_buffer PRIVATE ${pkgName}::${pkgName})

examples/list_pod_buffer/Makefile

@@ -0,0 +1,17 @@
+INCLUDE:=-I../../kubernetes/ -I/usr/local/include/kubernetes/
+LIBS:=-L../../kubernetes/build -lyaml -lwebsockets -lkubernetes -L/usr/local/lib
+CFLAGS:=-g
+BIN:=list_pod_buffer_bin
+
+.PHONY : all clean test memcheck
+all:
+	gcc main.c $(CFLAGS) $(INCLUDE) $(LIBS) -o $(BIN)
+
+test:
+	./$(BIN)
+
+memcheck:
+	valgrind --tool=memcheck --leak-check=full ./$(BIN)
+
+clean:
+	rm ./$(BIN)

examples/list_pod_buffer/main.c

@@ -0,0 +1,135 @@
+#include <config/kube_config.h>
+#include <api/CoreV1API.h>
+#include <stdio.h>
+
+#define ENV_KUBECONFIG "KUBECONFIG"
+#ifndef _WIN32
+#define ENV_HOME "HOME"
+#else
+#define ENV_HOME "USERPROFILE"
+#endif
+
+#define KUBE_CONFIG_DEFAULT_LOCATION "%s/.kube/config"
+
+static char *getWorkingConfigFile(const char *configFileNamePassedIn)
+{
+    char *configFileName = NULL;
+    const char *kubeconfig_env = NULL;
+    const char *homedir_env = NULL;
+
+    if (configFileNamePassedIn) {
+        configFileName = strdup(configFileNamePassedIn);
+    } else {
+        homedir_env = getenv(ENV_HOME);
+        if (homedir_env) {
+            int configFileNameSize = strlen(homedir_env) + strlen(KUBE_CONFIG_DEFAULT_LOCATION) + 1;
+            configFileName = calloc(configFileNameSize, sizeof(char));
+            if (configFileName) {
+                snprintf(configFileName, configFileNameSize, KUBE_CONFIG_DEFAULT_LOCATION, homedir_env);
+            }
+        }
+    }
+
+    return configFileName;
+}
+
+static char *getFileData(const char *filePath)
+{
+    char *data = NULL;
+    char *kubeConfigFile = getWorkingConfigFile(filePath);
+    if (kubeConfigFile) {
+        FILE *kubeFile = fopen(kubeConfigFile, "r");
+        if (kubeFile) {
+            fseek(kubeFile, 0, SEEK_END);
+            long fsize = ftell(kubeFile);
+            fseek(kubeFile, 0, SEEK_SET);
+
+            data = calloc(1, fsize + 1);
+            if (data) {
+                fread(data, 1, fsize, kubeFile);
+            }
+
+            fclose(kubeFile);
+        } else {
+            printf("Could not open %s!\n", kubeConfigFile);
+        }
+
+        free(kubeConfigFile);
+    } else {
+        printf("Could not determine the path to kubernetes configuration file! Tried: ENV_KUBECONFIG = %s and ENV_HOME = %s\n",
+            getenv(ENV_KUBECONFIG), getenv(ENV_HOME) );
+    }
+    
+
+    return data;
+}
+
+void list_pod(apiClient_t * apiClient)
+{
+    v1_pod_list_t *pod_list = NULL;
+    pod_list = CoreV1API_listNamespacedPod(apiClient, "default",    /*namespace */
+                                           NULL,    /* pretty */
+                                           NULL,    /* allowWatchBookmarks */
+                                           NULL,    /* continue */
+                                           NULL,    /* fieldSelector */
+                                           NULL,    /* labelSelector */
+                                           NULL,    /* limit */
+                                           NULL,    /* resourceVersion */
+                                           NULL,    /* resourceVersionMatch */
+                                           NULL,    /* sendInitialEvents */
+                                           NULL,    /* timeoutSeconds */
+                                           NULL /* watch */
+        );
+    printf("The return code of HTTP request=%ld\n", apiClient->response_code);
+    if (pod_list) {
+        printf("Get pod list:\n");
+        listEntry_t *listEntry = NULL;
+        v1_pod_t *pod = NULL;
+        list_ForEach(listEntry, pod_list->items) {
+            pod = listEntry->data;
+            printf("\tThe pod name: %s\n", pod->metadata->name);
+        }
+        v1_pod_list_free(pod_list);
+        pod_list = NULL;
+    } else {
+        printf("Cannot get any pod.\n");
+    }
+}
+
+int main()
+{
+    char *basePath = NULL;
+    sslConfig_t *sslConfig = NULL;
+    list_t *apiKeys = NULL;
+
+    char *dataBuffer = getFileData(NULL);   /* NULL means loading configuration from $HOME/.kube/config */
+    if (dataBuffer == NULL) {
+        printf("Cannot get kubernetes configuration from file.\n");
+        return -1;
+    }
+
+    int rc = load_kube_config_buffer(&basePath, &sslConfig, &apiKeys, dataBuffer);
+    if (rc != 0) {
+        printf("Cannot load kubernetes configuration.\n");
+        return -1;
+    }
+    apiClient_t *apiClient = apiClient_create_with_base_path(basePath, sslConfig, apiKeys);
+    if (!apiClient) {
+        printf("Cannot create a kubernetes client.\n");
+        return -1;
+    }
+
+    list_pod(apiClient);
+
+    apiClient_free(apiClient);
+    apiClient = NULL;
+    free_client_config(basePath, sslConfig, apiKeys);
+    basePath = NULL;
+    sslConfig = NULL;
+    apiKeys = NULL;
+    apiClient_unsetupGlobalEnv();
+    free(dataBuffer);
+    dataBuffer = NULL;
+
+    return 0;
+}

kubernetes/config/kube_config.c

@@ -304,24 +304,17 @@ static int kuberconfig_auth_provider(kubeconfig_property_t * current_user, kubec
     return rc;
 }
 
-int load_kube_config(char **pBasePath, sslConfig_t ** pSslConfig, list_t ** pApiKeys, const char *configFileName)
+int load_kube_config_common(char **pBasePath, sslConfig_t ** pSslConfig, list_t ** pApiKeys, kubeconfig_t * kubeconfig)
 {
-    static char fname[] = "load_kube_config()";
+    static char fname[] = "load_kube_config_common()";
     int rc = 0;
     const kubeconfig_property_t *current_context = NULL;
     const kubeconfig_property_t *current_cluster = NULL;
     kubeconfig_property_t *current_user = NULL;
 
-    kubeconfig_t *kubeconfig = kubeconfig_create();
-    if (!kubeconfig) {
-        fprintf(stderr, "%s: Cannot create kubeconfig.[%s]\n", fname, strerror(errno));
-        return -1;
-    }
-
-    kubeconfig->fileName = getWorkingConfigFile(configFileName);
     rc = kubeyaml_load_kubeconfig(kubeconfig);
     if (0 != rc) {
-        fprintf(stderr, "%s: Cannot load the kubeconfig %s\n", fname, kubeconfig->fileName);
+        fprintf(stderr, "%s: Cannot load the kubeconfig %s\n", fname, kubeconfig->fileName ? kubeconfig->fileName : kubeconfig->buffer);
         rc = -1;
         goto end;
     }
@@ -393,8 +386,40 @@ int load_kube_config(char **pBasePath, sslConfig_t ** pSslConfig, list_t ** pApi
     }
 
   end:
-    kubeconfig_free(kubeconfig);
-    kubeconfig = NULL;
+    return rc;
+}
+
+int load_kube_config(char **pBasePath, sslConfig_t ** pSslConfig, list_t ** pApiKeys, const char *configFileName)
+{
+    static char fname[] = "load_kube_config()";
+    int rc = 0;
+
+    kubeconfig_t kubeconfig;
+    memset(&kubeconfig, 0, sizeof(kubeconfig_t));
+
+    kubeconfig.fileName = getWorkingConfigFile(configFileName);
+
+    rc = load_kube_config_common(pBasePath, pSslConfig, pApiKeys, &kubeconfig);
+
+    kubeconfig_free_members(&kubeconfig);
+
+    return rc;
+}
+
+int load_kube_config_buffer(char **pBasePath, sslConfig_t ** pSslConfig, list_t ** pApiKeys, const char *buffer)
+{
+    static char fname[] = "load_kube_config_buffer()";
+    int rc = 0;
+
+    kubeconfig_t kubeconfig;
+    memset(&kubeconfig, 0, sizeof(kubeconfig_t));
+
+    kubeconfig.buffer = strdup(buffer);
+
+    rc = load_kube_config_common(pBasePath, pSslConfig, pApiKeys, &kubeconfig);
+
+    kubeconfig_free_members(&kubeconfig);
+
     return rc;
 }
 

kubernetes/config/kube_config.h

@@ -46,6 +46,44 @@ extern "C" {
 
     int load_kube_config(char **pBasePath, sslConfig_t ** pSslConfig, list_t ** pApiKeys, const char *configFileName);
 
+/*
+ * load_kube_config_buffer
+ *
+ *
+ * Description:
+ *
+ *
+ * Load kubernetes cluster configuration from specfied buffer
+ *
+ *
+ * Return:
+ *
+ *   0     Success
+ *  -1     Failed
+ *
+ *
+ * Parameter:
+ *
+ *
+ * IN:
+
+ * buffer : kubernetes cluster configuration data
+ *
+ *
+ * OUT:
+ *
+ * pBasePath: The pointer to API server address
+ * pSslConfig: The pointer to SSL configuration for client
+ * pApiKeys: The pointer to API tokens for client
+ *
+ * The memory will be allocated inside this function. User 
+ * should call free_client_config to free the memory after 
+ * these parameters are not used.
+ *
+ */
+
+    int load_kube_config_buffer(char **pBasePath, sslConfig_t ** pSslConfig, list_t ** pApiKeys, const char *buffer);
+
 /*
  * free_client_config
  *

kubernetes/config/kube_config_model.c

@@ -214,7 +214,7 @@ kubeconfig_t *kubeconfig_create()
     return config;
 }
 
-void kubeconfig_free(kubeconfig_t * kubeconfig)
+void kubeconfig_free_members(kubeconfig_t * kubeconfig)
 {
     if (!kubeconfig) {
         return;
@@ -224,6 +224,10 @@ void kubeconfig_free(kubeconfig_t * kubeconfig)
         free(kubeconfig->fileName);
         kubeconfig->fileName = NULL;
     }
+    if (kubeconfig->buffer) {
+        free(kubeconfig->buffer);
+        kubeconfig->buffer = NULL;
+    }
     if (kubeconfig->apiVersion) {
         free(kubeconfig->apiVersion);
         kubeconfig->apiVersion = NULL;
@@ -252,6 +256,15 @@ void kubeconfig_free(kubeconfig_t * kubeconfig)
         kubeconfig_properties_free(kubeconfig->contexts, kubeconfig->contexts_count);
         kubeconfig->contexts = NULL;
     }
+}
+
+void kubeconfig_free(kubeconfig_t * kubeconfig)
+{
+    if (!kubeconfig) {
+        return;
+    }
+
+    kubeconfig_free_members(kubeconfig);
 
     free(kubeconfig);
 }

kubernetes/config/kube_config_model.h

@@ -88,6 +88,7 @@ extern "C" {
 
     typedef struct kubeconfig_t {
         char *fileName;
+        char *buffer;
         char *apiVersion;
         char *preferences;
         char *kind;
@@ -112,9 +113,17 @@ extern "C" {
     kubeconfig_property_t **kubeconfig_properties_create(int contexts_count, kubeconfig_property_type_t type);
     void kubeconfig_properties_free(kubeconfig_property_t ** properties, int properties_count);
 
+    // allocate kubeconfig_t structure on heap
     kubeconfig_t *kubeconfig_create();
+
+    // free a kubeconfig_t structure allocated on heap by a call to kubeconfig_create
     void kubeconfig_free(kubeconfig_t * kubeconfig);
 
+    // free internal members of a kubeconfig_t structure.
+    // used when releasing resources for a kubeconfig_t that was not allocated using kubeconfig_create
+    // for example a kubeconfig_t allocated on stack
+    void kubeconfig_free_members(kubeconfig_t * kubeconfig);
+
 #ifdef  __cplusplus
 }
 #endif

kubernetes/config/kube_config_yaml.c

@@ -430,7 +430,12 @@ int kubeyaml_load_kubeconfig(kubeconfig_t * kubeconfig)
 {
     static char fname[] = "kubeyaml_load_kubeconfig()";
 
-    /* Set a file input. */
+    if (kubeconfig->fileName && kubeconfig->buffer) {
+        fprintf(stderr, "%s: Cannot use both kubeconfig->fileName and kubeconfig->buffer.\n", fname);
+        return -1;
+    }
+
+    /* Set a file input or use the provided buffer. */
     FILE *input = NULL;
     if (kubeconfig->fileName) {
         input = fopen(kubeconfig->fileName, "rb");
@@ -438,17 +443,23 @@ int kubeyaml_load_kubeconfig(kubeconfig_t * kubeconfig)
             fprintf(stderr, "%s: Cannot open the file %s.[%s]\n", fname, kubeconfig->fileName, strerror(errno));
             return -1;
         }
+    } else if (kubeconfig->buffer) {
+        // Nothing to do here for now.
     } else {
-        fprintf(stderr, "%s: The kubeconf file name needs be set by kubeconfig->fileName .\n", fname);
+        fprintf(stderr, "%s: One of the kubeconfig->fileName or kubeconfig->buffer needs to be set.\n", fname);
         return -1;
     }
 
+    /* Create the Parser object. */
     yaml_parser_t parser;
     yaml_document_t document;
 
-    /* Create the Parser object. */
     yaml_parser_initialize(&parser);
+    if (input) {
         yaml_parser_set_input_file(&parser, input);
+    } else {
+        yaml_parser_set_input_string(&parser, (const unsigned char *) kubeconfig->buffer, strlen(kubeconfig->buffer));
+    }
 
     int done = 0;
     while (!done) {
@@ -469,12 +480,16 @@ int kubeyaml_load_kubeconfig(kubeconfig_t * kubeconfig)
 
     /* Cleanup */
     yaml_parser_delete(&parser);
+    if (input) {
         fclose(input);
+    }
     return 0;
 
   error:
     yaml_parser_delete(&parser);
+    if (input) {
         fclose(input);
+    }
     return -1;
 }
 

kubernetes/config/kube_config_yaml.h

@@ -24,6 +24,9 @@ extern "C" {
  *
  * IN:
  * kubeconfig->fileName: kubernetes cluster configuration file name
+ * kubeconfig->buffer: kubernetes cluster configuration data; this is considered only if kubeconfig->fileName is set to NULL
+ * 
+ * Note: One may use either kubeconfig->fileName or kubeconfig->buffer but not both at the same time.
  * 
  * OUT:
  * kubeconfig: kubernetes cluster configuration