Dockerfile

FROM ubuntu

RUN apt update
RUN apt install -y libmysqlclient-dev gcc rsync

mysql-client.c

#include<mysql.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>

int main() {
	MYSQL *mysql = mysql_init(NULL);
	printf("%p\n", mysql);
	{
		const char *host = getenv("TWITTER_REVIEW_DB_PORT_3306_TCP_ADDR");
		const char *password = getenv("TWITTER_REVIEW_DB_ENV_MYSQL_PASSWORD");
		const char *database = getenv("TWITTER_REVIEW_DB_ENV_MYSQL_DATABASE");
		const char *user = getenv("TWITTER_REVIEW_DB_ENV_MYSQL_USER");
		const int port = atoi(getenv("TWITTER_REVIEW_DB_PORT_3306_TCP_PORT"));
		MYSQL *error = mysql_real_connect(mysql, host, user, password, database, port, "", 0);
		if (error == NULL) {
			fprintf(stderr, "mysql_real_connect: error\n");
			mysql_close(mysql);
			exit(1);
		}
	}
	printf("server info: %s\n", mysql_get_server_info(mysql));
	{
		my_bool error = mysql_autocommit(mysql, 0);
		if (error) {
			fprintf(stderr, "mysql_autocommit: error\n");
			mysql_close(mysql);
			exit(1);
		}
	}
	{
		int error = mysql_query(mysql, "START TRANSACTION");
		if (error) {
			fprintf(stderr, "mysql_query: error\n");
			mysql_close(mysql);
			exit(1);
		}
	}
	{
		MYSQL_STMT *stmt = mysql_stmt_init(mysql);
		if (stmt == NULL) {
			fprintf(stderr, "mysql_stmt_init: error\n");
			mysql_close(mysql);
			exit(1);
		}
		{
			const char * const stmt_str = "SELECT `display_name` FROM `user` WHERE `id` = ?";
			int error = mysql_stmt_prepare(stmt, stmt_str, strlen(stmt_str));
			if (error) {
				fprintf(stderr, "mysql_stmt_prepare: error\n");
				mysql_close(mysql);
				exit(1);
			}
		}
		MYSQL_RES *result_metadata = mysql_stmt_result_metadata(stmt);
		if (result_metadata == NULL) {
			fprintf(stderr, "mysql_stmt_result_metadata: error\n");
			mysql_close(mysql);
			exit(1);
		}
		MYSQL_FIELD *field;
		while(field = mysql_fetch_field(result_metadata))
		{
			printf("field name: %s\n", field->name);
		}
		long long user_id = 1;
		MYSQL_BIND param;
		unsigned long user_id_length = sizeof(user_id);
		memset(&param, 0, 1);
		param.buffer_type = MYSQL_TYPE_LONGLONG;
		param.buffer = &user_id;
		param.buffer_length = sizeof(user_id);
		param.is_null = NULL;
		param.length = &user_id_length;
		{
			my_bool error = mysql_stmt_bind_param(stmt, &param);
			if (error) {
				fprintf(stderr, "mysql_stmt_bind_param: error\n");
				mysql_close(mysql);
				exit(1);
			}
		}
		{
			int error = mysql_stmt_execute(stmt);
			if (error) {
				fprintf(stderr, "mysql_stmt_execute: error\n");
				mysql_close(mysql);
				exit(1);
			}
		}
		MYSQL_BIND result;
		char display_name[100];
		unsigned long display_name_length;
		my_bool display_name_error;
		memset(&result, 0, 1);
		result.buffer = display_name;
		result.buffer_length = sizeof(display_name) * sizeof(display_name[0]);
		result.is_null = NULL;
		result.length = &display_name_length;
		result.error = &display_name_error;
		{
			my_bool error = mysql_stmt_bind_result(stmt, &result);
			if (error) {
				fprintf(stderr, "mysql_stmt_bind_result\n");
				mysql_close(mysql);
				exit(1);
			}
		}
		// {
		// 	int fetch_result = mysql_stmt_fetch(stmt);
		// 	switch (fetch_result) {
		// 		case MYSQL_NO_DATA:
		// 			printf("mysql_stmt_fetch: MYSQL_NO_DATA\n");
		// 			break;
		// 		case MYSQL_DATA_TRUNCATED:
		// 			printf("mysql_stmt_fetch: MYSQL_DATA_TRUNCATED\n");
		// 			break;
		// 		default:
		// 			printf("mysql_stmt_fetch: %d\n", fetch_result);
		// 	}
		// 	printf("display_name: %s\n", display_name);
		// 	switch (result.buffer_type) {
		// 		case MYSQL_TYPE_BLOB:
		// 			printf("display_name type: MYSQL_TYPE_BLOB\n");
		// 		default:
		// 			printf("display_name type: %d\n", result.buffer_type);
		// 	}
		// 	printf("display_name_length: %ld\n", display_name_length);
		// 	printf("display_name_error: %d\n", display_name_error);
		// }
		{
			my_ulonglong rows = mysql_stmt_affected_rows(stmt);
			printf("mysql_stmt_affected_rows: %ld\n", (long)rows);
		}
		{
			MYSQL_STMT *stmt2 = mysql_stmt_init(mysql);
			if (stmt == NULL) {
				fprintf(stderr, "mysql_stmt_init: error\n");
				mysql_close(mysql);
				exit(1);
			}
			{
				const char * const stmt_str = "SELECT `email` FROM `user` WHERE `id` = ?";
				int error = mysql_stmt_prepare(stmt2, stmt_str, strlen(stmt_str));
				if (error) {
					fprintf(stderr, "mysql_stmt_prepare: error\n");
					fprintf(stderr, "error message: %s\n", mysql_stmt_error(stmt2));
					mysql_close(mysql);
					exit(1);
				}
			}
		}
		mysql_free_result(result_metadata);
		{
			my_bool error = mysql_stmt_close(stmt);
			if (error) {
				fprintf(stderr, "mysql_stmt_close: error\n");
				mysql_close(mysql);
				exit(1);
			}
		}
	}
	mysql_close(mysql);
	return 0;
}