container_info.h

/*
 *
 * (C) 2018-22 - ntop.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#ifndef __CONTAINER_INFO_HPP__
#define __CONTAINER_INFO_HPP__ 1

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <unordered_map>
#include <set>
#include <string>
 
struct container_info {
  struct {
    std::string name;
  } docker;
  
  struct {
    std::string name, pod, ns;
  } kube;
};

// Cache cleaning and namespace update interval in seconds
#define REFRESH_TIME 30

struct cache_entry {
  int num_uses;
  struct container_info content;
};

class ContainerInfo {
 private:
  // Cache where to store the queries results
  std::unordered_map<std::string, struct cache_entry> gQueryCache;

  // Namespace cache
  std::set<std::string> namespaces;
  
  char ctr_path[64];

  /*
   * Gather namespaces from ctr or docker-containerd-ctr
   */
  int update_namespaces();

  /* 
   * Removes from the cache all those entries that have
   * been accessed less than MIN_VISITS times
   */
  void clean_cache();
  
  /*
   * Create the entry if it does not exist, otherwise updates the content
   */
  void update_cache_entry(char* t_containerid, struct cache_entry *t_dqr);

  /* parse_response - fill a container_info data structure with the information returned by a query to
   *   the docker daemon
   * buff: if NULL a dummy entry will be created (not added to the cache)
   * return 0 if no error occurred -1 otherwise 
   */
  int parse_response(const char* buff, ssize_t buffsize, struct container_info *entry);

  /* 
   * update_query_cache - query to docker api from docker socket (/var/run/docker.sock) and caches the result.
   * @t_containerid: full length cgroup id
   * @t_dqr: filled with the information gathered if no error occurred
   * returns 0 if no error occurres and container info has been found, otherwise -1
   * note: the same operation can be done using 
   *       `$ curl --unix-socket /var/run/docker.sock http://localhost/containers/<container-id>/json`
   */
  int dockerd_update_query_cache(char* t_containerid, struct container_info **t_dqr);

  /* 
   * update_query_cache - exec ctr (i.e. containerd cli) to retrieve information
   *  concerning the container. If ctr is not available it will be tried: docker-containerd-ctr
   * @t_containerid: full length cgroup id
   * @t_ns: target namespace
   * @t_dqr: filled with the information gathered if no error occurred
   * returns 0 if no error occurres and container info has been found, otherwise -1
   * note: the same operation can be done using 
   *       `$ sudo ctr --namespace=<namespace> containers info <container-id>`
   */
  int containerd_update_query_cache (char* t_containerid, struct container_info **t_dqr);

  /* *********************************** */
  // ===== ===== CACHE CHECK ===== ===== //
  /* *********************************** */
  /*
   * container_id_cached - check if containers info have been cached
   *    and if some info are available stores them in *t_dqs
   * @t_containerid: docker container ID
   * @t_dqs: will point to the cache entry if no error occurs (returns != -1)
   * returns 0 if the cache contains information concerning the container
   *      -1 if there no entry corresponding to the ID provided. 1 if 
   *    there is an entry associated with the ID but there isn't 
   *    information available
   */
  int container_id_find_in_cache(char *t_containerid, struct container_info **t_dqs);

 public:
  ContainerInfo();
  ~ContainerInfo();

  /*
   * Retrieves container information
   * @t_containerId: container ID
   * @t_dqs: will point to the container informations if no error occurs (returns != -1)
   * returns 0 if some info has been found, -1 otherwise   
   */
  int get_container_info(char* t_containerId, container_info **t_dqr);
};

#endif /* __CONTAINER_INFO_HPP__ */