feat: containers memory check plugin

Signed-off-by: Davide Madrisan <[email protected]>

include/container.h

@@ -80,11 +80,12 @@ extern "C"
   long long docker_memory_get_total_pgpgout (
     struct docker_memory_desc *memdesc);
 
-  const char *image_shortname (const char *image);
-
   int docker_running_containers (char *socket, unsigned int *count,
 		  		 const char *image, char **perfdata,
 				 bool verbose);
+  int docker_running_containers_memory (char *socket,
+					long long unsigned int *memory,
+					char **perfdata, bool verbose);
 
 #ifdef __cplusplus
 }

include/json_helpers.h

@@ -28,7 +28,8 @@ extern "C"
   int json_token_streq (const char *json, jsmntok_t * tok, const char *s);
   char *json_token_tostr (char *json, jsmntok_t * t);
   jsmntok_t *json_tokenise (const char *json, size_t *ntoken);
-  void json_printf_pretty (const char *json, char **dump, int indent);
+  void json_dump_pretty (const char *json, char **dump, int indent);
+  int json_search (const char *json, const char *path, char **value);
 
 #ifdef __cplusplus
 }

lib/container.c

@@ -45,18 +45,20 @@
 #include "url_encode.h"
 #include "xalloc.h"
 #include "xasprintf.h"
+#include "xstrton.h"
 
 /* Hide all jsmn API symbols by making them static */
 #define JSMN_STATIC
 #include "jsmn.h"
 
 #define DOCKER_CONTAINERS_JSON  0x01
+#define DOCKER_STATS_JSON       0x02
 
 /* returns the last portion of the given container image.
    example:
      "prom/prometheus:v2.39.0"  -->  "prometheus:v2.39.0"
    note that docker just removes the prefix "docker.io/".  */
-const char *
+static const char *
 image_shortname (const char *image)
 {
   const char *strip = strrchr (image, '/');
@@ -69,9 +71,11 @@ image_shortname (const char *image)
   return strip;
 }
 
-/* parse the json stream returned by Docker and return a pointer to the
-   hashtable containing the values of the discovered 'tokens'.
-   return NULL if the data cannot be parsed.  */
+/* parse the json stream returned by the Docker/Podman API and return a pointer
+   to the hashtable containing the values of the discovered 'tokens'.
+   return NULL if the data cannot be parsed.
+   the function 'convert' allows a manipulation of the data before saving it in
+   the hashtable.  */
 
 static hashtable_t *
 docker_json_parser_search (const char *json, const char *token,
@@ -94,7 +98,7 @@ docker_json_parser_search (const char *json, const char *token,
 
 	  dbg ("found token \"%s\" with value \"%s\" at position %d\n",
 	       token, value, buffer[i].start);
-	  counter_put (hashtable, convert (value), increment);
+	  counter_put (hashtable, convert ? convert (value) : value, increment);
 	  free (value);
 	}
     }
@@ -156,14 +160,15 @@ docker_init (CURL **curl_handle, chunk_t *chunk, const char *socket)
   curl_easy_setopt (*curl_handle, CURLOPT_WRITEFUNCTION,
 		    write_memory_callback);
   curl_easy_setopt (*curl_handle, CURLOPT_WRITEDATA, (void *) chunk);
+  curl_easy_setopt (*curl_handle, CURLOPT_NOPROGRESS, 1L);
 
   /* some servers don't like requests that are made without a user-agent
      field, so we provide one */
   curl_easy_setopt (*curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0");
 }
 
 static CURLcode
-docker_get (CURL *curl_handle, const int query)
+docker_get (CURL *curl_handle, const int query, const char *id)
 {
   CURLcode res;
   char *api_version, *class, *url, *filter = NULL;
@@ -181,18 +186,23 @@ docker_get (CURL *curl_handle, const int query)
       plugin_error (STATE_UNKNOWN, 0, "unknown docker query");
     case DOCKER_CONTAINERS_JSON:
       filter = url_encode ("{\"status\":{\"running\":true}}");
-      class = "containers/json";
+      class = xasprintf ("containers/json");
       url = filter ?
 	xasprintf ("http://v%s/%s?filters=%s", api_version, class, filter) :
 	xasprintf ("http://v%s/%s", api_version, class);
       break;
+    case DOCKER_STATS_JSON:
+      class = xasprintf ("containers/%s/stats", id);
+      url = xasprintf ("http://v%s/%s?stream=false", api_version, class);
+      break;
     }
 
   dbg ("docker rest url: %s\n", url);
 
   curl_easy_setopt (curl_handle, CURLOPT_URL, url);
   res = curl_easy_perform (curl_handle);
 
+  free (class);
   free (filter);
   free (url);
 
@@ -213,47 +223,67 @@ docker_close (CURL *curl_handle, chunk_t *chunk)
 
 #endif /* NPL_TESTING */
 
-/* Returns the number of running Docker containers  */
-
-int
-docker_running_containers (char *socket, unsigned int *count,
-			   const char *image, char **perfdata, bool verbose)
+static int
+docker_api_call (char *socket, chunk_t *chunk, CURL *curl_handle,
+		 const char *search_key, bool verbose)
 {
-  chunk_t chunk;
-  hashtable_t *hashtable;
-  unsigned int running_containers = 0;
-
 #ifndef NPL_TESTING
 
-  CURL *curl_handle = NULL;
   CURLcode res;
 
-  docker_init (&curl_handle, &chunk, socket);
-  res = docker_get (curl_handle, DOCKER_CONTAINERS_JSON);
+  curl_handle = NULL;
+  docker_init (&curl_handle, chunk, socket);
+  res = docker_get (curl_handle, DOCKER_CONTAINERS_JSON, NULL);
   if (CURLE_OK != res)
     {
-      docker_close (curl_handle, &chunk);
+      docker_close (curl_handle, chunk);
       plugin_error (STATE_UNKNOWN, errno, "%s", curl_easy_strerror (res));
     }
 
 #else
 
   int err;
-  if ((err = docker_get (&chunk, DOCKER_CONTAINERS_JSON)) != 0)
+  if ((err = docker_get (chunk, DOCKER_CONTAINERS_JSON, NULL)) != 0)
     return err;
 
 #endif /* NPL_TESTING */
 
-  assert (chunk.memory);
-  dbg ("%zu bytes retrieved\n", chunk.size);
-  dbg ("json data: %s", chunk.memory);
+  assert (chunk->memory);
+  dbg ("%zu bytes retrieved\n", chunk->size);
+  dbg ("json data: %s", chunk->memory);
+
+#ifdef ENABLE_DEBUG
+  char *dump;
+
+  json_dump_pretty (chunk->memory, &dump, 1);
+  dbg ("json data pretty formatted:%s", dump);
+  free (dump);
+#endif
+
+  return 0;
+}
+
+/* Returns the number of running Docker/Podman containers grouped by images  */
+
+int
+docker_running_containers (char *socket, unsigned int *count,
+			   const char *image, char **perfdata, bool verbose)
+{
+  chunk_t chunk;
+  CURL *curl_handle = NULL;
+
+  hashtable_t *hashtable;
+  unsigned int running_containers = 0;
+  char *search_key = "Image";
+
+  docker_api_call (socket, &chunk, curl_handle, search_key, verbose);
 
   hashtable =
-    docker_json_parser_search (chunk.memory, "Image", image_shortname, 1);
+    docker_json_parser_search (chunk.memory, search_key, image_shortname, 1);
   if (NULL == hashtable)
     plugin_error (STATE_UNKNOWN, 0,
-		  "unable to parse the json data for \"Image\"s");
-  dbg ("number of docker unique images: %u\n",
+		  "unable to parse the json data for \"%s\"s", search_key);
+  dbg ("number of docker unique containers (by %s): %u\n", search_key,
        counter_get_unique_elements (hashtable));
 
   if (image)
@@ -290,3 +320,100 @@ docker_running_containers (char *socket, unsigned int *count,
 
   return 0;
 }
+
+#ifndef NPL_TESTING
+
+/* Returns the memory usage of a Docker/Podman container  */
+static int
+docker_container_memory (char *socket, const char *id,
+			 long long unsigned int *memory, bool verbose)
+{
+  chunk_t chunk;
+  CURL *curl_handle = NULL;
+  CURLcode res;
+  char *errmesg = NULL;
+  int ret;
+
+  docker_init (&curl_handle, &chunk, socket);
+  res = docker_get (curl_handle, DOCKER_STATS_JSON, id);
+  if (CURLE_OK != res)
+    {
+      docker_close (curl_handle, &chunk);
+      plugin_error (STATE_UNKNOWN, errno, "%s", curl_easy_strerror (res));
+    }
+
+  assert (chunk.memory);
+  dbg ("%zu bytes retrieved\n", chunk.size);
+  dbg ("json data: %s", chunk.memory);
+
+#ifdef ENABLE_DEBUG
+  /*
+  char *dump;
+
+  json_dump_pretty (chunk.memory, &dump, 1);
+  dbg ("json data pretty formatted:%s", dump);
+  free (dump);
+  */
+#endif
+
+  /* get the memory usage  */
+  char *value = NULL;
+  json_search (chunk.memory, ".memory_stats.usage", &value);
+
+  /* FIXME: remove cast  */
+  ret = sizetollint (value, (long long int *)memory, &errmesg);
+  if (ret < 0)
+    plugin_error (STATE_UNKNOWN, errno
+		  , "failed to convert container memory value: %s"
+		  , errmesg);
+
+  free (value);
+
+  return 0;
+}
+
+/* Returns the memory usage of running Docker/Podman containers  */
+
+int
+docker_running_containers_memory (char *socket, long long unsigned int *memory,
+				  char **perfdata, bool verbose)
+{
+  chunk_t chunk;
+  CURL *curl_handle = NULL;
+  hashtable_t *hashtable;
+  char *search_key = "Id";
+
+  /* get the list of running containers  */
+  docker_api_call (socket, &chunk, curl_handle, search_key, verbose);
+
+  hashtable =
+    docker_json_parser_search (chunk.memory, search_key, NULL, 1);
+  if (NULL == hashtable)
+    plugin_error (STATE_UNKNOWN, 0,
+		  "unable to parse the json data for \"%s\"s", search_key);
+  dbg ("number of docker containers: %u\n",
+       counter_get_unique_elements (hashtable));
+
+  long long unsigned int memory_usage;
+  *memory = 0;
+
+  /* FIXME: this loop must be threaded and run in parallel  */
+  for (unsigned int j = 0; j < hashtable->uniq; j++)
+    {
+      const char *id = hashtable->keys[j];
+      docker_container_memory (socket, id, &memory_usage, verbose);
+      dbg ("memory usage for container id \"%s\": %llu\" bytes\n", id,
+	   memory_usage);
+      *memory += (memory_usage >> 10);
+    }
+
+  docker_close (
+#ifndef NPL_TESTING
+                 curl_handle,
+#endif
+                 &chunk);
+
+  return 0;
+}
+
+#endif

lib/json_helpers.c

@@ -133,7 +133,7 @@ json_dump (const char *json, jsmntok_t *t, size_t count, int indent,
 }
 
 void
-json_printf_pretty (const char *json, char **dump, int indent)
+json_dump_pretty (const char *json, char **dump, int indent)
 {
   size_t ntoken, size;
   FILE *stream = open_memstream (dump, &size);
@@ -143,3 +143,49 @@ json_printf_pretty (const char *json, char **dump, int indent)
 
   fclose (stream);
 }
+
+int
+json_search (const char *json, const char *path, char **value)
+{
+  char *p, *object, *label, *saveptr;
+  size_t i, ntoken;
+  bool found_label = false, found_object = false;
+
+  dbg ("checking for %s in the json data...\n", path);
+  jsmntok_t *tok = json_tokenise (json, &ntoken);
+
+  p = xstrdup (path);
+  object = strtok_r (p, ".", &saveptr);
+  label = strtok_r (0, ".", &saveptr);
+
+  if (object == NULL || label == NULL)
+    return -1;
+
+  dbg ("ckeckin for label \"%s\" in the object \"%s\"\n", label, object);
+
+  /* FIXME: the search algorithm sucks :( */
+  for (i = 0; i < ntoken; i++)
+    {
+      if (0 == json_token_streq (json, &tok[i], object))
+	{
+	  dbg ("found object \"%s\"\n", object);
+	  found_object = true;
+	}
+      else if (found_object && (tok[i].type == JSMN_STRING)
+	  && (0 == json_token_streq (json, &tok[i], label)))
+	{
+	  dbg ("found label \"%s\"\n", label);
+	  found_label = true;
+	  /* get the associated value */
+	  size_t strsize = tok[i + 1].end - tok[i + 1].start;
+	  *value = xmalloc (strsize + 1);
+	  memcpy (*value, json + tok[i + 1].start, strsize);
+	  break;
+	}
+    }
+  if (found_label && found_object && NULL != *value)
+    dbg ("found label \"%s\" in the object \"%s\" with value \"%s\"\n", label,
+	 object, *value);
+
+  return 0;
+}