chore(libsinsp): add some comments

Signed-off-by: Roberto Scolaro <[email protected]>

userspace/libsinsp/container.h

@@ -226,10 +226,12 @@ class sinsp_container_manager : public libsinsp::container_engine::container_cac
 	 * \brief do we want to start a new lookup for container metadata?
 	 * @param container_id the container id we want to look up
 	 * @param ctype the container engine that is doing the lookup
+	 * @param engine_index index of container engine in case of multiple
+	 * engines per container type
 	 * @return true if there's no lookup in progress and we're free to start
 	 * a new one, false otherwise
 	 *
-	 * This method effectively checks if m_lookups[container_id][ctype]
+	 * This method effectively checks if m_lookups[container_id][ctype][engine_index]
 	 * exists, without creating unnecessary map entries along the way.
 	 */
 	bool should_lookup(const std::string& container_id,

userspace/libsinsp/container_engine/containerd.cpp

@@ -27,6 +27,9 @@ limitations under the License.
 using namespace libsinsp::container_engine;
 using namespace libsinsp::runc;
 
+// Containers created via ctr use the "default" namespace (instead of the cri "k8s.io" namespace)
+// which will result in the `/default` cgroup path.
+// https://github.com/containerd/containerd/blob/3b15606e196e450cf817fa9f835ab5324b35a28b/pkg/namespaces/context.go#L32
 constexpr const cgroup_layout CONTAINERD_CGROUP_LAYOUT[] = {{"/default/", ""}, {nullptr, nullptr}};
 
 constexpr const std::string_view CONTAINERD_SOCKETS[] = {

userspace/libsinsp/container_engine/cri.cpp

@@ -245,6 +245,8 @@ bool cri::resolve(sinsp_threadinfo *tinfo, bool query_os_for_missing_info) {
 	} else {
 		cache->notify_new_container(container, tinfo);
 	}
+	// note: with more than one container runtime we cannot be sure if a resolution is enough
+	// and we have to query all the runtimes.
 	return false;
 }