MCOL-5496: Merge CMAPI code to engine repo.

[add] cmapi code to engine

cmapi/mcs_node_control/models/node_status.py

@@ -0,0 +1,91 @@
+import logging
+import socket
+
+from cmapi_server.constants import MCS_DATA_PATH, MCS_MODULE_FILE_PATH
+from mcs_node_control.models.dbrm import DBRM
+from mcs_node_control.models.misc import get_dbroots_list, read_module_id
+from mcs_node_control.models.process import get_host_uptime
+
+
+PROC_NAMES = ['ExeMgr', 'PrimProc', 'WriteEngine', 'controllernode',
+              'workernode', 'cmagent', 'DMLProc', 'DDLProc']
+
+
+module_logger = logging.getLogger()
+
+
+class NodeStatus:
+    """Class to tell the status of the node.
+
+    Inspects runtime of the cluster and OS and returns its observations.
+    """
+    def get_cluster_mode(self):
+        """Reads cluster mode.
+
+        Cluster can be in readwrite or readonly modes. It can be also ready or
+        not ready but it is not important at this point. We pesume if there is
+        no connection with DBRM master then the cluster is readonly.
+
+        TODO:
+            - Is it ok to have those method here in NodeStatus?
+              Move to DBRM.
+            - pass 'root' and config_filename arguments
+              (likewise dbrm.set_cluster_mode)
+
+        :rtype: string
+        """
+        try:
+            with DBRM() as dbrm:
+                return dbrm.get_cluster_mode()
+        except (ConnectionRefusedError, RuntimeError, socket.error):
+            module_logger.error(
+                'Cannot establish or use DBRM connection.',
+                exc_info=True
+            )
+            return 'readonly'
+
+
+    def get_dbrm_status(self):
+        """reads DBRM status
+
+        DBRM Block Resolution Manager operates in two modes:
+        master and slave. This m() returns the mode of this node
+        looking for controllernode process running.
+
+        :rtype: string
+        """
+        return DBRM.get_dbrm_status()
+
+    def get_dbroots(self, path:str = MCS_DATA_PATH):
+        """searches for services
+
+        The method returns numeric ids of dbroots available.
+
+        :rtype: generator of ints
+        """
+        for id in get_dbroots_list(path):
+            yield id
+
+
+    def get_host_uptime(self):
+        """Retrieves uptime in seconds.
+
+        :rtype: int : seconds
+        """
+        return get_host_uptime()
+
+
+    def get_module_id(self):
+        """Retrieves module ID from MCS_MODULE_FILE_PATH.
+
+        :rtype: int : seconds
+        """
+        func_name = 'get_module_id'
+        try:
+            module_id = read_module_id()
+        except FileNotFoundError:
+            module_id = 0
+            module_logger.error(
+                f'{func_name} {MCS_MODULE_FILE_PATH} file is absent.'
+            )
+        return module_id