MCOL-5496: Merge CMAPI code to engine repo.

[add] cmapi code to engine

cmapi/mcs_node_control/models/process.py

@@ -0,0 +1,110 @@
+import os
+import time
+
+import psutil
+
+PROCFS_PATH = '/proc/' # Linux only
+
+
+def open_binary(fname, **kwargs):
+    return open(fname, "rb", **kwargs)
+
+
+def get_host_uptime():
+    """
+    Return the system boot time expressed in seconds since the epoch.
+
+    :rtype: int : diff b/w current epoch and boot epoch
+    """
+    path = f'{PROCFS_PATH}stat'
+    boot_time = 0
+    with open_binary(path) as f:
+        for line in f:
+            if line.startswith(b'btime'):
+                boot_time = float(line.strip().split()[1])
+                return int(time.time() - int(boot_time))
+        return 0
+
+
+class Process():
+    """An interface to retrieve data from proc."""
+    def get_proc_iterator(self):
+        for pid in self.pids():
+            yield pid
+
+
+    def pids(self):
+        """Returns a list of PIDs currently running on the system."""
+        return [int(x) for x in os.listdir(PROCFS_PATH) if x.isdigit()]
+
+
+    def name(self, pid: int):
+        """Method to retrive name associated with the pid."""
+        return self.parse_stat_file(pid)['name']
+
+
+    def parse_stat_file(self, pid: int):
+        """Parse /proc/{pid}/stat file and return a dict with various
+        process info.
+
+        Using "man proc" as a reference: where "man proc" refers to
+        position N always substract 3 (e.g ppid position 4 in
+        'man proc' == position 1 in here).
+        """
+        ret = {}
+        try:
+            with open_binary(f"{PROCFS_PATH}{pid}/stat") as f:
+                data = f.read()
+            # Process name is between parentheses. It can contain spaces and
+            # other parentheses. This is taken into account by looking for
+            # the first occurrence of "(" and the last occurence of ")".
+            rpar = data.rfind(b')')
+            name = data[data.find(b'(') + 1:rpar]
+            fields = data[rpar + 2:].split()
+
+            ret['name'] = name
+            ret['status'] = fields[0]
+            ret['ppid'] = fields[1]
+            ret['ttynr'] = fields[4]
+            ret['utime'] = fields[11]
+            ret['stime'] = fields[12]
+            ret['children_utime'] = fields[13]
+            ret['children_stime'] = fields[14]
+            ret['create_time'] = fields[19]
+            ret['cpu_num'] = fields[36]
+            ret['blkio_ticks'] = fields[39]  # aka 'delayacct_blkio_ticks'
+        except (PermissionError, ProcessLookupError, FileNotFoundError):
+            ret['name'] = ''
+            ret['status'] = ''
+            ret['ppid'] = ''
+            ret['ttynr'] = ''
+            ret['utime'] = ''
+            ret['stime'] = ''
+            ret['children_utime'] = ''
+            ret['children_stime'] = ''
+            ret['create_time'] = ''
+            ret['cpu_num'] = ''
+            ret['blkio_ticks'] = ''  # aka 'delayacct_blkio_ticks'
+        return ret
+
+    @staticmethod
+    def check_process_alive(proc_name: str) -> bool:
+        """Check process running.
+
+        :param proc_name: process name
+        :type proc_name: str
+        :return: True if process running, otherwise False
+        :rtype: bool
+        """
+        # Iterate over the all the running process
+        for proc in psutil.process_iter():
+            try:
+                # Check if process name equals to the given name string.
+                if proc_name.lower() == proc.name().lower():
+                    return True
+            except (
+                psutil.NoSuchProcess, psutil.AccessDenied,
+                psutil.ZombieProcess
+            ):
+                pass
+        return False