[core] add cgroups checks

meshroom/core/cgroup.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python
+# coding:utf-8
+
+import os
+
+#Try to retrieve limits of memory for the current process' cgroup
+def getCgroupMemorySize():
+
+    #first of all, get pid of process
+    pid = os.getpid()
+
+    #Get cgroup associated with pid
+    filename = f"/proc/{pid}/cgroup"
+
+    cgroup = None
+    try:
+        with open(filename, "r") as f :
+
+            #cgroup file is a ':' separated table
+            #lookup a line where the second field is "memory"
+            lines = f.readlines()
+            for line in lines:
+                tokens = line.rstrip("\r\n").split(":")
+                if len(tokens) < 3:
+                    continue
+                if tokens[1] == "memory":
+                    cgroup = tokens[2]
+    except IOError:
+        pass
+
+    if cgroup is None:
+        return -1
+
+    size = -1
+    filename = f"/sys/fs/cgroup/memory/{cgroup}"
+    try:
+        with open(filename, "r") as f :
+            value = f.read().rstrip("\r\n")
+            if value.isnumeric():
+                size = int(value)
+    except IOError:
+        pass
+
+    return size
+
+def parseNumericList(str):
+
+    nList = []
+    for item in str.split(','):
+        if '-' in item:
+            start, end = item.split('-')
+            start = int(start)
+            end = int(end)
+            nList.extend(range(start, end + 1))
+        else:
+            value = int(item)
+            nList.append(value)
+
+    return nList
+
+#Try to retrieve limits of cores for the current process' cgroup
+def getCgroupCpuCount():
+
+    #first of all, get pid of process
+    pid = os.getpid()
+
+    #Get cgroup associated with pid
+    filename = f"/proc/{pid}/cgroup"
+
+    cgroup = None
+    try:
+        with open(filename, "r") as f :
+
+            #cgroup file is a ':' separated table
+            #lookup a line where the second field is "memory"
+            lines = f.readlines()
+            for line in lines:
+                tokens = line.rstrip("\r\n").split(":")
+                if len(tokens) < 3:
+                    continue
+                if tokens[1] == "cpuset":
+                    cgroup = tokens[2]
+    except IOError:
+        pass
+
+    if cgroup is None:
+        return -1
+
+    size = -1
+    filename = f"/sys/fs/cgroup/cpuset/{cgroup}/cpuset.cpus"
+    try:
+        with open(filename, "r") as f :
+            value = f.read().rstrip("\r\n")
+            nlist = parseNumericList(value)
+            size = len(nlist)
+
+    except IOError:
+        pass
+
+    return size
+