[v2] cpu_layout: refactor to meet python standards

diff --git a/usertools/cpu_layout.py b/usertools/cpu_layout.py
index cc39638213d0..1e4577143ac5 100755
--- a/usertools/cpu_layout.py
+++ b/usertools/cpu_layout.py
@@ -2,65 +2,92 @@ 
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2010-2014 Intel Corporation
 # Copyright(c) 2017 Cavium, Inc. All rights reserved.
+"""
+Show CPU layout
+"""
+SYS_DEVICES_CPU = "/sys/devices/system/cpu"
 
-sockets = []
-cores = []
-core_map = {}
-base_path = "/sys/devices/system/cpu"
-fd = open("{}/kernel_max".format(base_path))
-max_cpus = int(fd.read())
-fd.close()
-for cpu in range(max_cpus + 1):
-    try:
-        fd = open("{}/cpu{}/topology/core_id".format(base_path, cpu))
-    except IOError:
-        continue
-    except:
-        break
-    core = int(fd.read())
-    fd.close()
-    fd = open("{}/cpu{}/topology/physical_package_id".format(base_path, cpu))
-    socket = int(fd.read())
-    fd.close()
-    if core not in cores:
-        cores.append(core)
-    if socket not in sockets:
-        sockets.append(socket)
-    key = (socket, core)
-    if key not in core_map:
-        core_map[key] = []
-    core_map[key].append(cpu)
-
-print(format("=" * (47 + len(base_path))))
-print("Core and Socket Information (as reported by '{}')".format(base_path))
-print("{}\n".format("=" * (47 + len(base_path))))
-print("cores = ", cores)
-print("sockets = ", sockets)
-print("")
-
-max_processor_len = len(str(len(cores) * len(sockets) * 2 - 1))
-max_thread_count = len(list(core_map.values())[0])
-max_core_map_len = (max_processor_len * max_thread_count)  \
+
+def print_coremap(sockets, cores, core_map):
+    '''print core, thread, socket mapping'''
+    max_processor_len = len(str(len(cores) * len(sockets) * 2 - 1))
+    max_thread_count = len(list(core_map.values())[0])
+    max_core_map_len = (max_processor_len * max_thread_count)  \
                       + len(", ") * (max_thread_count - 1) \
                       + len('[]') + len('Socket ')
-max_core_id_len = len(str(max(cores)))
-
-output = " ".ljust(max_core_id_len + len('Core '))
-for s in sockets:
-    output += " Socket %s" % str(s).ljust(max_core_map_len - len('Socket '))
-print(output)
-
-output = " ".ljust(max_core_id_len + len('Core '))
-for s in sockets:
-    output += " --------".ljust(max_core_map_len)
-    output += " "
-print(output)
-
-for c in cores:
-    output = "Core %s" % str(c).ljust(max_core_id_len)
-    for s in sockets:
-        if (s,c) in core_map:
-            output += " " + str(core_map[(s, c)]).ljust(max_core_map_len)
-        else:
-            output += " " * (max_core_map_len + 1)
+
+    max_core_id_len = len(str(max(cores)))
+
+    output = " ".ljust(max_core_id_len + len('Core '))
+    for socket in sockets:
+        output += " Socket %s" % str(socket).ljust(max_core_map_len -
+                                                   len('Socket '))
+    print(output)
+
+    output = " ".ljust(max_core_id_len + len('Core '))
+    for socket in sockets:
+        output += " --------".ljust(max_core_map_len)
+        output += " "
     print(output)
+
+    for core in cores:
+        output = "Core %s" % str(core).ljust(max_core_id_len)
+        for socket in sockets:
+            if (socket, core) in core_map:
+                output += " " + str(core_map[(socket,
+                                              core)]).ljust(max_core_map_len)
+            else:
+                output += " " * (max_core_map_len + 1)
+        print(output)
+
+
+def print_header(sockets, cores):
+    '''print the core socket information header'''
+    header_len = 47 + len(SYS_DEVICES_CPU)
+    print(format("=" * header_len))
+    print("Core and Socket Information (as reported by '{}')".format(
+        SYS_DEVICES_CPU))
+    print("{}\n".format("=" * header_len))
+    print("cores = ", cores)
+    print("sockets = ", sockets)
+    print("")
+
+
+def main():
+    '''program main function'''
+
+    with open("{}/kernel_max".format(SYS_DEVICES_CPU)) as kernel_max:
+        max_cpus = int(kernel_max.read())
+
+    core_map = {}
+    sockets = []
+    cores = []
+
+    for cpu in range(max_cpus + 1):
+        topo_path = "{}/cpu{}/topology/".format(SYS_DEVICES_CPU, cpu)
+        try:
+            with open(topo_path + "core_id") as core_id:
+                core = int(core_id.read())
+        except FileNotFoundError:
+            break
+        except IOError:
+            continue
+
+        with open(topo_path + "physical_package_id") as package_id:
+            socket = int(package_id.read())
+
+        if core not in cores:
+            cores.append(core)
+        if socket not in sockets:
+            sockets.append(socket)
+        key = (socket, core)
+        if key not in core_map:
+            core_map[key] = []
+        core_map[key].append(cpu)
+
+    print_header(sockets, cores)
+    print_coremap(sockets, cores, core_map)
+
+
+if __name__ == "__main__":
+    main()