[spp] [PATCH 3/3] spp-ctl: add API for getting CPU layout

[ogawa.yasufumi@lab.ntt.co.jp]

From: Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>

To get CPU layout for considering assignment, add a REST API for
getting the layout. It calls a helper tool `cpu_layout.py` and returns
the result in JSON. Here is an example.

  [
    {
      "socket_id": 0,
      "cores": [
        {"core_id": 1, "cpus": [1, 5]},
        {"core_id": 2, "cpus": [2, 6]},
        ...
      ]
    },
    {
      "socket_id: 1,
      "cores: [
        ...
      ]
    },
  ]

Signed-off-by: Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>
---
 src/spp-ctl/spp_ctl.py    | 25 +++++++++++++++++++++++++
 src/spp-ctl/spp_webapi.py |  4 ++++
 2 files changed, 29 insertions(+)

diff --git a/src/spp-ctl/spp_ctl.py b/src/spp-ctl/spp_ctl.py
index c4dd4b2..f276442 100644
--- a/src/spp-ctl/spp_ctl.py
+++ b/src/spp-ctl/spp_ctl.py
@@ -6,7 +6,9 @@ eventlet.monkey_patch()
 
 import argparse
 import errno
+import json
 import logging
+import os
 import socket
 import subprocess
 
@@ -19,6 +21,8 @@ LOG = logging.getLogger(__name__)
 
 MSG_SIZE = 4096
 
+# relative path of `cpu_layout.py`
+CPU_LAYOUT_TOOL = 'tools/helpers/cpu_layout.py'
 
 class Controller(object):
 
@@ -142,6 +146,27 @@ class Controller(object):
             procs.append(p)
         return procs
 
+    def get_cpu_layout(self):
+        """Get cpu layout with helper tool 'cpu_layout.py'."""
+
+        # This script is 'src/spp-ctl/spp_ctl.py' and it expect to find
+        # the tool in tools/helpers/cpu_layout.py'.
+        cmd_path = "{}/../../{}".format(
+                os.path.dirname(__file__), CPU_LAYOUT_TOOL)
+
+        if os.path.exists(cmd_path):
+            # Get cpu layout as bytes of JSON foramtted string
+            cmd_res = subprocess.check_output(
+                    [cmd_path, '--json'],  # required '--json' option
+                    stderr=subprocess.STDOUT)
+
+            # Decode bytes to str
+            return json.loads(cmd_res.decode('utf-8'))
+
+        else:
+            LOG.error("'{}' cannot be found.".format(CPU_LAYOUT_TOOL))
+            return None
+
     def do_exit(self, proc_type, proc_id):
         removed_id = None  # remove proc info of ID from self.procs
         for proc in self.procs.values():
diff --git a/src/spp-ctl/spp_webapi.py b/src/spp-ctl/spp_webapi.py
index 10b4098..39530dd 100644
--- a/src/spp-ctl/spp_webapi.py
+++ b/src/spp-ctl/spp_webapi.py
@@ -152,11 +152,15 @@ class V1Handler(BaseHandler):
 
     def set_route(self):
         self.route('/processes', 'GET', callback=self.get_processes)
+        self.route('/cpus', 'GET', callback=self.get_cpu_layout)
 
     def get_processes(self):
         LOG.info("get processes called.")
         return self.ctrl.get_processes()
 
+    def get_cpu_layout(self):
+        LOG.info("get cpu layout called.")
+        return self.ctrl.get_cpu_layout()
 
 class V1VFCommon(object):
     """Define common methods for vf and mirror handler."""
-- 
2.7.4