ui: added Actions

Added ability to perform actions on different parts of the GUI, based on
conditions defined in json files.

There's only one Action of type Highlight for now, to colorize cells and
rows.

There're 3 Highlight actions defined by default:
 - rules: applied to the rules view to colorize the columns Enabled and
   Action.
 - firewall: applied to the fw rules to colorize the columns Action and
   Enabled.
 - common: applied to the rest of the views to colorize the column
   Action.

Users can add new actions to the directory
~/.config/opensnitch/actions/, as .json files. The format is defined
below.

Example of a Highlight action to colorize cells and rows, based on
different texts (simple texts/strings for now):
{
  "name": "commonDelegateConfig",
  "actions": {
    "highlight": {
      "cells": [
        {
          "text": ["allow", "✓ online"],
          "cols": [1, 2, 3],
          "color": "green",
          "bgcolor": "",
          "alignment": ["center"]
        }
      ],
      "rows": [
        {
          "text": ["block-domains"],
          "cols": [8],
          "color": "white",
          "bgcolor": "darkMagenta",
          "alignment": []
        }
      ]
    }
}

Closes: #555

ui/opensnitch/actions/__init__.py

@@ -0,0 +1,157 @@
+from PyQt5.QtCore import QObject
+
+import json
+import os
+import glob
+import sys
+
+from opensnitch.actions import highlight
+from opensnitch.actions.default_configs import commonDelegateConfig, rulesDelegateConfig, fwDelegateConfig
+
+class Actions(QObject):
+    """List of actions to perform on the data that is displayed on the GUI.
+    Whenever an item matches a condition an action is applied, for example:
+        - if the text of a cell matches a condition for the given columns,
+        then the properties of the cell/row and the text are customized.
+
+    There's only 1 action supported right now:
+        - highlight: for customizing rows and cells appearance.
+
+    There're 3 actions by default of type Highlight:
+        - rules: applied to the rules to colorize the columns Enabled and
+        Action
+        - firewall: applied to the fw rules to colorize the columns Action and
+        Target.
+        - common: applied to the rest of the views to colorize the column
+        Action.
+
+    Users can modify the default actions, by adding more patterns to colorize.
+    At the same time they can also create new actions to be applied on certain views.
+
+    The format of the actions is JSON:
+        {
+        "created": "....",
+        "name": "...",
+        "actions": {
+            "highlight": {
+                "cells": [
+                        {
+                            "text": ["allow", "True", "online"],
+                            "cols": [3,5,6],
+                            "color": "green",
+                        },
+                        {
+                            "text": ["deny", "False", "offline"],
+                            "cols": [3,5,6],
+                            "color": "red",
+                        }
+                    ],
+                "rows": []
+            }
+        }
+
+    """
+    __instance = None
+
+    # list of loaded actions
+    _actions = None
+
+
+    KEY_ACTIONS = "actions"
+    KEY_NAME = "name"
+    KEY_TYPE = "type"
+
+    # TODO: emit a signal when the actions are (re)loaded
+    # reloaded_signal = pyQtSignal()
+
+    # default paths to look for actions
+    _paths = [
+        os.path.dirname(sys.modules[__name__].__file__) + "/data/",
+        os.path.expanduser("~/.config/opensnitch/actions/")
+    ]
+
+    @staticmethod
+    def instance():
+        if Actions.__instance == None:
+            Actions.__instance = Actions()
+        return Actions.__instance
+
+    def __init__(self, parent=None):
+        QObject.__init__(self)
+        self._actions_list = {}
+        try:
+            os.makedirs(os.path.expanduser("~/.config/opensnitch/actions/"), 0o700)
+        except:
+            pass
+
+    def _load_default_configs(self):
+        self._actions_list[commonDelegateConfig[Actions.KEY_NAME]] = self.compile(commonDelegateConfig)
+        self._actions_list[rulesDelegateConfig[Actions.KEY_NAME]] = self.compile(rulesDelegateConfig)
+        self._actions_list[fwDelegateConfig[Actions.KEY_NAME]] = self.compile(fwDelegateConfig)
+
+    def loadAll(self):
+        """look for actions firstly on default system path, secondly on
+        user's home.
+        If a user customizes existing configurations, they'll be saved under
+        the user's home directory.
+
+        Action files are .json files.
+        """
+        self._load_default_configs()
+
+        for path in self._paths:
+            for jfile in glob.glob(os.path.join(path, '*.json')):
+                self.load(jfile)
+
+    def load(self, action_file):
+        """read a json file from disk and create the action."""
+        with open(action_file, 'r') as fd:
+            data=fd.read()
+            obj = json.loads(data)
+            self._actions_list[obj[Actions.KEY_NAME]] = self.compile(obj)
+
+    def compile(self, obj):
+        try:
+            if Actions.KEY_NAME not in obj or obj[Actions.KEY_NAME] == "":
+                return None
+            if obj.get(Actions.KEY_ACTIONS) == None:
+                return None
+
+            for action in obj[Actions.KEY_ACTIONS]:
+                if action == highlight.Highlight.NAME:
+                    h = highlight.Highlight(obj[Actions.KEY_ACTIONS][action])
+                    h.compile()
+                    obj[Actions.KEY_ACTIONS][action]= h
+                else:
+                    print("Actions exception: Action '{0}' not supported yet".format(obj[Actions.KEY_NAME]))
+
+            return obj
+        except Exception as e:
+            print("Actions.compile() exception:", e)
+            return None
+
+
+
+    def getAll(self):
+        return self._actions_list
+
+    def deleteAll(self):
+        self._actions_list = {}
+
+    def get(self, name):
+        try:
+            return self._actions_list[name]
+        except Exception as e:
+            print("get() exception:", e)
+            return None
+
+    def delete(self, name):
+        try:
+            del self._actions_list[name]
+            # TODO:
+            # self.reloaded_signal.emit()
+        except:
+            pass
+
+    def isValid(self):
+        pass

ui/opensnitch/actions/default_configs.py

@@ -0,0 +1,128 @@
+
+# common configuration to highlight Action column
+commonDelegateConfig = {
+  "name": "commonDelegateConfig",
+  "created": "",
+  "updated": "",
+  "actions": {
+    "highlight": {
+      "cells": [
+        {
+          "text": ["allow", "\u2713 online"],
+          "operator": "==",
+          "cols": [1, 2, 3],
+          "color": "green",
+          "bgcolor": "",
+          "alignment": ["center"]
+        },
+        {
+          "text": ["deny", "\u2613 offline"],
+          "cols": [1, 2, 3],
+          "color": "red",
+          "bgcolor": "",
+          "alignment": ["center"]
+        },
+        {
+          "text": ["reject"],
+          "cols": [1, 2, 3],
+          "color": "purple",
+          "bgcolor": "",
+          "alignment": ["center"]
+        }
+      ],
+      "rows": []
+    }
+  }
+}
+
+# firewall rules configuration to highlight Enabled and Action columns
+fwDelegateConfig = {
+  "name": "defaultFWDelegateConfig",
+  "created": "",
+  "updated": "",
+  "actions": {
+    "highlight": {
+      "cells": [
+        {
+          "text": [
+            "allow",
+            "True",
+            "accept",
+            "jump",
+            "masquerade",
+            "snat",
+            "dnat",
+            "tproxy",
+            "queue",
+            "redirect",
+            "True",
+            "ACCEPT"
+          ],
+          "cols": [7, 10],
+          "color": "green",
+          "bgcolor": "",
+          "alignment": ["center"]
+        },
+        {
+          "text": [
+            "deny",
+            "False",
+            "drop",
+            "DROP",
+            "stop"
+          ],
+          "cols": [7, 10],
+          "color": "red",
+          "bgcolor": "",
+          "alignment": ["center"]
+        },
+        {
+          "text": [
+            "reject",
+            "return"
+          ],
+          "cols": [7, 10],
+          "color": "purple",
+          "bgcolor": "",
+          "alignment": ["center"]
+        }
+      ],
+      "rows": []
+    }
+  }
+}
+
+# rules configuration to highlight Enabled and Action columns
+rulesDelegateConfig = {
+  "name": "defaultRulesDelegateConfig",
+  "created": "",
+  "updated": "",
+  "actions": {
+    "highlight": {
+      "cells": [
+        {
+          "text": ["allow", "True"],
+          "cols": [3, 4],
+          "color": "green",
+          "bgcolor": "",
+          "alignment": ["center"]
+        },
+        {
+          "text": ["deny", "False"],
+          "cols": [3, 4],
+          "color": "red",
+          "bgcolor": "",
+          "alignment": ["center"]
+        },
+        {
+          "text": ["reject"],
+          "cols": [3, 4],
+          "color": "purple",
+          "bgcolor": "",
+          "alignment": ["center"]
+        }
+      ],
+      "rows": []
+    }
+  }
+}