Split internal classes to individual modules

We used to have one module(internal) which exposed all internal
classes for frontend, backend, haproxy and server. This was a bit
suboptimal approach in terms of modules management and therefore
we create individual modules for each class.

Author: Pavlos Parissis

docs/source/dev/api.rst

@@ -40,7 +40,19 @@ meant for external use.
 .. autoclass:: Server
    :members:
 
-.. automodule:: haproxyadmin.internal
+.. automodule:: haproxyadmin.internal.haproxy
+   :members:
+   :private-members:
+
+.. automodule:: haproxyadmin.internal.frontend
+   :members:
+   :private-members:
+
+.. automodule:: haproxyadmin.internal.backend
+   :members:
+   :private-members:
+
+.. automodule:: haproxyadmin.internal.server
    :members:
    :private-members:
 

haproxyadmin/haproxy.py

@@ -17,7 +17,7 @@
 from haproxyadmin.utils import (is_unix_socket, cmd_across_all_procs, converter,
                                 calculate, isint, should_die, check_command,
                                 check_output, compare_values, connected_socket)
-from haproxyadmin.internal import _HAProxyProcess
+from haproxyadmin.internal.haproxy import _HAProxyProcess
 from haproxyadmin.exceptions import CommandFailed
 
 

haproxyadmin/internal/__init__.py

@@ -0,0 +1,126 @@
+# -*- coding: utf-8 -*-
+#
+# pylint: disable=superfluous-parens
+#
+"""
+haproxyadmin.internal.backend
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This module provides a class, which is used within haproxyadmin for creating a
+object to work with a backend. This object is associated only with a single
+HAProxy process.
+
+"""
+from haproxyadmin.internal.server import _Server
+
+class _Backend:
+    """Class for interacting with a backend in one HAProxy process.
+
+    :param hap_process: a :class::`_HAProxyProcess` object.
+    :param name: backend name.
+    :type name: ``string``
+    :param iid: unique proxy id of the backend.
+    :type iid: ``integer``
+    """
+    def __init__(self, hap_process, name, iid):
+        self.hap_process = hap_process
+        self._name = name
+        self.hap_process_nb = self.hap_process.process_nb
+        self._iid = iid
+
+    @property
+    def name(self):
+        """Return a string which is the name of the backend"""
+        return self._name
+
+    @property
+    def iid(self):
+        """Return Proxy ID"""
+        data = self.stats_data()
+        self._iid = data.iid
+
+        return self._iid
+
+    @property
+    def process_nb(self):
+        """Return the process number of the haproxy process
+
+        :rtype: ``int``
+        """
+        return int(self.hap_process_nb)
+
+    def stats_data(self):
+        """Return stats data
+
+        Check documentation of ``stats_data`` method in :class:`_Frontend`.
+
+        :rtype: ``utils.CSVLine`` object
+        """
+        # Fetch data using the last known iid
+        try:
+            data = self.hap_process.backends_stats(self._iid)[self.name]
+        except KeyError:
+            # A lookup on HAProxy with the current id doesn't return
+            # an object with our name.
+            # Most likely object got different id due to a reshuffle in conf.
+            # Thus retrieve all objects to get latest data for the object.
+            try:
+                data = self.hap_process.backends_stats()[self.name]
+            except KeyError:
+                # The object has gone from running configuration!
+                # We cant recover from this situation.
+                raise
+
+        return data['stats']
+
+    def stats(self):
+        """Build dictionary for all statistics reported by HAProxy.
+
+        :return: A dictionary with statistics
+        :rtype: ``dict``
+        """
+        data = self.stats_data()
+        keys = data.heads
+        values = data.parts
+
+        return dict(zip(keys, values))
+
+    def metric(self, name):
+        data = self.stats_data()
+
+        return getattr(data, name)
+
+    def command(self, cmd):
+        """Send command to HAProxy
+
+        :param cmd: command to send
+        :type cmd: ``string``
+        :return: the output of the command
+        :rtype: ``string``
+        """
+        return self.hap_process.command(cmd)
+
+    def servers(self, name=None):
+        """Return a list of _Server objects for each server of the backend.
+
+        :param name: (optional): server name to lookup, defaults to None.
+        :type name: ``string``
+        """
+        servers = []
+        return_list = []
+
+        servers = self.hap_process.servers_stats(self.name, self.iid)
+        if name is not None:
+            if name in servers:
+                return_list.append(_Server(self,
+                                           name,
+                                           servers[name].sid))
+            else:
+                return []
+        else:
+            for _name in servers:
+                return_list.append(_Server(self,
+                                           _name,
+                                           servers[_name].sid))
+
+        return return_list

haproxyadmin/internal/backend.py

@@ -0,0 +1,114 @@
+# -*- coding: utf-8 -*-
+#
+# pylint: disable=superfluous-parens
+#
+"""
+haproxyadmin.internal.frontend
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This module provides a class, which is used within haproxyadmin for creating a
+object to work with a frontend. This object is associated only with a single
+HAProxy process.
+
+
+"""
+
+
+class _Frontend:
+    """Class for interacting with a frontend in one HAProxy process.
+
+    :param hap_process: a :class:`_HAProxyProcess` object.
+    :param name: frontend name.
+    :type name: ``string``
+    :param iid: unique proxy id of the frontend.
+    :type iid: ``integer``
+    """
+    def __init__(self, hap_process, name, iid):
+        self.hap_process = hap_process
+        self._name = name
+        self.hap_process_nb = self.hap_process.process_nb
+        self._iid = iid
+
+    @property
+    def name(self):
+        """Return a string which is the name of the frontend"""
+        return self._name
+
+    @property
+    def iid(self):
+        """Return Proxy ID"""
+        data = self.stats_data()
+        self._iid = data.iid
+
+        return self._iid
+
+    @property
+    def process_nb(self):
+        return int(self.hap_process_nb)
+
+    def stats_data(self):
+        """Return stats data
+
+        :rtype: ``utils.CSVLine`` object
+
+        HAProxy assigns unique ids to each object during the startup.
+        The id can change when configuration changes, objects order
+        is reshuffled or additions/removals take place.
+        In those cases the id we store at the instantiation of the object may
+        reference to another object or even to non-existent object when
+        configuration takes places afterwards.
+
+        The technique we use is quite simple. When an object is created
+        we store the name and the id. In order to detect if iid is changed,
+        we simply send a request to fetch data only for the given iid and check
+        if the current id points to an object of the same type
+        (frontend, backend, server) which has the same name.
+        """
+        # Fetch data using the last known iid
+        try:
+            data = self.hap_process.frontends_stats(self._iid)[self.name]
+        except KeyError:
+            # A lookup on HAProxy with the current id doesn't return
+            # an object with our name.
+            # Most likely object got different id due to a reshuffle in conf.
+            # Thus retrieve all objects to get latest data for the object.
+            try:
+                # This will basically request all object of the type
+                data = self.hap_process.frontends_stats()[self.name]
+            except KeyError:
+                # The object has gone from running configuration!
+                # This occurs when object was removed from configuration
+                # and haproxy was reloaded or frontend was shutdowned.
+                # We cant recover from this situation
+                raise
+
+        return data
+
+    def stats(self):
+        """Build dictionary for all statistics reported by HAProxy.
+
+        :return: A dictionary with statistics
+        :rtype: ``dict``
+8. split internal to multiple files
+        """
+        data = self.stats_data()
+        keys = data.heads
+        values = data.parts
+
+        return dict(zip(keys, values))
+
+    def metric(self, name):
+        """Return the value of a metric"""
+        data = self.stats_data()
+
+        return getattr(data, name)
+
+    def command(self, cmd):
+        """Run command to HAProxy
+
+        :param cmd: a valid command to execute.
+        :type cmd: ``string``
+        :return: 1st line of the output.
+        :rtype: ``string``
+        """
+        return self.hap_process.command(cmd)