exports: riemann export implemented and documented

This patch introduces a new export method for sending metrics to
__Riemann__ server using _TCP_ protocol. The module can be enabled like
all the other exports in __Glances__, specifying the `--export-riemann`
option.

Sending metrics to Riemann requires
[bernhard](https://github.com/banjiewen/bernhard) that is
the most popular _Riemann client_ written in python.

In the configuration file you can only specify the `host` and `port`
that riemann is listening for new connections on. Later new options are
planned to be added like __SSL__ support and __UDP__.

Documentation and manpages are refreshed according to the modifications
in the config options and introducing the usage of Riemann export.

Signed-off-by: Gergő Nagy <grigori.grant@gmail.com>

README.rst

@@ -50,6 +50,7 @@ Optional dependencies:
 - ``docker-py`` (for the Docker monitoring support) [Linux-only]
 - ``matplotlib`` (for graphical/chart support)
 - ``pika`` (for the RabbitMQ/ActiveMQ export module)
+- ``bernhard`` (for the Riemann export module)
 - ``py-cpuinfo`` (for the Quicklook CPU info module)
 - ``scandir`` (for the Folders plugin) [Only for Python < 3.5]
 
@@ -223,6 +224,28 @@ Puppet
 
 You can install Glances using ``Puppet``: https://github.com/rverchere/puppet-glances
 
+Known issue on RHEL/CentOS/Fedora installation
+==============================================
+
+For Python 2.6 RedHat-based distros there might be an issue with starting Glances:
+
+```
+Traceback (most recent call last):
+File "/usr/bin/glances", line 5, in <module>
+from pkg_resources import load_entry_point
+File "/usr/lib/python2.6/site-packages/pkg_resources.py", line 2655, in <module>
+workingset.require(_requires)
+File "/usr/lib/python2.6/site-packages/pkg_resources.py", line 648, in require
+needed = self.resolve(parse_requirements(requirements))
+File "/usr/lib/python2.6/site-packages/pkg_resources.py", line 546, in resolve
+raise DistributionNotFound(req)
+pkg_resources.DistributionNotFound: argparse
+```
+
+Try upgrading setuptools, has been proven to solve the problem: 
+    
+    sudo pip install -U setuptools
+
 Usage
 =====
 
@@ -274,7 +297,7 @@ Gateway to other services
 =========================
 
 Glances can export stats to: ``CSV`` file, ``InfluxDB``, ``OpenTSDB``,
-``StatsD``, ``ElasticSearch`` and ``RabbitMQ`` server.
+``StatsD``, ``RabbitMQ`` and  ``Riemann`` server.
 
 How to contribute ?
 ===================

docs/cmds.rst

@@ -139,6 +139,10 @@ Command-Line Options
 
     export stats to RabbitMQ broker (pika lib needed)
 
+.. option:: --export-riemann
+
+    export stats to Riemann server (bernhard lib needed)
+
 .. option:: --export-elasticsearch
 
     export stats to an Elasticsearch server (elasticsearch lib needed)

docs/gw/riemann.rst

@@ -0,0 +1,20 @@
+.. _riemann:
+
+Riemann
+========
+
+You can export statistics to an ``Riemann`` server (using TCP protocol). The
+connection should be defined in the Glances configuration file as
+following:
+
+.. code-block:: ini
+
+    [rabbitmq]
+    host=localhost
+    port=5555
+
+and run Glances with:
+
+.. code-block:: console
+
+    $ glances --export-riemann

docs/man/glances.1

@@ -214,6 +214,11 @@ export stats to RabbitMQ broker (pika lib needed)
 .UNINDENT
 .INDENT 0.0
 .TP
+.B \-\-export\-riemann
+export stats to Riemann server (bernhard lib needed)
+.UNINDENT
+.INDENT 0.0
+.TP
 .B \-\-export\-elasticsearch
 export stats to an Elasticsearch server (elasticsearch lib needed)
 .UNINDENT

glances/exports/glances_riemann.py

@@ -0,0 +1,93 @@
+# -*- coding: utf-8 -*-
+#
+# This file is part of Glances.
+#
+# Copyright (C) 2015 Nicolargo <nicolas@nicolargo.com>
+#
+# Glances is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Glances is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+"""JMS interface class."""
+
+import socket
+import sys
+from numbers import Number
+
+from glances.compat import NoOptionError, NoSectionError, range
+from glances.logger import logger
+from glances.exports.glances_export import GlancesExport
+
+# Import pika for Riemann
+import bernhard
+
+
+class Export(GlancesExport):
+
+    """This class manages the Riemann export module."""
+
+    def __init__(self, config=None, args=None):
+        """Init the Riemann export IF."""
+        super(Export, self).__init__(config=config, args=args)
+
+        # Load the rabbitMQ configuration file
+        self.riemann_host = None
+        self.riemann_port = None
+        self.hostname = socket.gethostname()
+        self.export_enable = self.load_conf()
+        if not self.export_enable:
+            sys.exit(2)
+
+        # Init the rabbitmq client
+        self.client = self.init()
+
+    def load_conf(self, section="riemann"):
+        """Load the Riemann configuration in the Glances configuration file."""
+        if self.config is None:
+            return False
+        try:
+            self.riemann_host = self.config.get_value(section, 'host')
+            self.riemann_port = int(self.config.get_value(section, 'port'))
+        except NoSectionError:
+            logger.critical("No riemann configuration found")
+            return False
+        except NoOptionError as e:
+            logger.critical("Error in the Riemann configuration (%s)" % e)
+            return False
+        else:
+            logger.debug("Load Riemann from the Glances configuration file")
+        return True
+
+    def init(self):
+        """Init the connection to the Riemann server."""
+        if not self.export_enable:
+            return None
+        try:
+            client = bernhard.Client(host=self.riemann_host, port=self.riemann_port)
+            return client
+        except Exception as e:
+            logger.critical("Connection to Riemann failed : %s " % e)
+            return None
+
+    def export(self, name, columns, points):
+        """Write the points in Riemann."""
+        for i in range(len(columns)):
+            if not isinstance(points[i], Number):
+                continue
+            else:
+                data = { 'host': self.hostname, 'service': name + " " + columns[i], 'metric': points[i] }
+                logger.debug(data)
+                try:
+                    self.client.send(data)
+                except Exception as e:
+                    logger.error("Can not export stats to Riemann (%s)" % e)
+

glances/main.py

@@ -163,6 +163,8 @@ Start the client browser (browser mode):\n\
                             dest='export_elasticsearch', help='export stats to an ElasticSearch server (elasticsearch lib needed)')
         parser.add_argument('--export-rabbitmq', action='store_true', default=False,
                             dest='export_rabbitmq', help='export stats to rabbitmq broker (pika lib needed)')
+        parser.add_argument('--export-riemann', action='store_true', default=False,
+                            dest='export_riemann', help='export stats to riemann broker (bernhard lib needed)')
         # Client/Server option
         parser.add_argument('-c', '--client', dest='client',
                             help='connect to a Glances server by IPv4/IPv6 address or hostname')