a72f907eef
This patch adds a plugin that reads metrics from JSON files. This
makes it very easy to integrate with Monasca -- instead of writing
a new plugin, simply write your metrics to a file.
The advantage of this mechanism is that:
- It's simple and easy to understand
- It is asynchronous with Monasca Agent. There are two technical
advantages to this:
- Your check does not need to run at same frequency as
the agent.
- If your check blocks, this does not affect other checks
in the agent because the agent is not blocked.
- You can create the metrics as a side effect of doing other
stuff. For example, a server process can write the JSON
file while it is processing requests. With the normal plugin
architecture, you need to write code that talks to your
server process to access the metrics.
- You can write the check code in any language.
Change-Id: I1e998fa677e16cc04d46edd46d0e6433131825e7
41 lines
1.2 KiB
Python
41 lines
1.2 KiB
Python
# (c) Copyright 2016 Hewlett Packard Enterprise Development LP
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from monasca_setup import agent_config
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import monasca_setup.detection
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import os
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VAR_CACHE_DIR = '/var/cache/monasca_json_plugin'
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class JsonPlugin(monasca_setup.detection.ArgsPlugin):
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"""Detect if /var/cache/monasca_json_plugin exists
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This builds a config for the json_plugin. This detects if
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/var/cache/monasca_json_plugin exists and if so,
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builds a configuration for it.
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Users are free to add their own configs.
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"""
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def __init__(self, template_dir, overwrite=True, args=None):
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super(JsonPlugin, self).__init__(
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template_dir, overwrite, args)
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def _detect(self):
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self.available = False
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if os.path.isdir(VAR_CACHE_DIR):
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self.available = True
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def build_config(self):
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"""Build the config as a Plugins object and return."""
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config = agent_config.Plugins()
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config['json_plugin'] = {'init_config': None,
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'instances': [{'name': VAR_CACHE_DIR,
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'metrics_dir': VAR_CACHE_DIR}]}
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return config
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def dependencies_installed(self):
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"""Return True if dependencies are installed."""
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return True
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