check-json 0.1.4

A Nagios/Icinga plugin for monitoring JSON files with Jq filters

check_json

Check_json is a Nagios/Icinga2 plugin for monitoring JSON files with Jq filters.

Requires Python 3.6+

Installation

You can install with pip:

python3 -m pip install check-json

Or install from source:

git clone https://gitlab.com/cspeterson/check_json.git check_json.git
pip install check_json.git

Usage

Pass the plugin any number of Jq filters and a JSON file. The plugin will report OK so long as no filters evaluate to false or null.

Outputs Nagios standard perfdata for each filter reported with 1 for success and 0 for failure.

If a given filter is concluded by a comment string of the format # some-descriptive-string, it will be used as the perfdata label for that filter.

For all of the things you can do in a filter, refer to the JQ Manual for for your version of libjq.

# A minimal example: report OK if a single filter evaluates to other
# than false/null.
check_json --filter '.select(somekey)' /path/to/jsonfile

# As above, but label that filter "myfilter" in the reporting

check_json --filter '.select(somekey) # myfilter' /path/to/jsonfile

# Multiple, separate filters
check_json --filter '.somekey != "somevalue"' --filter '.otherkey != "othervalue"' /path/to/jsonfile

# Source a filter from a jsonfile
check_json --filter-file /path/to/filterfile /path/to/jsonfile

Icinga2

Here is an Icinga2 CheckCommand object for this plugin:

object CheckCommand "check_json" {
  command = [ PluginDir + "/check_json", ]
  arguments = {    "--fail-status" = {
      description = "Specify the status to report when a filter comes back false/null. Defaults to warning."
      set_if = "$check_json_fail_status$"
      value = "$check_json_fail_status$"
    }
    "--filter" = {
      description = "A JQ filter to run on the given JSON file."
      set_if = "$check_json_filter$"
      value = "$check_json_filter$"
    }
    "--filter-file" = {
      description = "A file containing a JQ filter to run on the given JSON file."
      set_if = "$check_json_filter_file$"
      value = "$check_json_filter_file$"
    }
    jsonfile = {
      description = "The path to the file to inspect"
      value = "$check_json_jsonfile$"
    }
  }
}

NOTE on the command path: the above Icinga2 configuration object points to the check_json command in Icinga2's configured PluginDir, but this can be configured however you like. For instance:

• point it to wherever it is installed by its full path
• symlink from the specified path to the actual script.
• or take the kludge route, leave it as-is, and copy check_json/__main__.py from this repo into PluginDir + "/check_json"

Up to you!

Limitations

What this plugin is not for:

• Huge JSON files. This plugin processes and filters the entire JSON file given every time it runs.
• Keeping place in a log file over time. For that (though with admittedly simpler pattern matching), see check_logfiles.

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

To run the test suite:

# Up to you to create virtual environments etc
# make dependencies
make

Please make sure to update tests as appropriate.

License

MIT