Fluentbit

Fluentbit charm libraries.

This library contains two main classes: FluentbitProvider and FluentbitClient. FluentbitProvider class is instantiated in the Fluentbit Server charm, and receives configuration data through a relation to other charms. FluentbitClient class should be instantiated in any charm that wants to ship logs via Fluentbit.

Forwarding logs using Fluentbit

To forward logs from your charm to a centralized place using Fluentbit, instantiate the FluentbitClient() class and handle the relation_created event in your main charm code. In this event, your charm must pass all the configuration parameters necessary to configure Fluentbit: the inputs, the parsers, and the filters.

For example:

class MyCharm(CharmBase):
    def __init__(self, *args):
        super().__init__(*args)

        self._fluentbit = FluentbitClient(self, "fluentbit")

        self.framework.observe(self.on.fluentbit.relation_created,
                               self._fluentbit_relation_created)

    def _fluentbit_relation_created(self, event):
        cfg = [{"input": [("name",     "tail"),
                          ("path",     "/var/log/foo/bar.log"),
                          ("path_key", "filename"),
                          ("tag",      "foo"),
                          ("parser",   "bar")]},
               {"parser": [("name",        "bar"),
                           ("format",      "regex"),
                           ("regex",       "^\[(?<time>[^\]]*)\] (?<log>.*)$"),
                           ("time_key",    "time"),
                           ("time_format", "%Y-%m-%dT%H,%M,%S.%L")]}]
        self._fluentbit.configure(cfg)

The configuration object must be a list of dictionaries. Each dictionary must contain one key. The key must be the section of Fluentbit's processing pipeline. Valid ones are:

• input
• filter
• parser
• multiline_parser
• output

The value of each key must be a list of all configuration entries. Each entry is a tuple (or list) of values to be rendered in the configuration files.

Your charm's metadata.yaml should have the Fluentbit relation entry in the requires section:

requires:
      fluentbit:
          interface: fluentbit

FluentbitProvider class

This class receives the configuration data and forwards to the Fluentbit Charm, to rewrite the configuration files and restart the service. This class should only be instantiated by Fluentbit Charm.

Caveats

The charm does not validate the configuration files before restarting the service. It is the charm author's responsibility to ensure the configuration is correct.