input: output: Bind log api from fluent-bit

[cosmo0920]

Related to #19.

I binded the fundamental APIs to use fluent-bit's logging mechanism.
With this patch, we can call flb_log_print and flb_log_check via flb_api interface.

Signed-off-by: Hiroshi Hatake [email protected]

[cosmo0920]

@nicolasparada Could you add logging interface in top of this PR?

[cosmo0920]

I tried to implement Logger interface for Golang plugin.
Not that this implementation needs to work with the latest fluent/fluent-bit#5056 patch.

[nicolasparada]

Is the log level always required?

We can have something like:

logger.Log(msg, args...)
level.Error(logger).Log(msg, args...)

If we can skip the log level.

[cosmo0920]

Oh, good point. In fluent-bit's logging system, log level is always required. But, in Golang world, we can implement a builder for constructing logger.
I'll continue to consider builder pattern in this logger implementation.

[nicolasparada]

That's ok, if it always required in fluent-bit, we can follow that with Go too.
Be aligned in the APIs is important.

[nicolasparada]

I wouldn't make this a package level thing.
Maybe Init() method on the plugin could receive it in its args.

[nicolasparada]

Init() is already receiving too many args.

ctx context.Context
conf plugin.ConfigLoader
metrics plugin.Metrics

And adding plugin.Logger to those... Maybe we can pass a struct with all of those in there.

type Fluentbit struct {
  Conf plugin.ConfigLoader
  Metrics plugin.Metrics
  Logger plugin.Logger
}

Init() can now looks like this:

func (myPlugin) Init(ctx context.Context, fbit plugin.Fluentbit) error {
  fbit.Config.String("some_param")
  fbit.Metrics.NewCounter("my_counter", "desc")
  fbit.Logger.Info("calling init")

  return nil
}

[cosmo0920]

Looks good. I implemented your suggestion. ¡Genial!

[niedbalski]

@cosmo0920 2 things I would like to add 👍🏻

1. Please expand the README.md with an example that uses logger.
2. Please add a test to validate that logger works in the dummy plugin

Thanks!

[cosmo0920]

I added the commit to reflect the argument changes on Init

[cosmo0920]

2. Please add a test to validate that logger works in the dummy plugin

I think that we should do in test plugins that is implemented in testdata.

[cosmo0920]

Oh, CI is failed. I'll take a look later.

[cosmo0920]

CI got green! 💚