Ability to filter by label without a match

[sparrowt]

I tried to use @label in order to reduce duplication across multiple filter patterns, however I get this:

error_class=Fluent::ConfigError error="Missing <match> sections in <label @MYLABEL> section"

What I am trying to do:

<source>
  ...
  tag "something.long.and.complicated"
  @label @MYLABEL
</source>
<source>
  # some other source
</source>

<label @MYLABEL>
  # Filters which should only get applied to MYLABEL
  <filter **>
    ...
  </filter>
  <filter **>
    ...
  </filter>
</label>

<match **>
  # output everything to the same place
</match>

Unfortunately this doesn't work and I don't want to move the <match> inside the <label> block because it applies to messages from other sources/labels too.

Instead I am forced to do this:

<source>
  ...
  tag "something.long.and.complicated"
</source>
<source>
  # some other source
</source>

<filter something.long.and.complicated>
  ...
</filter>
<filter something.long.and.complicated>
  ...
</filter>

<match **>
  # output everything to the same place
</match>

Note now that "something.long.and.complicated" is repeated 3 times in my config file which isn't very DRY

Is there a reason can't be used just for without the requirement to have a in there too?

[adelbordbari]

same problem
i get error_class=Fluent::ConfigError error="Missing <match> sections in <label @success> section"

[daipom]

A label of Fluentd is an independent routing definition without source.
Once routed to a label, routing is usually completed within that label.
So, you must set one or more match to a label.

Indeed, something like a filter-only label would be useful to manage multiple combinations of filter sets and match sets.
For this, you can use out_relabel or out_rewrite_tag_filter to re-route events to another label or ROOT (@ROOT).

Example:
(I have not confirmed that it works. Please try it and let me know if it does not work.)

# Source using filter-A
<source>
  @label @filter-A
  ...
</source>

# Source not using filter-A
<source>
  @label @output-A
  ...
</source>

<label @filter-A>
  <filter **>...</filter>
  <filter **>...</filter>
  <match **>
    @type relabel
    @label @output-A
  </match>
</label>

<label @output-A>
  <match **>...</match>
</label>