Built-in placeholders for dynamic collection are not work

[askstw]

Hi, the placeholders for dynamic collection name are not work.

collection ${tag[1]}-%Y%m%d

Is there a bug are any suggestion ?

We got collection name "testfile-%Y%m%d" , not our excepted

[agup006]

@askstw in the buffer section try adding tag, I added a note a while back on needing them defined in buffer to use as placeholder for the HTTP endpoint - I might need to add to all docs

Example in buffer section

<buffer tag,key>
  # buffer parameters
</buffer>

[repeatedly]

If you want to use time based placeholders, need to specify time in buffer keys. Here is an example in official article: https://docs.fluentd.org/configuration/buffer-section#placeholders