xlator.md

Notes for translator authors

Variable params substitution

Some xlators require non-static information such as brick path or volume id to be populated by glusterd2 in xlator's options in volfile. Xlators can set a placeholder/varstring in the .default_value field of its options table. Glusterd2 will replace this placeholder/varstring with actual values during volfile generation.

Here's a list of supported varstrings:

volume.id
volume.name
volume.type
volume.redundancy
volume.transport
volume.auth.username
volume.auth.password

brick.id
brick.hostname
brick.peerid
brick.path
brick.volumename
brick.volumeid

Example code from xlators/features/index/src/index.c:

struct volume_options options[] = {
        { .key  = {"index-base" },
          .type = GF_OPTION_TYPE_PATH,
          .description = "path where the index files need to be stored",
          .default_value = "{{ brick.path }}/.glusterfs/indices"
        },
...
}

The varstring {{ brick.path }} will be substituted with actual path of the brick during volfile generation. This is how it'll end up in the generated brick volfile:

volume test-index
    type features/index
    option index-base /export/brick2/data/.glusterfs/indices
    option xattrop-pending-watchlist trusted.afr.test
    subvolumes test-barrier
end-volume