Khepri 0.18.0

At this point, Khepri should be considered Beta. The API will likely evolve and future releases will likely introduce breaking changes.

What's new in Khepri 0.18.0

Support multi-table projections

Khepri 0.18.0 supports extended projections that need to manage several ETS tables. This is useful to maintain multiple views of the same set of records, or to organise a complex structured view of that set of records accross several tables to provide more efficient updates and lookups.

To declare a multi-table projection, you can provide the list of tables along with their specific ETS options:

Options = #{tables => #{my_table_1 => #{type => set},
                        my_table_2 => #{type => bag}},
            read_concurrency => true},
khepri_projection:new(my_projection, fun extended_fun/4, Options).

Your projection function is then called with a map of table names/TIDs instead of a single TID:

extended_fun(Tables, Path, OldProps, NewProps) ->
    #{my_table_1 := Tid1,
      my_table_2 := Tid2} = Tables,
    ...

See #366.

Other changes

• Add an internal API to wait for a machine version or behaviour to be effective in a cluster (#374).
• Ra was bumped from Ra 2.16.12 to 3.1.2 (#340, #347, #364, #375, #378, #382).

Download

Khepri is available from Hex.pm: https://hex.pm/packages/khepri/0.18.0

Upgrade

Using Rebar:

1. Update your rebar.config:

   %% In rebar.config
   {deps, [{khepri, "0.18.0"}]}.

2. Run rebar3 upgrade khepri.

Using Erlang.mk:

1. Update your Makefile:

   %% In your Makefile
   dep_khepri = hex 0.18.0

2. Remove the deps/khepri directory. The new version will be fetched the next time you build your project.

Documentation

The documentation for Khepri is available on Hex.pm.