The environment is a map used for passing data and configuration choices into pallet. The environment may be specified at various scopes. The environment contributed by each scope will be merged.

Environment API

The environment can be accessed with pallet.environment/get-environment.

Pallet Specific Keys

Pallet recognises specific keys in the environment.

:algorithms : a map that can be used to specify specific algorithms to override the pallet defaults

:groups : a map, keyed on group name (keyword), that can specify node-spec details

:phase : a map of phase defintions, that all group-specs will extend

Specifying Environment Values


In config.clj, the environment may be specified at the top level, and/or at the service level.

  ;; general environment
  :environment {:algorithms
                {:lift-fn pallet.core/parallel-lift
                 :converge-fn pallet.core/parallel-adjust-node-counts}}
  :services {:vb4
             {:provider "aws-ec2"
              ;; environment specific to :vb4 service
              {:proxy ""
               :mirror {:apache ""}}}})

lift and converge Arguments

Both lift and converge can be passed an environment map using the :environment keyword.