Build Context (ctx)

The build context ctx is passed to all build steps as the second parameter.

It provides a couple of values that are necessary to more deeply hook into the internals of LambdaCD:

:result-channel

This is a core.async channel that allows you to set intermediate values about the step result while a build step is running. Most of the time, this will be used to update the output (:out) or status (:status) of the step to inform the user about the steps progress via the UI.

The message format is a tuple of the key you want to set and a value. Updates to the same key overwrite previous values.

E.g. to update the output of your build step:

(async/>!! (:result-channel ctx) [:out msg])

:config

The config-value initially passed into assemble-pipeline