HCL2 builds do not send the packer_user_variables config key to the
builder, provisioner and post-processor plugins. Legacy JSON builds
send this key (through CoreBuild.packerConfig()). Without the key, the
plugin SDK keeps interpolate.Context.UserVariables nil. Then the
template function {{ user "name" }} fails with 'error calling user:
test'. This failure occurs in each string that a plugin interpolates at
run time, for example the contents of the vagrant post-processor's
vagrantfile_template.
Add the function PackerConfig.userVariableValues(). This function
converts the input variable values to strings, equivalent to the legacy
user variables. The core sends the map at each plugin handoff point:
builder, provisioner, post-processor, and enforced provisioner.
The map does not contain the sensitive variables. A sensitive value
goes to a plugin only if the template refers to it explicitly. The map
does not contain values that are not primitive (lists, maps, objects).
Legacy user variables were always strings.
Co-authored-by: Claude Fable 5 <[email protected]>