Can we add a comment here exaplaining why is this being harcoded and linking to terraform issue?

could we not do some kind of map here in the variables?

amis = {
 eu-west-1 => 'ami-123',
 us-east-1 => 'ami-456',
}

etc..

and then use that var to replace on the end..

 "${atlas_artifact.mesos-master.metadata_full.region-${var.amis.${region}}}"

above code is syntactically incorrect but you get the gist

or even just use the region string without the AMi map? -

varname = "atlas_artifact.mesos-master.metadata_full.region-${var.region}”

ami = ${varname}

Dont think that interpolation is supported by terraform. -> "${atlas_artifact.mesos-master.metadata_full.region-${var.amis.${region}}}"

Think we can harcode it as ${atlas_artifact.mesos-master.metadata_full.region-eu-west-1}
or create a static map region -> ami-id
Then just ami = lookup(var.amis, var.region)

Static mapping would need to be updated every time we build images and the atlas_artifact resource shoudl be removed as it would be useless if we go for second option.

As enxebre mentioned the interpolation is not supported by terraform. I tested it with terraform version 0.6.1 (the newest one). So the code:

varname = "atlas_artifact.mesos-master.metadata_full.region-${var.region}”

ami = ${varname}

and my version mentioned in the terraform ticket:

ami = "${lookup(atlas_artifact.mesos-master.metadata_full, concat("region-", var.region))}"

don't work.