What is people's recommendation when moving from a large terraform base to pulumi? tf2pulumi is lacking tf 0.12 support, so I can't test its quality of output. I suspect it's going to be a rewrite from scratch?

https://github.com/pulumi/tf2pulumi may give you a head start. There is probably some work to factor your source into logical modules. https://github.com/pulumi/pulumi-terraform can also work with existing infrastructure deployed with Pulumi if you want to keep using terraform and add new resources that reference your existing terraform resources via Pulumi.

If there is a large pile of TF, then using

tf2pulumi

will save you a ton of time. I would honestly consider porting back to TF 0.11 compatible syntax so you can use tf2pulumi. I’ll bet that’s net less work than rewriting from scratch (assuming thousands of lines of TF).

Yeah, we've got around 3000 lines of TF. Most of it uses just the no

${}

syntax, so might be better to backport than waiting for tf2pulumi to support tf 0.12

There's a shortcut you can use if you are 1:1 with Terraform (for example if you used

tf2pulumi

). By adding a little dozen line or so script in your project - you should be able to automatically

import

all resources from a

.tfstate

. I'll see if we can get this checked in somewhere - but I've seen it used with at least one customer - here's an outline in the meantime: 1. Add a config setting to allow passing a path to a

.tfstate

file to import resources from that state. 2. Write some code in your Pulumi program to extract the Terraform resource name and cloud provider id of each resource from the

.tfstate

JSON file referenced in step 1 3. Create a mapping table of Pulumi type names (like

aws:elasticache/cluster:Cluster

) to Terraform type names (like

aws_elasticache_cluster

) for all the different types you use (most likely only 20-30) 4. Add a call to

pulumi.runtime.registerStackTransformation

(https://www.pulumi.com/docs/reference/pkg/nodejs/pulumi/pulumi/runtime/#registerStackTransformation) at the beginning of your Pulumi program (before any resources are registered), which transform every resource by adding a

import: <id>

to it, looking up the

<id>

based on (2) and (3) above only if (1) is set. The result is that every resource will automatically try to import the matching Terraform resource. I'll share a working code example soon - but hopefully the above gives an idea of the technique. We plan to try to make this a "built-in" feature of

tf2pulumi

in the near future - but for now it's something that is very possible with just a handful of lines of code.