guildencrantz/tfvarser repository overview

⁠tfvarser

Ever want to convert an HCL tfvars file to JSON? Or a JSON tfvars file to HCL? Or merge two tfvars files? No? Good for you!

If, however, you want (or just need) to do these tfvarser should help.

⁠Installation

⁠Go Binary

go get github.com/guildencrantz/tfvarser

⁠Docker Image

docker pull guildencrantz/tfvarser:1

⁠Usage

tfvarser -hcl terraform.tfvars -json new_values.json

This will read the terraform.tfvars, then add the contents of new_values.json (overwriting any keys that are in terraform.tfvars with values from new_values.json, or just adding new keys) and output, to stdout, the merged config (in hcl).

You can specify -hcl and -json as many times as you want. All files are processed in left-to-right flag order, regardless of format.

By default the output is hcl, however you can output json with -output json.

Likewise by default values from latter configs will override earlier configs, however you can suppress this behavior (so that once a key is set it's not overwritten) by setting -overwrite false.

Refer to tfvarser -help for current flags.

⁠Why?

More than once now I've found I needed to merge configs. In this case after importing existing infrastructure into terraform I need to build the config so that it won't just destroy all that existing infrastructure. Well, I have most of the needed config in JSON, and the few pieces that aren't in that JSON are in an existing tfvars file. Since the tooling assumes environment specific configurations will be in tfvars file it was easier to write this than to update that to handle tfvars.json files.

⁠Caveats

In addition to the normal "heh, this was written very quickly after hours, you get what you pay for and you're on your own" it should be noted that this tool, though it generically reads HCL and JSON, and generically outputs HCL and JSON, it does expect that the inputs will be maps. If you pass in a file that's not a map at the top level I believe it'll silently skip that file? Not 100% sure (note the current test coverage).