databricks-cli/terraform/runner.go

79 lines
2.2 KiB
Go

/*
How to simplify terraform configuration for the project?
---
Solve the following adoption slowers:
- remove the need for `required_providers` block
- authenticate Databricks provider with the same DatabricksClient
- skip downloading and locking Databricks provider every time (few seconds)
- users won't have to copy-paste these into their configs:
```hcl
terraform {
required_providers {
databricks = {
source = "databrickslabs/databricks"
}
}
}
provider "databricks" {
}
```
Terraform Plugin SDK v2 is using similar techniques for testing providers. One may find
details in github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource/plugin.go. In short:
- init provider isntance
- start terraform plugin GRPC server
- "reattach" providers and specify the `tfexec.Reattach` options, which essentially
forward GRPC address to terraform subprocess.
- this can be done by either adding a source depenency on Databricks provider
or adding a special launch mode to it.
For now
---
Let's see how far we can get without GRPC magic.
*/
package terraform
import (
"context"
"github.com/hashicorp/go-version"
"github.com/hashicorp/hc-install/product"
"github.com/hashicorp/hc-install/releases"
"github.com/hashicorp/terraform-exec/tfexec"
)
// installs terraform to a temporary directory (for now)
func installTerraform(ctx context.Context) (string, error) {
// TODO: let configuration and/or environment variable specify
// terraform binary. Or detect if terraform is installed in the $PATH
installer := &releases.ExactVersion{
Product: product.Terraform,
Version: version.Must(version.NewVersion("1.1.0")),
}
return installer.Install(ctx)
}
func newTerraform(ctx context.Context, workDir string, env map[string]string) (*tfexec.Terraform, error) {
execPath, err := installTerraform(ctx)
if err != nil {
return nil, err
}
// TODO: figure out how to cleanup/skip `.terraform*` files and dirs, not to confuse users
// one of the options: take entire working directory with *.tf files and move them to tmpdir.
// make it optional, of course, otherwise debugging may become super hard.
tf, err := tfexec.NewTerraform(workDir, execPath)
if err != nil {
return nil, err
}
err = tf.SetEnv(env)
if err != nil {
return nil, err
}
return tf, err
}