From 06db8376bc296969f4eb830d0ef8fa49f5fd7dd2 Mon Sep 17 00:00:00 2001
From: Serge Smertin <serge.smertin@databricks.com>
Date: Sat, 21 May 2022 15:23:37 +0200
Subject: [PATCH] local and remote `.tfstate` utilities

---
 project/project.go       |  14 +++++-
 terraform/runner.go      | 105 +++++++++++++++++++++++++++++++++++++++
 terraform/runner_test.go |   3 ++
 3 files changed, 120 insertions(+), 2 deletions(-)

diff --git a/project/project.go b/project/project.go
index 38221f04a..4ea22ea4c 100644
--- a/project/project.go
+++ b/project/project.go
@@ -71,6 +71,17 @@ func (i *inner) Me() *scim.User {
 	return &me
 }
 
+func (i *inner) DeploymentIsolationPrefix() string {
+	if i.project.Isolation == None {
+		return i.project.Name
+	}
+	if i.project.Isolation == Soft {
+		me := i.Me()
+		return fmt.Sprintf("%s/%s", i.project.Name, me.UserName)
+	}
+	panic(fmt.Errorf("unknow project isolation: %s", i.project.Isolation))
+}
+
 func (i *inner) DevelopmentCluster(ctx context.Context) (cluster clusters.ClusterInfo, err error) {
 	api := clusters.NewClustersAPI(ctx, i.Client()) // TODO: rewrite with normal SDK
 	if i.project.DevCluster == nil {
@@ -82,8 +93,7 @@ func (i *inner) DevelopmentCluster(ctx context.Context) (cluster clusters.Cluste
 			err = fmt.Errorf("projects with soft isolation cannot have named clusters")
 			return
 		}
-		me := i.Me()
-		dc.ClusterName = fmt.Sprintf("dev/%s/%s", i.project.Name, me.UserName)
+		dc.ClusterName = fmt.Sprintf("dev/%s", i.DeploymentIsolationPrefix())
 	}
 	if dc.ClusterName == "" {
 		err = fmt.Errorf("please either pick `isolation: soft` or specify a shared cluster name")
diff --git a/terraform/runner.go b/terraform/runner.go
index 452dedc45..ba3335ea0 100644
--- a/terraform/runner.go
+++ b/terraform/runner.go
@@ -39,14 +39,119 @@ Let's see how far we can get without GRPC magic.
 package terraform
 
 import (
+	"bytes"
 	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
 
+	"github.com/databricks/bricks/project"
+	"github.com/databrickslabs/terraform-provider-databricks/storage"
 	"github.com/hashicorp/go-version"
 	"github.com/hashicorp/hc-install/product"
 	"github.com/hashicorp/hc-install/releases"
 	"github.com/hashicorp/terraform-exec/tfexec"
+
+	tfjson "github.com/hashicorp/terraform-json"
 )
 
+const DeploymentStateRemoteLocation = "dbfs:/FileStore/deployment-state"
+
+type TerraformDeployer struct {
+	WorkDir string
+	CopyTfs bool
+
+	tf *tfexec.Terraform
+}
+
+func (d *TerraformDeployer) Init(ctx context.Context) error {
+	if d.CopyTfs {
+		panic("copying tf configuration files to a temporary dir not yet implemented")
+	}
+	// TODO: most likely merge the methods
+	exec, err := newTerraform(ctx, d.WorkDir, map[string]string{})
+	if err != nil {
+		return err
+	}
+	d.tf = exec
+	return nil
+}
+
+func (d *TerraformDeployer) remoteTfstateLoc() string {
+	prefix := project.Current.DeploymentIsolationPrefix()
+	return fmt.Sprintf("%s/%s/terraform.tfstate", DeploymentStateRemoteLocation, prefix)
+}
+
+func (d *TerraformDeployer) remoteState(ctx context.Context) (*tfjson.State, error) {
+	dbfs := storage.NewDbfsAPI(ctx, project.Current.Client())
+	raw, err := dbfs.Read(d.remoteTfstateLoc())
+	if err != nil {
+		return nil, err
+	}
+	return d.tfstateFromReader(bytes.NewBuffer(raw))
+}
+
+func (d *TerraformDeployer) openLocalState() (*os.File, error) {
+	return os.Open(fmt.Sprintf("%s/terraform.tfstate", d.WorkDir))
+}
+
+func (d *TerraformDeployer) localState() (*tfjson.State, error) {
+	raw, err := d.openLocalState()
+	if err != nil {
+		return nil, err
+	}
+	return d.tfstateFromReader(raw)
+}
+
+func (d *TerraformDeployer) tfstateFromReader(reader io.Reader) (*tfjson.State, error) {
+	var state tfjson.State
+	state.UseJSONNumber(true)
+	decoder := json.NewDecoder(reader)
+	decoder.UseNumber()
+	err := decoder.Decode(&state)
+	if err != nil {
+		return nil, err
+	}
+	err = state.Validate()
+	if err != nil {
+		return nil, err
+	}
+	return &state, nil
+}
+
+func (d *TerraformDeployer) uploadTfstate(ctx context.Context) error {
+	// scripts/azcli-integration/terraform.tfstate
+	dbfs := storage.NewDbfsAPI(ctx, project.Current.Client())
+	f, err := d.openLocalState()
+	if err != nil {
+		return err
+	}
+	raw, err := io.ReadAll(f)
+	if err != nil {
+		return err
+	}
+	// TODO: make sure that deployment locks are implemented
+	return dbfs.Create(d.remoteTfstateLoc(), raw, true)
+}
+
+func (d *TerraformDeployer) downloadTfstate(ctx context.Context) error {
+	remote, err := d.remoteState(ctx)
+	if err != nil {
+		return err
+	}
+	local, err := d.openLocalState()
+	if err != nil {
+		return err
+	}
+	raw, err := json.Marshal(remote)
+	if err != nil {
+		return err
+	}
+	_, err = io.Copy(local, bytes.NewBuffer(raw))
+	return err
+}
+
 // installs terraform to a temporary directory (for now)
 func installTerraform(ctx context.Context) (string, error) {
 	// TODO: let configuration and/or environment variable specify
diff --git a/terraform/runner_test.go b/terraform/runner_test.go
index abd939467..a8c5d9ee4 100644
--- a/terraform/runner_test.go
+++ b/terraform/runner_test.go
@@ -36,6 +36,9 @@ func TestSomething(t *testing.T) {
 		if r.Type != "databricks_job" {
 			continue
 		}
+		// TODO: validate that libraries on jobs defined in *.tf and libraries 
+		// in `install_requires` defined in setup.py are the same. Exist with 
+		// the explanatory error otherwise.
 		found = true
 		// resource "databricks_job" "this"
 		assert.Equal(t, "this", r.Name)