Run terraform plan -destroy when destroy flag is enabled (#168)

* destroy plan

* destroy plan

* nit

* nit2

* remove unneeded decorator

* nit

server/lyft/decorators/destroy_plan_step_runner_wrapper.go

@@ -0,0 +1,21 @@
+package decorators
+
+import (
+	"github.com/runatlantis/atlantis/server/events"
+	"github.com/runatlantis/atlantis/server/events/models"
+)
+
+const Deprecated = "deprecated"
+const Destroy = "-destroy"
+
+type DestroyPlanStepRunnerWrapper struct {
+	events.StepRunner
+}
+
+func (d *DestroyPlanStepRunnerWrapper) Run(ctx models.ProjectCommandContext, extraArgs []string, path string, envs map[string]string) (string, error) {
+	// DestroyPlan tag is true when the Terraform client should construct a destroy plan given a repo config.
+	if ctx.Tags[Deprecated] == Destroy {
+		extraArgs = append(extraArgs, Destroy)
+	}
+	return d.StepRunner.Run(ctx, extraArgs, path, envs)
+}

server/lyft/decorators/destroy_plan_step_runner_wrapper_test.go

@@ -0,0 +1,128 @@
+package decorators_test
+
+import (
+	"fmt"
+	"github.com/hashicorp/go-version"
+	"github.com/runatlantis/atlantis/server/core/runtime"
+	"github.com/runatlantis/atlantis/server/core/terraform/mocks"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/runatlantis/atlantis/server/events/models"
+	"github.com/runatlantis/atlantis/server/logging"
+	"github.com/runatlantis/atlantis/server/lyft/decorators"
+
+	. "github.com/petergtz/pegomock"
+	. "github.com/runatlantis/atlantis/testing"
+)
+
+func TestRun_DestroyPlan(t *testing.T) {
+	RegisterMockTestingT(t)
+
+	// Create the env/workspace.tfvars file.
+	tmpDir, cleanup := TempDir(t)
+	defer cleanup()
+	err := os.MkdirAll(filepath.Join(tmpDir, "env"), 0700)
+	Ok(t, err)
+
+	cases := []struct {
+		description string
+		expPlanArgs []string
+		tags        map[string]string
+	}{
+		{
+			description: "uses destroy plan",
+			expPlanArgs: []string{
+				"plan",
+				"-input=false",
+				"-refresh",
+				"-out",
+				fmt.Sprintf("%q", filepath.Join(tmpDir, "workspace.tfplan")),
+				"-var",
+				"atlantis_user=\"username\"",
+				"-var",
+				"atlantis_repo=\"owner/repo\"",
+				"-var",
+				"atlantis_repo_name=\"repo\"",
+				"-var",
+				"atlantis_repo_owner=\"owner\"",
+				"-var",
+				"atlantis_pull_num=2",
+				"extra",
+				"args",
+				"-destroy",
+				"comment",
+				"args",
+			},
+			tags: map[string]string{
+				decorators.Deprecated: decorators.Destroy,
+			},
+		},
+		{
+			description: "no destroy plan",
+			expPlanArgs: []string{
+				"plan",
+				"-input=false",
+				"-refresh",
+				"-out",
+				fmt.Sprintf("%q", filepath.Join(tmpDir, "workspace.tfplan")),
+				"-var",
+				"atlantis_user=\"username\"",
+				"-var",
+				"atlantis_repo=\"owner/repo\"",
+				"-var",
+				"atlantis_repo_name=\"repo\"",
+				"-var",
+				"atlantis_repo_owner=\"owner\"",
+				"-var",
+				"atlantis_pull_num=2",
+				"extra",
+				"args",
+				"comment",
+				"args",
+			},
+			tags: map[string]string{},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.description, func(t *testing.T) {
+			// Using version >= 0.10 here so we don't expect any env commands.
+			terraform := mocks.NewMockClient()
+			tfVersion, _ := version.NewVersion("0.10.0")
+			logger := logging.NewNoopLogger(t)
+			planStepRunner := runtime.PlanStepRunner{
+				TerraformExecutor: terraform,
+				DefaultTFVersion:  tfVersion,
+			}
+			stepRunner := decorators.DestroyPlanStepRunnerWrapper{
+				StepRunner: &planStepRunner,
+			}
+			ctx := models.ProjectCommandContext{
+				Log:                logger,
+				Workspace:          "workspace",
+				RepoRelDir:         ".",
+				User:               models.User{Username: "username"},
+				EscapedCommentArgs: []string{"comment", "args"},
+				Pull: models.PullRequest{
+					Num: 2,
+				},
+				BaseRepo: models.Repo{
+					FullName: "owner/repo",
+					Owner:    "owner",
+					Name:     "repo",
+				},
+				Tags: c.tags,
+			}
+			When(terraform.RunCommandWithVersion(ctx, tmpDir, c.expPlanArgs, map[string]string(nil), tfVersion, "workspace")).ThenReturn("output", nil)
+
+			output, err := stepRunner.Run(ctx, []string{"extra", "args"}, tmpDir, map[string]string(nil))
+			Ok(t, err)
+
+			// Verify that we next called for the actual
+			terraform.VerifyWasCalledOnce().RunCommandWithVersion(ctx, tmpDir, c.expPlanArgs, map[string]string(nil), tfVersion, "workspace")
+			Equals(t, "output", output)
+		})
+	}
+}

server/server.go

@@ -58,9 +58,9 @@ import (
 	"github.com/runatlantis/atlantis/server/events"
 	"github.com/runatlantis/atlantis/server/events/models"
 	"github.com/runatlantis/atlantis/server/events/vcs"
-	lyft_vcs "github.com/runatlantis/atlantis/server/events/vcs/lyft"
 	"github.com/runatlantis/atlantis/server/events/vcs/bitbucketcloud"
 	"github.com/runatlantis/atlantis/server/events/vcs/bitbucketserver"
+	lyft_vcs "github.com/runatlantis/atlantis/server/events/vcs/lyft"
 	"github.com/runatlantis/atlantis/server/events/webhooks"
 	"github.com/runatlantis/atlantis/server/events/yaml"
 	"github.com/runatlantis/atlantis/server/logging"
@@ -539,19 +539,24 @@ func NewServer(userConfig UserConfig, config Config) (*Server, error) {
 		WorkingDir: workingDir,
 	}
 
+	planStepRunner := &runtime.PlanStepRunner{
+		TerraformExecutor:   terraformClient,
+		DefaultTFVersion:    defaultTfVersion,
+		CommitStatusUpdater: commitStatusUpdater,
+		AsyncTFExec:         terraformClient,
+	}
+	destroyPlanStepRunnerWrapper := &lyftDecorators.DestroyPlanStepRunnerWrapper{
+		StepRunner: planStepRunner,
+	}
+
 	projectCommandRunner := &events.DefaultProjectCommandRunner{
 		Locker:           projectLocker,
 		LockURLGenerator: router,
 		InitStepRunner: &runtime.InitStepRunner{
 			TerraformExecutor: terraformClient,
 			DefaultTFVersion:  defaultTfVersion,
 		},
-		PlanStepRunner: &runtime.PlanStepRunner{
-			TerraformExecutor:   terraformClient,
-			DefaultTFVersion:    defaultTfVersion,
-			CommitStatusUpdater: commitStatusUpdater,
-			AsyncTFExec:         terraformClient,
-		},
+		PlanStepRunner:        destroyPlanStepRunnerWrapper,
 		ShowStepRunner:        showStepRunner,
 		PolicyCheckStepRunner: policyCheckRunner,
 		ApplyStepRunner: &runtime.ApplyStepRunner{