From 85295e5c23b1ab79c25a12825ee589f2d62409d1 Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Sat, 2 Dec 2017 17:31:28 -0500
Subject: [PATCH] watch for cancellation in plan and refresh

Cancellation in the local backend was only implemented for apply.
---
 backend/local/backend_apply.go   |  8 --------
 backend/local/backend_plan.go    | 32 +++++++++++++++++++++++++------
 backend/local/backend_refresh.go | 33 ++++++++++++++++++++++++++++----
 3 files changed, 55 insertions(+), 18 deletions(-)

diff --git a/backend/local/backend_apply.go b/backend/local/backend_apply.go
index 446343181..9789e0b7c 100644
--- a/backend/local/backend_apply.go
+++ b/backend/local/backend_apply.go
@@ -151,14 +151,6 @@ func (b *Local) opApply(
 		_, applyErr = tfCtx.Apply()
 		// we always want the state, even if apply failed
 		applyState = tfCtx.State()
-
-		/*
-			// Record any shadow errors for later
-			if err := ctx.ShadowError(); err != nil {
-				shadowErr = multierror.Append(shadowErr, multierror.Prefix(
-					err, "apply operation:"))
-			}
-		*/
 	}()
 
 	// Wait for the apply to finish or for us to be interrupted so
diff --git a/backend/local/backend_plan.go b/backend/local/backend_plan.go
index a4e92c1c7..380ce1742 100644
--- a/backend/local/backend_plan.go
+++ b/backend/local/backend_plan.go
@@ -101,14 +101,34 @@ func (b *Local) opPlan(
 		}
 	}
 
-	// Perform the plan
-	log.Printf("[INFO] backend/local: plan calling Plan")
-	plan, err := tfCtx.Plan()
-	if err != nil {
-		runningOp.Err = errwrap.Wrapf("Error running plan: {{err}}", err)
-		return
+	// Perform the plan in a goroutine so we can be interrupted
+	var plan *terraform.Plan
+	var planErr error
+	doneCh := make(chan struct{})
+	go func() {
+		defer close(doneCh)
+		log.Printf("[INFO] backend/local: plan calling Plan")
+		plan, planErr = tfCtx.Plan()
+	}()
+
+	select {
+	case <-ctx.Done():
+		if b.CLI != nil {
+			b.CLI.Output("stopping plan operation...")
+		}
+
+		// Stop execution
+		go tfCtx.Stop()
+
+		// Wait for completion still
+		<-doneCh
+	case <-doneCh:
 	}
 
+	if planErr != nil {
+		runningOp.Err = errwrap.Wrapf("Error running plan: {{err}}", planErr)
+		return
+	}
 	// Record state
 	runningOp.PlanEmpty = plan.Diff.Empty()
 
diff --git a/backend/local/backend_refresh.go b/backend/local/backend_refresh.go
index 282e63045..0cf50b759 100644
--- a/backend/local/backend_refresh.go
+++ b/backend/local/backend_refresh.go
@@ -3,6 +3,7 @@ package local
 import (
 	"context"
 	"fmt"
+	"log"
 	"os"
 	"strings"
 
@@ -12,6 +13,7 @@ import (
 	"github.com/hashicorp/terraform/command/clistate"
 	"github.com/hashicorp/terraform/config/module"
 	"github.com/hashicorp/terraform/state"
+	"github.com/hashicorp/terraform/terraform"
 )
 
 func (b *Local) opRefresh(
@@ -78,11 +80,34 @@ func (b *Local) opRefresh(
 		}
 	}
 
-	// Perform operation and write the resulting state to the running op
-	newState, err := tfCtx.Refresh()
+	// Perform the refresh in a goroutine so we can be interrupted
+	var newState *terraform.State
+	var refreshErr error
+	doneCh := make(chan struct{})
+	go func() {
+		defer close(doneCh)
+		newState, err = tfCtx.Refresh()
+		log.Printf("[INFO] backend/local: plan calling Plan")
+	}()
+
+	select {
+	case <-ctx.Done():
+		if b.CLI != nil {
+			b.CLI.Output("stopping refresh operation...")
+		}
+
+		// Stop execution
+		go tfCtx.Stop()
+
+		// Wait for completion still
+		<-doneCh
+	case <-doneCh:
+	}
+
+	// write the resulting state to the running op
 	runningOp.State = newState
-	if err != nil {
-		runningOp.Err = errwrap.Wrapf("Error refreshing state: {{err}}", err)
+	if refreshErr != nil {
+		runningOp.Err = errwrap.Wrapf("Error refreshing state: {{err}}", refreshErr)
 		return
 	}