have Meta.Backend use a Config rather than loading

Instead of providing the a path in BackendOpts, provide a loaded
*config.Config instead. This reduces the number of places where
configuration is loaded.

command/apply.go

@@ -132,9 +132,14 @@ func (c *ApplyCommand) Run(args []string) int {
 		}
 	*/
 
+	var conf *config.Config
+	if mod != nil {
+		conf = mod.Config()
+	}
+
 	// Load the backend
 	b, err := c.Backend(&BackendOpts{
-		ConfigPath: configPath,
+		Config: conf,
 		Plan:   plan,
 	})
 	if err != nil {

command/console.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/helper/wrappedstreams"
 	"github.com/hashicorp/terraform/repl"
 
@@ -43,8 +44,16 @@ func (c *ConsoleCommand) Run(args []string) int {
 		return 1
 	}
 
+	var conf *config.Config
+	if mod != nil {
+		conf = mod.Config()
+	}
+
 	// Load the backend
-	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	b, err := c.Backend(&BackendOpts{
+		Config: conf,
+	})
+
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
 		return 1

command/env_delete.go

@@ -43,8 +43,17 @@ func (c *EnvDeleteCommand) Run(args []string) int {
 		return 1
 	}
 
+	cfg, err := c.Config(configPath)
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load root config module: %s", err))
+		return 1
+	}
+
 	// Load the backend
-	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	b, err := c.Backend(&BackendOpts{
+		Config: cfg,
+	})
+
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
 		return 1

command/env_list.go

@@ -26,8 +26,17 @@ func (c *EnvListCommand) Run(args []string) int {
 		return 1
 	}
 
+	cfg, err := c.Config(configPath)
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load root config module: %s", err))
+		return 1
+	}
+
 	// Load the backend
-	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	b, err := c.Backend(&BackendOpts{
+		Config: cfg,
+	})
+
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
 		return 1

command/env_new.go

@@ -46,8 +46,16 @@ func (c *EnvNewCommand) Run(args []string) int {
 		return 1
 	}
 
+	conf, err := c.Config(configPath)
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load root config module: %s", err))
+	}
+
 	// Load the backend
-	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	b, err := c.Backend(&BackendOpts{
+		Config: conf,
+	})
+
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
 		return 1

command/env_select.go

@@ -31,8 +31,17 @@ func (c *EnvSelectCommand) Run(args []string) int {
 		return 1
 	}
 
+	conf, err := c.Config(configPath)
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load root config module: %s", err))
+		return 1
+	}
+
 	// Load the backend
-	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	b, err := c.Backend(&BackendOpts{
+		Config: conf,
+	})
+
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
 		return 1

command/graph.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/config/module"
 	"github.com/hashicorp/terraform/dag"
 	"github.com/hashicorp/terraform/terraform"
@@ -62,9 +63,14 @@ func (c *GraphCommand) Run(args []string) int {
 		}
 	}
 
+	var conf *config.Config
+	if mod != nil {
+		conf = mod.Config()
+	}
+
 	// Load the backend
 	b, err := c.Backend(&BackendOpts{
-		ConfigPath: configPath,
+		Config: conf,
 		Plan:   plan,
 	})
 	if err != nil {

command/import.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/config/module"
 	"github.com/hashicorp/terraform/terraform"
 )
@@ -60,8 +61,15 @@ func (c *ImportCommand) Run(args []string) int {
 		}
 	}
 
+	var conf *config.Config
+	if mod != nil {
+		conf = mod.Config()
+	}
+
 	// Load the backend
-	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	b, err := c.Backend(&BackendOpts{
+		Config: conf,
+	})
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
 		return 1

command/init.go

@@ -106,11 +106,7 @@ func (c *InitCommand) Run(args []string) int {
 	// If we're performing a get or loading the backend, then we perform
 	// some extra tasks.
 	if flagGet || flagBackend {
-		// Load the configuration in this directory so that we can know
-		// if we have anything to get or any backend to configure. We do
-		// this to improve the UX. Practically, we could call the functions
-		// below without checking this to the same effect.
-		conf, err := config.LoadDir(path)
+		conf, err := c.Config(path)
 		if err != nil {
 			c.Ui.Error(fmt.Sprintf(
 				"Error loading configuration: %s", err))
@@ -145,7 +141,7 @@ func (c *InitCommand) Run(args []string) int {
 			}
 
 			opts := &BackendOpts{
-				ConfigPath:  path,
+				Config:      conf,
 				ConfigExtra: flagConfigExtra,
 				Init:        true,
 			}

command/meta_backend.go

@@ -9,11 +9,9 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
-	"os"
 	"path/filepath"
 	"strings"
 
-	"github.com/hashicorp/errwrap"
 	"github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/hcl"
 	"github.com/hashicorp/terraform/backend"
@@ -29,9 +27,9 @@ import (
 
 // BackendOpts are the options used to initialize a backend.Backend.
 type BackendOpts struct {
-	// ConfigPath is a path to a file or directory containing the backend
-	// configuration (declaration).
-	ConfigPath string
+	// Module is the root module from which we will extract the terraform and
+	// backend configuration.
+	Config *config.Config
 
 	// ConfigFile is a path to a file that contains configuration that
 	// is merged directly into the backend configuration when loaded
@@ -178,71 +176,34 @@ func (m *Meta) Operation() *backend.Operation {
 
 // backendConfig returns the local configuration for the backend
 func (m *Meta) backendConfig(opts *BackendOpts) (*config.Backend, error) {
-	// If no explicit path was given then it is okay for there to be
-	// no backend configuration found.
-	emptyOk := opts.ConfigPath == ""
-
-	// Determine the path to the configuration.
-	path := opts.ConfigPath
-
-	// If we had no path set, it is an error. We can't initialize unset
-	if path == "" {
-		path = "."
-	}
-
-	// Expand the path
-	if !filepath.IsAbs(path) {
-		var err error
-		path, err = filepath.Abs(path)
+	if opts.Config == nil {
+		// check if the config was missing, or just not required
+		conf, err := m.Config(".")
 		if err != nil {
-			return nil, fmt.Errorf(
-				"Error expanding path to backend config %q: %s", path, err)
-		}
-	}
-
-	log.Printf("[DEBUG] command: loading backend config file: %s", path)
-
-	// We first need to determine if we're loading a file or a directory.
-	fi, err := os.Stat(path)
-	if err != nil {
-		if os.IsNotExist(err) && emptyOk {
-			log.Printf(
-				"[INFO] command: backend config not found, returning nil: %s",
-				path)
-			return nil, nil
-		}
-
 			return nil, err
 		}
 
-	var f func(string) (*config.Config, error) = config.LoadFile
-	if fi.IsDir() {
-		f = config.LoadDir
-	}
-
-	// Load the configuration
-	c, err := f(path)
-	if err != nil {
-		// Check for the error where we have no config files and return nil
-		// as the configuration type.
-		if errwrap.ContainsType(err, new(config.ErrNoConfigsFound)) {
-			log.Printf(
-				"[INFO] command: backend config not found, returning nil: %s",
-				path)
+		if conf == nil {
+			log.Println("[INFO] command: no config, returning nil")
 			return nil, nil
 		}
 
-		return nil, err
+		log.Println("[WARNING] BackendOpts.Config not set, but config found")
+		opts.Config = conf
 	}
 
+	c := opts.Config
+
 	// If there is no Terraform configuration block, no backend config
 	if c.Terraform == nil {
+		log.Println("[INFO] command: empty terraform config, returning nil")
 		return nil, nil
 	}
 
 	// Get the configuration for the backend itself.
 	backend := c.Terraform.Backend
 	if backend == nil {
+		log.Println("[INFO] command: empty backend config, returning nil")
 		return nil, nil
 	}
 

command/meta_new.go

@@ -2,7 +2,9 @@ package command
 
 import (
 	"fmt"
+	"log"
 	"os"
+	"path/filepath"
 	"strconv"
 
 	"github.com/hashicorp/errwrap"
@@ -51,6 +53,66 @@ func (m *Meta) Module(path string) (*module.Tree, error) {
 	return mod, nil
 }
 
+// Config loads the root config for the path specified. Path may be a directory
+// or file. The absence of configuration is not an error and returns a nil Config.
+func (m *Meta) Config(path string) (*config.Config, error) {
+	// If no explicit path was given then it is okay for there to be
+	// no backend configuration found.
+	emptyOk := path == ""
+
+	// If we had no path set, it is an error. We can't initialize unset
+	if path == "" {
+		path = "."
+	}
+
+	// Expand the path
+	if !filepath.IsAbs(path) {
+		var err error
+		path, err = filepath.Abs(path)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"Error expanding path to backend config %q: %s", path, err)
+		}
+	}
+
+	log.Printf("[DEBUG] command: loading backend config file: %s", path)
+
+	// We first need to determine if we're loading a file or a directory.
+	fi, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) && emptyOk {
+			log.Printf(
+				"[INFO] command: backend config not found, returning nil: %s",
+				path)
+			return nil, nil
+		}
+
+		return nil, err
+	}
+
+	var f func(string) (*config.Config, error) = config.LoadFile
+	if fi.IsDir() {
+		f = config.LoadDir
+	}
+
+	// Load the configuration
+	c, err := f(path)
+	if err != nil {
+		// Check for the error where we have no config files and return nil
+		// as the configuration type.
+		if errwrap.ContainsType(err, new(config.ErrNoConfigsFound)) {
+			log.Printf(
+				"[INFO] command: backend config not found, returning nil: %s",
+				path)
+			return nil, nil
+		}
+
+		return nil, err
+	}
+
+	return c, nil
+}
+
 // Plan returns the plan for the given path.
 //
 // This only has an effect if the path itself looks like a plan.

command/plan.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/config/module"
 )
 
@@ -68,9 +69,13 @@ func (c *PlanCommand) Run(args []string) int {
 		}
 	}
 
+	var conf *config.Config
+	if mod != nil {
+		conf = mod.Config()
+	}
 	// Load the backend
 	b, err := c.Backend(&BackendOpts{
-		ConfigPath: configPath,
+		Config: conf,
 		Plan:   plan,
 	})
 	if err != nil {

command/providers.go

@@ -52,7 +52,9 @@ func (c *ProvidersCommand) Run(args []string) int {
 	}
 
 	// Load the backend
-	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	b, err := c.Backend(&BackendOpts{
+		Config: root.Config(),
+	})
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
 		return 1

command/push.go

@@ -11,6 +11,7 @@ import (
 	"github.com/hashicorp/atlas-go/archive"
 	"github.com/hashicorp/atlas-go/v1"
 	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/terraform"
 )
 
@@ -98,9 +99,14 @@ func (c *PushCommand) Run(args []string) int {
 		return 1
 	}
 
+	var conf *config.Config
+	if mod != nil {
+		conf = mod.Config()
+	}
+
 	// Load the backend
 	b, err := c.Backend(&BackendOpts{
-		ConfigPath: configPath,
+		Config: conf,
 	})
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))

command/refresh.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/hashicorp/terraform/backend"
+	"github.com/hashicorp/terraform/config"
 	"github.com/hashicorp/terraform/terraform"
 )
 
@@ -43,8 +44,15 @@ func (c *RefreshCommand) Run(args []string) int {
 		return 1
 	}
 
+	var conf *config.Config
+	if mod != nil {
+		conf = mod.Config()
+	}
+
 	// Load the backend
-	b, err := c.Backend(&BackendOpts{ConfigPath: configPath})
+	b, err := c.Backend(&BackendOpts{
+		Config: conf,
+	})
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))
 		return 1

command/unlock.go

@@ -43,9 +43,15 @@ func (c *UnlockCommand) Run(args []string) int {
 		return 1
 	}
 
+	conf, err := c.Config(configPath)
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Failed to load root config module: %s", err))
+		return 1
+	}
+
 	// Load the backend
 	b, err := c.Backend(&BackendOpts{
-		ConfigPath: configPath,
+		Config: conf,
 	})
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("Failed to load backend: %s", err))