Implement CLI, version command

.gitignore

@@ -1,3 +1,4 @@
 *.dll
+*.exe
 example.tf
 vendor/

command/version.go

@@ -0,0 +1,39 @@
+package command
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/mitchellh/cli"
+)
+
+// VersionCommand is a Command implementation prints the version.
+type VersionCommand struct {
+	Revision          string
+	Version           string
+	VersionPrerelease string
+	Ui                cli.Ui
+}
+
+func (c *VersionCommand) Help() string {
+	return ""
+}
+
+func (c *VersionCommand) Run(_ []string) int {
+	var versionString bytes.Buffer
+	fmt.Fprintf(&versionString, "Terraform v%s", c.Version)
+	if c.VersionPrerelease != "" {
+		fmt.Fprintf(&versionString, ".%s", c.VersionPrerelease)
+
+		if c.Revision != "" {
+			fmt.Fprintf(&versionString, " (%s)", c.Revision)
+		}
+	}
+
+	c.Ui.Output(versionString.String())
+	return 0
+}
+
+func (c *VersionCommand) Synopsis() string {
+	return "Prints the Terraform version"
+}

command/version_test.go

@@ -0,0 +1,11 @@
+package command
+
+import (
+	"testing"
+
+	"github.com/mitchellh/cli"
+)
+
+func TestVersionCommand_implements(t *testing.T) {
+	var _ cli.Command = &VersionCommand{}
+}

commands.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"os"
+
+	"github.com/hashicorp/terraform/command"
+	"github.com/mitchellh/cli"
+)
+
+// Commands is the mapping of all the available Terraform commands.
+var Commands map[string]cli.CommandFactory
+
+func init() {
+	ui := &cli.BasicUi{Writer: os.Stdout}
+
+	Commands = map[string]cli.CommandFactory{
+		"version": func() (cli.Command, error) {
+			return &command.VersionCommand{
+				Revision:          GitCommit,
+				Version:           Version,
+				VersionPrerelease: VersionPrerelease,
+				Ui:                ui,
+			}, nil
+		},
+	}
+}

main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+
+	"github.com/mitchellh/cli"
+)
+
+func main() {
+	os.Exit(realMain())
+}
+
+func realMain() int {
+	log.SetOutput(ioutil.Discard)
+
+	// Get the command line args. We shortcut "--version" and "-v" to
+	// just show the version.
+	args := os.Args[1:]
+	for _, arg := range args {
+		if arg == "-v" || arg == "--version" {
+			newArgs := make([]string, len(args)+1)
+			newArgs[0] = "version"
+			copy(newArgs[1:], args)
+			args = newArgs
+			break
+		}
+	}
+
+	cli := &cli.CLI{
+		Args:     args,
+		Commands: Commands,
+		HelpFunc: cli.BasicHelpFunc("terraform"),
+	}
+
+	exitCode, err := cli.Run()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error executing CLI: %s\n", err.Error())
+		return 1
+	}
+
+	return exitCode
+}

terraform/resource_provider.go

@@ -0,0 +1,21 @@
+package terraform
+
+// ResourceProvider is an interface that must be implemented by any
+// resource provider: the thing that creates and manages the resources in
+// a Terraform configuration.
+type ResourceProvider interface {
+	// Configure configures the provider itself with the configuration
+	// given. This is useful for setting things like access keys.
+	//
+	// Configure returns a list of warnings and a potential error.
+	Configure(config map[string]interface{}) ([]string, error)
+
+	// Resources returns all the available resource types that this provider
+	// knows how to manage.
+	Resources() []ResourceType
+}
+
+// ResourceType is a type of resource that a resource provider can manage.
+type ResourceType struct {
+	Name string
+}

version.go

@@ -0,0 +1,12 @@
+package main
+
+// The git commit that was compiled. This will be filled in by the compiler.
+var GitCommit string
+
+// The main version number that is being run at the moment.
+const Version = "0.1.0"
+
+// A pre-release marker for the version. If this is "" (empty string)
+// then it means that it is a final release. Otherwise, this is a pre-release
+// such as "dev" (in development), "beta", "rc1", etc.
+const VersionPrerelease = "dev"