Add support for remote state (#60)

* add support for remote state in version 0.9
* remove .terraform/terraform.tfstate as a source

README.md

@@ -94,11 +94,25 @@ Can be provisioned separately with:
 ## More Usage
 
 Ansible doesn't seem to support calling a dynamic inventory script with params,
-so if you need to specify the location of your state file, set the `TF_STATE`
+so if you need to specify the location of your state file or terraform directory, set the `TF_STATE`
 environment variable before running `ansible-playbook`, like:
 
+
 	TF_STATE=deploy/terraform.tfstate ansible-playbook --inventory-file=/path/to/terraform-inventory deploy/playbook.yml
 
+	or
+
+	TF_STATE=../terraform ansible-playbook --inventory-file=/path/to/terraform-inventory deploy/playbook.yml
+
+If `TF_STATE` is a file, it parses the file as json, if `TF_STATE` is a directory, it runs `terraform state pull` inside the directory, which is supports both local and remote terraform state.
+
+It looks for state config in this order
+
+- `TF_STATE`: environment variable of where to find either a statefile or a terraform project
+- `TI_TFSTATE`: another environment variable similar to TF_STATE
+- `terraform.tfstate`: it looks in the state file in the current directory.
+- `.`: lastly it assumes you are at the root of a terraform project.
+
 Alternately, if you need to do something fancier (like downloading your state
 file from S3 before running), you might wrap this tool with a shell script, and
 call that instead. Something like:

input.go

@@ -25,11 +25,5 @@ func GetInputPath(fs vfs.Filesystem, env venv.Env) string {
 		return fn
 	}
 
-	fn = ".terraform/terraform.tfstate"
-	_, err = fs.Stat(fn)
-	if err == nil {
-		return fn
-	}
-
-	return ""
+	return "."
 }

input_test.go

@@ -13,11 +13,12 @@ import (
 )
 
 func TestGetInputPath(t *testing.T) {
-	assert.Equal(t, "", GetInputPath(memfs.Create(), venv.Mock()))
+	assert.Equal(t, ".", GetInputPath(memfs.Create(), venv.Mock()))
 	assert.Equal(t, "aaa", GetInputPath(memfs.Create(), envWith(map[string]string{"TF_STATE": "aaa"})))
 	assert.Equal(t, "bbb", GetInputPath(memfs.Create(), envWith(map[string]string{"TI_TFSTATE": "bbb"})))
 	assert.Equal(t, "terraform.tfstate", GetInputPath(fsWithFiles([]string{"terraform.tfstate"}), venv.Mock()))
-	assert.Equal(t, ".terraform/terraform.tfstate", GetInputPath(fsWithFiles([]string{".terraform/terraform.tfstate"}), venv.Mock()))
+	assert.Equal(t, ".", GetInputPath(fsWithFiles([]string{".terraform/terraform.tfstate"}), venv.Mock()))
+	assert.Equal(t, "terraform", GetInputPath(fsWithDirs([]string{"terraform"}), envWith(map[string]string{"TF_STATE": "terraform"})))
 }
 
 func envWith(env map[string]string) venv.Env {
@@ -53,6 +54,21 @@ func fsWithFiles(filenames []string) vfs.Filesystem {
 	return fs
 }
 
+func fsWithDirs(dirs []string) vfs.Filesystem {
+	fs := memfs.Create()
+
+	var err error
+
+	for _, fp := range dirs {
+		err = vfs.MkdirAll(fs, fp, 0700)
+		if err != nil {
+			panic(err)
+		}
+	}
+
+	return fs
+}
+
 // TODO: Upgrade this later with file contents.
 func touchFile(fs vfs.Filesystem, filename string) error {
 	return writeFile(fs, filename, []byte{}, 0600)

main.go

@@ -1,11 +1,13 @@
 package main
 
 import (
+	"bytes"
 	"flag"
 	"fmt"
 	"github.com/adammck/venv"
 	"github.com/blang/vfs"
 	"os"
+	"os/exec"
 	"path/filepath"
 )
 
@@ -23,17 +25,13 @@ func main() {
 		return
 	}
 
-	if file == "" {
 	fs := vfs.OS()
+	if file == "" {
+
 		env := venv.OS()
 		file = GetInputPath(fs, env)
 	}
 
-	if file == "" {
-		fmt.Printf("Usage: %s [options] path\n", os.Args[0])
-		os.Exit(1)
-	}
-
 	if !*list && *host == "" && !*inventory {
 		fmt.Fprint(os.Stderr, "Either --host or --list must be specified")
 		os.Exit(1)
@@ -45,6 +43,16 @@ func main() {
 		os.Exit(1)
 	}
 
+	f, err := fs.Stat(path)
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Invalid file: %s\n", err)
+		os.Exit(1)
+	}
+
+	var s state
+
+	if !f.IsDir() {
 		stateFile, err := os.Open(path)
 		defer stateFile.Close()
 		if err != nil {
@@ -52,12 +60,38 @@ func main() {
 			os.Exit(1)
 		}
 
-	var s state
 		err = s.read(stateFile)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "Error reading tfstate file: %s\n", err)
 			os.Exit(1)
 		}
+	}
+
+	if f.IsDir() {
+		cmd := exec.Command("terraform", "state", "pull")
+		cmd.Dir = path
+		var out bytes.Buffer
+		cmd.Stdout = &out
+
+		err = cmd.Run()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error running `terraform state pull` in directory %s, %s\n", path, err)
+			os.Exit(1)
+		}
+
+		err = s.read(&out)
+
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error reading `terraform state pull` output: %s\n", err)
+			os.Exit(1)
+		}
+
+	}
+
+	if s.Modules == nil {
+		fmt.Printf("Usage: %s [options] path\npath: this is either a path to a state file or a folder from which `terraform commands` are valid\n", os.Args[0])
+		os.Exit(1)
+	}
 
 	if *list {
 		os.Exit(cmdList(os.Stdout, os.Stderr, &s))