terraform-inventory/main.go

package main

import (
	"bytes"
	"flag"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"

	"github.com/adammck/venv"
	"github.com/blang/vfs"
)

var version = flag.Bool("version", false, "print version information and exit")
var list = flag.Bool("list", false, "list mode")
var host = flag.String("host", "", "host mode")
var inventory = flag.Bool("inventory", false, "inventory mode")

func main() {
	flag.Parse()
	file := flag.Arg(0)

	if *version == true {
		fmt.Printf("%s version %s\n", os.Args[0], versionInfo())
		return
	}

	fs := vfs.OS()
	if file == "" {

		env := venv.OS()
		file = GetInputPath(fs, env)
	}

	if !*list && *host == "" && !*inventory {
		fmt.Fprint(os.Stderr, "Either --host or --list must be specified")
		os.Exit(1)
	}

	path, err := filepath.Abs(file)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Invalid file: %s\n", err)
		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 stateAnyTerraformVersion

	if !f.IsDir() {
		stateFile, err := os.Open(path)
		defer stateFile.Close()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error opening tfstate file: %s\n", err)
			os.Exit(1)
		}

		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", "show", "-json")
		cmd.Dir = path
		var out bytes.Buffer
		cmd.Stdout = &out

		err = cmd.Run()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error running `terraform show -json` in directory %s, %s, falling back to trying Terraform pre-0.12 command\n", path, err)

			cmd = exec.Command("terraform", "state", "pull")
			cmd.Dir = path
			out.Reset()
			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: %s\n", err)
			os.Exit(1)
		}
	}

	if s.TerraformVersion == TerraformVersionUnknown {
		fmt.Fprintf(os.Stderr, "Unknown state format\n\nUsage: %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 (s.TerraformVersion == TerraformVersionPre0dot12 && s.StatePre0dot12.Modules == nil) ||
		(s.TerraformVersion == TerraformVersion0dot12 && s.State0dot12.Values.RootModule == nil) {
		fmt.Fprintf(os.Stderr, "No modules found in state\n\nUsage: %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))
	} else if *inventory {
		os.Exit(cmdInventory(os.Stdout, os.Stderr, &s))
	} else if *host != "" {
		os.Exit(cmdHost(os.Stdout, os.Stderr, &s, *host))
	}
}