Merge pull request #94 from pressly/resolve_vars

Resolve ENV VARs locally

Author: VojtechVitek

cmd/sup/main.go

@@ -246,9 +246,17 @@ func main() {
 		network.Hosts = hosts
 	}
 
-	// --env flag sets environment variables and overrides values defined in Supfile
 	var vars sup.EnvList
-	var supEnv string
+	for _, val := range append(conf.Env, network.Env...) {
+		vars.Set(val.Key, val.Value)
+	}
+	if err := vars.ResolveValues(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	// Parse CLI --env flag env vars, define $SUP_ENV and override values defined in Supfile.
+	var cliVars sup.EnvList
 	for _, env := range envVars {
 		if len(env) == 0 {
 			continue
@@ -261,16 +269,16 @@ func main() {
 			continue
 		}
 		vars.Set(env[:i], env[i+1:])
+		cliVars.Set(env[:i], env[i+1:])
 	}
-	if len(vars) > 0 {
-		network.Env = append(network.Env, vars...)
 
-		// Separate loop to omit duplicated keys.
-		for _, v := range vars {
-			supEnv += fmt.Sprintf(" -e %v=%q", v.Key, v.Value)
-		}
-		network.Env.Set("SUP_ENV", strings.TrimSpace(supEnv))
+	// SUP_ENV is generated only from CLI env vars.
+	// Separate loop to omit duplicates.
+	supEnv := ""
+	for _, v := range cliVars {
+		supEnv += fmt.Sprintf(" -e %v=%q", v.Key, v.Value)
 	}
+	vars.Set("SUP_ENV", strings.TrimSpace(supEnv))
 
 	// Create new Stackup app.
 	app, err := sup.New(conf)
@@ -282,7 +290,7 @@ func main() {
 	app.Prefix(!disablePrefix)
 
 	// Run all the commands in the given network.
-	err = app.Run(network, commands...)
+	err = app.Run(network, vars, commands...)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)

sup.go

@@ -13,7 +13,7 @@ import (
 	"golang.org/x/crypto/ssh"
 )
 
-const VERSION = "0.4"
+const VERSION = "0.5"
 
 type Stackup struct {
 	conf   *Supfile
@@ -30,17 +30,12 @@ func New(conf *Supfile) (*Stackup, error) {
 // Run runs set of commands on multiple hosts defined by network sequentially.
 // TODO: This megamoth method needs a big refactor and should be split
 //       to multiple smaller methods.
-func (sup *Stackup) Run(network *Network, commands ...*Command) error {
+func (sup *Stackup) Run(network *Network, envVars EnvList, commands ...*Command) error {
 	if len(commands) == 0 {
 		return errors.New("no commands to be run")
 	}
 
-	// Process all ENVs into a string of form
-	// `export FOO="bar"; export BAR="baz";`.
-	env := ``
-	for _, v := range append(sup.conf.Env, network.Env...) {
-		env += v.AsExport() + " "
-	}
+	env := envVars.AsExport()
 
 	// Create clients for every host (either SSH or Localhost).
 	var bastion *SSHClient

supfile.go

@@ -9,6 +9,8 @@ import (
 	"os/exec"
 	"strings"
 
+	"github.com/pkg/errors"
+
 	"gopkg.in/yaml.v2"
 )
 
@@ -70,7 +72,7 @@ func (e EnvVar) AsExport() string {
 
 // EnvList is a list of environment variables that maps to a YAML map,
 // but maintains order, enabling late variables to reference early variables.
-type EnvList []EnvVar
+type EnvList []*EnvVar
 
 func (e *EnvList) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	items := []yaml.MapItem{}
@@ -91,20 +93,55 @@ func (e *EnvList) UnmarshalYAML(unmarshal func(interface{}) error) error {
 
 // Set key to be equal value in this list.
 func (e *EnvList) Set(key, value string) {
-
 	for i, v := range *e {
 		if v.Key == key {
 			(*e)[i].Value = value
 			return
 		}
 	}
 
-	*e = append(*e, EnvVar{
+	*e = append(*e, &EnvVar{
 		Key:   key,
 		Value: value,
 	})
 }
 
+func (e *EnvList) ResolveValues() error {
+	if len(*e) == 0 {
+		return nil
+	}
+
+	exports := ""
+	for i, v := range *e {
+		exports += v.AsExport()
+
+		cmd := exec.Command("bash", "-c", exports+"echo -n "+v.Value+";")
+		cwd, err := os.Getwd()
+		if err != nil {
+			return err
+		}
+		cmd.Dir = cwd
+		resolvedValue, err := cmd.Output()
+		if err != nil {
+			return errors.Wrapf(err, "resolving env var %v failed", v.Key)
+		}
+
+		(*e)[i].Value = string(resolvedValue)
+	}
+
+	return nil
+}
+
+func (e *EnvList) AsExport() string {
+	// Process all ENVs into a string of form
+	// `export FOO="bar"; export BAR="baz";`.
+	exports := ``
+	for _, v := range *e {
+		exports += v.AsExport() + " "
+	}
+	return exports
+}
+
 type ErrMustUpdate struct {
 	Msg string
 }
@@ -173,10 +210,10 @@ func NewSupfile(file string) (*Supfile, error) {
 
 		fallthrough
 
-	case "0.4":
+	case "0.4", "0.5":
 
 	default:
-		return nil, ErrMustUpdate{"unsupported version"}
+		return nil, ErrMustUpdate{"unsupported version " + conf.Version}
 	}
 
 	for i, network := range conf.Networks {