feat: Added env var support

* to be used like

```hcl
var options = []tfexec.PlanOption{
  tfexec.EnvVar("SOME_ENV_VAR", "SOME_VALUE"),
  tfexec.EnvVar("OTHER_ENV_VAR", "OTHER_VALUE"),
}
```

Author: vfoucault

tfexec/apply.go

@@ -25,12 +25,16 @@ type applyConfig struct {
 	// Vars: each var must be supplied as a single string, e.g. 'foo=bar'
 	vars     []string
 	varFiles []string
+
+	// EnvVars support
+	envVars map[string]string
 }
 
 var defaultApplyOptions = applyConfig{
 	lock:        true,
 	parallelism: 10,
 	refresh:     true,
+	envVars:     map[string]string{},
 }
 
 // ApplyOption represents options used in the Apply method.
@@ -66,6 +70,10 @@ func (opt *VarFileOption) configureApply(conf *applyConfig) {
 	conf.varFiles = append(conf.varFiles, opt.path)
 }
 
+func (opt *EnvVarOption) configureApply(conf *applyConfig) {
+	conf.envVars[opt.key] = opt.value
+}
+
 func (opt *LockOption) configureApply(conf *applyConfig) {
 	conf.lock = opt.lock
 }
@@ -157,6 +165,11 @@ func (tf *Terraform) applyCmd(ctx context.Context, opts ...ApplyOption) (*exec.C
 	}
 
 	mergeEnv := map[string]string{}
+
+	for kvar, kvalue := range c.envVars {
+		mergeEnv[kvar] = kvalue
+	}
+
 	if c.reattachInfo != nil {
 		reattachStr, err := c.reattachInfo.marshalString()
 		if err != nil {

tfexec/apply_test.go

@@ -26,6 +26,8 @@ func TestApplyCmd(t *testing.T) {
 			StateOut("teststateout"),
 			VarFile("foo.tfvars"),
 			VarFile("bar.tfvars"),
+			EnvVar("blah", "diblah"),
+			EnvVar("other_env_var", "other_value"),
 			Lock(false),
 			Parallelism(99),
 			Refresh(false),
@@ -62,6 +64,6 @@ func TestApplyCmd(t *testing.T) {
 			"-var", "var1=foo",
 			"-var", "var2=bar",
 			"testfile",
-		}, nil, applyCmd)
+		}, map[string]string{"blah": "diblah", "other_env_var": "other_value"}, applyCmd)
 	})
 }

tfexec/destroy.go

@@ -24,13 +24,17 @@ type destroyConfig struct {
 	// Vars: each var must be supplied as a single string, e.g. 'foo=bar'
 	vars     []string
 	varFiles []string
+
+	// EnvVars
+	envVars map[string]string
 }
 
 var defaultDestroyOptions = destroyConfig{
 	lock:        true,
 	lockTimeout: "0s",
 	parallelism: 10,
 	refresh:     true,
+	envVars:     map[string]string{},
 }
 
 // DestroyOption represents options used in the Destroy method.
@@ -70,6 +74,10 @@ func (opt *VarFileOption) configureDestroy(conf *destroyConfig) {
 	conf.varFiles = append(conf.varFiles, opt.path)
 }
 
+func (opt *EnvVarOption) configureDestroy(conf *destroyConfig) {
+	conf.envVars[opt.key] = opt.value
+}
+
 func (opt *LockOption) configureDestroy(conf *destroyConfig) {
 	conf.lock = opt.lock
 }
@@ -144,6 +152,11 @@ func (tf *Terraform) destroyCmd(ctx context.Context, opts ...DestroyOption) (*ex
 	}
 
 	mergeEnv := map[string]string{}
+
+	for kvar, kvalue := range c.envVars {
+		mergeEnv[kvar] = kvalue
+	}
+
 	if c.reattachInfo != nil {
 		reattachStr, err := c.reattachInfo.marshalString()
 		if err != nil {

tfexec/destroy_test.go

@@ -37,7 +37,22 @@ func TestDestroyCmd(t *testing.T) {
 	})
 
 	t.Run("override all defaults", func(t *testing.T) {
-		destroyCmd, err := tf.destroyCmd(context.Background(), Backup("testbackup"), LockTimeout("200s"), State("teststate"), StateOut("teststateout"), VarFile("testvarfile"), Lock(false), Parallelism(99), Refresh(false), Target("target1"), Target("target2"), Var("var1=foo"), Var("var2=bar"), Dir("destroydir"))
+		destroyCmd, err := tf.destroyCmd(context.Background(),
+			Backup("testbackup"),
+			LockTimeout("200s"),
+			State("teststate"),
+			StateOut("teststateout"),
+			VarFile("testvarfile"),
+			Lock(false),
+			Parallelism(99),
+			Refresh(false),
+			Target("target1"),
+			Target("target2"),
+			Var("var1=foo"),
+			Var("var2=bar"),
+			Dir("destroydir"),
+			EnvVar("blah", "diblah"),
+			EnvVar("other_env_var", "other_value"))
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -60,6 +75,6 @@ func TestDestroyCmd(t *testing.T) {
 			"-var", "var1=foo",
 			"-var", "var2=bar",
 			"destroydir",
-		}, nil, destroyCmd)
+		}, map[string]string{"blah": "diblah", "other_env_var": "other_value"}, destroyCmd)
 	})
 }

tfexec/import.go

@@ -19,12 +19,14 @@ type importConfig struct {
 	stateOut           string
 	vars               []string
 	varFiles           []string
+	envVars            map[string]string
 }
 
 var defaultImportOptions = importConfig{
 	allowMissingConfig: false,
 	lock:               true,
 	lockTimeout:        "0s",
+	envVars:            map[string]string{},
 }
 
 // ImportOption represents options used in the Import method.
@@ -72,6 +74,10 @@ func (opt *VarFileOption) configureImport(conf *importConfig) {
 	conf.varFiles = append(conf.varFiles, opt.path)
 }
 
+func (opt *EnvVarOption) configureImport(conf *importConfig) {
+	conf.envVars[opt.key] = opt.value
+}
+
 // Import represents the terraform import subcommand.
 func (tf *Terraform) Import(ctx context.Context, address, id string, opts ...ImportOption) error {
 	cmd, err := tf.importCmd(ctx, address, id, opts...)
@@ -129,6 +135,11 @@ func (tf *Terraform) importCmd(ctx context.Context, address, id string, opts ...
 	args = append(args, address, id)
 
 	mergeEnv := map[string]string{}
+
+	for kvar, kvalue := range c.envVars {
+		mergeEnv[kvar] = kvalue
+	}
+
 	if c.reattachInfo != nil {
 		reattachStr, err := c.reattachInfo.marshalString()
 		if err != nil {

tfexec/import_test.go

@@ -46,6 +46,8 @@ func TestImportCmd(t *testing.T) {
 			Var("var1=foo"),
 			Var("var2=bar"),
 			AllowMissingConfig(true),
+			EnvVar("blah", "diblah"),
+			EnvVar("other_env_var", "other_value"),
 		)
 		if err != nil {
 			t.Fatal(err)
@@ -66,6 +68,6 @@ func TestImportCmd(t *testing.T) {
 			"-var", "var2=bar",
 			"my-addr2",
 			"my-id2",
-		}, nil, importCmd)
+		}, map[string]string{"blah": "diblah", "other_env_var": "other_value"}, importCmd)
 	})
 }

tfexec/options.go

@@ -117,6 +117,15 @@ func DryRun(dryRun bool) *DryRunOption {
 	return &DryRunOption{dryRun}
 }
 
+type EnvVarOption struct {
+	key, value string
+}
+
+// EnvVar represents a kv env var
+func EnvVar(key, value string) *EnvVarOption {
+	return &EnvVarOption{key, value}
+}
+
 type FSMirrorOption struct {
 	fsMirror string
 }

tfexec/plan.go

@@ -21,6 +21,7 @@ type planConfig struct {
 	targets      []string
 	vars         []string
 	varFiles     []string
+	envVars      map[string]string
 }
 
 var defaultPlanOptions = planConfig{
@@ -29,6 +30,7 @@ var defaultPlanOptions = planConfig{
 	lockTimeout: "0s",
 	parallelism: 10,
 	refresh:     true,
+	envVars:     map[string]string{},
 }
 
 // PlanOption represents options used in the Plan method.
@@ -44,6 +46,10 @@ func (opt *VarFileOption) configurePlan(conf *planConfig) {
 	conf.varFiles = append(conf.varFiles, opt.path)
 }
 
+func (opt *EnvVarOption) configurePlan(conf *planConfig) {
+	conf.envVars[opt.key] = opt.value
+}
+
 func (opt *VarOption) configurePlan(conf *planConfig) {
 	conf.vars = append(conf.vars, opt.assignment)
 }
@@ -168,6 +174,11 @@ func (tf *Terraform) planCmd(ctx context.Context, opts ...PlanOption) (*exec.Cmd
 	}
 
 	mergeEnv := map[string]string{}
+
+	for kvar, kvalue := range c.envVars {
+		mergeEnv[kvar] = kvalue
+	}
+
 	if c.reattachInfo != nil {
 		reattachStr, err := c.reattachInfo.marshalString()
 		if err != nil {

tfexec/plan_test.go

@@ -52,7 +52,9 @@ func TestPlanCmd(t *testing.T) {
 			Var("android=paranoid"),
 			Var("brain_size=planet"),
 			VarFile("trillian"),
-			Dir("earth"))
+			Dir("earth"),
+			EnvVar("blah", "diblah"),
+			EnvVar("other_env_var", "other_value"))
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -77,6 +79,6 @@ func TestPlanCmd(t *testing.T) {
 			"-var", "android=paranoid",
 			"-var", "brain_size=planet",
 			"earth",
-		}, nil, planCmd)
+		}, map[string]string{"blah": "diblah", "other_env_var": "other_value"}, planCmd)
 	})
 }