Move integration test and add backend check (#5)

The integration test no longer builds and uses the binary
but runs the Cobra command directly. Also, an additional
check is added that makes sure the backend Terraform was
initialized with matches the backend configuration of the
current run. This avoids that state is accidentally pushed
to the wrong backend when switching environments.

cmd/gotf/gotf.go

@@ -28,6 +28,19 @@ import (
 )
 
 func Execute() {
+	command := newGotfCommand()
+	if err := command.Execute(); err != nil {
+		var exitCode int
+		if err, ok := err.(*exec.ExitError); ok {
+			exitCode = err.ExitCode()
+		} else {
+			exitCode = 1
+		}
+		os.Exit(exitCode)
+	}
+}
+
+func newGotfCommand() *cobra.Command {
 	var cfgFile string
 	params := opts.NewMapOpts()
 	var debug bool
@@ -69,17 +82,9 @@ gotf is a Terraform wrapper facilitating configurations for various environments
 	command.Flags().StringVarP(&moduleDir, "module-dir", "m", "", "The module directory to run Terraform in")
 	command.Flags().SetInterspersed(false)
 	command.SetVersionTemplate("{{ .Version }}\n")
+	command.SilenceUsage = true
 	if err := command.MarkFlagRequired("module-dir"); err != nil {
 		log.Fatalln(err)
 	}
-
-	if err := command.Execute(); err != nil {
-		var exitCode int
-		if err, ok := err.(*exec.ExitError); ok {
-			exitCode = err.ExitCode()
-		} else {
-			exitCode = 1
-		}
-		os.Exit(exitCode)
-	}
+	return command
 }

cmd/gotf/gotf_test.go

@@ -0,0 +1,143 @@
+package gotf
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestExecute(t *testing.T) {
+	type testRun struct {
+		args    []string
+		want    []string
+		wantErr bool
+	}
+
+	tests := []struct {
+		name string
+		runs []testRun
+	}{
+		{
+			name: "happy path",
+			runs: []testRun{
+				{
+					args: []string{"-d", "-c", "testdata/test-config-prod.yaml", "-p", "env=prod", "-m", "testdata/01_testmodule", "init", "-no-color"},
+					want: []string{"Terraform has been successfully initialized!"},
+				},
+				{
+					args: []string{"-d", "-c", "testdata/test-config-prod.yaml", "-p", "env=prod", "-m", "testdata/01_testmodule", "plan", "-no-color"},
+					want: []string{
+						"# null_resource.echo will be created",
+						"Plan: 1 to add, 0 to change, 0 to destroy.",
+					},
+				},
+				{
+					args: []string{"-d", "-c", "testdata/test-config-prod.yaml", "-p", "env=prod", "-m", "testdata/01_testmodule", "apply", "-auto-approve", "-no-color"},
+					want: []string{`foo = 42
+mapvar = {
+  entry1 = {
+    value1 = testvalue1
+    value2 = true
+  }
+  entry2 = {
+    value1 = testvalue2
+    value2 = false
+  }
+}`},
+				},
+			},
+		},
+		{
+			name: "backend check",
+			runs: []testRun{
+				{
+					args: []string{"-d", "-c", "testdata/test-config-prod.yaml", "-p", "env=prod", "-m", "testdata/01_testmodule", "init", "-no-color"},
+					want: []string{"Terraform has been successfully initialized!"},
+				},
+				{
+					args: []string{"-d", "-c", "testdata/test-config-prod.yaml", "-p", "env=prod", "-m", "testdata/01_testmodule", "plan", "-no-color"},
+					want: []string{
+						"# null_resource.echo will be created",
+						"Plan: 1 to add, 0 to change, 0 to destroy.",
+					},
+				},
+				{
+					args: []string{"-d", "-c", "testdata/test-config-dev.yaml", "-p", "env=dev", "-m", "testdata/01_testmodule", "plan", "-no-color"},
+					want: []string{
+						"Configured backend does not match current environment",
+						"Got: .terraform/terraform-testmodule-prod.tfstate",
+						"Want: .terraform/terraform-testmodule-dev.tfstate",
+						"Run terraform init -reconfigure!",
+					},
+					wantErr: true,
+				},
+				{
+					args: []string{"-d", "-c", "testdata/test-config-dev.yaml", "-p", "env=dev", "-m", "testdata/01_testmodule", "init", "-reconfigure"},
+					want: []string{
+						"Terraform has been successfully initialized!",
+					},
+				},
+				{
+					args: []string{"-d", "-c", "testdata/test-config-dev.yaml", "-p", "env=dev", "-m", "testdata/01_testmodule", "plan", "-no-color"},
+					want: []string{
+						"# null_resource.echo will be created",
+						"Plan: 1 to add, 0 to change, 0 to destroy.",
+					},
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			os.RemoveAll("testdata/01_testmodule/.terraform")
+
+			tempDir, err := ioutil.TempDir("", "gotf")
+			panicOnError(err)
+			defer os.RemoveAll(tempDir)
+
+			panicOnError(os.Setenv("XDG_CACHE_HOME", filepath.Join(tempDir, "test")))
+
+			for _, run := range tt.runs {
+				got, err := runGotf(run.args)
+				if run.wantErr {
+					assert.Error(t, err)
+				} else {
+					assert.NoError(t, err)
+				}
+				for _, want := range run.want {
+					assert.Contains(t, got, want)
+				}
+			}
+		})
+	}
+}
+
+func panicOnError(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+func runGotf(args []string) (string, error) {
+	oldStdout := os.Stdout
+	oldStderr := os.Stderr
+	defer func() {
+		os.Stdout = oldStdout
+		os.Stderr = oldStderr
+	}()
+
+	command := newGotfCommand()
+	r, w, _ := os.Pipe()
+	os.Stdout = w
+	os.Stderr = w
+	command.SetArgs(args)
+	err := command.Execute()
+	w.Close()
+	bytes, _ := ioutil.ReadAll(r)
+	output := string(bytes)
+	println(output)
+	return output, err
+}

cmd/gotf/testdata/01_testmodule/test-prod.tfvars

@@ -0,0 +1 @@
+bar = "bazvalue"

test/testdata/test_config.yaml → cmd/gotf/testdata/test-config-dev.yaml

@@ -19,4 +19,4 @@ vars:
 envs:
   BAR: barvalue
 backendConfigs:
-  path: .tfstate/terraform.tfstate
+  path: .terraform/terraform-{{ .Vars.state_key }}-dev.tfstate

cmd/gotf/testdata/test-config-prod.yaml

@@ -0,0 +1,22 @@
+terraformVersion: "0.12.20"
+varFiles:
+  - 01_testmodule/test-{{ .Params.env }}.tfvars
+vars:
+  foo: 42
+  mapvar: |-
+    {
+      entry1 = {
+        value1 = testvalue1
+        value2 = true
+      }
+      entry2 = {
+        value1 = testvalue2
+        value2 = false
+      }
+    }
+  module_dir: "{{ base .Params.moduleDir }}"
+  state_key: '{{ (splitn "_" 2 (base .Params.moduleDir))._1 }}'
+envs:
+  BAR: barvalue
+backendConfigs:
+  path: .terraform/terraform-{{ .Vars.state_key }}-prod.tfstate

pkg/tf/terraform.go

@@ -15,7 +15,11 @@
 package terraform
 
 import (
+	"encoding/json"
 	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/craftypath/gotf/pkg/config"
@@ -54,6 +58,9 @@ func (tf *Terraform) Execute(args ...string) error {
 	tf.appendVarArgs(env)
 	tf.appendBackendConfigs(env)
 
+	if err := tf.checkBackendConfig(args...); err != nil {
+		return err
+	}
 	return tf.shell.Execute(env, tf.moduleDir, tf.binaryPath, args...)
 }
 
@@ -95,6 +102,46 @@ func (tf *Terraform) appendBackendConfigs(env map[string]string) {
 	}
 }
 
+func (tf *Terraform) checkBackendConfig(args ...string) error {
+	if len(args) >= 2 {
+		if args[0] == "init" {
+			for _, arg := range args[1:] {
+				if arg == "-reconfigure" {
+					return nil
+				}
+			}
+		}
+	}
+
+	backendFile := filepath.Join(tf.moduleDir, ".terraform", "terraform.tfstate")
+	bytes, err := ioutil.ReadFile(backendFile)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return err
+	}
+
+	var backendJson map[string]interface{}
+	if err := json.Unmarshal(bytes, &backendJson); err != nil {
+		return err
+	}
+
+	for k, v := range tf.config.BackendConfigs {
+		b := backendJson["backend"].(map[string]interface{})
+		c := b["config"].(map[string]interface{})
+		currentVal := c[k]
+		if v != currentVal {
+			return fmt.Errorf(`Configured backend does not match current environment
+Got: %s
+Want: %s
+
+Run terraform init -reconfigure!`, currentVal, v)
+		}
+	}
+	return nil
+}
+
 func stringMapAppend(target map[string]string, src map[string]string) {
 	for k, v := range src {
 		target[k] = v